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

Yes, the 70 or 75 is the Aspect Ratio, and the aspect ratio is relative to
the width, 225 or 235, etc. Multiply the width by the aspect ratio to find
the size of one sidewall, there are two sidewalls -- one at the top and one
at the bottom -- that must be added together, then added to the rim diameter
to find the overall diameter of the tire.

A 225/75 and a 235/70 (same rim size) are essentially identical in diameter,
but one is wider.
A 225/70 and a 235/75 are completely different. The 235 is both taller and
wider because 75% of 235 is a much larger number than 70% of 225.





"Bowgus" <bowgus@rogers.com> wrote in message
news:ja-dnZ2dnZ2zrIDMnZ2dnelAvd6dnZ2dRVn-z52dnZ0@rogers.com...
> The 75 or 70 is the ratio of the height to the width ... or vice versa ...
> I
> think :-) So if the width is 235 (mm), and the ratio is 70, then the
> height
> is 70 % of 235 (mm) and if 75, then 75% of 235. I dunno ... some people
> like
> the look of a 70, or 75 ... apart from that, unless the diameter becomes
> so
> drastic so as to affect braking, I don't see that it's a consideration. I
> myself "like the look" of my 235/75 Michelins (summer tires) on my
> Cherokee.
>
>> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
>> 245)
>>
>>
>>
>
>

J Strickland

Yes, the 70 or 75 is the Aspect Ratio, and the aspect ratio is relative to
the width, 225 or 235, etc. Multiply the width by the aspect ratio to find
the size of one sidewall, there are two sidewalls -- one at the top and one
at the bottom -- that must be added together, then added to the rim diameter
to find the overall diameter of the tire.

A 225/75 and a 235/70 (same rim size) are essentially identical in diameter,
but one is wider.
A 225/70 and a 235/75 are completely different. The 235 is both taller and
wider because 75% of 235 is a much larger number than 70% of 225.





"Bowgus" <bowgus@rogers.com> wrote in message
news:ja-dnZ2dnZ2zrIDMnZ2dnelAvd6dnZ2dRVn-z52dnZ0@rogers.com...
> The 75 or 70 is the ratio of the height to the width ... or vice versa ...
> I
> think :-) So if the width is 235 (mm), and the ratio is 70, then the
> height
> is 70 % of 235 (mm) and if 75, then 75% of 235. I dunno ... some people
> like
> the look of a 70, or 75 ... apart from that, unless the diameter becomes
> so
> drastic so as to affect braking, I don't see that it's a consideration. I
> myself "like the look" of my 235/75 Michelins (summer tires) on my
> Cherokee.
>
>> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
>> 245)
>>
>>
>>
>
>

J Strickland

Yes, the 70 or 75 is the Aspect Ratio, and the aspect ratio is relative to
the width, 225 or 235, etc. Multiply the width by the aspect ratio to find
the size of one sidewall, there are two sidewalls -- one at the top and one
at the bottom -- that must be added together, then added to the rim diameter
to find the overall diameter of the tire.

A 225/75 and a 235/70 (same rim size) are essentially identical in diameter,
but one is wider.
A 225/70 and a 235/75 are completely different. The 235 is both taller and
wider because 75% of 235 is a much larger number than 70% of 225.





"Bowgus" <bowgus@rogers.com> wrote in message
news:ja-dnZ2dnZ2zrIDMnZ2dnelAvd6dnZ2dRVn-z52dnZ0@rogers.com...
> The 75 or 70 is the ratio of the height to the width ... or vice versa ...
> I
> think :-) So if the width is 235 (mm), and the ratio is 70, then the
> height
> is 70 % of 235 (mm) and if 75, then 75% of 235. I dunno ... some people
> like
> the look of a 70, or 75 ... apart from that, unless the diameter becomes
> so
> drastic so as to affect braking, I don't see that it's a consideration. I
> myself "like the look" of my 235/75 Michelins (summer tires) on my
> Cherokee.
>
>> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
>> 245)
>>
>>
>>
>
>

J Strickland

Yes, the 70 or 75 is the Aspect Ratio, and the aspect ratio is relative to
the width, 225 or 235, etc. Multiply the width by the aspect ratio to find
the size of one sidewall, there are two sidewalls -- one at the top and one
at the bottom -- that must be added together, then added to the rim diameter
to find the overall diameter of the tire.

