Mike Romain

The taller tire has a taller sidewall so the sidewall bulges out more.
The measurements really are at the widest part of the sidewall, not at
the tread.

That is why the OP 'could' end up with the same width tread with those
changes in profile and height sizes, but a tape measure will tell for
sure.

My 33" sidewalls look like this ( ), My 31's looked like | |

Mike

J Strickland wrote:
>
> Ddi you make this change on the same rims, or did you change rims too?
>
> There is something here that one of us is missing because there is no point
> in giving a spec for tire size if that spec has no basis in reality. Why
> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm vs.
> 235mm, if they are really something else entirely?
>
> I'm not arguing that you find the 9.50s work better than the 10.50s, I have
> every reason to think you are correct in this. I don't have the same kind of
> driving environment where I am, and we find around here that wider is
> better, but we need to float above dry sand and dirt and the larger foot
> print works better here. I'm sure that if I brought my Jeep to your house,
> it would give me lots of trouble, especially in winter.
>
> What I am suggesting is that if your tread on the ground is only 7.5 with a
> 9.50 tire, then there is another factor because the tread on the ground
> should be closer to 9 than 7. In any case, the OP isn't getting any benefit
> from this discussion.
>
> His Grand should be fine for him with a 245/70 from the perspective of
> fitment. Whether or not it provides any better performance is beyond me, but
> my guess is that the actual tread pattern will play a larger role than the
> tire size.
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:43209419.9F6DB4BA@sympatico.ca...
> > The 'book' width measurements are not at the tread, they are at the
> > sidewall.
> >
> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
> > ground went from 10.25" to 7.5". I got a 'radical' increase in
> > traction.
> >
> > Mike
> >
> > J Strickland wrote:
> >>
> >> Not if the change was from 225 to 235. These numbers represent the tread
> >> width in mm, and 10mm is the functional equivelent of 3/8".
> >>
> >> Now, there is some misunderstanding (at least on my part) of just exactly
> >> where they measure 225 or 235, and the actual tread blocks being square
> >> on
> >> one tire and rounded off on the other might play a role in your
> >> perception
> >> of an inch difference, but the actual difference is 10mm. Your point
> >> being
> >> that you are looking at the tread patch on the ground is not lost on me
> >> ...
> >>
> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> news:432080F0.DECA6CD5@sympatico.ca...
> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was a
> >> > big disappointment. I believe there was over an inch of actual tread
> >> > width difference.
> >> >
> >> > Mike
> >> >
> >> > J Strickland wrote:
> >> >>
> >> >> The width is the 225/235/245 number. The 70/75 number is the height of
> >> >> the
> >> >> sidewall.
> >> >>
> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference in
> >> >> these
> >> >> tires will be the amount of sidewall, and the overall diameter -- the
> >> >> 65
> >> >> will be the smallest and the 75 will be the tallest.
> >> >>
> >> >> You might have noticed a loss of traction when you changed from 225s
> >> >> to
> >> >> 235s, because this would represent the width of the tire. A 225/75 and
> >> >> a
> >> >> 235/70 are within 10mm of being the same diameter.
> >> >>
> >> >> I am a poor judge of what happens in snow, but it's difficult for me
> >> >> to
> >> >> see
> >> >> where one would notice a difference in 10mm in diameter. I have to
> >> >> suspect
> >> >> there are tread patterns and other things that enter into the
> >> >> discussion.
> >> >>
> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> news:43203D52.2560BD48@sympatico.ca...
> >> >> >I will second that. We lost a 'lot' of traction when we went from a
> >> >> >225
> >> >> > to a 235 while keeping the same profile even. Going to a wider 70
> >> >> > series adds to the loss.
> >> >> >
> >> >> > Mike
> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> >> > 88 Cherokee 235 BFG AT's
> >> >> >
> >> >> > Bowgus wrote:
> >> >> >>
> >> >> >> A consideration ... if you drive in snow, and will be using the
> >> >> >> 245s
> >> >> >> they
> >> >> >> may be too wide. I say this because the 235 is too wide for my XJ
> >> >> >> in
> >> >> >> snow
> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use 225
> >> >> >> snow
> >> >> >> tires ... which unfortunately are due for replacement this coming
> >> >> >> winter
> >> >> >> :-(
> >> >> >>
> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with 225/75R16 -
> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
> >> >> >> > with speedometer or front turning clearance under the cowling
> >> >> >> > or any other considerations on going from the 75 to the 70 ?
> >> >> >> > It seems like the overall outside tire diameter is the same, but
> >> >> >> > ??
> >> >> >> >
> >> >> >> >
> >> >> >> >

J Strickland

Well, yeah, I get that.

But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
would account for why the 9.50s measured 10.25 and the 10.50s were also
10.25. I can see where the 10.50s actually measure at 10.25, and I can see
how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
the 9.50s get reported as 7.5.

If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
the 10" rims, then there's no way they would be 7.5". See?





