A few wheel questions (Offset, Spacers, etc.)

[SpeedTheory]

Will be using 16x7.5 w/225/50/16 tires for STS autocross in a 1991 318is. Just curious about a few things.

A. What offset should I use (want to avoid spacers if possible).
B. Will the tires clear stock fenders/struts okay? Will I need to roll?
C. Will I NEED to use spacers?

Thanks,
-Ryan

[z31maniac]

If your car has the LSD, you will be in STX my friend.

[SpeedTheory]

No LSD, for this very reason.

[bobross]

Anyway i can get the last 7 of your vin speedthory?

[SpeedTheory]

Car is not in my possession currently. Back in VA and I'm in FL.

How does that affect anything?

[drifty340i]

Offset for 16x7.5 w/225/50/16 tires would be around 20p to 28p in my opinion.


Im using 20p with my 225/45/16s no issues

[Mystikal]

The tires are huge, you may not be able to get them in there. And even if you do, if you hit a bump mid-corner your fenders are screwed.

Back down to a 215/45/16 RT-615. It's the fastest 140+ treadwear 16" tire you can easily fit on an E30.

Jay

[SpeedTheory]

If I was forced into running thin Azenis this car wouldn't even take place. It is to be a nationally competitive STS car, and running a bottom-tier Street Touring tire won't cut the mustard. Would rolling the fenders help?

[Mystikal]

Heh, alright.

You're looking at rolling the fenders, modifying the plastic fender liners, and some banging in with a hammer. It will be trial and error, most guys don't try to run tires that tall and wide.

What are STS rules anyways? 235/40/17 will be a lot easier to fit.

Jay

[SpeedTheory]

Limit is 225. Don't want to add the weight of a 17in wheel. My real limit is rolling fenders & adding spacers.

[FredK]

225 max, 140 min treadwear, Pirelli PZero Corsa not allowed.

What tires meet these specs and are head and heels above RT615s?

[SpeedTheory]

Bridgestone RE-01R, Dunlop Direzza Z1, Yokohama Advan Neova AD07, even the Hankook Z212 is a better tire. To non class-competitive autocrossers, which I assume most of the people on here are, the difference between .5-1 second per run wouldn't matter, but this could be the difference between trophying & not, and at National Tour/ProSolo (where I think this car is really going to shine over the Civics that have dominated STS in the past), its a big deal. I may end up dropping to 15s and hoping that I end up with a better tire selection as the big players continue to release new sizes, and Kumho comes out with the new Ecsta XS, and Toyo with the R1R.

[Mystikal]

Yeah, that's what I was going to suggest. You can already get a 225/50/15 R-S2, and there's always the hope that the new XS and R1R will have a wide range of sizes too.

I still think the RT-615 is a faster than the R-S2 though. I don't know why GRM's tests (like this one: http://www.srtforums.com/forums/f136...e-test-344939/) don't match what the fastest guys are running (RE-01R and AD07).

Jay

[SpeedTheory]

The Z1 is available in Japan in the 225/45/16, but not in the US. I've got until the '08 season to get my tire situation figured out, I can't imagine I'll be ready in it to take it to nationals this year. May find an E36 STX co-drive.

[FredK]

Well, I hope they do release some more tires in the smaller sizes!