flatsics

Sean I just weighed my wheels:
CCW 18's with 275/35/18 43.5 lbs
Forgeline 17's with 275/40/17 43.5 lbs

Reportedly Buckley's wheels weigh 13 lbs
Hoosier 275/35/15 weighs 21 lbs
total weight 34 lbs

Sean F

thanks doug

BostonDMD

After all this evidence, I am shocked "Sean's Rule" was not passed.......

LPM911

Noooooo!!!!!

hey now, aren't we forgetting another G class racer?

good hands

Wouldn't have forgotten you if you had some graphics

FredC

Was never about weight.

Sean F

Lower final drive ratio by approximately 6%.

Gary R.

Maybe if it was 10% it would have been enough.....

Glen

If I were running in the class You guys are discussing I would try 15 inch rears and 17 or 18 inch fronts...not joking...
Also think its humorous someone wanted the 15 disallowed, isn't that what came on the car"stock"?

Chris M.

TELL 'EM!!!!!!!!

FredC

No one proposed to disallow 15s for the 2010 rule book. The proposal was about rolling diameter (which includes the tire dimension). Funny how such important details get lost....

paradisenb

Tire cost would be a big factor going from 18s to 15s. I calculated less than 3.5 sets to reach breakout on the cost of the 15" wheels.

17s to 15s is a different story with just over a $100.00/set savings. That's a lot of tires to reach break even.

I'm guessing these would be noticable on slower tracks with lots of turns like Barber. Maybe LRP is the same. Not some much for RA or VIR. Correct?

NaroEscape

since the rules change thread has turned into a discussion of the merits of 15" wheels....anybody know who could make 11 x 15 and 12 x 15 wheels?

FredC

That much of a delta on cost from 18 to 15 would be appealing to me for sure.

The 15s seem to help a lot coming out of slow turns (especially if the slow turn doesn't lead to an obscenely long straight). At the Glen this year, I was impressed to see how much a certain car was pulling away from me at the start, going up the toe of the boot, and between 8 and 9. That guy was running 17s at the Glen last year and he didn't pull away as much if at all. I will say that the 15s made him use gears a lot more than I did, which takes away from the benefit of the smaller rolling diameter, especially when down-shifting.

John H

I was curious because I was thinking the 15's would weigh more and offset the "final" gear ratio change v. the rolling resistance and unsprung weight. I had no idea the weights would be so close.