"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4320A545.100B17A3@sympatico.ca...
> The taller tire has a taller sidewall so the sidewall bulges out more.
> The measurements really are at the widest part of the sidewall, not at
> the tread.
>
> That is why the OP 'could' end up with the same width tread with those
> changes in profile and height sizes, but a tape measure will tell for
> sure.
>
> My 33" sidewalls look like this ( ), My 31's looked like | |
>
> Mike
>
> J Strickland wrote:
>>
>> Ddi you make this change on the same rims, or did you change rims too?
>>
>> There is something here that one of us is missing because there is no
>> point
>> in giving a spec for tire size if that spec has no basis in reality. Why
>> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
>> vs.
>> 235mm, if they are really something else entirely?
>>
>> I'm not arguing that you find the 9.50s work better than the 10.50s, I
>> have
>> every reason to think you are correct in this. I don't have the same kind
>> of
>> driving environment where I am, and we find around here that wider is
>> better, but we need to float above dry sand and dirt and the larger foot
>> print works better here. I'm sure that if I brought my Jeep to your
>> house,
>> it would give me lots of trouble, especially in winter.
>>
>> What I am suggesting is that if your tread on the ground is only 7.5 with
>> a
>> 9.50 tire, then there is another factor because the tread on the ground
>> should be closer to 9 than 7. In any case, the OP isn't getting any
>> benefit
>> from this discussion.
>>
>> His Grand should be fine for him with a 245/70 from the perspective of
>> fitment. Whether or not it provides any better performance is beyond me,
>> but
>> my guess is that the actual tread pattern will play a larger role than
>> the
>> tire size.
>>
>> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> news:43209419.9F6DB4BA@sympatico.ca...
>> > The 'book' width measurements are not at the tread, they are at the
>> > sidewall.
>> >
>> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
>> > ground went from 10.25" to 7.5". I got a 'radical' increase in
>> > traction.
>> >
>> > Mike
>> >
>> > J Strickland wrote:
>> >>
>> >> Not if the change was from 225 to 235. These numbers represent the
>> >> tread
>> >> width in mm, and 10mm is the functional equivelent of 3/8".
>> >>
>> >> Now, there is some misunderstanding (at least on my part) of just
>> >> exactly
>> >> where they measure 225 or 235, and the actual tread blocks being
>> >> square
>> >> on
>> >> one tire and rounded off on the other might play a role in your
>> >> perception
>> >> of an inch difference, but the actual difference is 10mm. Your point
>> >> being
>> >> that you are looking at the tread patch on the ground is not lost on
>> >> me
>> >> ...
>> >>
>> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> news:432080F0.DECA6CD5@sympatico.ca...
>> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
>> >> > a
>> >> > big disappointment. I believe there was over an inch of actual
>> >> > tread
>> >> > width difference.
>> >> >
>> >> > Mike
>> >> >
>> >> > J Strickland wrote:
>> >> >>
>> >> >> The width is the 225/235/245 number. The 70/75 number is the height
>> >> >> of
>> >> >> the
>> >> >> sidewall.
>> >> >>
>> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
>> >> >> in
>> >> >> these
>> >> >> tires will be the amount of sidewall, and the overall diameter --
>> >> >> the
>> >> >> 65
>> >> >> will be the smallest and the 75 will be the tallest.
>> >> >>
>> >> >> You might have noticed a loss of traction when you changed from
>> >> >> 225s
>> >> >> to
>> >> >> 235s, because this would represent the width of the tire. A 225/75
>> >> >> and
>> >> >> a
>> >> >> 235/70 are within 10mm of being the same diameter.
>> >> >>
>> >> >> I am a poor judge of what happens in snow, but it's difficult for
>> >> >> me
>> >> >> to
>> >> >> see
>> >> >> where one would notice a difference in 10mm in diameter. I have to
>> >> >> suspect
>> >> >> there are tread patterns and other things that enter into the
>> >> >> discussion.
>> >> >>
>> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> >> news:43203D52.2560BD48@sympatico.ca...
>> >> >> >I will second that. We lost a 'lot' of traction when we went from
>> >> >> >a
>> >> >> >225
>> >> >> > to a 235 while keeping the same profile even. Going to a wider
>> >> >> > 70
>> >> >> > series adds to the loss.
>> >> >> >
>> >> >> > Mike
>> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> >> >> > 88 Cherokee 235 BFG AT's
>> >> >> >
>> >> >> > Bowgus wrote:
>> >> >> >>
>> >> >> >> A consideration ... if you drive in snow, and will be using the
>> >> >> >> 245s
>> >> >> >> they
>> >> >> >> may be too wide. I say this because the 235 is too wide for my
>> >> >> >> XJ
>> >> >> >> in
>> >> >> >> snow
>> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
>> >> >> >> 225
>> >> >> >> snow
>> >> >> >> tires ... which unfortunately are due for replacement this
>> >> >> >> coming
>> >> >> >> winter
>> >> >> >> :-(
>> >> >> >>
>> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
>> >> >> >> message
>> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
>> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
>> >> >> >> > 225/75R16 -
>> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
>> >> >> >> > with speedometer or front turning clearance under the cowling
>> >> >> >> > or any other considerations on going from the 75 to the 70 ?
>> >> >> >> > It seems like the overall outside tire diameter is the same,
>> >> >> >> > but
>> >> >> >> > ??
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >

J Strickland

Well, yeah, I get that.

But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
would account for why the 9.50s measured 10.25 and the 10.50s were also
10.25. I can see where the 10.50s actually measure at 10.25, and I can see
how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
the 9.50s get reported as 7.5.

If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
the 10" rims, then there's no way they would be 7.5". See?





"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4320A545.100B17A3@sympatico.ca...
> The taller tire has a taller sidewall so the sidewall bulges out more.
> The measurements really are at the widest part of the sidewall, not at
> the tread.
>
> That is why the OP 'could' end up with the same width tread with those
> changes in profile and height sizes, but a tape measure will tell for
> sure.
>
> My 33" sidewalls look like this ( ), My 31's looked like | |
>
> Mike
>
> J Strickland wrote:
>>
>> Ddi you make this change on the same rims, or did you change rims too?
>>
>> There is something here that one of us is missing because there is no
>> point
>> in giving a spec for tire size if that spec has no basis in reality. Why
>> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
>> vs.
>> 235mm, if they are really something else entirely?
>>
>> I'm not arguing that you find the 9.50s work better than the 10.50s, I
>> have
>> every reason to think you are correct in this. I don't have the same kind
>> of
>> driving environment where I am, and we find around here that wider is
>> better, but we need to float above dry sand and dirt and the larger foot
>> print works better here. I'm sure that if I brought my Jeep to your
>> house,
>> it would give me lots of trouble, especially in winter.
>>
>> What I am suggesting is that if your tread on the ground is only 7.5 with
>> a
>> 9.50 tire, then there is another factor because the tread on the ground
>> should be closer to 9 than 7. In any case, the OP isn't getting any
>> benefit
>> from this discussion.
>>
>> His Grand should be fine for him with a 245/70 from the perspective of
>> fitment. Whether or not it provides any better performance is beyond me,
>> but
>> my guess is that the actual tread pattern will play a larger role than
>> the
>> tire size.
>>
>> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> news:43209419.9F6DB4BA@sympatico.ca...
>> > The 'book' width measurements are not at the tread, they are at the
>> > sidewall.
>> >
>> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
>> > ground went from 10.25" to 7.5". I got a 'radical' increase in
>> > traction.
>> >
>> > Mike
>> >
>> > J Strickland wrote:
>> >>
>> >> Not if the change was from 225 to 235. These numbers represent the
>> >> tread
>> >> width in mm, and 10mm is the functional equivelent of 3/8".
>> >>
>> >> Now, there is some misunderstanding (at least on my part) of just
>> >> exactly
>> >> where they measure 225 or 235, and the actual tread blocks being
>> >> square
>> >> on
>> >> one tire and rounded off on the other might play a role in your
>> >> perception
>> >> of an inch difference, but the actual difference is 10mm. Your point
>> >> being
>> >> that you are looking at the tread patch on the ground is not lost on
>> >> me
>> >> ...
>> >>
>> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> news:432080F0.DECA6CD5@sympatico.ca...
>> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
>> >> > a
>> >> > big disappointment. I believe there was over an inch of actual
>> >> > tread
>> >> > width difference.
>> >> >
>> >> > Mike
>> >> >
>> >> > J Strickland wrote:
>> >> >>
>> >> >> The width is the 225/235/245 number. The 70/75 number is the height
>> >> >> of
>> >> >> the
>> >> >> sidewall.
>> >> >>
>> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
>> >> >> in
>> >> >> these
>> >> >> tires will be the amount of sidewall, and the overall diameter --
>> >> >> the
>> >> >> 65
>> >> >> will be the smallest and the 75 will be the tallest.
>> >> >>
>> >> >> You might have noticed a loss of traction when you changed from
>> >> >> 225s
>> >> >> to
>> >> >> 235s, because this would represent the width of the tire. A 225/75
>> >> >> and
>> >> >> a
>> >> >> 235/70 are within 10mm of being the same diameter.
>> >> >>
>> >> >> I am a poor judge of what happens in snow, but it's difficult for
>> >> >> me
>> >> >> to
>> >> >> see
>> >> >> where one would notice a difference in 10mm in diameter. I have to
>> >> >> suspect
>> >> >> there are tread patterns and other things that enter into the
>> >> >> discussion.
>> >> >>
>> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> >> news:43203D52.2560BD48@sympatico.ca...
>> >> >> >I will second that. We lost a 'lot' of traction when we went from
>> >> >> >a
>> >> >> >225
>> >> >> > to a 235 while keeping the same profile even. Going to a wider
>> >> >> > 70
>> >> >> > series adds to the loss.
>> >> >> >
>> >> >> > Mike
>> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> >> >> > 88 Cherokee 235 BFG AT's
>> >> >> >
>> >> >> > Bowgus wrote:
>> >> >> >>
>> >> >> >> A consideration ... if you drive in snow, and will be using the
>> >> >> >> 245s
>> >> >> >> they
>> >> >> >> may be too wide. I say this because the 235 is too wide for my
>> >> >> >> XJ
>> >> >> >> in
>> >> >> >> snow
>> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
>> >> >> >> 225
>> >> >> >> snow
>> >> >> >> tires ... which unfortunately are due for replacement this
>> >> >> >> coming
>> >> >> >> winter
>> >> >> >> :-(
>> >> >> >>
>> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
>> >> >> >> message
>> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
>> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
>> >> >> >> > 225/75R16 -
>> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
>> >> >> >> > with speedometer or front turning clearance under the cowling
>> >> >> >> > or any other considerations on going from the 75 to the 70 ?
>> >> >> >> > It seems like the overall outside tire diameter is the same,
>> >> >> >> > but
>> >> >> >> > ??
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >

