I am planning to purchase new rims and tires for the track. I will plan on going to slicks in the future (if my ability ever gets me there). I intend to go with 265/30-18 up front and 315/30-18 rears. The rolling diameters are 25.2 and 25.5 respectively, so there should be no problem with the 4wd system. I know I will have to mold the front wheel wells in order to avoid rubbing. I am hoping that the big fronts will last longer and also take away some of the understeer.

For rims, I will probably go with Fikse or Kinesis as I want strong and light (BBS mag are a little brittle and I don't need the last ounces of weight reduction). I am thinking of going with 9.5" width up front, and 11" in the rear.

Any input or suggestions?

 

Why not go with 12" wheels in the back? Since you'd be using 315/30's and that's a GT2 size.

 

The 12" would be heavier and the recommended width on the fronts is 9-10.5 so 9.5 should be OK, and rears, 10.5-11.5 in the rear, I though 11 or maybe 11.5 would be good in the rear. It's a little strange P went with the 12 when that is outside of Michelins recommendations.

 

A couple of suggestions...go with 275's in front rather than 265's. Much better balanced handling. I am told that this is mainly from the fact that these fronts are just slightly larger diameter than the 315 rears rather than just slightly smaller. Of course the extra width cannot hurt. Go with 10 inch width front rims. You will have to remove the plastic fender liners and have some protective shields fabbed up (I had it done in aluminum) to protect the radiators, etc.

 

John:

MPSC's aren't available in 275's. Can you show me a shot of your shields?

 

I used PS-2's...you are correct that the MPSC's do not come in the 275 size. I have a set of 265 and 315 MPSC's on 9.5 and 12 rims (Fikse Profil 10)...interested?

I will try to post some pics of the install this weekend.

 

I'd get 12" rear rims, that way you may be able to go to 325 or 335 width rear tires in the future.

 

I didnt want to go up to 335s on my car so I opted for 9 and 11's. This will let me run up to 265 and 315s comfortably. I am really hoping that Toyo comes out with some new sizes soon so that I can run the RA1s in that combo. Right now I have 235/285 SSRs. I'll see how well they work on the track.

 

John has me taken care of.

 

Tim,

Do you know the equation for calculating the rolling diameter? TIA

Lou

 

I think it really depends upon the manufacturer so they get manuf specs. I got it from tire rack.

 

Wider wheels will improve handling as the tires will have less roll. I would go with the widest wheels possible, not the widest possible tires.