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[taratorko]

Will a 225/40/18 tire fit the stock 18x8.5 rear wheels? I am planning to use the stock wheels for winter drive since they are already scratched, but I am not clear if I will be able to put on the rear wheel the same size tire as the front.

If it fits, could the wider rear wheel cause any problems on snow/ice (as long as I have the same tire on the front and the rear)?

Thanks.

[JeffL]

yes. I run 225/40/18 snow tires all around on my factory 189's for the winter. They fit fine on the rear 8.5 inch wheels.

[taratorko]

Thanks

[Malek@MRF]

225 on an 8.5 inch wide wheel is unsafe and not recommended. 235 is the minimum.

[CirrusSR22]

Your tire manufacturer's website, as well as tirerack.com, will list approved rims widths for each tire.

[david @ eas]

Yeah you can run a 225 on a 8.5" wheel. It'll be a bit stretched but 1 series guys do it, E36 guys do it all the time. No worries, it's fine to run, just watch out for those curbs

[GregL]

Originally Posted by Malekreza11

225 on an 8.5 inch wide wheel is unsafe and not recommended. 235 is the minimum.

225/40/18 tires are generally designed to be mounted on wheels up to 9" wide, it's perfectly fine. I myself run 235/35/19 on 9.5" rears.

[VMRWheels]

Originally Posted by jurrian @ eas

Yeah you can run a 225 on a 8.5" wheel. It'll be a bit stretched but 1 series guys do it, E36 guys do it all the time. No worries, it's fine to run, just watch out for those curbs

+1. We have done a handful of 225 on 8.5" combo's without a problem.

-Charles@VMRWheels

[Malek@MRF]

Yes it is possible to do. I have done it in the past.

However, it is not recommended by most tire manufacturers.

[GregL]

Originally Posted by Malekreza11

Yes it is possible to do. I have done it in the past.

However, it is not recommended by most tire manufacturers.

Why not? The rim width range is 7.5-9" for this size. With companies so afraid of liability in this day and age, I don't see them publishing compatible rim widths unless it's 100% safe to do so.

[taratorko]

Going for Nokian's. Manufacturer's site states that 225/40/18 can be installed on 7.5 - 9 inches wide wheels (8" native). So I should be good to go. Thanks for the tip on checking the website

[Malek@MRF]

Originally Posted by GregL

Why not? The rim width range is 7.5-9" for this size. With companies so afraid of liability in this day and age, I don't see them publishing compatible rim widths unless it's 100% safe to do so.

Most tires are different.. With Falkens and tires that naturally are narrow and stretched, it is very possible. On other higher end tires, this is generally not recommended..

If you look at their recommended width, it will say so.

In general, stretching tires is not recommended. IMO it doesn't look good either even if you don't consider the performance degradation.

[GregL]

Originally Posted by Malekreza11

Most tires are different.. With Falkens and tires that naturally are narrow and stretched, it is very possible. On other higher end tires, this is generally not recommended..

If you look at their recommended width, it will say so.

In general, stretching tires is not recommended. IMO it doesn't look good either even if you don't consider the performance degradation.

I don't mean to argue, but where can I find this information? My understanding is that the whole range is considered recommended, while the single width published in charts is there as an industry standard measuring requirement with which the other figures are generated.

Also while I agree that stretching tires is not recommended, my definition is that as long as it's within the rim width range it's not a stretch as the bead still sits perfectly on any rim within that range. This is what I call a stretch:

[Peter@VMRWheels]

Wow thats a stretched tire! In general, the "information" you are looking for will mostly be based on hearsay/advice from experienced vendors and enthusiasts.

With charts and recommendation sheets already being considered, a Kumho ECSTA SPT is noticeably wider than a Bridgestone Potenza series tire.

In this particular example, a 225/40/18 tire on a 18x8.5" wheel - the Kumho SPT will not look stretched whatsoever, while a Potenza will have that "rounded" look where the rim face might even stick out beyond the side wall. This observation is based on our experience in working with these wheels/tires on a day to day basis.

Originally Posted by GregL

I don't mean to argue, but where can I find this information? My understanding is that the whole range is considered recommended, while the single width published in charts is there as an industry standard measuring requirement with which the other figures are generated.

Also while I agree that stretching tires is not recommended, my definition is that as long as it's within the rim width range it's not a stretch as the bead still sits perfectly on any rim within that range. This is what I call a stretch:

[remmib]

Yes, 225/40 fits on 8.5" wide wheels.

[Malek@MRF]

Originally Posted by Peter@VMRWheels

Wow thats a stretched tire! In general, the "information" you are looking for will mostly be based on hearsay/advice from experienced vendors and enthusiasts.

With charts and recommendation sheets already being considered, a Kumho ECSTA SPT is noticeably wider than a Bridgestone Potenza series tire.

In this particular example, a 225/40/18 tire on a 18x8.5" wheel - the Kumho SPT will not look stretched whatsoever, while a Potenza will have that "rounded" look where the rim face might even stick out beyond the side wall. This observation is based on our experience in working with these wheels/tires on a day to day basis.

I agree.. SPT's do run a little wide. They also have a more squared sidewall.

This information can all be found by the tire manufacturer.. Look through their website.

Again, I will say it.. 225 on an 8.5 is possible.. I have done it myself.. However, the performance is pure garbage and it is UNSAFE. I had an instance where the tire collapsed through a turn and the rim edge came into contact with the ground. Why? Tire was not wide enough.

[JeffL]

This is for a snow set up. Not extreme performance driving. It will be 100% fine. Looking at mine you can't visibly tell which wheel is an 8 and which is an 8.5.

[GregL]

Originally Posted by Malekreza11

This information can all be found by the tire manufacturer.. Look through their website.

Again, I will say it.. 225 on an 8.5 is possible.. I have done it myself.. However, the performance is pure garbage and it is UNSAFE. I had an instance where the tire collapsed through a turn and the rim edge came into contact with the ground. Why? Tire was not wide enough.

I'm really sorry to keep dragging this on, but again, where? What I see on the charts is the approved rim width range, and then a measured rim width with which the other measurements must comply for the sake of industry standards for each particular size. I fail to find any manufacturer's website that states they recommend any 1 particular width out of that range along with a note that any of the other approved sizes may be unsafe or perform any less. I can't find any mention of this on the Tire Rack's info section either.

But please don't get me wrong, I completely agree with Peter in that someone with the experience to have seen many difference brand tires in the same size will know firsthand how they sit differently on the same rim despite being the same size. However I'm talking about what information the manufacturers make available to the public who don't have access to this kind of inside knowledge.