J Strickland

Well, yeah, I get that.

But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
would account for why the 9.50s measured 10.25 and the 10.50s were also
10.25. I can see where the 10.50s actually measure at 10.25, and I can see
how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
the 9.50s get reported as 7.5.

If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
the 10" rims, then there's no way they would be 7.5". See?





"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4320A545.100B17A3@sympatico.ca...
> The taller tire has a taller sidewall so the sidewall bulges out more.
> The measurements really are at the widest part of the sidewall, not at
> the tread.
>
> That is why the OP 'could' end up with the same width tread with those
> changes in profile and height sizes, but a tape measure will tell for
> sure.
>
> My 33" sidewalls look like this ( ), My 31's looked like | |
>
> Mike
>
> J Strickland wrote:
>>
>> Ddi you make this change on the same rims, or did you change rims too?
>>
>> There is something here that one of us is missing because there is no
>> point
>> in giving a spec for tire size if that spec has no basis in reality. Why
>> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
>> vs.
>> 235mm, if they are really something else entirely?
>>
>> I'm not arguing that you find the 9.50s work better than the 10.50s, I
>> have
>> every reason to think you are correct in this. I don't have the same kind
>> of
>> driving environment where I am, and we find around here that wider is
>> better, but we need to float above dry sand and dirt and the larger foot
>> print works better here. I'm sure that if I brought my Jeep to your
>> house,
>> it would give me lots of trouble, especially in winter.
>>
>> What I am suggesting is that if your tread on the ground is only 7.5 with
>> a
>> 9.50 tire, then there is another factor because the tread on the ground
>> should be closer to 9 than 7. In any case, the OP isn't getting any
>> benefit
>> from this discussion.
>>
>> His Grand should be fine for him with a 245/70 from the perspective of
>> fitment. Whether or not it provides any better performance is beyond me,
>> but
>> my guess is that the actual tread pattern will play a larger role than
>> the
>> tire size.
>>
>> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> news:43209419.9F6DB4BA@sympatico.ca...
>> > The 'book' width measurements are not at the tread, they are at the
>> > sidewall.
>> >
>> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
>> > ground went from 10.25" to 7.5". I got a 'radical' increase in
>> > traction.
>> >
>> > Mike
>> >
>> > J Strickland wrote:
>> >>
>> >> Not if the change was from 225 to 235. These numbers represent the
>> >> tread
>> >> width in mm, and 10mm is the functional equivelent of 3/8".
>> >>
>> >> Now, there is some misunderstanding (at least on my part) of just
>> >> exactly
>> >> where they measure 225 or 235, and the actual tread blocks being
>> >> square
>> >> on
>> >> one tire and rounded off on the other might play a role in your
>> >> perception
>> >> of an inch difference, but the actual difference is 10mm. Your point
>> >> being
>> >> that you are looking at the tread patch on the ground is not lost on
>> >> me
>> >> ...
>> >>
>> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> news:432080F0.DECA6CD5@sympatico.ca...
>> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
>> >> > a
>> >> > big disappointment. I believe there was over an inch of actual
>> >> > tread
>> >> > width difference.
>> >> >
>> >> > Mike
>> >> >
>> >> > J Strickland wrote:
>> >> >>
>> >> >> The width is the 225/235/245 number. The 70/75 number is the height
>> >> >> of
>> >> >> the
>> >> >> sidewall.
>> >> >>
>> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
>> >> >> in
>> >> >> these
>> >> >> tires will be the amount of sidewall, and the overall diameter --
>> >> >> the
>> >> >> 65
>> >> >> will be the smallest and the 75 will be the tallest.
>> >> >>
>> >> >> You might have noticed a loss of traction when you changed from
>> >> >> 225s
>> >> >> to
>> >> >> 235s, because this would represent the width of the tire. A 225/75
>> >> >> and
>> >> >> a
>> >> >> 235/70 are within 10mm of being the same diameter.
>> >> >>
>> >> >> I am a poor judge of what happens in snow, but it's difficult for
>> >> >> me
>> >> >> to
>> >> >> see
>> >> >> where one would notice a difference in 10mm in diameter. I have to
>> >> >> suspect
>> >> >> there are tread patterns and other things that enter into the
>> >> >> discussion.
>> >> >>
>> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> >> news:43203D52.2560BD48@sympatico.ca...
>> >> >> >I will second that. We lost a 'lot' of traction when we went from
>> >> >> >a
>> >> >> >225
>> >> >> > to a 235 while keeping the same profile even. Going to a wider
>> >> >> > 70
>> >> >> > series adds to the loss.
>> >> >> >
>> >> >> > Mike
>> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> >> >> > 88 Cherokee 235 BFG AT's
>> >> >> >
>> >> >> > Bowgus wrote:
>> >> >> >>
>> >> >> >> A consideration ... if you drive in snow, and will be using the
>> >> >> >> 245s
>> >> >> >> they
>> >> >> >> may be too wide. I say this because the 235 is too wide for my
>> >> >> >> XJ
>> >> >> >> in
>> >> >> >> snow
>> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
>> >> >> >> 225
>> >> >> >> snow
>> >> >> >> tires ... which unfortunately are due for replacement this
>> >> >> >> coming
>> >> >> >> winter
>> >> >> >> :-(
>> >> >> >>
>> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
>> >> >> >> message
>> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
>> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
>> >> >> >> > 225/75R16 -
>> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
>> >> >> >> > with speedometer or front turning clearance under the cowling
>> >> >> >> > or any other considerations on going from the 75 to the 70 ?
>> >> >> >> > It seems like the overall outside tire diameter is the same,
>> >> >> >> > but
>> >> >> >> > ??
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >

J Strickland

Well, yeah, I get that.