A 225/75 and a 235/70 (same rim size) are essentially identical in diameter,
but one is wider.
A 225/70 and a 235/75 are completely different. The 235 is both taller and
wider because 75% of 235 is a much larger number than 70% of 225.





"Bowgus" <bowgus@rogers.com> wrote in message
news:ja-dnZ2dnZ2zrIDMnZ2dnelAvd6dnZ2dRVn-z52dnZ0@rogers.com...
> The 75 or 70 is the ratio of the height to the width ... or vice versa ...
> I
> think :-) So if the width is 235 (mm), and the ratio is 70, then the
> height
> is 70 % of 235 (mm) and if 75, then 75% of 235. I dunno ... some people
> like
> the look of a 70, or 75 ... apart from that, unless the diameter becomes
> so
> drastic so as to affect braking, I don't see that it's a consideration. I
> myself "like the look" of my 235/75 Michelins (summer tires) on my
> Cherokee.
>
>> hmmmm - any other thoughts on going from the 75 to the 70 (225 to the
>> 245)
>>
>>
>>
>
>

J Strickland

Do the math. 75% of 225 and 70% of 235 are only different by 4.25mm in the
height of one sidewall. Surely this is not a significant difference.




"Billy Ray" <Billy_Ray@SPAMfuse.net> wrote in message
news:e5b10$4320e00b$d8449845$19481@FUSE.NET...
> It depends on where you plan to drive.
>
> On the road, or in sand, you will have increased lateral traction from the
> wider tire. Off road, in snow or mud, you will have better forward
> traction.
>
> Another consideration is your vehicle. A Grand Cherokee was not designed
> for maximum on-road traction. The 75 series tire will probably provide
> more traction than the Grand could handle given its high center of
> gravity.
>
> A further consideration of tire type. You will have a better off-road
> selection with the 75 series and a better selection of on-road tires with
> the 70 series.
>
> A final consideration in the discourse is appearance. There are different
> standards for 'city' and 'country' Jeeps.
>
> Conclusion:
> What are your priorities?
> --
> .
> Billy_Ray@SPAM.fuse.net (remove SPAM)
> 2002 Jeep WJ 4 Liter Automatic
> Brilliant Black Crystal Pearl Coat
> Sharing is why we are all here....... or should be.
> .
> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
> news:BI4Ue.266$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

Do the math. 75% of 225 and 70% of 235 are only different by 4.25mm in the
height of one sidewall. Surely this is not a significant difference.




"Billy Ray" <Billy_Ray@SPAMfuse.net> wrote in message
news:e5b10$4320e00b$d8449845$19481@FUSE.NET...
> It depends on where you plan to drive.
>
> On the road, or in sand, you will have increased lateral traction from the
> wider tire. Off road, in snow or mud, you will have better forward
> traction.
>
> Another consideration is your vehicle. A Grand Cherokee was not designed
> for maximum on-road traction. The 75 series tire will probably provide
> more traction than the Grand could handle given its high center of
> gravity.
>
> A further consideration of tire type. You will have a better off-road
> selection with the 75 series and a better selection of on-road tires with
> the 70 series.
>
> A final consideration in the discourse is appearance. There are different
> standards for 'city' and 'country' Jeeps.
>
> Conclusion:
> What are your priorities?
> --
> .
> Billy_Ray@SPAM.fuse.net (remove SPAM)
> 2002 Jeep WJ 4 Liter Automatic
> Brilliant Black Crystal Pearl Coat
> Sharing is why we are all here....... or should be.
> .
> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
> news:BI4Ue.266$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

Do the math. 75% of 225 and 70% of 235 are only different by 4.25mm in the
height of one sidewall. Surely this is not a significant difference.




