Mike Romain

Jeff, they make the actual physical tread on a BFG 33x9.5" tire 7.5".

Putting the tire on a wider or narrower rim is not going to change this
7.5" tread width. It 'can' change the sidewall width which is why the
'book' says the tire is X big on the proper rim with the proper
pressure.

The tread width has nothing to do with the 'book' size of the tire.
This gets more pronounced as the tires get taller due to the bulge in
the sidewall.

I would recommend you go play with a tape measure the next time you see
a bunch of mounted large tires. When I figured this out back in the
70's it was a surprise to me too. There is a 'large' variation between
brands.

Mike

Jeff Strickland wrote:
>
> In all fairness, Mike, the attitude of the sidewalls has to do withthe width
> of the tire, the width of the rim, and the air pressure. Assuming the
> airpressure and the rim width are correct, then yes, the sidewalls of a 50
> series will very straight. But the 50 Series part isn't the reason. The
> reason is the 275, or whatever, part matches the width of the rim.
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320AF68.58255946@sympatico.ca...
> >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

Jeff, they make the actual physical tread on a BFG 33x9.5" tire 7.5".

Putting the tire on a wider or narrower rim is not going to change this
7.5" tread width. It 'can' change the sidewall width which is why the
'book' says the tire is X big on the proper rim with the proper
pressure.

The tread width has nothing to do with the 'book' size of the tire.
This gets more pronounced as the tires get taller due to the bulge in
the sidewall.

I would recommend you go play with a tape measure the next time you see
a bunch of mounted large tires. When I figured this out back in the
70's it was a surprise to me too. There is a 'large' variation between
brands.

Mike

Jeff Strickland wrote:
>
> In all fairness, Mike, the attitude of the sidewalls has to do withthe width
> of the tire, the width of the rim, and the air pressure. Assuming the
> airpressure and the rim width are correct, then yes, the sidewalls of a 50
> series will very straight. But the 50 Series part isn't the reason. The
> reason is the 275, or whatever, part matches the width of the rim.
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320AF68.58255946@sympatico.ca...
> >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

Jeff, they make the actual physical tread on a BFG 33x9.5" tire 7.5".

Putting the tire on a wider or narrower rim is not going to change this
7.5" tread width. It 'can' change the sidewall width which is why the
'book' says the tire is X big on the proper rim with the proper
pressure.

The tread width has nothing to do with the 'book' size of the tire.
This gets more pronounced as the tires get taller due to the bulge in
the sidewall.

I would recommend you go play with a tape measure the next time you see
a bunch of mounted large tires. When I figured this out back in the
70's it was a surprise to me too. There is a 'large' variation between
brands.

Mike

Jeff Strickland wrote:
>
> In all fairness, Mike, the attitude of the sidewalls has to do withthe width
> of the tire, the width of the rim, and the air pressure. Assuming the
> airpressure and the rim width are correct, then yes, the sidewalls of a 50
> series will very straight. But the 50 Series part isn't the reason. The
> reason is the 275, or whatever, part matches the width of the rim.
>
> "Mike Romain" <romainm@sympatico.ca> wrote in message
> news:4320AF68.58255946@sympatico.ca...
> >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
> >> >> >> >> >> > ??
> >> >> >> >> >> >
> >> >> >> >> >> >
> >> >> >> >> >> >

J Strickland

Adds up? What adds up? Not the diameter difference.

If one tire size is 10mm larger than another, you do not add 10 four times
to come up with 40. (Adding 10 four times does equal 40, but the difference
is not an additive difference, so adding the differences up is not something
you would do -- well you might do it, but I wouldn't.)





"Bowgus" <bowgus@rogers.com> wrote in message
news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> 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.
>
>

J Strickland

Adds up? What adds up? Not the diameter difference.

If one tire size is 10mm larger than another, you do not add 10 four times
to come up with 40. (Adding 10 four times does equal 40, but the difference
is not an additive difference, so adding the differences up is not something
you would do -- well you might do it, but I wouldn't.)