But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
would account for why the 9.50s measured 10.25 and the 10.50s were also
10.25. I can see where the 10.50s actually measure at 10.25, and I can see
how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
the 9.50s get reported as 7.5.

If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
the 10" rims, then there's no way they would be 7.5". See?





"Mike Romain" <romainm@sympatico.ca> wrote in message
news:4320A545.100B17A3@sympatico.ca...
> The taller tire has a taller sidewall so the sidewall bulges out more.
> The measurements really are at the widest part of the sidewall, not at
> the tread.
>
> That is why the OP 'could' end up with the same width tread with those
> changes in profile and height sizes, but a tape measure will tell for
> sure.
>
> My 33" sidewalls look like this ( ), My 31's looked like | |
>
> Mike
>
> J Strickland wrote:
>>
>> Ddi you make this change on the same rims, or did you change rims too?
>>
>> There is something here that one of us is missing because there is no
>> point
>> in giving a spec for tire size if that spec has no basis in reality. Why
>> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
>> vs.
>> 235mm, if they are really something else entirely?
>>
>> I'm not arguing that you find the 9.50s work better than the 10.50s, I
>> have
>> every reason to think you are correct in this. I don't have the same kind
>> of
>> driving environment where I am, and we find around here that wider is
>> better, but we need to float above dry sand and dirt and the larger foot
>> print works better here. I'm sure that if I brought my Jeep to your
>> house,
>> it would give me lots of trouble, especially in winter.
>>
>> What I am suggesting is that if your tread on the ground is only 7.5 with
>> a
>> 9.50 tire, then there is another factor because the tread on the ground
>> should be closer to 9 than 7. In any case, the OP isn't getting any
>> benefit
>> from this discussion.
>>
>> His Grand should be fine for him with a 245/70 from the perspective of
>> fitment. Whether or not it provides any better performance is beyond me,
>> but
>> my guess is that the actual tread pattern will play a larger role than
>> the
>> tire size.
>>
>> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> news:43209419.9F6DB4BA@sympatico.ca...
>> > The 'book' width measurements are not at the tread, they are at the
>> > sidewall.
>> >
>> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
>> > ground went from 10.25" to 7.5". I got a 'radical' increase in
>> > traction.
>> >
>> > Mike
>> >
>> > J Strickland wrote:
>> >>
>> >> Not if the change was from 225 to 235. These numbers represent the
>> >> tread
>> >> width in mm, and 10mm is the functional equivelent of 3/8".
>> >>
>> >> Now, there is some misunderstanding (at least on my part) of just
>> >> exactly
>> >> where they measure 225 or 235, and the actual tread blocks being
>> >> square
>> >> on
>> >> one tire and rounded off on the other might play a role in your
>> >> perception
>> >> of an inch difference, but the actual difference is 10mm. Your point
>> >> being
>> >> that you are looking at the tread patch on the ground is not lost on
>> >> me
>> >> ...
>> >>
>> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> news:432080F0.DECA6CD5@sympatico.ca...
>> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
>> >> > a
>> >> > big disappointment. I believe there was over an inch of actual
>> >> > tread
>> >> > width difference.
>> >> >
>> >> > Mike
>> >> >
>> >> > J Strickland wrote:
>> >> >>
>> >> >> The width is the 225/235/245 number. The 70/75 number is the height
>> >> >> of
>> >> >> the
>> >> >> sidewall.
>> >> >>
>> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
>> >> >> in
>> >> >> these
>> >> >> tires will be the amount of sidewall, and the overall diameter --
>> >> >> the
>> >> >> 65
>> >> >> will be the smallest and the 75 will be the tallest.
>> >> >>
>> >> >> You might have noticed a loss of traction when you changed from
>> >> >> 225s
>> >> >> to
>> >> >> 235s, because this would represent the width of the tire. A 225/75
>> >> >> and
>> >> >> a
>> >> >> 235/70 are within 10mm of being the same diameter.
>> >> >>
>> >> >> I am a poor judge of what happens in snow, but it's difficult for
>> >> >> me
>> >> >> to
>> >> >> see
>> >> >> where one would notice a difference in 10mm in diameter. I have to
>> >> >> suspect
>> >> >> there are tread patterns and other things that enter into the
>> >> >> discussion.
>> >> >>
>> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
>> >> >> news:43203D52.2560BD48@sympatico.ca...
>> >> >> >I will second that. We lost a 'lot' of traction when we went from
>> >> >> >a
>> >> >> >225
>> >> >> > to a 235 while keeping the same profile even. Going to a wider
>> >> >> > 70
>> >> >> > series adds to the loss.
>> >> >> >
>> >> >> > Mike
>> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
>> >> >> > 88 Cherokee 235 BFG AT's
>> >> >> >
>> >> >> > Bowgus wrote:
>> >> >> >>
>> >> >> >> A consideration ... if you drive in snow, and will be using the
>> >> >> >> 245s
>> >> >> >> they
>> >> >> >> may be too wide. I say this because the 235 is too wide for my
>> >> >> >> XJ
>> >> >> >> in
>> >> >> >> snow
>> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
>> >> >> >> 225
>> >> >> >> snow
>> >> >> >> tires ... which unfortunately are due for replacement this
>> >> >> >> coming
>> >> >> >> winter
>> >> >> >> :-(
>> >> >> >>
>> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
>> >> >> >> message
>> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
>> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
>> >> >> >> > 225/75R16 -
>> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
>> >> >> >> > with speedometer or front turning clearance under the cowling
>> >> >> >> > or any other considerations on going from the 75 to the 70 ?
>> >> >> >> > It seems like the overall outside tire diameter is the same,
>> >> >> >> > but
>> >> >> >> > ??
>> >> >> >> >
>> >> >> >> >
>> >> >> >> >

Mike Romain

I am only talking the road patch width with proper rims at proper
pressure. The 'book' measurement is 9.5" which is the widest part of
the sidewall. because the sidewall has the bulge, the tread is only
made 7.5" to balance the shape.

