I'm running 225/50-16 Bridgestone Potenza RE-01 tires on Rota Slipstream 16x6.5 wheels on my 2007 MCS. The tires have a noticable bulge from being on such narrow wheels.

The reason I'm using street tires is that I'm running in a G-Stock Street tire class here in Southern California. I use my car as a daily driver in addition to autocross. FWIW the 225/50-16 is cheaper than other sizes, and my thoughts were along the lines of more rubber for less $$$ is better. Now I'm wondering if more rubber might be less utilized (due to a curved profile on the tread), and heavier than a smaller tire would be and slowing down my autocross times.

I went with 16 inch wheels because the widest rubber I could get on 17's is 225, and that would be no wider than what will fit on 16's.

I would appreciate any input from the wizen fellow AutoX's here.

 

225 is safe. I was running 225/50/15 victoracers on 15x6.5 Konig's last season (we're pretty lenient on some rules for stock classes). I've read somewhere that someone was running 235's on stock rims. If you're worried about rubbing, or if you're getting a little bit, you can easily fix it with a 5mm spacer; that's the maximum allowed.

 

a 225 RE01R is sized like a 235. I'm concerned about running them in 215 on a 7", so I wouldn't recommend a 225 on a 6.5". Look at the manufacturer's site (or tirerack.com) for specs on your size - I doubt it's recommended to go below 7". Can you do it? yes, but it's not ideal

 

Let me correct something here. the Rule is you can run wheels with an offset +/- .25 inches from stock. So this means that with the stock wheels you can run a 6.35mm spacer (1/4 inch)

In the OP case he is running Rota's with a 45mm offset, so he could legally add a 3.35 mm spacer in Stock class. If you found some 72mm offset wheels, you could legally run a 30mm spacer... Not that you would really want to do that.

 

Back on topic. In stock class you can run any size tire you can squeeze onto a stock size wheel. Since you are limited in wheel width it makes sense to try to add more grip by using wider tires. the tradeoff is slightly less crisp response

I will be running my car in our stock street tire class this year, and will most likely be running the 235/40/17 RE-01R on 17x7s. Nice and wide, but with stock height.

 

If you want optimal, IMHO, I'd go with a Yokohama Advan Neova AD07 in 235/40/17 on a 17x7 42mm offset wheel. Or, as Keith mentioned, the Bridgestone re-01r is a good choice too. Kumho is coming out with a new street tire that will be competitive and Toyo(I think) has the new R888(I think), those are worth looking at too if they come out with a 235/40/17 and show to be as good as the Yoko's or Bridgestones. If you decide to stick with 16's, I really think the 225/50/16 is too tall to be optimal. I'd probably rather be on a Bridgestone RE-01R in 205/45/16 since its shorter but it won't be optimal compared to the 17's IMHO. Hopefully the Kumho or Toyo with have a wider/shorter 16, but, I'd guess they might have a 225/45/16 at best, which would be worth considering if the tire proves competitive. ;-) Bottom line is, there are potentially tons of choices, let someone else figure out which tire manufacture is best in the coming months unless you want to spend a ton testing. ;-)

 

Thanks for the responses Guys,

Oasis T: Is there any reason besides being too tall that makes you say these tires are not optimal? I have noticed a definite decrease in feedback when compared to my 40 series OEM run flats, but also a huge increase in traction. Does lack of feedback make the car slower, or just feel slower? I think it does hurt me in the slaloms when I really cant tell what the tires are doing.

For reference I've had these tires for 30 Autocrosses runs and 2K miles of street driving with No rubbing, and this is a G Stock legal tire and wheel.

 

When I started to run my MCS in GS, I used 215/40R16 V710s. Short, and I did not think that the tire was providing the ultimate grip. I then bought 2 - 225/50R16 V710s for the front, and the grip went up a fair bit. Overall, the tire combo was faster, but MAN did the gearing get messed up. The car did not pull anywhere near as hard as previously. I never got any tire rubbing.

I run in Canada, and our courses are apparently much tighter than the average National course. As such, I do not know of a great 16" tire combination, as the 215 and 205 section width tires are probably not enough, but the 225/50s are just too tall. I think that the 225/40R17 is proabably a better GS choice.

When it coems to response times, you just need to anticipate what the tire or car is going to do.

 

I have some 225/45R16 Yokohama Advan 048's on order right now. I'll let you guys know how well they work. When using the stock wheels, this tire is shorter than the stock tire but much wider, I'll just have to see how much they hang off the sides.

 

I have the tires mounted and on the car now! They look GREAT. The 225/45r16 has to be the widest tire you can fit on the rim that is still a hair shorter than the stock one. They hang off the sides a bit, but it is actually less than I expected. I can't believe that others have not tried these tires yet. I know they are expensive, but from my research I believe that they will be very competitive. Plus, if you want, you can put your wheels on at home then drive to the track. If you had Kuhmo's or Hoosiers you could not do this.

 

The 048s are sticky when new but age fast. I had them on the Elise and after several track days they had plenty of tread left but were hard as bricks. Not sure if the 888s are better.

 

That is common with the medium hard compounds that come on the Elise. The medium compound is said to stay soft much longer. I have the medium compound tires so we'll just have to see.

 

Specs for this tire indicate rims from 6"-8" are ok.

http://www.tirerack.com/tires/Spec.j...m%3D25VR6RE01R

 

Not to complicate things, but the question of what size tire is the largest you can get on a rim width will vary with the tire.

Hoosiers have always worked well stuffed on a narrow rim (the CRX guys were running 225s on 5 inch rims), but Kumhos generally hate to be stretched.

Based on the way my RE01Rs are wearing, I think 225 would work on a 6.5'rim.

 

They do fit and I've been using them for DD and AutoX for some time with no rubbing on Rota Slipstream 16X6.5 wheels.