Fikse set me up for a narrowbody 997S with 8.5x18 fronts and 11x18 rears, sized for the 245/305 RA1s I run. Some are using a wider rear (12"), but I'm really not sure why. 245/305 is a good differential in the staggered setup. My car tops out at 150 (and I'm still learning this crazy rear-engined car) at Watkins Glen on the back straight and I've not experienced any "floating" -- the car, tires, etc. were all rock solid.

 

Alex,
Beautiful RS & wheels!!
What size are your front and rear Michelin's? Are they Cups?
Are your 18" wheels 9" & 12" (F & R) ?
Thanks
George

 

i love the ra1 on my sm but didn't like the r888 or the nitto's. fyi r888 and nt-01 get noisy when new way before you reach their limit.

 

you just want to break 2:00 at TH!

 

Mooty- let me know what you think after trying R888 in the 305/35. Car was extremely unstable at high speed and during high speed braking. I tried the following to no avail:
- Change rear toe
- Change AOA of wing
- Rebalanced twice
- Change rear sway (for other reasons)
-- Different wheels/tires

I did not have the tire shaved, but from start to end (full tread to 35HC ... almost zero tread left) never was fully stable. Last weekend I also tried a different rear set of 305/35/18s from Stephan and had same issue....but switched to Hoosiers and had no problem. He also noticed it and won't drive that size rear R888 tire anymore. He had the 315/35/18 R888 and said it was fine. I like the R888 a lot as far as feel, slip angle, feedback, so hopefully the new size will help with the stability problem ... of course they are no Hoosier

So sounds like it might be R888 in that size vs that size in general since other folks aren't having issues with RA1 same size.

 

I have tried a bunch of tires and can probably save you some money and headaches! Wheels CCW 18x 9 front and 12 rear. Could not be more satisfied than with John's custumer service/wheels.
-Toyo R888 245, 305. As Ryan mentionned good grip but very unstable at high speed. Would not use these again.
-Toyo R888 255, 315. Feels great. Were shaved and lasted about the same as hoosiers (but are not as good)
Toyo Ra1 245, 305. Worked just fine.
-MPSC 235, 315. Lots of rear grip. Terrible understeer. Needs more rubber in the front.
-MPSC 235, 295. Works very well. Changes gear ratio significantly.
-Hoosier 245, 315. Best of all. Just feel great even after 25 heat cycles!
However hoosiers do not last very long. I am hoping for a front MPSC245 or 255 to add to a 315.
Also would love to try the BF Goodrich R1 when they come with the right size.
Has anyone tried the Khumo 710?
Please share your feed back,

Stephan

 

i did 2:00:09 today... BUT it's with bypass. ugh.....

 

wow, you guys are making me very nervous about R888.

i also run CCW 18x 9 front and 12 rear; love them.


-Toyo R888 245, 305.
-Toyo R888 255, 315.

did you guys figure out why the smaller tires weren't stable but the wider ones were?

and they last as little as hoosiers?

 

Mooty,

The wider tires feel stable because they have shorter sidewalls (that's the only explanation I can come up with!). Mine did not last long but they were shaved.

Good luck. Let us know what you think.

Stephan

 

<< -MPSC 235, 295. Works very well. Changes gear ratio significantly.>>

Hi, Stephan, I'm not sure, but we may have met at Summit Point.

Anyway, please explain... the 235's pushed when used with the 315 rears, but not with the narrower 295's?
I'm wanting to increase my fronts to 245's and rears to 315... does that mean the car will feel better & more planted with this setup?? (I assume we're talking about 18x9" and 18x12" sizes here.)

With the Hoosier's, how many heat cycles can you get out of them? (Or, would you choose the wider MPSC?)

Thank you.

 

The Khumo 710 was rumored to be better than the Hoosier at the POC Laguna Seca event in August, but I was unable to confirm.

 

George,

We might have met at Summit as I hang out there a lot! 245, 315 Hoosiers with full soft front and full stiff rear make the car very well balanced. 235, 315 MPSC make the car push like crazy. Need more front tire with the MPSC 315. 245, 305 or 255, 315 R888 make the car well balanced as well. Though 245, 315 R888 are unstable at high speed especially under braking. Hoosiers I do anywhere between 4 to 6 track days depending on temperatures and driver (wife). At 25 heat cycles they do not grip as well as at first but they still make the car feel good compared to the others.

 

Thanks lawjdc They're super-light, no more spacers and we like them so much we're doing a set of 18s so we can go to the track (theoretically lol!).

 

Thanks George! I went with stock sizes on the tires for now.. those are cups yes.

This set is actually a 19 inch set up (although 18s like that are on the way) and we went +3mm and then anothe +5mm to nuker the rear spacer. In the front we did a +3 also.

 

<<Hoosiers with full soft front and full stiff rear make the car very well balanced.>>

Stephan,
What do you mean by soft front and full stiff rear? Are you referring to the tires or suspension?

OK, with an 18" setup with 245 and 315 Hoosiers, what kind of cold/hot tire pressures do you find work well?