sweanders

I believe that the max width with perfect ET on the front wheels would be 275 mm but you will then increase the turning radius. 255 won a 9" front wheel would probably work well with a matching ET. Try and stay as close to the stock measurements so that you don't get to much scrub. Also with the wider tires you might run into overheating of the power steering fluid when tracking the car.

Be careful with the width of the PS Cup wheels since they are wider than most other tires in the same size.. Their 295 mm is for some reason wider that BS or Pirellis 295 mm..

Don't know if it could be because of race advantages in classes where the tires are size limited.

MattH is probably the 951 tire guru, I agree with his size recommendations.

You might have to look into getting an adjusted alignment as well.

RolexNJ

sweanders: Thanks for the heads-up on the potential width issue with the PS Cups. And it did cross my mind that whatever size I go with will add more stress to the steering rack/fluid. Do you know of anyone who tracks their cars with bigger tires that has had any issues with that?

sweanders

I know of 928 people with that kind of problem, would imagine that it is no different on the 951. But then if you drive like they do you probably know more about cars and the whole art of "what-breaks-next-itis" than most people..

EDIT: I am no track guru, still a beginner learning stuff.

RolexNJ

Thanks for the tip. Interesting. And yes I do love those Sharks too! Sweet.

And you're no track Guru, just learning yourself? Right... Rumor has, and I can't say who the people were too, said that you used to train Michael and Ralf Schmuchaer before they made it big? Hummmm.

APKhaos

The balance issue is important. Going much larger rear vs front will introduce understeer, and there comes a point where its impossible to dial out the understeer induced by the larger rear tire.

The limiting factors for the size of the front tire are the clearance issues [obvious] and the suspension loading issues, which are less obvious and only a factor if you are driving the car hard on the track. We are seeing hub failures due to the combination of large, sticky tires and high track loadings. Racers Edge is now producing billet hubs that are clearly stronger than the stock casting, but at some point they are simply shifting the loads to the next weak component. In this case, its the spindles.

I have run Proxes RA-1 in 255/45 and Hoosier in 245/40. Had one hub failure already. Remember, this is full-out racing in a heavy stock class. The weight makes the loads higher.

You should be able to balance a 255 front with a 275 rear, but going much higher in the rear will result in understeer that can't be easily dialled out even with a full coil-over suspension where changing springs is an easy option.

RolexNJ

Tony: Thanks for the education, especially as it applies to a fully tracked car. Very valid points, however my car isnt now or will be one. It is a garage queen, show car, street car, and "maybe" a track car a few times a year. I just wanted to know the optimal tire setup to give me the best traction/neutral handling. So "if" I get the itch to track it and get on it, the car has the optimal package. But my car will never see heavy usage at all.

And as I mentioned, MattH did say that the set-up would be pretty good. I may now go with a 295s, and as he said and you said, I can dial the under/oversteer to a degree. But according to him, that set-up should give me the best handling/traction, that it will fit, and keep the car to near neutral. And if anything, I want a bit of understeer versus oversteer too, given that I am putting down some good power. Also, I am plan to upgrade the caster blocks and control arms too.

Cheers and keep warm in VA, its cold here in NJ!

sweanders

Dude, I just checked out your website and am suprised that you still have the stock seats..

Since you will be sliding around so much in the seats if you gas as fast as the power will allow. I firmly believe that you should consider your butt/seat traction ratio instead of the amount of grip your tires can manage?

What kind of suspension setup are you running?

RolexNJ

Dude!?

I just got the car back from Lindsey, and then had Special Tool work on it. I have had like "zero" seat time to enjoy it, honestly. And I know about the seat dude, trust me. So that is in the plan at sometime, no rush. Again, this isnt a daily driver, isnt a track car. I barely drive it at all actually. But when I do, I enjoy it. And the suspension set-up is listed on the site.

sweanders

Damn it, stop having all the good answers when I am trying my best to find a reason to flame you..

Let me know when you plan on taking the car to the track, I'll have to come visit..

RolexNJ

You are a pisser pal! You are just killing me over there.

When I do track the car, you're gonna have to show me how to drive it. I've never driven a fast car. I think the fastest I ever drove was a Ford Fiesta? So this car is waaaaay above my head. You're gonna have to give me a crash course like you did Senna, Prost, and Mansell. But Im a quick learner too, so that will help, ha!



PS. Do you have web site dedicated to your Cup Car? I would love to see alot of pics of that one? Please dont make me go and search for hours on the Net. Also, and I know everyone wants this too, but, where the hell can I get videos in any format of some of the Cup races? If anyone should know, it "has to be you!"

sweanders

I am one of those guys who don't have a website anymore.. And a 951 Cup from 1986 is pretty much a stock 951 with stickers and a useless aluminium rollcage..

It will be interesting to see how it goes when I get the Vitesse stage 3, TiAl and other stuff that is waiting to get put on it.

The website is down but I am sure I will get a new one going during 2006 with some updated material. If all goes according to plan I will attend the Scuderia Hanseat Nürburgring education in May. Ishould get some interesting footage from there and also some comparison info on how a modified 2.5 liter 951 Cup goes against GT3's and 360's etc..

RolexNJ

Dude, you own a piece of history, dont say its just another 1986 car you dummy!

And trust me, you will see a difference, by both your butt and datalogging of the VR Stage 3. Good luck with that and the other goodies! And get some footage when you can, I know I would love it. And you will have a blast when you attend that school, a total blast! I have gone to both Skip Barber and also the ELF Winfield/Franham school at Paul Ricard in France - that one was just incredible. So many ex-F1 drivers went there and the track was incredible, although we didnt do the full track. Have fun!

sweanders

Rolex, the passenger seat in my car is still not spoken for during the Scuderia.. I was hoping that some insane (sane people don't strap themselves in a seat next to me) individual would like to spend 4 days at the 'ring with me.

RolexNJ

Fly me out there baby, Im ready!

sweanders

PM me and I will give you the details.