Try it on some different off road or any for that matter tires. You
will see radical varations from tread width to 'book' or sidewall width
according to how tall they are.

A 50 series tire has straight up sidewalls so they are most likely to
have the tread match the book size.

Mike

J Strickland wrote:
>
> Well, yeah, I get that.
>
> But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
> would account for why the 9.50s measured 10.25 and the 10.50s were also
> 10.25. I can see where the 10.50s actually measure at 10.25, and I can see
> how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
> the 9.50s get reported as 7.5.
>
> If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
> can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
> the 10" rims, then there's no way they would be 7.5". See?
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320A545.100B17A3@sympatico.ca...
> > The taller tire has a taller sidewall so the sidewall bulges out more.
> > The measurements really are at the widest part of the sidewall, not at
> > the tread.
> >
> > That is why the OP 'could' end up with the same width tread with those
> > changes in profile and height sizes, but a tape measure will tell for
> > sure.
> >
> > My 33" sidewalls look like this ( ), My 31's looked like | |
> >
> > Mike
> >
> > J Strickland wrote:
> >>
> >> Ddi you make this change on the same rims, or did you change rims too?
> >>
> >> There is something here that one of us is missing because there is no
> >> point
> >> in giving a spec for tire size if that spec has no basis in reality. Why
> >> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
> >> vs.
> >> 235mm, if they are really something else entirely?
> >>
> >> I'm not arguing that you find the 9.50s work better than the 10.50s, I
> >> have
> >> every reason to think you are correct in this. I don't have the same kind
> >> of
> >> driving environment where I am, and we find around here that wider is
> >> better, but we need to float above dry sand and dirt and the larger foot
> >> print works better here. I'm sure that if I brought my Jeep to your
> >> house,
> >> it would give me lots of trouble, especially in winter.
> >>
> >> What I am suggesting is that if your tread on the ground is only 7.5 with
> >> a
> >> 9.50 tire, then there is another factor because the tread on the ground
> >> should be closer to 9 than 7. In any case, the OP isn't getting any
> >> benefit
> >> from this discussion.
> >>
> >> His Grand should be fine for him with a 245/70 from the perspective of
> >> fitment. Whether or not it provides any better performance is beyond me,
> >> but
> >> my guess is that the actual tread pattern will play a larger role than
> >> the
> >> tire size.
> >>
> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> news:43209419.9F6DB4BA@sympatico.ca...
> >> > The 'book' width measurements are not at the tread, they are at the
> >> > sidewall.
> >> >
> >> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
> >> > ground went from 10.25" to 7.5". I got a 'radical' increase in
> >> > traction.
> >> >
> >> > Mike
> >> >
> >> > J Strickland wrote:
> >> >>
> >> >> Not if the change was from 225 to 235. These numbers represent the
> >> >> tread
> >> >> width in mm, and 10mm is the functional equivelent of 3/8".
> >> >>
> >> >> Now, there is some misunderstanding (at least on my part) of just
> >> >> exactly
> >> >> where they measure 225 or 235, and the actual tread blocks being
> >> >> square
> >> >> on
> >> >> one tire and rounded off on the other might play a role in your
> >> >> perception
> >> >> of an inch difference, but the actual difference is 10mm. Your point
> >> >> being
> >> >> that you are looking at the tread patch on the ground is not lost on
> >> >> me
> >> >> ...
> >> >>
> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> news:432080F0.DECA6CD5@sympatico.ca...
> >> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
> >> >> > a
> >> >> > big disappointment. I believe there was over an inch of actual
> >> >> > tread
> >> >> > width difference.
> >> >> >
> >> >> > Mike
> >> >> >
> >> >> > J Strickland wrote:
> >> >> >>
> >> >> >> The width is the 225/235/245 number. The 70/75 number is the height
> >> >> >> of
> >> >> >> the
> >> >> >> sidewall.
> >> >> >>
> >> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
> >> >> >> in
> >> >> >> these
> >> >> >> tires will be the amount of sidewall, and the overall diameter --
> >> >> >> the
> >> >> >> 65
> >> >> >> will be the smallest and the 75 will be the tallest.
> >> >> >>
> >> >> >> You might have noticed a loss of traction when you changed from
> >> >> >> 225s
> >> >> >> to
> >> >> >> 235s, because this would represent the width of the tire. A 225/75
> >> >> >> and
> >> >> >> a
> >> >> >> 235/70 are within 10mm of being the same diameter.
> >> >> >>
> >> >> >> I am a poor judge of what happens in snow, but it's difficult for
> >> >> >> me
> >> >> >> to
> >> >> >> see
> >> >> >> where one would notice a difference in 10mm in diameter. I have to
> >> >> >> suspect
> >> >> >> there are tread patterns and other things that enter into the
> >> >> >> discussion.
> >> >> >>
> >> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> >> news:43203D52.2560BD48@sympatico.ca...
> >> >> >> >I will second that. We lost a 'lot' of traction when we went from
> >> >> >> >a
> >> >> >> >225
> >> >> >> > to a 235 while keeping the same profile even. Going to a wider
> >> >> >> > 70
> >> >> >> > series adds to the loss.
> >> >> >> >
> >> >> >> > Mike
> >> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> >> >> > 88 Cherokee 235 BFG AT's
> >> >> >> >
> >> >> >> > Bowgus wrote:
> >> >> >> >>
> >> >> >> >> A consideration ... if you drive in snow, and will be using the
> >> >> >> >> 245s
> >> >> >> >> they
> >> >> >> >> may be too wide. I say this because the 235 is too wide for my
> >> >> >> >> XJ
> >> >> >> >> in
> >> >> >> >> snow
> >> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
> >> >> >> >> 225
> >> >> >> >> snow
> >> >> >> >> tires ... which unfortunately are due for replacement this
> >> >> >> >> coming
> >> >> >> >> winter
> >> >> >> >> :-(
> >> >> >> >>
> >> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
> >> >> >> >> message
> >> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
> >> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
> >> >> >> >> > 225/75R16 -
> >> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
> >> >> >> >> > with speedometer or front turning clearance under the cowling
> >> >> >> >> > or any other considerations on going from the 75 to the 70 ?
> >> >> >> >> > It seems like the overall outside tire diameter is the same,
> >> >> >> >> > but
> >> >> >> >> > ??
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> >

Mike Romain

I am only talking the road patch width with proper rims at proper
pressure. The 'book' measurement is 9.5" which is the widest part of
the sidewall. because the sidewall has the bulge, the tread is only
made 7.5" to balance the shape.

Try it on some different off road or any for that matter tires. You
will see radical varations from tread width to 'book' or sidewall width
according to how tall they are.

A 50 series tire has straight up sidewalls so they are most likely to
have the tread match the book size.

