Question re front slick

[stradman]

Hi guys,
I've got some 18 X 11 Forgelines and am looking to get some Pirelli Slicks. Options I was looking at are 305/645-18 and 305/660-18. I read on the Vette forums that some people are suggesting its best to use 305/660's rather than the 305/645's, as the latter don't last as long as the 305/660-18's due to tires having less air volume within them. The only down side of the 305/660-18 I see is that they are about an inch taller than the OEM sizes. Any opinions would be welcomed. Cheers

[Racingswh]

I am using the 305/645's with success. I like them very much. Seem to last okay.

I have not used the other size so I can't comment on wear. Sean (Poorsha on CF) uses the 660's but I believe he mentioned he was going to try the 645's.

I find the Pirelli DH to be quicker and last longer than the Hoosier A's. I also like the Pirelli rear 705 tire height better than the 345/35/18 Hoosier with my stock gearing.

[JonB ~ PartsRack]

The Year Matters....as with most things Viper. May be an issue on G5 due traction controls.

[stradman]

I am using the 305/645's with success. I like them very much. Seem to last okay.

I have not used the other size so I can't comment on wear. Sean (Poorsha on CF) uses the 660's but I believe he mentioned he was going to try the 645's.

I find the Pirelli DH to be quicker and last longer than the Hoosier A's. I also like the Pirelli rear 705 tire height better than the 345/35/18 Hoosier with my stock gearing.

Thats great news. I would prefer to use the 645's as they are very close to the OEM sizes and differential between that and the 705's should not cause any electronic problems. Have you let off some camber going to slicks? I have been told you actually don't need quite as much camber for the slicks so was thinking of going from -2.7 to about 2.2 or thereabouts at the front.

[Racingswh]

Thats great news. I would prefer to use the 645's as they are very close to the OEM sizes and differential between that and the 705's should not cause any electronic problems. Have you let off some camber going to slicks? I have been told you actually don't need quite as much camber for the slicks so was thinking of going from -2.7 to about 2.2 or thereabouts at the front.

-2.4 camber front and 0 toe to just a touch out seems to give fairly even tire wear and temp across the tire. 20-22 psi starting pressures. 30-32 hot. I will say I am going to keep a careful eye on it though this season. As suspension bushings wear allowing more movement often times you need to dial camber back in or replace the bushings.

I will say I have seen crazy levels of camber dialed in on Porsche's and their Michelin slicks. I just haven't seen that need. Temps are even and under 200 degrees Fahrenheit all the way across the tire face and grip is more than I can use. Thing sticks like glue.

[stradman]

-2.4 camber front and 0 toe to just a touch out seems to give fairly even tire wear and temp across the tire. 20-22 psi starting pressures. 30-32 hot. I will say I am going to keep a careful eye on it though this season. As suspension bushings wear allowing more movement often times you need to dial camber back in or replace the bushings.

I will say I have seen crazy levels of camber dialed in on Porsche's and their Michelin slicks. I just haven't seen that need. Temps are even and under 200 degrees Fahrenheit all the way across the tire face and grip is more than I can use. Thing sticks like glue.

Thanks for input Steve. That's really useful. Much appreciated. Once weather opens up a bit, in a few weeks, will be out and let you know. Picking up my car with new hopefully quieter mufflers this weekend so should be all good to go for the track again!

[Arizona Vipers]

I ran Pirelli's for awhile, but I ran a 325-650-18 front. Do they not make that anymore?
The 660's put my car in limp mode a couple times on the track for a lap, then the car "realized" i was on track and let me finish.

[stradman]

I ran Pirelli's for awhile, but I ran a 325-650-18 front. Do they not make that anymore?
The 660's put my car in limp mode a couple times on the track for a lap, then the car "realized" i was on track and let me finish.

Yeah I believe they do still have and make 325-650-18. Did you get any rubbing with these and will they fit ok on 11 inch rims? Also btw are you not getting your PM's Arizona??

[Arizona Vipers]

Yeah it will work just fine on your 11". I run a 12" no rubbing. When I run a 335 Hoosier I do get some rubbing on the plastic wheel well part, I've burnt a hole through it, no biggie.
I assume you're running 325-705-18 in the rear? I'll check my DM's now!

[stradman]

Yeah it will work just fine on your 11". I run a 12" no rubbing. When I run a 335 Hoosier I do get some rubbing on the plastic wheel well part, I've burnt a hole through it, no biggie.
I assume you're running 325-705-18 in the rear? I'll check my DM's now!

Yes will be running 325-705 although it will be a 19 at the back. Are you certain a 325-650-18 will fit on 11 inch front wheel and not rub Arizona?

[Arizona Vipers]

Yes will be running 325-705 although it will be a 19 at the back. Are you certain a 325-650-18 will fit on 11 inch front wheel and not rub Arizona?

Well nothing is certain with mods. I ran it on a 12" wheel and it didn't rub and the 12" wheel makes the tires much wider. But too many variables. Frame height, track, elevation changes, weight of your car, shock settings etc.
If it does rub the worst it can do is burn a hole through the plastic piece between the tire and the engine compartment. Mine has a hole in it, I don't care. But those were from the 335 Hoosiers. Your ACR is much heavier (Mine is about 3150lbs) than mine, so that can make a big difference too.