pics of New Wheels and GT3 Seats - 986 Forum - The Community for Porsche Boxster & Cayman Owners

Perfectlap · 05-09-2005, 11:40 AM

29F 36R for a conventional street tire as per Porsche.
26 and 32 didn't sound so bizarre to me given the ultra stiffness(make that super ultra stiff) of the sidewall.
Running a racing tire on the street with too high a pressure often results in excessive center wear but you're right the Porsche techs are probably told to dial in oversteer for the average P-Car driver, keeps them from getting into trouble.

Adam · 05-09-2005, 04:43 PM

I was thinking about putting 10mm spacers all around on my S...why would that be a bad thing for track/auto-X?

Perfectlap · 05-09-2005, 07:22 PM

using spacers results in more stress on the wheel bearings. I know Porsche sells spacer kits (5mm?) but I think they come with a disclaimer about racing/autox.
Heavily modified racing suspensions will often use them but that's a whole different story.

Adam · 05-09-2005, 07:33 PM

Ok. So it wouldn't hamper performance in anyway then? It just increases bearing wear. I thought alot of ppl on the boxster racing board had spacers and alot of them hit the track. Is this actually something to be concerned about with just occasional track use or an isolated incident? Why would heavily modified suspension reduce the load on the bearing?

Lux · 05-09-2005, 07:58 PM

I wouldn't worry about using spacers so long as it's not too excessive. Sure there's going to be more wear on the bearings. But so what? When you're autoxing or on the track you're also adding more stress on the brakes, tires, chassis, etc. Running 18" wheels adds more stress vs. 17", blah blah blah.

BTW, Porsche has a disclaimer about taking your car on the track...period; it's not just for the spacers.

And about the tire pressure issue:
It is a general concensus among a lot of the people on the Boxster racing board that Porsche's recommendation is garbage. It sets up the car to really understeer. Air up to 33F/36R and it'll feel like a different car. Having a stiff sidewall is great, but if you don't have enough air to support the car then you are risking a blowout due to stressing the sidewalls (see Ford Explorer fiasco) and damaging wheels. Run low pressure at your own risk!

-

Adam · 05-09-2005, 08:29 PM

Thankyou for your response Lux. I think I will get the spacers to fill out the wheel wells. 10mm seems like a good compromise between too large and too small of a change. I'm glad you said that about tire pressure...33/36 is exactly what is in mine right now. I go up to about 40 all around when I auto-x.

Brucelee · 05-10-2005, 06:55 AM

I just replaced a set of wheel bearings at my local dealer.

$615 per wheel.

Just thought I would add the cost element here.