ukrbmw

So, when I first got the car and was getting tires I faced a dilemma on how wide can you go without issues. I got a lot of advice and went through a lot of different sizes. I tried a bunch of standard stuff - 245/40/18 NT01s and RA1s - both of course fit without any issues. I also got a set of 255/35/18 Hoosiers from Vic, which also fit without any drama. I then went really crazy and got a set of 265/645/18 R80 slicks - they also fit, but very tight.

Here are the pics of 255/35/18 Hoosier A6 (driver side) and 265/645/18 Hoosier Slick (driver side) for comparison on clearance:

A6:




Slick



Hopefully this will answer some questions for those who are considering. Car is running close to 3 degrees of camber and 100mm ride height.

For the record, car feels much better on 255 tire vs 245 tire. Car felt very good on the slick as well, just took longer to come up to temp. Lap times were very similar, both sets of tires were pretty old (I corded the As and Slicks let go in the afternoon). Both sets were good for 2:05 laps on a very hot day.

New As are on and ready to go for VIR in 2 weeks! Getting pretty excited!

himself

What size wheels [width]?

-td

ukrbmw

They are 9 inch fronts.

LVDell

Close to 3 degrees? That's it?

loworbitsi

What is your front spring rate? Enough to keep the tire out of the fender under compression?

ukrbmw

Fronts are 1000, so no issues.

FFaust

Why the A6 and not R6?
I'm starting to look

mooty

i run the same.
R6 255/35, 315/30
R80/r100 265/645 and 305/645
800/1000 lbs springs
9.5" front
12" rear
if you drive straight, no rub
if you crank the str wheel more than 90 deg you will rub inside (spring side) makes some noises, but it's fine. i have no fender lip rub, but i rolled the fenders.

255 front is indeed better than 245 like OP said.

these large sizes were ran by NJGT and jrgordon a long time ago. now i believe them ;-)

Rceron

You guys run R6 255/35, 315/30 with stock offsets on front rims. With 255 up front do you put front swaybars on full stiff?

ukrbmw

It depends on your application. For just regular track days I'd go with R6s for very good grip and longevity. I use DOTs for time trials, so basically 10-15 minute session for best possible lap time. A6s are a 1-2 seconds faster, but only last 10-15 heat cycles.

I can't say about the stock offset. Called Forgeline and told them what I'm doing and they made a set for me, it fits very nicely.

My front sway bar is on middle setting.

FFaust

Thanks

ukrbmw

Anytime man - I've been tire hunting, trying for weeks and figuring out longevity and grip levels, including various slicks - Dunlops, Pirellis, etc.

Just scored two sets of brand new NT01s in 245/40/18 and 315/30/18 for $1000 a set mounted and balanced. Now I'm set for rain and DEs for a while!

mooty

ccw did the offset, i dont know what it is, but it's not oem.
i set front bar at middle and rear bar at one from full stiff

smsarchitects

With all the talk (and apparent success) of larger tires on the front and rear of 996 GT3 cars, I am curious as to why Porsche specs tires on 996 Cups are "narrower" at 245 or 24-64 in slicks and 305/315 or 27/280-680?
Rolling weight?

ukrbmw

Scott - spec tire is never about ultimate performance, it's always about equalizing all the competitors. What do Cup cars run in Grand -Am or world challenge?

I'm in an open class, so more rubber helps.