Does anyone know what the widest/best size tire (specifically Kumho V700) is for factory R81 wheels. I'd be using it specifically for autocross. I'm hoping to get Kosei K1's instead, but my be forced to go with used R81's for budget reasons. I know this wheel is a lot narrower than the K1 (5.5" vs. 7", I think). Any help would be appreciated. JR

 

to answer my own question, I believe the size I'm looking at is 205 50 15 for the OEM wheels as opposed to the 225 45 15's that the Kosei K1's could handle.

The question is, if I can get four OEM wheels for the cost of one Kosei, is the performance gain worth the extra money?

That is a question that I'll answer myself, as I continue this discussion later. With myself.

JR

 

Hey Jayar,

The stock R81 7-holes weigh 12 lbs, whereas the Kosei K1s weighs 13.5 lbs, so you are only looking at 1.5 lbs savings -- but it does add up. 1.5 times 4 wheels is 6 lbs times 4 is 24 lbs (since 1 lb savings at the wheel is the equivalent of 4 lbs savings elsewhere on the car). So that is a 24 lbs savings for wheels. Plus you may be able to save a little weight on tires as you would be using a smaller diameter tire, you may save another lb. per tire, who knows, so if so that would be 4 lbs there, and times 4 for 16 lbs total savings on tires. That's a total of 40 lbs.

Now look at the penalty of using the R81s. 225 width versus 205. I personally doubt if that would make up a 40 lb difference. Now look at the difference of whether the 5 and 1/2 inch wide R-81 wheel can handle the 205 Kumho tire very well. Several people have reported they use 205 on that width stock wheel. So, you may want to go for it.

You could opt for an even lighter wheel than the K1 or the R81, such as the SSR Comp or Volk Racing TE-37. Then there's no comparison, except for money issues, which always seem to be the deciding factor.

Have fun!

 

Let me make a correction from my calculations:

what I meant to say was the 1 lb savings is for the width not diameter -- from the 16 lb calculation.

 

Thanks for the detailed response. Definitely have some decisions to make. JR

 

If I were you I'd go with the new Kumho V710 205/50wr15. No need to shave them. If they came in a good 16" size I'd be running them.

 

So you think the V 710's would be better for autox even though they're 20mm narrower than the available V700's? I know the tread pattern is very different, but why do you prefer them? Thanks in advance.

 

>>So you think the V 710's would be better for autox even though they're 20mm narrower than the available V700's? I know the tread pattern is very different, but why do you prefer them? Thanks in advance.

I have heard from other experienced drivers at autocross that the Ecsta V710s are quite good for the money. You should talk to alex@tirerack about the sizes based on the rims you want to use. Wider may not always be better.

http://www.tirerack.com/tires/tires....del=Ecsta+V710
Quote:
ECSTA V710 radials are designed to provide quicker "turn-in" response, as well as increased traction and cornering speeds. In addition to looking like pro-level racing tires, ECSTA V710 tires perform like them as well, trading longevity for performance. Achieving the best performance requires that fresh ECSTA V710 tires be used as their performance level will drop off after a typical race weekend's use.

Victoracer V700
http://www.tirerack.com/tires/tires....ictoRacer+V700