Gary R.

Close? A 15" Buckley with 275 R6 is about 34LB, an 18" CCW with 275 R6 Hoosier is 43LB.. that's 9LB per wheel!

Glen

Still dont get it...just because low profile readily available cheaper tires with modern build technology became available over the years the desire was to outlaw the resulting rolling radius? Does that mean the aspect ratio is how You would govern what was legal on the respective wheels? Is that what You were referring to? Would't that increase costs, isn't the 15 tire cheaper? Wouldn't that force everyone to aftermarket wheels and higher cost tires?

Glen

This is why I would run 15 rears,(less weight, lower gearing) in the rear and 17/18's in the front(more weigh, lower aspect ratio, sharper turn in less deflection) lower cg more towards the front of car, where needed.

Gary R.

I'm wondering if just putting the 15's with 275/35 on the rear and run the 18's with 245/35 on front would work. Since Hoosier doesn't make a low profile 245/15 AFAIK and the currently available 15" R6s (other than the 275/35) have almost the identical rolling diameter and the 245/35/18 so why not? Sidewalls will match, only difference would be overall rear ride height and rake (approx 1/2") and front wheel weights.. is there a handling issue i'm overlooking?

Edit: Glen you out-typed me...

John H

I misread one of Crossman's posts regarding the diff between 18 and 17 as 18 and 15. My bad. I should just stay out of this one becaue I can't run 15's anyway. I did run different sidewall height Hoosiers on my previous GT car depending on the track. It definitely change the shift points.

dave morris

Was he in a D car? Just curious. Hi Fred.

FredC

no. E. But who knows, there were so many guys caught with bump steer kits...

Mike Buck

The 275/35 rear matches well with the 225/45 front. Same short RD. Don't get hung up on it being a "225". It is nearly as wide as other Hoosier "245's".

There is no free lunch when you go these shorter tires. By having less mass, they have a lower heat capacity. So they will heat up faster, but overheat more easily. I wouldn't even try them on my 3250lb tank, even if 15's did clear the brakes. On your light 911's they should be ok I guess.

The ALMS 911's run those huge rear tires to combat heat and durability issues. Bigger tire = more tire to abuse.