Is anyone running 12" rear wheels on a lowered 6-3 set up for track? I ask because I've had rubbing problems with this set-up (315 Hoosiers), but I've been told it should be fine. Would like to hear of any experiences out there.

 

They fit but offset is extremely important, even then some fender rolling and maybe trimming of pieces in the wheel well might be required.

Mooty and Rad (NJ-GT) come to mind as a couple that have successfully run them. John @ CCW wheels knows the magic offset but I don't know I've ever seen it published anywhere.

I think Rad even had 335's on his car at one point for Auto-x work

 

Ken, I'm running 12's, my car is not too much lower than stock. As Andy say's offset is important. I had rubbing against the thrust arm. Added a spacer and that is okay now. Camber for me is -2.5. No rubbing in fenders/well.

 

i run lowered on jrz coilovers and gmg adjustable suspension. 12x18 et 45 rear with 315/30-18 pirreli rubber. no issues rubbing at all but its very close on the inside.

 

John,

Same with mine. Initial set up was fine with 1/4 inch spacer, but now seems to rub on fender. Take spacer out, then it rubs on thrust arm. Can't quite figure it out but I'll keep tinkering.

Krazy,

I'm not 100% sure, but I suspect your turbo has a little more hip room in the rear. The GT3 has a narrow-body tub, which of course changed for the 997.

Thanks to all who chimed in. Hopefully all will be sorted out by mid-March

 

i dont remember the offset, it's been a while since i drove a 6.
but john at CCW can tell you.
i did roll and pull my fenders.
i also run almost -3 rear camber (memory fuzzy... but at least -2.5)
furthermore, my rear spring is 1000lbs so i dont bottom out much. car is 2650 lbs, fully stripped. i do mean FULLY stripped.

so of the rubbing you see may be due to you having too soft spring so car bottoms out?

 

My 12 inchers are from John at CCW. Springs are 1000 rear, 800 front. Can't remember camber, but that might be the only significant thing that changed between the time they didn't rub and the time they did. Car will get full drill soon, so hopefully 12's can still be used, but really probably not as important as tire size. Even with the fenders rolled and crushed, I doubt anything bigger than 315 will fit; we'll see.

 

Ken,

Strange, the CCW's I got for this car work fine with 315's And I don't need spacers with those. I use spacers for a set I bought prior to getting this car. No rubbing on thrust arm or fender. Camber is at neg. 2.5, but I'm not too much lower than stock. No rubber bushings and 900 rear spring. FWIW