I am not a fan of wheel spacers, lets get that out of the way. I bought a set of enkei rpf1's 18x9 +35 and 18x10 +38. The 18x10 fit fine out back but i have factory brembo's and the 18x9 needs a 20mm spacer to clear. Will a 20mm spacer pass tech for hpde/time trial? Whats better bolt on or longer stud spacers? Any spacer I will buy will be hubcentric. I have a set of 4 18x8.5 factory rear track wheels with bfg r1's mounted for track days but in case of rain or laziness I want to be able to just use the rpf1's.

 

Run longer wheel studs with open end lug nuts. That way the tech inspector can see full engagement of the lug nut on the stud. Slip on wheel spacers are very common in road racing.

 

A long time ago, I wrote about not using wheels spacers due to the expansion differences between steel and aluminum. I have since recanted after doing more mental exercising (I'm an engineer).

As long as the spacers are good quality hubcentric pieces, and the studs are long enough to engage at least the diameter of the stud AND you DO NOT torque the nut more than the spec torque rating, you should be fine.

 

John is exactly right about the wheel studs and lug nuts. Look for ARP which are very strong for studs. We run the same wheels with Brembo brakes and needed a 22mm front spacer and dont have any rub on the fenders. Our car is running the SCCA T2 setup and has the shorter stiff springs. You can get the wheel spacers at TC Kline in Hilliard Ohio 614.771.7744.

 

Wow I got responses from probably the most qualified guys on here. Thank you very much. I love calling tc kline, Pete is probably one of the nicest guys I have ever talked to/dealt with. I have their da koni's. As for the spacers I was going to buy H&R drs spacers 20mm and they come with longer studs. I imagine the studs are quality as I think they are tuv approved but I could be wrong. But thanks again for the very helpful responses

 

Great thread I just stumbled upon. . .

Are you guys talking solely about the slip-on wheel spacers (with longer studs)? What about the various types of spacers, typically in the 10-25mm range, like from Eibach, that provide their own "new" studs and use your stock studs to bolt to? I need to run a ~15-20mm in the front of our Stoptech-equipped Z with Enkeis as well.

 

And you don't even need hubcentricity. I ran Cal Speedway late last year with lug centric spacers (1/2" front, 1/4" rear) at speeds above 150 mph and had no vibration problems at all. Nothing broke, wheels didn't fly off, studs didn't shoot into the stands and impale the one spectator... :-)

 

Ordered the h&r drs spacers. If I ever have a stud problem I will just order arp and replace as needed. I was just worried about being rejected at tech, reading over any of these sanctioning bodies rules is like one of those word puzzles sometimes.