Mike

J Strickland wrote:
>
> Well, yeah, I get that.
>
> But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
> would account for why the 9.50s measured 10.25 and the 10.50s were also
> 10.25. I can see where the 10.50s actually measure at 10.25, and I can see
> how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
> the 9.50s get reported as 7.5.
>
> If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
> can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
> the 10" rims, then there's no way they would be 7.5". See?
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320A545.100B17A3@sympatico.ca...
> > The taller tire has a taller sidewall so the sidewall bulges out more.
> > The measurements really are at the widest part of the sidewall, not at
> > the tread.
> >
> > That is why the OP 'could' end up with the same width tread with those
> > changes in profile and height sizes, but a tape measure will tell for
> > sure.
> >
> > My 33" sidewalls look like this ( ), My 31's looked like | |
> >
> > Mike
> >
> > J Strickland wrote:
> >>
> >> Ddi you make this change on the same rims, or did you change rims too?
> >>
> >> There is something here that one of us is missing because there is no
> >> point
> >> in giving a spec for tire size if that spec has no basis in reality. Why
> >> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
> >> vs.
> >> 235mm, if they are really something else entirely?
> >>
> >> I'm not arguing that you find the 9.50s work better than the 10.50s, I
> >> have
> >> every reason to think you are correct in this. I don't have the same kind
> >> of
> >> driving environment where I am, and we find around here that wider is
> >> better, but we need to float above dry sand and dirt and the larger foot
> >> print works better here. I'm sure that if I brought my Jeep to your
> >> house,
> >> it would give me lots of trouble, especially in winter.
> >>
> >> What I am suggesting is that if your tread on the ground is only 7.5 with
> >> a
> >> 9.50 tire, then there is another factor because the tread on the ground
> >> should be closer to 9 than 7. In any case, the OP isn't getting any
> >> benefit
> >> from this discussion.
> >>
> >> His Grand should be fine for him with a 245/70 from the perspective of
> >> fitment. Whether or not it provides any better performance is beyond me,
> >> but
> >> my guess is that the actual tread pattern will play a larger role than
> >> the
> >> tire size.
> >>
> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> news:43209419.9F6DB4BA@sympatico.ca...
> >> > The 'book' width measurements are not at the tread, they are at the
> >> > sidewall.
> >> >
> >> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
> >> > ground went from 10.25" to 7.5". I got a 'radical' increase in
> >> > traction.
> >> >
> >> > Mike
> >> >
> >> > J Strickland wrote:
> >> >>
> >> >> Not if the change was from 225 to 235. These numbers represent the
> >> >> tread
> >> >> width in mm, and 10mm is the functional equivelent of 3/8".
> >> >>
> >> >> Now, there is some misunderstanding (at least on my part) of just
> >> >> exactly
> >> >> where they measure 225 or 235, and the actual tread blocks being
> >> >> square
> >> >> on
> >> >> one tire and rounded off on the other might play a role in your
> >> >> perception
> >> >> of an inch difference, but the actual difference is 10mm. Your point
> >> >> being
> >> >> that you are looking at the tread patch on the ground is not lost on
> >> >> me
> >> >> ...
> >> >>
> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> news:432080F0.DECA6CD5@sympatico.ca...
> >> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
> >> >> > a
> >> >> > big disappointment. I believe there was over an inch of actual
> >> >> > tread
> >> >> > width difference.
> >> >> >
> >> >> > Mike
> >> >> >
> >> >> > J Strickland wrote:
> >> >> >>
> >> >> >> The width is the 225/235/245 number. The 70/75 number is the height
> >> >> >> of
> >> >> >> the
> >> >> >> sidewall.
> >> >> >>
> >> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
> >> >> >> in
> >> >> >> these
> >> >> >> tires will be the amount of sidewall, and the overall diameter --
> >> >> >> the
> >> >> >> 65
> >> >> >> will be the smallest and the 75 will be the tallest.
> >> >> >>
> >> >> >> You might have noticed a loss of traction when you changed from
> >> >> >> 225s
> >> >> >> to
> >> >> >> 235s, because this would represent the width of the tire. A 225/75
> >> >> >> and
> >> >> >> a
> >> >> >> 235/70 are within 10mm of being the same diameter.
> >> >> >>
> >> >> >> I am a poor judge of what happens in snow, but it's difficult for
> >> >> >> me
> >> >> >> to
> >> >> >> see
> >> >> >> where one would notice a difference in 10mm in diameter. I have to
> >> >> >> suspect
> >> >> >> there are tread patterns and other things that enter into the
> >> >> >> discussion.
> >> >> >>
> >> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> >> news:43203D52.2560BD48@sympatico.ca...
> >> >> >> >I will second that. We lost a 'lot' of traction when we went from
> >> >> >> >a
> >> >> >> >225
> >> >> >> > to a 235 while keeping the same profile even. Going to a wider
> >> >> >> > 70
> >> >> >> > series adds to the loss.
> >> >> >> >
> >> >> >> > Mike
> >> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> >> >> > 88 Cherokee 235 BFG AT's
> >> >> >> >
> >> >> >> > Bowgus wrote:
> >> >> >> >>
> >> >> >> >> A consideration ... if you drive in snow, and will be using the
> >> >> >> >> 245s
> >> >> >> >> they
> >> >> >> >> may be too wide. I say this because the 235 is too wide for my
> >> >> >> >> XJ
> >> >> >> >> in
> >> >> >> >> snow
> >> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
> >> >> >> >> 225
> >> >> >> >> snow
> >> >> >> >> tires ... which unfortunately are due for replacement this
> >> >> >> >> coming
> >> >> >> >> winter
> >> >> >> >> :-(
> >> >> >> >>
> >> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
> >> >> >> >> message
> >> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
> >> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
> >> >> >> >> > 225/75R16 -
> >> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
> >> >> >> >> > with speedometer or front turning clearance under the cowling
> >> >> >> >> > or any other considerations on going from the 75 to the 70 ?
> >> >> >> >> > It seems like the overall outside tire diameter is the same,
> >> >> >> >> > but
> >> >> >> >> > ??
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> >

Mike Romain

I am only talking the road patch width with proper rims at proper
pressure. The 'book' measurement is 9.5" which is the widest part of
the sidewall. because the sidewall has the bulge, the tread is only
made 7.5" to balance the shape.

Try it on some different off road or any for that matter tires. You
will see radical varations from tread width to 'book' or sidewall width
according to how tall they are.

A 50 series tire has straight up sidewalls so they are most likely to
have the tread match the book size.

