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Alternate front tires sizes: 235/40-17 and 205/40-17

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Here are the commonly used combinations below, roughly from best to worst:

235/40-17 & 275/40-17 (Track sizes, front rubbing at full lock, lasts longer before overheating)

Falken RT615K+
Toyo R1R

Toyo RA1
Toyo R888R
Toyo RR
BFG G-Force R1S


235/40-17 & 265/35-18 (rubbing up front, more front grip)

Yokohama AD08R
Dunlop ZIII
Falken RT615K+

Toyo R888R


235/40-17 & 275/35-18 (rubbing up front, Common track setup, good wear/balance)

Dunlop ZIII
Falken RT615K+

Toyo RA1
Toyo R888R
Toyo RR
BFGoodrich G-Force R1

Somewhat of a beginner question from me. When you say using a 235/40-17 tire up front will obviously rub, do people go ahead and run that size anyways for a track-only tire since you might not care as much about rubbing, or would you put on spacers if possible to make more room? Or only possible with wider fenders?

Unfortunately it looks like the 17" aspect ratio is the limiting factor since half the field is 215/45-17 instead of 215/40-17, which eliminates the ExtremeContact Sports, Indy 500s, Potenza S-04s, and a bunch of others. Kind of a shame for just a small difference in aspect ratio.

Thanks @RYU for the note on the Maxxis VR-1 S2's, they look like a great all-around deal. Coincidentally the Maxxis US HQ is ~20 mins away from me. The VR-1 tread pattern looks very similar to the Direzza ZIIIs for a bit less money but no 2-year road hazard warranty from Tire Rack. Any thoughts on the VR-1s vs. Direzzas?
 
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Somewhat of a beginner question from me. When you say using a 235/40-17 tire up front will obviously rub, do people go ahead and run that size anyways for a track-only tire since you might not care as much about rubbing, or would you put on spacers if possible to make more room? Or only possible with wider fenders?

Unfortunately it looks like the 17" aspect ratio is the limiting factor since half the field is 215/45-17 instead of 215/40-17, which eliminates the ExtremeContact Sports, Indy 500s, Potenza S-04s, and a bunch of others. Kind of a shame for just a small difference in aspect ratio.

Thanks @RYU for the note on the Maxxis VR-1 S2's, they look like a great all-around deal. Coincidentally the Maxxis US HQ is ~20 mins away from me. The VR-1 tread pattern looks very similar to the Direzza ZIIIs for a bit less money but no 2-year road hazard warranty from Tire Rack. Any thoughts on the VR-1s vs. Direzzas?

The 235 width front tires are popular with track-focused owners who are constantly in search of more front grip. Because you're never really at full opposite-lock on the racing circuit, they tolerate the rubbing, since it only happens when maneuvering the car in and out of the pits/parking area. The real, permanent solution is to use the DF wider fenders like [MENTION=16531]stuntman[/MENTION] did in his article. This will permit you to use wheel offsets/spacers that move the inside edge of the tire further away from the wheel well without endangering your fenders. I'm not sure there is an offset/spacer option that will provide a rub-free solution for 235's on the factory wheel wells/fenders. But I do know that the car will tolerate more tire the closer you are to the stock ride height.
 
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Although I'm long retired from track events, I understand those folks wanting wider tires- on both ends.

But for street use where the OEM 215/40-17 size is not available, 205/40-17 seems a better choice to me than the too tall 215/45-17.

(These dimensions are from the Yoko A052, where all sizes are conveniently available.....)
.
 

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^^^^^^^^
Makes me think that the 205/40R17 fronts using Firestone Indy 500 tires for my 2004 could work out pretty well (Firestone does not offer 215/40R17). I'm leaning pretty hard in that direction for some new rubber for a new set of OEM replica wheels. That, and the Indy 500 tire tread looks pretty sexy to me, and at a reasonable price point.
 
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The 235 width front tires are popular with track-focused owners who are constantly in search of more front grip. Because you're never really at full opposite-lock on the racing circuit, they tolerate the rubbing, since it only happens when maneuvering the car in and out of the pits/parking area. The real, permanent solution is to use the DF wider fenders like @stuntman did in his article. This will permit you to use wheel offsets/spacers that move the inside edge of the tire further away from the wheel well without endangering your fenders. I'm not sure there is an offset/spacer option that will provide a rub-free solution for 235's on the factory wheel wells/fenders. But I do know that the car will tolerate more tire the closer you are to the stock ride height.

That makes sense. If I were to do something like that I'd have to budget for another dedicated wheel set ;).



Although I'm long retired from track events, I understand those folks wanting wider tires- on both ends.

But for street use where the OEM 215/40-17 size is not available, 205/40-17 seems a better choice to me than the too tall 215/45-17.

(These dimensions are from the Yoko A052, where all sizes are conveniently available.....)
.

