Anyone running R888's on the track?

[Achilles99]

I need some serious help with camber and pressures. I am getting a 30-40 degree temperature differential between the inside and outside of the tread. It should be 10 degree. Inside is hotter, indicating too much camber.

I was running at 42psi. I decided 42psi based on one thread, but after reading this other one I think I was overinflated by 8 psi.

Toyo R888 - an interesting read about tire pressure - Bimmerforums - The Ultimate BMW Forum

I started the rears at -2.5 camber, and over the past five events have gone down to -0.7 camber. STILL too much on the rears, I may go to 0 next time. Very strange, I wonder if it's the R888 design, the fact that they are used and heat cycled out (I get them from Berget), or if the Viper suspension just doesn't like them. I ran -1.5 in the rear and got great wear out of stock PS2's.

Would you guys decrease camber, decrease pressure, or both?

 

[Fatboy 18]

UK member 'ZS' Runs R888's on his Gen 2 RT/10. He has done a couple of track days in the UK, send him a PM, He might ba able to help?

Mark

 

[Fatboy 18]

double post ....sorry

 

[Achilles99]

Couldn't PM using that name, says not valid. Is that Z (as in Zebra) S (as in Sam)?

EDIT: Zed Sump, got it, I'll send him a PM. Thanks!

 

[Fatboy 18]

Couldn't PM using that name, says not valid. Is that Z (as in Zebra) S (as in Sam)?

Sorry my fault, Its 'Zed Sump'

Cheers Mark.

 

[Schulmann]

Yes I had similare feed backs from BMW guys last year.
Maybe there is a bad batch of rubber out there .... or this is an feature from R888.

I just bought a set of R888 for my BMW, I hope my set of tire will run better. It was as expensive as the Hoosiers even with a racer level 1 discount code. I should have bought the Hoosiers .... Last year I beat the hell out of my Hoosiers and they were holding very well event with a very bad alignment.

In Canada Toyo has stopped selling the R888 for Vipers.

Anyhow the R888 seems to have a delicate rubber. if you run too cold or if you run too hot it will not performe well. A Hoosier has a wider range operating temperature rubber.

The issue might be related to initiale heat cycling ... ?

 

[MTGTS]

42psi sounds like waaaay to much.
I run
-1.7 front
-1.3 rear

Start the rears @ about 30psi and the fronts @ 32psi for most tracks except Daytona.
888's like to be around 36psi HOT.

 

[Tusc]

MTGTS - just because I'm filing the 36psi figure away in my head for future reference, have you temp. checked the tires after running? Are the temps even across the tire when it has reached 36psi??

 

[MTGTS]

MTGTS - just because I'm filing the 36psi figure away in my head for future reference, have you temp. checked the tires after running? Are the temps even across the tire when it has reached 36psi??

no I haven't. Don't have a pyrometer yet

 

[PS78]

I've comparatively little time on the track to many on the VCA forums and haven't done much research on the Toyos i've had for the last 10k miles (2 sets). They are my road tyres too (guess i'm not driving it hard enough on the tracks!). Soft compound - I've read when they're tracked real hard, their best grip only stays for about 10 heat cycles... My set is:

stock/manual alignments
295/R18/30 front
335?R18/30 back
29-30psi all round when cold (stock)
1/2" lowered
10mm wider track front
20mm wider back

If UK Nadine has a moment, she could give proper in depth info, but she's probably board now, having done it so many times. She has been running Toyos, amongst others, for many years on her almost soley track s/c gts...

 

[TexasPettey]

Do you have a pyrometer? They're fairly inexpensive and the easiest way to tell how much pressure you should be running on a given day.

 

[Achilles99]

I have a pyrometer. Pressure seems to give OK readings at 42psi, but my inside/outside temps are too different (30 degrees). I'm wondering if less pressure would allow the tire to roll over more? I've already gone down to -0.7 camber, and am afraid to go lower.