"Bowgus" <bowgus@rogers.com> wrote in message
news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> 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.
>
>

J Strickland

Adds up? What adds up? Not the diameter difference.

If one tire size is 10mm larger than another, you do not add 10 four times
to come up with 40. (Adding 10 four times does equal 40, but the difference
is not an additive difference, so adding the differences up is not something
you would do -- well you might do it, but I wouldn't.)





"Bowgus" <bowgus@rogers.com> wrote in message
news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> 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.
>
>

J Strickland

Adds up? What adds up? Not the diameter difference.

If one tire size is 10mm larger than another, you do not add 10 four times
to come up with 40. (Adding 10 four times does equal 40, but the difference
is not an additive difference, so adding the differences up is not something
you would do -- well you might do it, but I wouldn't.)





"Bowgus" <bowgus@rogers.com> wrote in message
news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> 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.
>
>

J Strickland

One more time, Phil.

As a practical matter, a 225/75 and a 235/70 are identical. The 235 is 10mm
wider, which isn't an issue, and the 70 is 70% of 235, and affects the
diameter of the tire. a 225/75 and a 235/70 are different in the overall
diameter of 8.5mm, or a bit over 1/4" -- if I remember, a 5/16" nutdriver
can be replaced with an 8mm nutdriver. The tires are functional equivelents
when physical size is the only consideration.

But, physical size is seldom the only consideration when buying tires. The
tread design plays a critical role in how well a tire works.




"Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
news:BI4Ue.266$Aa1.194@newssvr23.news.prodigy.net. ..
>
> "Bowgus" <bowgus@rogers.com> wrote in message
> news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> > 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.
>>
> so - you're saying that with the narrow footprint there is probably more
> bite
> to the footprint - ala the psi of the footprint -
> vs the wider tire that will distribute the weight more
> and not take a bite out of snow, ice, slush, etc -
>
> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
> 245)
>
>
>

J Strickland

One more time, Phil.

As a practical matter, a 225/75 and a 235/70 are identical. The 235 is 10mm
wider, which isn't an issue, and the 70 is 70% of 235, and affects the
diameter of the tire. a 225/75 and a 235/70 are different in the overall
diameter of 8.5mm, or a bit over 1/4" -- if I remember, a 5/16" nutdriver
can be replaced with an 8mm nutdriver. The tires are functional equivelents
when physical size is the only consideration.

But, physical size is seldom the only consideration when buying tires. The
tread design plays a critical role in how well a tire works.




"Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
news:BI4Ue.266$Aa1.194@newssvr23.news.prodigy.net. ..
>
> "Bowgus" <bowgus@rogers.com> wrote in message
> news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> > 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.
>>
> so - you're saying that with the narrow footprint there is probably more
> bite
> to the footprint - ala the psi of the footprint -
> vs the wider tire that will distribute the weight more
> and not take a bite out of snow, ice, slush, etc -
>
> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
> 245)
>
>
>

J Strickland

One more time, Phil.

As a practical matter, a 225/75 and a 235/70 are identical. The 235 is 10mm
wider, which isn't an issue, and the 70 is 70% of 235, and affects the
diameter of the tire. a 225/75 and a 235/70 are different in the overall
diameter of 8.5mm, or a bit over 1/4" -- if I remember, a 5/16" nutdriver
can be replaced with an 8mm nutdriver. The tires are functional equivelents
when physical size is the only consideration.

But, physical size is seldom the only consideration when buying tires. The
tread design plays a critical role in how well a tire works.




"Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
news:BI4Ue.266$Aa1.194@newssvr23.news.prodigy.net. ..
>
> "Bowgus" <bowgus@rogers.com> wrote in message
> news:So-dnVNuPbMcLr3eRVn-gA@rogers.com...
>> > 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.
>>
> so - you're saying that with the narrow footprint there is probably more
> bite
> to the footprint - ala the psi of the footprint -
> vs the wider tire that will distribute the weight more
> and not take a bite out of snow, ice, slush, etc -
>
> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
> 245)
>
>
>