Difference between P225x75R15 and P235x75R15 on SUV

[Henning Schr?der]

I'm on Tire Rack and need to make a choice to help a friend. What's the *practical* difference of 10mm wider tread?

1. This SUV is a dozen years old & has never been off road
2. This SUV is used like a car & never carries a heavy load
3. What matters to the owner is economy & safety

From the standpoint of economy (e.g., miles per tire), I don't know if a 10mm wider tire will last longer or shorter. Do you?

From safety, I "guess" that 10mm more of tread width is safer, but the driver is a little old lady (literally) in a no-snow state, so, traction isn't really a problem.

Any idea what's best?

Stock OEM is 225x75R15 Current tires are 235x75R15 but I'm replacing all four.

What difference (practically) does 10mm make?

[bob_villain]

This is your 1st post...are you a nymshifter?

[Henning Schr?der]

bob_villain auf Sun, 19 Jun 2016 16:52:17 -0700 geschrieben ...

I have plenty of posts, just not to this newsgroup because I don't ask questions about buying parts.

I'm all over the mobile device newsgroups, for example. And, even if I were a "nym shifter", the question is a perfectly valid question.

Do you have a problem with the question?

Or are you just a paranoid Internet Nazi with hugely misplaced Draconian ideas that have no absolutely basis in reality?

[Paul in Houston TX]

225 & 235 are section widths, not tread width. Try to keep the tread width about the same as the wheel width. Measure the wheel bead to bead width then look up tables that list acceptable section widths for that wheel. Or, ask the tire place.

[Chet Kincaid]

Wouldn't changing require different wheels? Why not go with the size you already have?

[Steve W.]

For this use, None. The only thing that would be different is that the

235 tire is about 1/2 inch in diameter larger. The speedometer will read slower than actual speed.

Specification Sidewall Radius Diameter Circumference Difference

225/75-15 6.6in 14.1in 28.3in 88.9in 0% 235/75-15 6.9in 14.4in 28.9in 90.7in 2.1%

[Doug Miller]

Chet Kincaid wrote in news:WIydnc9K27flqPrKnZ2dnUU7- [e-mail]:

That's not enough of a difference in width to require different wheels.

[clare]

7.5 mm difference in hight (rolling diameter). It will make the speedo read just a tiny bit low. The difference in treadlife (increase) and traction (increase) will be so small as to be virtually undetectible by the driver.

[clare]

unless there is a clearance problem, a 235 will fit the same wheel as the 225. Only 10mm width difference, and 7.5mm diameter - or3.75mm standing height. I have 235 winter tires and 225 summer tires on my pickup

[trader_4]

Not much. With that small difference they will fit. In terms of how long they last, won't make any difference. I recall doing some calcs back in college that showed about one molecule worth of rubber comes off each revolution. Certainly that small difference isn't going to affect how many miles they last. If snow is a consideration, wider is usually worse for traction, because the tire can't dig throw the snow to the pavement as easily. Wider is also more susceptible to hydroplaning. But on dry pavement, wider has more traction.

[rbowman]

No.

Some sizes are more readily available or cheaper.

[rbowman]

Which is cheapest or is available in the brand/style you want? Like others have said there isn't enough difference to matter.

[Gordon Shumway]

You say you are on Tire Rack -- Call them, their people are there for questions just like yours.

[Henning Schr?der]

Chet Kincaid auf Sun, 19 Jun 2016 19:14:48 -0500 geschrieben ...

It's only a few millimeters. The wheels are the same for both widths.

[Henning Schr?der]

Steve W. auf Sun, 19 Jun 2016 20:44:05 -0400 geschrieben ...

Are you sure about the half inch diameter difference? Someone else calculated 7.5mm diameter - or3.75mm in ride height.

There are 25.4 mm in an inch, so half an inch would be more than a dozen millimeters, which isn't what the other guy said on diameter.

[Henning Schr?der]

clare auf Sun, 19 Jun 2016 21:15:26 -0400 geschrieben ...

Someone calculated the ride height to be half that 7.5mm, which is even a smaller difference.

The spare is the larger size, so, I guess the only difference might be when the spare is put on.

Would the extra 10mm width (and about 3.75mm in height) matter when the spare is being used?

[clare]

a basic understanding of tire numbering The 225 or 235 is the tire section width in mm. the 75 (or 70, or

60, or 55) is the aspect ratio - the decimal fraction of the section width that represents the tire hieght.

I DID make an error - the sidewall hight changes by 7.5 mm - so the diameter changes by 15mm - pretty close to 0 .6 inch.

My bad.

[clare]

Only with posi on clean dry pavement. - possibly. - with the spare on the drive axle.

[Henning Schr?der]

clare auf Sun, 19 Jun 2016 22:56:46 -0400 geschrieben ...

How it tire section different than tread width? Someone said they're different. I never used the term "tire section", but, I always thought the

225 or 235 was the width of the tire on the road, which, to me, is the tread width.

Is there a difference between tread width and tire section?

Thanks for confirming the strange math where the height of the tire is listed as an inch percentage of the mm "tire section" width.

So the ride height is a bit more than half an inch difference. That's small (unless the spare is being used, where the spare is the larger width).

[rbowman]

Not noticeable. It's a long story but I run 14" studded tires in the winter, 15" street tires in the summer. The ride height is different and the speedometer is off by about 10% but there are no other problems. I use the GPS speed rather than the speedometer and that is correct.