^^^^^^^^
Makes me think that the 205/40R17 fronts using Firestone Indy 500 tires for my 2004 could work out pretty well (Firestone does not offer 215/40R17). I'm leaning pretty hard in that direction for some new rubber for a new set of OEM replica wheels. That, and the Indy 500 tire tread looks pretty sexy to me, and at a reasonable price point.

So you would have a bit of stretch on an 8" wheel since there's only a 0.3" width difference? Looking up some examples it seems reasonable while keeping the same aspect ratio. Though the 205/40-17 Indy 500's are slightly smaller than the A052's in that chart so the stretch might be more pronounced, the example pics I can find with 8" wheels and 205/40-17 Indy 500's look to be a mid-level stretch. Example https://www.fitmentindustries.com/w...16-ford-fiesta-rota-titan-hr-lowering-springs.
 
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for 235's to work on the front assuming proper offset the rubbing is on the inside well not the fender edge. Also you have to remove the ribbed plastic fan shrouds...
 
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I recently got a set of Firestones for the S2000, and I'm pretty impressed so far. Didn't really get a chance to push them much, but I'm sure they will be fine for the street. I'd consider a set for the NSX. I think they would be less likely to pick up stones when hot as the Z11s. I expect they will wear a bit better also.
 
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I have 205/45/16 Conti Extreme on my 7" front wheels (where the OEM calls for 215's) and there is no stretch at all. The sidewalls are stacked perfectly vertically over the edge of the rim, which is what I understand from Billy's article as the ideal setup for handling. I'll update with a pic tonight
 
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So you would have a bit of stretch on an 8" wheel since there's only a 0.3" width difference? Looking up some examples it seems reasonable while keeping the same aspect ratio. Though the 205/40-17 Indy 500's are slightly smaller than the A052's in that chart so the stretch might be more pronounced, the example pics I can find with 8" wheels and 205/40-17 Indy 500's look to be a mid-level stretch.

Since the specified rim width for 205/40-17 seems to be 7" to 8", I wouldn't characterize its use on an 8" rim as a "stretch," which normally means a tire being used on a wider-than-recommended rim.

And with a width difference of only .3", that means each side of the tire is only offset inward .15", about 1/8". Pretty tiny difference.
 
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I agree, the Indy 500's have a 7-8" recommended wheel width so I'm sure it would be fine to use. I've also seen some cases where the recommended max width is reduced to 7.5", and pictures with the same specs that make the tire look more stretched than I would expect, but that might be down to variances in tire and wheel brands.

From Billy's tire selection sticky, he suggests tires ~0.5" narrower than the wheel width or the same as the wheel width for ideal sidewall preload and handling, so 7.5" tread width to an 8" wheel. He calls this a slight stretch, and with the Indy 500's 7.3" tread width I would call that a slight stretch.

Right now I'm actually torn between the Indy 500's and the Maxxis VR-1's but leaning more to the 500's, they edge out the Direzza's (if Direzza ~= VR-1) in all of Tire Rack's comparison categories including price and treadwear.
 
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Good to read all the conversation regarding stretch for the Indy 500's. Considering that the 02+ 17" front wheels are 7.5" wide (not 8" wide), from what I read above the 205/40R17 tires with 7.3" tread and a 7.5" wide wheel should look fine. I bet it's not perfect (since it's not 215/40R17 spec) but seems like it should be very close. Will be interested in seeing what Honcho's pic looks like (even though it is on a 16" rim).
 
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For a 7.5" wheel I think the 500's would be right within the optimal tread width range. It might actually be better for you than a 215/40-17 tire, the Direzzas for example have 7.8" tread width which is actually 0.3" above what Billy considers ideal for handling. To me a 205/40-17 would actually be the default tire choice in that case.

For my purposes (17x8" Advan RGIII), the difference in width is 0.7" which is a bit more pronounced but like centerpunch says is still within the 500's mfg. recommended wheel widths. Some googling says there might be trouble finding chain stores that will actually mount them though, or make you promise they're for "track use only". No way I'm taking my new wheels to a chain store anyways..

Honcho posted this in his build thread, looks perfect to me. The Contis have exactly 7" tread width on those 7" wheels which is square anyways. They make a 205/45-17 but I'm not sure if you would end up rubbing with the 45 aspect sidewalls.
ACtC-3ca7wIAhdiLRx4TEbjlvAFukb4vNdwA0KpmYhE2iP-9JaVsKvzqQpqqUujPi8ip4S5lcSLLZM3sQudf2QVxr02E9nvB7y5otVa_fAJM54rKIsEd7XUvaOHxmdBDIRvSTQH-7DMb2r6LYiYBc8tsPFdR=w966-h1287-no
 
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Sorry guys- I had a class action mediation that ran to almost 10 pm last night, so I basically went home and then to bed. I'll try to get those pics tonight.
 
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For a 7.5" wheel I think the 500's would be right within the optimal tread width range. It might actually be better for you than a 215/40-17 tire, the Direzzas for example have 7.8" tread width which is actually 0.3" above what Billy considers ideal for handling. To me a 205/40-17 would actually be the default tire choice in that case.

