originalmotorhead

Hello Everyone,
My 2000 Boxster had developed a funny wear problem with the front tires. Both front tires have cupped on the inside inch and a half of the tread, however the rest of the tire is perfectly flat and has 50% tread left. I bought the car with 34k miles and these tires on it and I had the alignment set right after I got the car.(went to NTB - maybe the problem) I now hafev 44k miles and the front tires look good other than the cupped inside edges. The rear tires have worn evenly over the entire tread and are near replacement limits.

My question # 1 is:
Is this type of wear normal for the boxster suspension ? Three tires shops have told me the wear is probably normal due to the camber and caster setup for the car. I took the car back to NTB today and they checked it and the readings are within the specs that their computer says is OK. They also told me the wear is probably normal for a sports car. I would consult me locak P dealer but those guys are bad news bears !

My second question is:
I'm going to try some Kumho Ecsta Supra 712's since they are pretty inexpensive and many of my friends with rice burners seem to like them. Anyone on the board run them on 18" rims ? Any feedback, I'm going Monday night to get some installed.

Thanks !
Tom
Columbus, Oh

djantlive

Supra 712 are crap, total waste of money. If you want to go cheap, get Yokohama ES100 or Bridgestone 750.

Is NTB a chain?? I'd get another shop to do an alignment check. Also, have you kept the air pressure on the tires? Don't trust shops like Sears, Goodyears, PepBoys.

originalmotorhead

djantlive,

I try to check air pressure about once a week or every other week.

NTB-national tire & battery is a chain and I've used them before on other cars with good success. I had a Prelude with 4 wheel steering and they did a superb job on that. They have a Hunter laser alignment jig that is probably the same thing every other shop uses. It's probably hit or miss if you get a punk working on your car or an experienced person when you go in on a early saturday morning for an alignment.

I read in one of the Porsche & 911 world issues that the Yoko's wear out really early so I didn't look at them yet.

Tom

ar38070

However they are doing the alignment they should be able to provide you with the actual numbers. On a stock suspension the front should be between 0 and -.5 degrees camber. The toe should be slightly toe in (1/16" to 1/8"). Caster cannot be adjusted.

As far as your wear problem is concerned I would scrutinize the toe in numbers. On a stock suspension camber is not too adjustable and probably not the problem.

Have a look at the kumho ecsta mx. $20 more than the 712's. Other boxster owners have tried them and liked them.

djantlive

Ecsta MX is a good tire, unlike 712. MX may not be too good in rain though. Since you are in OH, you should check Tirerack for MX's all season rating.

I've had Yokohama and they wear well. Bridgestone is equally good.

designman

Toe-out accelerates wear on the inner tread. Toe angle also significantly affects directional stability. Check out the following article that originally appeared in Grassroots Motorsports. Also, I would only have the suspension aligned by someone who knows Porsches.

http://www.ozebiz.com.au/racetech/theory/align.html

poindex30

I had the Potenza 750s on both my 944 and 540 and I liked them a lot. I currently have Kuhmo 712s on both of my cars and they are very good also. I autocross both cars and I didn't want to spend the extra money on the 750s when I only get about 15k miles on the rear tires. I have been pleasantly surprised by performance of the Kuhmos.

Mickey

originalmotorhead

I'll dig out the printout they gave me with the camber, caster, toe figures and post it here

I was looking at the rear suspension tonight and I can see two places on each side to easily adjust the rear end. (looks like one for toe and the other for camber) However, I can see only one place to adjust the front end and that is the toe via the Tie Rods. Where are the other adjustments for the front end ?

Tom

ar38070

Camber is adjusted at the top of the struts. You remove the two plastic covers on either side of the battery cover. There are three nuts securing the top of the strut to the body. The three strut studs reside in slots. You move the top of the strut left and right to adjust the camber.