Lanny Curlett

I'm running huge tires 345/18 Rear. 325/18 front. I'm not getting the heat into them so not getting the grip I want. All you other 951 racers what are you running and what results are you getting. I have big reds on the front and stock 951s brakes on the rear. I have 18" wheels anywhere from 9-13" wide available. Help?

333pg333

Pics Lanny? That's a lot of tyre. Especially with a very light car. What brand and compound are you running?
What aero? I am going with 305 / 320 Hoosier R80s. Haven't got any data yet. Ran briefly them in 265/285 and they were plenty grippy. Are you getting much of a range cold to hot psi?
You could come down in wheel/tyre size but maintain trackwidth by using spacers perhaps?

2bridges

I suspect a 275 front with 295 or 315 rear would be better suited to getting some heat in the tires...... maybe eve a 275 all around if your track layout and ambient temp don't support it

fast951

Same problem here with Hoosiers 335 & 305 x18 on a 2540# 951! I also know a couple of racers who experienced the same issue.
I'm going to 285 front; 305 or 315 rear..

dand86951

Lanny, you know my set up and the last set I have gone with were 295/35/18front and 315 rear Hoosier R6. Overall this combo felt pretty good.

Lanny Curlett

Hi Dan,

It was our last conversation at the Indy that triggered this thread. The reason I'm asking is I have 10 & 12 wide 17" Bogarts that will fit the rear but won't fit over Big Reds on the front. The 12s will take a 315 easily. I just want to get it right this time now that I have 4 x 13", 2 x 12" 2 x 11" and about 8 x 10" 18" wheels and a world of slicks from 930 Harold. Oh well.

Lanny Curlett

I have a tire issue and, like any other male, size matters. I need to get the size down, heat up and lower the *** end of the car. Watch this link. He passes me at minute 9 in the video. You can see the tires and how high the rear end is. Enjoy the, and I quote here, "analog g-force indicator" on the dash. The car is a 996 (I think) Cup Car. Definitely cup car whatever iteration.

Lemming

275's all around has worked well for me. Last setup had the car at just over 2500 (with me) and between 300 and 350 rwhp depending on boost (SC).

dand86951

Lanny, my 17" CCW would fit over my Big Reds with the 322mm rotor?

Also, the video from inside a 997 GT3 conveted to Cup Car spec driven by a very good driver, and it does show your car being too high in the rear. Last year I tried a set of Michelin take offs which were 27/65/18 frt and 30/65/18r. That combo felt pretty good also.

333pg333

Not sure what the Bogart wheel is but 17"x10" should fit over BRs easily. Bit hard to tell in that film and it makes things look worse as the Cup car could go in hard under brakes where you were probably worried about lack of grip.

Lanny Curlett

Worried about lack of grip is an understatement. I had "several" lurid, smoky lock ups going into corners one and to a lesser degree turn 5 where the cup car passes me. Fun and exciting in a strange way?

savvas944

seems that the tire compound and track temp .suspension and car weight
has more to do with grip than the witdh of tire
although the offset of the wheel is important also
Tried several compos but the best for my N/A 968
wide body and cup suspension and MO30 roll bars seem to be;

260/650X18 FR on 10j et 65 front 20 mm spacers
270/650x18 RR on 11j et 45 rear with 10 mm

I feel also that 270 in the front and 305 in the rr should be the max for 968.