"Billy Ray" <Billy_Ray@SPAMfuse.net> wrote in message
news:e5b10$4320e00b$d8449845$19481@FUSE.NET...
> It depends on where you plan to drive.
>
> On the road, or in sand, you will have increased lateral traction from the
> wider tire. Off road, in snow or mud, you will have better forward
> traction.
>
> Another consideration is your vehicle. A Grand Cherokee was not designed
> for maximum on-road traction. The 75 series tire will probably provide
> more traction than the Grand could handle given its high center of
> gravity.
>
> A further consideration of tire type. You will have a better off-road
> selection with the 75 series and a better selection of on-road tires with
> the 70 series.
>
> A final consideration in the discourse is appearance. There are different
> standards for 'city' and 'country' Jeeps.
>
> Conclusion:
> What are your priorities?
> --
> .
> Billy_Ray@SPAM.fuse.net (remove SPAM)
> 2002 Jeep WJ 4 Liter Automatic
> Brilliant Black Crystal Pearl Coat
> Sharing is why we are all here....... or should be.
> .
> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
> news:BI4Ue.266$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

Do the math. 75% of 225 and 70% of 235 are only different by 4.25mm in the
height of one sidewall. Surely this is not a significant difference.




"Billy Ray" <Billy_Ray@SPAMfuse.net> wrote in message
news:e5b10$4320e00b$d8449845$19481@FUSE.NET...
> It depends on where you plan to drive.
>
> On the road, or in sand, you will have increased lateral traction from the
> wider tire. Off road, in snow or mud, you will have better forward
> traction.
>
> Another consideration is your vehicle. A Grand Cherokee was not designed
> for maximum on-road traction. The 75 series tire will probably provide
> more traction than the Grand could handle given its high center of
> gravity.
>
> A further consideration of tire type. You will have a better off-road
> selection with the 75 series and a better selection of on-road tires with
> the 70 series.
>
> A final consideration in the discourse is appearance. There are different
> standards for 'city' and 'country' Jeeps.
>
> Conclusion:
> What are your priorities?
> --
> .
> Billy_Ray@SPAM.fuse.net (remove SPAM)
> 2002 Jeep WJ 4 Liter Automatic
> Brilliant Black Crystal Pearl Coat
> Sharing is why we are all here....... or should be.
> .
> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
> news:BI4Ue.266$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)
>>
>>
>>
>
>

Billy Ray

You are somewhat correct as far as it goes. 75% of 225 mm is 168.75 mm and
70% of 245 mm is 171.5 mm for a difference of 2.75 mm

There is a difference in the lower profile tires which hasn't been mentioned
in sidewall stiffness (roll) which affects handling on-road but as I
mentioned before the suspension of a Grand cannot really utilize the benefit
due to its high center of gravity.

The poster's original question was, I believe, would there be any
interference problem in his WJ. My answer then and now is No, there is no
problem as both are listed in the manual and on the door placard as
alternates.

FWIW I recently put 225-75X16s on my WJ but my original thought was to get
the 245-70-16s

--
..
Billy_Ray@SPAM.fuse.net (remove SPAM)
2002 Jeep WJ 4 Liter Automatic
Brilliant Black Crystal Pearl Coat
Sharing is why we are all here....... or should be.


..
"J Strickland" <spam@nospam.net> wrote in message
news:HOadnc2nIv6YTLzeRVn-qQ@ez2.net...
> Do the math. 75% of 225 and 70% of 235 are only different by 4.25mm in the
> height of one sidewall. Surely this is not a significant difference.
>
>
>
>
> "Billy Ray" <Billy_Ray@SPAMfuse.net> wrote in message
> news:e5b10$4320e00b$d8449845$19481@FUSE.NET...
>> It depends on where you plan to drive.
>>
>> On the road, or in sand, you will have increased lateral traction from
>> the wider tire. Off road, in snow or mud, you will have better forward
>> traction.
>>
>> Another consideration is your vehicle. A Grand Cherokee was not designed
>> for maximum on-road traction. The 75 series tire will probably provide
>> more traction than the Grand could handle given its high center of
>> gravity.
>>
>> A further consideration of tire type. You will have a better off-road
>> selection with the 75 series and a better selection of on-road tires with
>> the 70 series.
>>
>> A final consideration in the discourse is appearance. There are
>> different standards for 'city' and 'country' Jeeps.
>>
>> Conclusion:
>> What are your priorities?
>> --
>> .
>> Billy_Ray@SPAM.fuse.net (remove SPAM)
>> 2002 Jeep WJ 4 Liter Automatic
>> Brilliant Black Crystal Pearl Coat
>> Sharing is why we are all here....... or should be.
>> .
>> "Phil Schuman" <pschuman_NO_SPAM_ME@interserv.com> wrote in message
>> news:BI4Ue.266$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)
>>>
>>>
>>>
>>
>>
>
>