For my purposes (17x8" Advan RGIII), the difference in width is 0.7" which is a bit more pronounced but like centerpunch says is still within the 500's mfg. recommended wheel widths. Some googling says there might be trouble finding chain stores that will actually mount them though, or make you promise they're for "track use only". No way I'm taking my new wheels to a chain store anyways..

Honcho posted this in his build thread, looks perfect to me. The Contis have exactly 7" tread width on those 7" wheels which is square anyways. They make a 205/45-17 but I'm not sure if you would end up rubbing with the 45 aspect sidewalls.
ACtC-3ca7wIAhdiLRx4TEbjlvAFukb4vNdwA0KpmYhE2iP-9JaVsKvzqQpqqUujPi8ip4S5lcSLLZM3sQudf2QVxr02E9nvB7y5otVa_fAJM54rKIsEd7XUvaOHxmdBDIRvSTQH-7DMb2r6LYiYBc8tsPFdR=w966-h1287-no

Good to know. Nice looking aftermarket rims. :)

As for "chain stores", we have a Firestone that uses a touch-less tire installation machine. Very expensive equipment. I plan to use that facility to install new tires on my new rims this Spring. I've used their service to install winter tires on winter rims that I have for the wife's 718. I feel comfortable with that store and glad we have one in the area.
 
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Running a tire with a tread with 0.5" narrower than the wheel is to optimize handling, response, and grip FOR THAT TIRE SIZE.

IE: When selecting a WHEEL, if you want a given 215 width tire that has a 7.5" treadwidth, then pick a 8" wheel.


If you already have a 7.5" wheel:
-Then you'll reduce overall grip by choosing a 7" tire over a 7.5" tire, but the 7" will have better steering response.


I hope that helps clarify things.
 
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***MODERATOR NOTE***

Created a new thread for this discussion, since it was not really about 17" or 18" wheels/tires.

As promised, here are some fitment pictures. The tire is stacked directly over the side of the rim. These are 7" wheels and 205/45/16 Continental ECS.

ACtC-3dsOgpSntg-2DJ4P6SyX2QKZLt8KEhNrqrbm0N2G6hKL3K2pay7NJguQiNr3J_NTBscbi1pBxOnPMYGeESaTSWQK-FrBwbZhlrCZdjOLLRYGMEL5LAjVqpZuiF0yNRpSYnhemvZRfDWH-_s9mBazhS0=w973-h1297-no


ACtC-3duwfVGQdVaPMER_cgYPOvSvr9FFVaUsdc3KFiVK-B7Ch19iIzkAT1rDW136reCWF0L3fzxLUXiTfKm1GFud1mxFpZKAu6hFTDnB7Kj43-HsSlhzu91-y7B3QyYDHlE2_gZMqpSKsMcoYuOftICx-Hl=w1730-h1297-no


ACtC-3cNTnb7hJ0CxvOI7BaYB-jItiYFmHPYX2hciHjrB7TSKmY5oTuLrvhTB9KOeeO-YfQzauft851KK437SHRf6vdZFgPHlzUGf5kbKls4uyNJ4XIF3oYR-PHsrtNkNp5i0FYTTocHhYC1MMfhKGs2yWHl=w1730-h1297-no
 
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Thanks all. I think I'm understanding this better.

So the 205/40-17, 7.3" TW Indy 500's will have less overall grip than the same tire at 215/40-17, ~7.8" TW (if they made that size), but the former will have somewhat better steering response? I assume this also means the 205 might have more understeering tendency?

I keep flip-flopping between the 500's and VR-1's, but I might just go 500's since they should last longer. It would be another few months at least before I try any real performance driving and I probably shouldn't be buying more expensive tires to shave off theoretical seconds for my first time going ;)
 
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Thanks all. I think I'm understanding this better.

So the 205/40-17, 7.3" TW Indy 500's will have less overall grip than the same tire at 215/40-17, ~7.8" TW (if they made that size), but the former will have somewhat better steering response? I assume this also means the 205 might have more understeering tendency?

I keep flip-flopping between the 500's and VR-1's, but I might just go 500's since they should last longer. It would be another few months at least before I try any real performance driving and I probably shouldn't be buying more expensive tires to shave off theoretical seconds for my first time going ;)

Yes, because the contact patch is smaller on the 205's versus the 215's, you will have less overall grip and the car may push slightly more, since there is less friction for steering input. However, at this level of difference (0.5"), only a driver at Billy's level is honestly going to be able to tell the difference.
 
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Here are some pics of my setup for reference.

Firehawk Indy 500's in 205/40-17 and 265/35-18
Advan RGIII in 17x8 +38 and 18x10 +35

Front wheels in front, rears in back. The fronts have a decent stretch (7.3" tread width on 8" wheel) but reasonable. The RGIII's protruding lip makes it seem more stretched than it is. The rears are close to square with a very slight stretch.
x3ow01C.jpg


Top down of front wheel.
t3LjpMv.jpg
 
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