Mike

J Strickland wrote:
>
> Well, yeah, I get that.
>
> But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
> would account for why the 9.50s measured 10.25 and the 10.50s were also
> 10.25. I can see where the 10.50s actually measure at 10.25, and I can see
> how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
> the 9.50s get reported as 7.5.
>
> If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
> can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
> the 10" rims, then there's no way they would be 7.5". See?
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320A545.100B17A3@sympatico.ca...
> > The taller tire has a taller sidewall so the sidewall bulges out more.
> > The measurements really are at the widest part of the sidewall, not at
> > the tread.
> >
> > That is why the OP 'could' end up with the same width tread with those
> > changes in profile and height sizes, but a tape measure will tell for
> > sure.
> >
> > My 33" sidewalls look like this ( ), My 31's looked like | |
> >
> > Mike
> >
> > J Strickland wrote:
> >>
> >> Ddi you make this change on the same rims, or did you change rims too?
> >>
> >> There is something here that one of us is missing because there is no
> >> point
> >> in giving a spec for tire size if that spec has no basis in reality. Why
> >> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
> >> vs.
> >> 235mm, if they are really something else entirely?
> >>
> >> I'm not arguing that you find the 9.50s work better than the 10.50s, I
> >> have
> >> every reason to think you are correct in this. I don't have the same kind
> >> of
> >> driving environment where I am, and we find around here that wider is
> >> better, but we need to float above dry sand and dirt and the larger foot
> >> print works better here. I'm sure that if I brought my Jeep to your
> >> house,
> >> it would give me lots of trouble, especially in winter.
> >>
> >> What I am suggesting is that if your tread on the ground is only 7.5 with
> >> a
> >> 9.50 tire, then there is another factor because the tread on the ground
> >> should be closer to 9 than 7. In any case, the OP isn't getting any
> >> benefit
> >> from this discussion.
> >>
> >> His Grand should be fine for him with a 245/70 from the perspective of
> >> fitment. Whether or not it provides any better performance is beyond me,
> >> but
> >> my guess is that the actual tread pattern will play a larger role than
> >> the
> >> tire size.
> >>
> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> news:43209419.9F6DB4BA@sympatico.ca...
> >> > The 'book' width measurements are not at the tread, they are at the
> >> > sidewall.
> >> >
> >> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
> >> > ground went from 10.25" to 7.5". I got a 'radical' increase in
> >> > traction.
> >> >
> >> > Mike
> >> >
> >> > J Strickland wrote:
> >> >>
> >> >> Not if the change was from 225 to 235. These numbers represent the
> >> >> tread
> >> >> width in mm, and 10mm is the functional equivelent of 3/8".
> >> >>
> >> >> Now, there is some misunderstanding (at least on my part) of just
> >> >> exactly
> >> >> where they measure 225 or 235, and the actual tread blocks being
> >> >> square
> >> >> on
> >> >> one tire and rounded off on the other might play a role in your
> >> >> perception
> >> >> of an inch difference, but the actual difference is 10mm. Your point
> >> >> being
> >> >> that you are looking at the tread patch on the ground is not lost on
> >> >> me
> >> >> ...
> >> >>
> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> news:432080F0.DECA6CD5@sympatico.ca...
> >> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
> >> >> > a
> >> >> > big disappointment. I believe there was over an inch of actual
> >> >> > tread
> >> >> > width difference.
> >> >> >
> >> >> > Mike
> >> >> >
> >> >> > J Strickland wrote:
> >> >> >>
> >> >> >> The width is the 225/235/245 number. The 70/75 number is the height
> >> >> >> of
> >> >> >> the
> >> >> >> sidewall.
> >> >> >>
> >> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
> >> >> >> in
> >> >> >> these
> >> >> >> tires will be the amount of sidewall, and the overall diameter --
> >> >> >> the
> >> >> >> 65
> >> >> >> will be the smallest and the 75 will be the tallest.
> >> >> >>
> >> >> >> You might have noticed a loss of traction when you changed from
> >> >> >> 225s
> >> >> >> to
> >> >> >> 235s, because this would represent the width of the tire. A 225/75
> >> >> >> and
> >> >> >> a
> >> >> >> 235/70 are within 10mm of being the same diameter.
> >> >> >>
> >> >> >> I am a poor judge of what happens in snow, but it's difficult for
> >> >> >> me
> >> >> >> to
> >> >> >> see
> >> >> >> where one would notice a difference in 10mm in diameter. I have to
> >> >> >> suspect
> >> >> >> there are tread patterns and other things that enter into the
> >> >> >> discussion.
> >> >> >>
> >> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> >> news:43203D52.2560BD48@sympatico.ca...
> >> >> >> >I will second that. We lost a 'lot' of traction when we went from
> >> >> >> >a
> >> >> >> >225
> >> >> >> > to a 235 while keeping the same profile even. Going to a wider
> >> >> >> > 70
> >> >> >> > series adds to the loss.
> >> >> >> >
> >> >> >> > Mike
> >> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> >> >> > 88 Cherokee 235 BFG AT's
> >> >> >> >
> >> >> >> > Bowgus wrote:
> >> >> >> >>
> >> >> >> >> A consideration ... if you drive in snow, and will be using the
> >> >> >> >> 245s
> >> >> >> >> they
> >> >> >> >> may be too wide. I say this because the 235 is too wide for my
> >> >> >> >> XJ
> >> >> >> >> in
> >> >> >> >> snow
> >> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
> >> >> >> >> 225
> >> >> >> >> snow
> >> >> >> >> tires ... which unfortunately are due for replacement this
> >> >> >> >> coming
> >> >> >> >> winter
> >> >> >> >> :-(
> >> >> >> >>
> >> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
> >> >> >> >> message
> >> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
> >> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
> >> >> >> >> > 225/75R16 -
> >> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
> >> >> >> >> > with speedometer or front turning clearance under the cowling
> >> >> >> >> > or any other considerations on going from the 75 to the 70 ?
> >> >> >> >> > It seems like the overall outside tire diameter is the same,
> >> >> >> >> > but
> >> >> >> >> > ??
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> >

Mike Romain

I am only talking the road patch width with proper rims at proper
pressure. The 'book' measurement is 9.5" which is the widest part of
the sidewall. because the sidewall has the bulge, the tread is only
made 7.5" to balance the shape.

Try it on some different off road or any for that matter tires. You
will see radical varations from tread width to 'book' or sidewall width
according to how tall they are.

A 50 series tire has straight up sidewalls so they are most likely to
have the tread match the book size.

