Tires For Boxster S

[aramati]

I purchased an 01 Boxster S. I need advice regarding tires. This is what's on it now:

Front: Dunlop SP Sport 9090 N-0 225/40 ZR 18
Rear: Dunlop SP Sport Super Sport Racer 265/35 ZR 18

I noticed the mismatch when I experienced a front wheel vibration at about 70 mph. A Porsche Dealer in Tucson (on my way back to Vegas) balanced the fronts. It moved the vibration point to 80 mph. The tires still have about 4K miles to go.

Here are my questions:
-Is the mismatch causing the vibration? Do I need a better wheel balancing job? Do I need new tires?
- If I need new tires what would you recommend for a combination performance for street/Auto-X?

Your advice will be much appreciated.
Regards,

[jwocky]

Michelin Pilot Sport 2... doesn't get much better than that.

[Richard Truss]

I will need tires soon as well. I have heard that Kuhmos (sp?) have good wear life. I am looking for something that will last over the "super stick that will wear out in a week" type of tires. What does everyone recommend for good tire wear, and hopefully a good price?

its good to see another member from Las Vegas!

[RandallNeighbour]

Richard, I have Kumhos and I like them... not expensive and seem to wear well. Just don't buy the cheapest Kumhos they make as I'm told they are noisy tires after six thousand miles and require rotation to stay quiet, which we can't do easily...

I will say this though. I'm going to knock off my rubber and have it moved left to right and vise versa on both the front and back here soon... I bet I can get more miles out of them by doing this.

[larez2]

Using different model tires front and rear won't cause vibration you feel through the steering wheel. Out of balance tire(s) would, but since you already got them balanced, I don't think rebalancing them again will help. Are you feeling serious shaking vibrations, or are they road feedback type vibrations.

There is something called road force variation balancing; balancing the tire under load. Most Discount Tire stores have the Hunter 9700 which can balance using road force variation. It cost $80 for 4 tires when I got it done. This may or may not help.

http://www.sullivantire.com/xcessorize/hunter.aspx

Maybe you need an alignment? How does the tread wear look? I recently got a wheel alignment, but it was because of my tire wear, not vibrations.

Good Luck,
Larez2

[Adam]

I agree with Jwocky. PS 2's have the best combination of track performance and everyday driveability. I plan on getting them when when my original pilot sports wear out. I think the tires are one place where you shouldn't compromise. They will cost a pretty penny though.

[racer_d]

Originally Posted by aramati

- If I need new tires what would you recommend for a combination performance for street/Auto-X?

Your advice will be much appreciated.
Regards,

Check the rulebook!

Changing tires can affect the class you run in. An "R" comp tire can put you in an improved or modified class that, depending on what you have done to your car can put you at an extreme disadvantage. Many clubs use a treadwear rating of 140 as a guideline. Above 140=street tire. Below 140=competition tire.

[Sammy]

Originally Posted by racer_d

Check the rulebook!

Changing tires can affect the class you run in. An "R" comp tire can put you in an improved or modified class that, depending on what you have done to your car can put you at an extreme disadvantage. Many clubs use a treadwear rating of 140 as a guideline. Above 140=street tire. Below 140=competition tire.

I was worried about this as well but in all the events I've ran with SCCA my Victoracers didn't move me into a different class (kind of sort of but not really). In Chicago and Milwaukee SCCA the race tires make you a true AS. Before I put race tires on I would run "Street Tire" AS or "Street Tire" RWD. I'm pretty sure SCCA nationals is set up this way as well even thought I doubt anyone shows up without race tread.

This has been my experience so I'm hoping a SCCA rule expert can comment...

Of course there are autocross clubs outside of SCCA...

[John V]

Originally Posted by Sammy

I was worried about this as well but in all the events I've ran with SCCA my Victoracers didn't move me into a different class (kind of sort of but not really). In Chicago and Milwaukee SCCA the race tires make you a true AS. Before I put race tires on I would run "Street Tire" AS or "Street Tire" RWD. I'm pretty sure SCCA nationals is set up this way as well even thought I doubt anyone shows up without race tread.

This has been my experience so I'm hoping a SCCA rule expert can comment...

Of course there are autocross clubs outside of SCCA...

The National classing structure doesn't have any "street tire stock" classes like Milwaukee region (and others) do. Nationally, whether you run R-comps or regular (140+ treadwear tires) your Boxster is in A Stock.

My co-driver and I are signed up for the Milwaukee National Tour, you should show up and help us fill up A Stock with Boxsters!

[edevlin]

Quote:

"Four months ago I purchased the SP 9090 Dunlop tires. While driving home in the rain the other night I experienced severe hydroplaning. To my surprise; I noticed that my rear tires were completely worn out. I only have 2400 miles on the tires. I'm very disappointed with Dunlop tires... Has anyone else had wear problems with the 9090 tires?"

Originally Posted by Jetmd


I just got back from a road trip to Florida this week, 700+ miles each way. On the way back today there was a lot of rain down south, and I was suprised at how much my PS2's were hydroplaning. The rear tires have less than 4k on them and are showing less than 3/16" of tread. I have been trying to take it easy on this set of rears, but it looks like I will not get 6K out of them. BTW, the front set has 9K+ on them and is showing 1/4" of tread.

Ed