I'd like to move up a size or two for my 997TT. In theory, 245/315 or 245/325 (GT2 tires) sounds like improved performance. Can anyone comment or advise me of possible downsides with these larger tires on 19" or 20" rims, especially with handling on the track and with stock suspension. The TechArt cars run these but only with after market suspension and 20 inch rims but after a recent changes I'm not yet ready for new suspension.

Thanks, hate to lay out the $ for the tires only to find out it was a mistake unless I want to start a chain of $ mods.

 

Larger wheel diameter usually = more weight...bad

 

Unsprung rotational mass (ie wheels and tires) have a much greater effect on your acceleration than sprung mass. Ie the effect of adding 1lb unsprung is much more significant (I forget the exact factor, perhaps 4 to 1) than sprung mass. So add 1lb to your wheel setup at each corner, you just added 16lbs of extra weight to your car essentially. And I believe that ratio might be even larger.

Bigger wheels = more weight = slower accel/deccel.

 

I use 18" for track and 20" for bling.

 

More wear on the suspension, higher price on tires, taller acceleration.

 

Bling Baby Bling.... Ride it on DUBS yo!!

 

I guess I left myself wide open to the "bling" comments although I'm more interested in the performance side of things. From your comments I can see that the extra patch of rubber on the track offered by larger tires is offset by a number of factors. Weight and suspension trade offs seem to suggest staying the tried and true 19" PS2s and rims. At least the new rims have saved me some weight.

I suspect the GT2 tires work well because of rear-wheel drive and therefore NOT on the AWD 997TT (or am I reading your posts incorrectly?).

K.

 

If you want a nice look go for 19" Monoblocks and lowering, I think one of the best looking wheels are the P40 HRE's.

 

Alpine...where are the spinners? You gots to have dem...

 

B-Dawg - you knows I gots dem..They are getting some gold electroplation ya dig. It's tight!!

Check this out yo...Since my ride is White know what im saying - i thought damn how bout some white sidewalls yo! I know I know - you diggin it. Don't hate the playa!!



In regards to Mean Machines comments - that would be a good combo and compromise.

If I were to go for 19's it would have to be a Monoblock design or a wheel without a large lip.

 

Thanks for the info. I guess this thread is off in a different (equally interesting) direction. No disrespect intended.
If anyone can advise me how to find out about GT2 tires on a 997TT please let me know. Maybe PCA?
If not, enjoy your rides.
K.

 

Kafka997 It's all good No worries.

In regards to the GT2 tires what are you meaning about MPSC's for the GT2 they are same size as the GT3/RS tires. There are a few people running them on their Turbo's now. Are you worried about how it will affect your AWD compared to the 2WD from the GT2?

Please clarify - we are a helpful bunch. Well Bobby is not but most of us are

 

Rear MPSC for GT2 325
Rear MPSC for GT3 305

 

In straight-line acceleration the tires would be completely pointless, I dunno about you, but in a straight line my tires dont spin, so Im already beneath the threshold of adhesion at full acceleration.

Under cornering there is a lot of squealing, so I imagine having a bit more rubber might give you a bit more stick. But depending on the tires you are currently running you are probably better off using OEM sizing and just upgrading to an overall better tire. (street -> cup -> slicks)

What tires are you currently running?

 

aawwww...why all the hate'n?

Kafka997...there are several sponsors here that carry excellent choices for lightweight wheels...common favorites include Champion and HRE monoblocks...for those with deep pockets...there are carbon fiber wheels by Dymag.

The Techart wheels you mentioned earlier...are very very very heavy...did I say heavy?