Tire rack test on tire width vs wheel width

[nissanfanatic]

Came across an interesting test from back in August that I thought I'd share on wheel width vs tire width on a 2022 BRZ.

Tires Tested
215/45R17 Bridgestone Potenza RE-71RS
225/45R17 Bridgestone Potenza RE-71RS
245/40R17 Bridgestone Potenza RE-71RS

Wheels Tested
17" x 7" Enkei Racing RPF1 (Black Painted)
17" x 8" Enkei Racing RPF1 (Bright Silver Painted)
17" x 9" Enkei Racing RPF1 (Gold Painted)

https://www.tirerack.com/tires/tests...y.jsp?ttid=296

If this was shared elsewhere I apologize. Searched on here and using a google dork and didn't see this link.

[DarkPira7e]

Actually a very cool comparison. I don't think enough data is provided from people who use unconventional tire/wheel matchups- this is great.

[CedN]

This was a really good test, would be interesting to see how the different combinations (or at least some of them) held up over a days worth of track time.

[Capt Spaulding]

Very enlightening. Many thanks.

[RedReplicant]

Matches up with what Emilio / Hollis has been saying

So what did we learn? The key takeaways are that in the dry, a wider tire does not automatically mean faster lap times. Using a wheel width that properly supports the tire will provide faster laps than a wider tire with very little wheel support. We saw this in our testing - the 215/45R17 tire on the 9" wide wheel was noticeably faster than the much wider 245/40R17 tire on the 7" wide wheel. That's not to say tire width doesn't matter, though, as the 225/45R17 combinations were all faster than the 215/45R17s. The 245/40R17 on the 9" wide wheel was very close to the 225/45R17 on the same wheel. If we could fit a 10" wheel width on our test cars, the pattern seems to indicate a 245 on a 10" would have been the fastest combination of all.

In the wet, a narrower tire is generally faster than a wide one, and once again, more support from the wheel is better. The 215s on the 8s and 215s on the 9s were the fastest combinations in the wet. The 215s on 7s, 225s on 8s, and 225s on 9s were a step back from there, and all the 245s, along with the 225s on 7s, set the slowest wet laps of the test.

[bmacfrs]

So it seems for track use, the most common setup is 245/40-17 on a 17x9.
I dont recall seeing many options for a 17x10 in this bolt pattern as the results suggest would be better for that tire size. I did find this Apex wheel in a 17x9.5.
https://www.apexraceparts.com/store/...brz-wheel.html
Anyone has used those yet?

[glhs386]

Very interesting. I was on the verge of buying yet another set of 245/40s for my 17x9 RPF1s for the next autocross season. Now I'm wondering if 225/45 is the way to go. The fact that they're also less expensive is a nice bonus. I've had friendly debates with people who insist that any tire stretch whatsoever is bad for performance, regardless of how mild. This test seems to throw that theory out the window.

[Capt Spaulding]

Originally Posted by glhs386

Very interesting. I was on the verge of buying yet another set of 245/40s for my 17x9 RPF1s for the next autocross season. Now I'm wondering if 225/45 is the way to go. The fact that they're also less expensive is a nice bonus. I've had friendly debates with people who insist that any tire stretch whatsoever is bad for performance, regardless of how mild. This test seems to throw that theory out the window.

It was eye opening for me. I was in the “never stretch “ camp.

[Grady]

Once again the 225 is the fastest on this car stock. Was surprised to se such a change with wheel width.

Edit, Makes me think about reconsidering changing out my 7.5 width PP wheels. Even tho I have not found a wheel I like better.

[Desertnate]

I might be splitting hairs, but I wonder how a stock 7.5 wheel would do? I've read the article a couple times and didn't see where they spefically stated anything about the size of the control wheel/tire set. I wonder if they used stock size as the control?

I'm going to stay in DS with my Gen 2 car which means a 7.5" wheel. I was planning on going with a 225 tire on a 17" wheel, but I wonder if it is really that much difference over a 215 tire. Fortunately, the Falken 660's are the same price in those sizes right now, so it becomes a performance question.

[Capt Spaulding]

Originally Posted by Desertnate

I might be splitting hairs, but I wonder how a stock 7.5 wheel would do? I've read the article a couple times and didn't see where they spefically stated anything about the size of the control wheel/tire set. I wonder if they used stock size as the control?

I'm going to stay in DS with my Gen 2 car which means a 7.5" wheel. I was planning on going with a 225 tire on a 17" wheel, but I wonder if it is really that much difference over a 215 tire. Fortunately, the Falken 660's are the same price in those sizes right now, so it becomes a performance question.

Based on my reading of the Tire Rack piece, it sounds like the 215 might be slightly quicker but, perhaps, edgier.

[new2subaru]

Originally Posted by Desertnate

I might be splitting hairs, but I wonder how a stock 7.5 wheel would do? I've read the article a couple times and didn't see where they spefically stated anything about the size of the control wheel/tire set. I wonder if they used stock size as the control?

I'm going to stay in DS with my Gen 2 car which means a 7.5" wheel. I was planning on going with a 225 tire on a 17" wheel, but I wonder if it is really that much difference over a 215 tire. Fortunately, the Falken 660's are the same price in those sizes right now, so it becomes a performance question.

I personally don't think it would make much difference unless you're a very experienced/skilled driver. I run a 205 on a 7" wheel. the 205 A052 (and most other 200TW tires) are wider than stock 215's.

[Desertnate]

Originally Posted by Capt Spaulding

Based on my reading of the Tire Rack piece, it sounds like the 215 might be slightly quicker but, perhaps, edgier.

Not sure either when you split the differnce between two of the sizes they tested.

Originally Posted by new2subaru

I personally don't think it would make much difference unless you're a very experienced/skilled driver. I run a 205 on a 7" wheel. the 205 A052 (and most other 200TW tires) are wider than stock 215's.

Thanks. I wasn't sure how noticeable it would be based on the article. I think I lean much closer to the "amateur hack" side of the spectrum than "skilled", so I doubt I'd notice it. I may try a 225 on a 17x7.5 just to see how it feels.

[glhs386]

Originally Posted by Desertnate

I'm going to stay in DS with my Gen 2 car which means a 7.5" wheel. I was planning on going with a 225 tire on a 17" wheel, but I wonder if it is really that much difference over a 215 tire. Fortunately, the Falken 660's are the same price in those sizes right now, so it becomes a performance question.

Based on my measurements most 215s are square on a 7.5" wheel, a 225 would be slightly pinched. Based on the test results, I'd stick with a 215.