SoR

iTrader: (19)

I was looking to buy some new rims for my car and the options for the wheels I like are:

17x8" (like stock)
17x9"
18x9"

If I calculate the revolutions per mile for different tire sizes, the only ones that come extremely close are:

235/45-17 (for stock size and 9")
265/40-17 (17x9" rims)
235/40-18 (18x9" ??? )
265/35-18 (18x9" rims)

265 tires actually have 9.5" as a recommended rim size and I'm not sure if they would actually fit the 9" rim and even better, would they fit on the Evo without rubbing?
The spec sheet for Toyo T1-S says 235/40-18 is for 8.5" rims and I'm not sure if they would also fit my (future) 9" rims.
Every other size has significant increase or decrease in rev/mile.

To me 265 looks too wide and I don't see a benefit of moving to a wider/bigger rim if the tire has to either stay the same or seriously impair performance.

For people that do road courses or have experience with that kind of racing, what rim size and tires would you recommend?
Thanks

erioshi

You are defenitely on the right track here, but another thing to remember is that different tire vendors may have different recommended rim sizes for a given tire size. It sounds odd, but since each tire has it's own "receipe" for a sidewall, they differ in the amount of flex that is ok, and the shape of the sidewall (and therefore overall tire width).

One thing you didn't mention is if your car is stock, lowered or has coilovers. All of those will affect wheel size and clearence. Start with the tire and size you want to use, and choose a rim width based on that. One other note, but sure to compare the tire vendor's revolutions per mile figure to that of the stock Advans to verify that the size is similiar. Again, different tires can vary slightly despite being the same size.

I know I would like wider wheels and tires, especially at the track. Good luck!

ColinL

I dunno, 265 seems damn big without modifying the sheetmetal more than a little. 245 is plenty. I'd use a 245/40-17 on a 17x8.5 or 17x9.

Neal@tirerack

iTrader: (25)

People I've spoken with, and sold product to, have had better luck with the 245/40-17's. Some have tried 255's and 265's, but usually end up sending them back because they rubbed.

SoR

iTrader: (19)

Unfortunately you guys don't sell Toyo tires which I had good experience with.
I was looking at T1-S for the street and maybe RA-1 for the track.
I've been reading here on Evom that Kumho MX are good for the street as well for less $$.
I would like to stay away from stock Advans. They're very nice but also very expensive.

From tirerack and Toyo website...

Stock Advans are 822 revs/mile.
Toyo T1-S revs/mile:
245/40-17 - 839
255/40-17 - 830
235/45-17 - 818
245/35-18 - 839
255/35-18 - 830
235/40-18 - 818

Toyo RA-1 revs/mile:
235/45-17 - 834
255/40-17 - 828
and I didn't find anything for 18" rims for RA-1s (?!)

I don't know the info on other tires but from above (accuracy wise) my best bet would be going with stock size rims and 9" width so I can fit either stock tire specs or maybe 255/40 for the track.

At this point my car is not lowered. I would look into doing that once I choose the rims and tires I'm gonna go with.
Any suggestions? Experiences with18s versus 17s for the road course?

SoR

iTrader: (19)

No road course guys? I know I live in the drag-land but someone has to know...

sophis

iTrader: (7)

I have road raced on 17x9 w/ 245/45/17 Falken Azenis tires at Willow Springs and it does rub/well ate away part of my inner plastic fender wall on the front passenger side (well the taller sidewall of the 245/45 did not help). Whats the offset on those 17x9" rims? 265 on a 17x9 will most likely rub in the back (depending on camber) and in the front inner fender wall. However, as erioshi mentioned, different tire manufacturers recommend different settings. For a 17x9" rim, I would recommend either 245/40 or 255/40. A lot depends on the offset of the wheels and how much negative camber you are going to run.

SoR

iTrader: (19)

Offset for the Buddy Club QF rims are +35 for both 17x9" and 18x9".
Are you still running 17x9 or did you switch to something else?
thx

MalibuJack

iTrader: (5)

Actually the stock 235 advans ate up my inner fender also.. I think the 245-40-18's are only a few mm taller than the 235-45-17 size I have spoken to several people who have used this size with satisfactory results.

sophis

iTrader: (7)

The +35 along with the 245/40/17 should be fine. But I am surprised that with 17x9 with stock advan rubbed MailbuJack. I am trying to sell my 5zigen rims and tires right now so I am running the stock rims right now.

erioshi

OT on fender liner rubbing:

Interesting, the only time I've ever had rubbing (even with a 2" drop) was when when my car's suspension tuning was way out of whack. I had set it up using ride height to dial iin my coilovers; I could tell it wasn't right, but didn't have the scales to cornerweight it. At a "test & tune" day at a local track, my passenger heard a slight rubbing from the right front.

A couple of days later I sent the car in for cornerweighting; it was way out of balance. After being properly corner weighted, the car kept the same side lowered height, but no more rubbing; even in 130+ mph corners.

One other note; my coilovers provide significantly more clearence to the springs than the stock suspension did.

ez76

iTrader: (5)

Reviving this thread to ask:

How do you figure out the optimal wheel width for a tire width, or put the other way, the optimal tire width for a given wheel width (to make it most "square")?

If you don't know the manufacturer's recommendation, is there some formula e.g. "90% of the tire width is the optimal rim width?"

erioshi

I've heard that the tire width and and rim width should be within about 1/2" of each other. I'm sure there is better information out there, but I usually just google until I can find some reliable published specs and recomended rim sizes.