Mike

J Strickland wrote:
>
> Well, yeah, I get that.
>
> But, you said your 9.50s were 7.5 inches wide. The explanation you just gave
> would account for why the 9.50s measured 10.25 and the 10.50s were also
> 10.25. I can see where the 10.50s actually measure at 10.25, and I can see
> how 9.50s might also come in at 10.25. Where I'm getting tripped up is when
> the 9.50s get reported as 7.5.
>
> If the 10.50s were mounted on 10" rims and the 9.50s are on 7" rims, then I
> can see where the 9.50s would be 7.5" wide, but if the 9.50s also went onto
> the 10" rims, then there's no way they would be 7.5". See?
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320A545.100B17A3@sympatico.ca...
> > The taller tire has a taller sidewall so the sidewall bulges out more.
> > The measurements really are at the widest part of the sidewall, not at
> > the tread.
> >
> > That is why the OP 'could' end up with the same width tread with those
> > changes in profile and height sizes, but a tape measure will tell for
> > sure.
> >
> > My 33" sidewalls look like this ( ), My 31's looked like | |
> >
> > Mike
> >
> > J Strickland wrote:
> >>
> >> Ddi you make this change on the same rims, or did you change rims too?
> >>
> >> There is something here that one of us is missing because there is no
> >> point
> >> in giving a spec for tire size if that spec has no basis in reality. Why
> >> tell the consumer the tires are 9.5 when they are really 7.5, or 225mm
> >> vs.
> >> 235mm, if they are really something else entirely?
> >>
> >> I'm not arguing that you find the 9.50s work better than the 10.50s, I
> >> have
> >> every reason to think you are correct in this. I don't have the same kind
> >> of
> >> driving environment where I am, and we find around here that wider is
> >> better, but we need to float above dry sand and dirt and the larger foot
> >> print works better here. I'm sure that if I brought my Jeep to your
> >> house,
> >> it would give me lots of trouble, especially in winter.
> >>
> >> What I am suggesting is that if your tread on the ground is only 7.5 with
> >> a
> >> 9.50 tire, then there is another factor because the tread on the ground
> >> should be closer to 9 than 7. In any case, the OP isn't getting any
> >> benefit
> >> from this discussion.
> >>
> >> His Grand should be fine for him with a 245/70 from the perspective of
> >> fitment. Whether or not it provides any better performance is beyond me,
> >> but
> >> my guess is that the actual tread pattern will play a larger role than
> >> the
> >> tire size.
> >>
> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> news:43209419.9F6DB4BA@sympatico.ca...
> >> > The 'book' width measurements are not at the tread, they are at the
> >> > sidewall.
> >> >
> >> > When I went from a 31x10.5" mud to a 33x9.5" mud, the tread on the
> >> > ground went from 10.25" to 7.5". I got a 'radical' increase in
> >> > traction.
> >> >
> >> > Mike
> >> >
> >> > J Strickland wrote:
> >> >>
> >> >> Not if the change was from 225 to 235. These numbers represent the
> >> >> tread
> >> >> width in mm, and 10mm is the functional equivelent of 3/8".
> >> >>
> >> >> Now, there is some misunderstanding (at least on my part) of just
> >> >> exactly
> >> >> where they measure 225 or 235, and the actual tread blocks being
> >> >> square
> >> >> on
> >> >> one tire and rounded off on the other might play a role in your
> >> >> perception
> >> >> of an inch difference, but the actual difference is 10mm. Your point
> >> >> being
> >> >> that you are looking at the tread patch on the ground is not lost on
> >> >> me
> >> >> ...
> >> >>
> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> news:432080F0.DECA6CD5@sympatico.ca...
> >> >> > Could be, we went from Hercules 'terra Trac' to BFG AT's and it was
> >> >> > a
> >> >> > big disappointment. I believe there was over an inch of actual
> >> >> > tread
> >> >> > width difference.
> >> >> >
> >> >> > Mike
> >> >> >
> >> >> > J Strickland wrote:
> >> >> >>
> >> >> >> The width is the 225/235/245 number. The 70/75 number is the height
> >> >> >> of
> >> >> >> the
> >> >> >> sidewall.
> >> >> >>
> >> >> >> A 225/65, 225/70, and 225/75 are all the same width. The difference
> >> >> >> in
> >> >> >> these
> >> >> >> tires will be the amount of sidewall, and the overall diameter --
> >> >> >> the
> >> >> >> 65
> >> >> >> will be the smallest and the 75 will be the tallest.
> >> >> >>
> >> >> >> You might have noticed a loss of traction when you changed from
> >> >> >> 225s
> >> >> >> to
> >> >> >> 235s, because this would represent the width of the tire. A 225/75
> >> >> >> and
> >> >> >> a
> >> >> >> 235/70 are within 10mm of being the same diameter.
> >> >> >>
> >> >> >> I am a poor judge of what happens in snow, but it's difficult for
> >> >> >> me
> >> >> >> to
> >> >> >> see
> >> >> >> where one would notice a difference in 10mm in diameter. I have to
> >> >> >> suspect
> >> >> >> there are tread patterns and other things that enter into the
> >> >> >> discussion.
> >> >> >>
> >> >> >> "Mike Romain" <romainm@sympatico.ca> wrote in message
> >> >> >> news:43203D52.2560BD48@sympatico.ca...
> >> >> >> >I will second that. We lost a 'lot' of traction when we went from
> >> >> >> >a
> >> >> >> >225
> >> >> >> > to a 235 while keeping the same profile even. Going to a wider
> >> >> >> > 70
> >> >> >> > series adds to the loss.
> >> >> >> >
> >> >> >> > Mike
> >> >> >> > 86/00 CJ7 Laredo, 33x9.5 BFG Muds, 'glass nose to tail in '00
> >> >> >> > 88 Cherokee 235 BFG AT's
> >> >> >> >
> >> >> >> > Bowgus wrote:
> >> >> >> >>
> >> >> >> >> A consideration ... if you drive in snow, and will be using the
> >> >> >> >> 245s
> >> >> >> >> they
> >> >> >> >> may be too wide. I say this because the 235 is too wide for my
> >> >> >> >> XJ
> >> >> >> >> in
> >> >> >> >> snow
> >> >> >> >> ... but the XJ is a lighter vehicle I believe (unibody). I use
> >> >> >> >> 225
> >> >> >> >> snow
> >> >> >> >> tires ... which unfortunately are due for replacement this
> >> >> >> >> coming
> >> >> >> >> winter
> >> >> >> >> :-(
> >> >> >> >>
> >> >> >> >> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in
> >> >> >> >> message
> >> >> >> >> news:3VMTe.684$au2.349@newssvr17.news.prodigy.com. ..
> >> >> >> >> > The Grand Cherokee OE tires are the Wrangler ST with
> >> >> >> >> > 225/75R16 -
> >> >> >> >> > I was wondering if the 245/70R16 sizes cause any probs
> >> >> >> >> > with speedometer or front turning clearance under the cowling
> >> >> >> >> > or any other considerations on going from the 75 to the 70 ?
> >> >> >> >> > It seems like the overall outside tire diameter is the same,
> >> >> >> >> > but
> >> >> >> >> > ??
> >> >> >> >> >
> >> >> >> >> >
> >> >> >> >> >

Bowgus

> I am a poor judge of what happens in snow, but it's difficult for me to
see
> where one would notice a difference in 10mm in diameter. I have to suspect
> there are tread patterns and other things that enter into the discussion.


Well, with 4 tires, 225 to 235 adds up to almost 2 inches ... and in slush
and so on at speed, it's enough to affect my puny little 3000 lb Cherokee.
As to the heavier trucks, no problem I'm sure. Now if I went to 245s, yikes.