My tires wear on the inside edge (as do all 993’s). I was wondering what would happen if I took the tires off the rims and put the left one on the right side and right one on the left side. I know the tire stores say No, but why no? The rotation would be the same. At $250.00 per tire, I’d like to squeeze every mile out of them.

 

Before/when you do this make sure you have the Camber and the Toe checked...

 

I used to do this on the front tires of my 911SC, suspension set up for the track and also daily driver (-2 neg) if I recall correctly. Also did this on the current set of rears on my 993. Never a problem as far as I could see. As you said, rotation is correct. I've heard you can do this with the Hoosiers without regard to the rotation arrows, but I'd consult with a "higher authority" before trying.
Right now the big issue is the worn rears and front tires having lots of tread left. I can easily feel the rears wanting to tramline on the highways and with the wet NW weather combined with low tread its more "interesting" than I care for.
Time for new treads..................

Jeff

 

Yes make sure your toe is to spec. Off-spec toe will exacerbate tire wear tremendously. I was going though 255/35/18 bridgestone s03's on my M3 every 4000 miles because my toe was off.

 

Well depends...you can't do this will all tire models.

 

Really? You sure? Only time mine do is when the alignment is out.

RE switching tires inner vs. outer surface; would not do this. Far as I know, on some of thse high-performance tires the bead and sidewall reinforcement might be different inner vs. outer, so you could be asking for major trouble.

 

If your inside tread is wearing out, it's most likely due to too much negative camber more than a toe issue. Either way, you'll need to get an alignment by an experienced shop who can set your kinematic toe.

 

I will also chime in on the Alignment issue. I just replaced my rears after about 10K miles and they were worn perfectly inside to out. IT IS ALL IN THE ALIGNMENT. Get a good one.

Since you are in Mission Viejo, Take it over to Hergesheimer's in Lake Forest, www.herg.net and they will take good care of you. no affliation, etc...

 

With respect to the alignment, I just had the boys at Hergesheimer’s (local Orange County Porsche experts) perform a four wheel laser wheel alignment. I told them to set the car up for maximum tire wear. They said the car “had” an aggressive alignment, meaning good for handling, poor for tire life. My current front tires look new on the outside, but ½ gone on the inside. The rears look almost new inside & out. By the way, I’m running Dunlop 9000’s, not the best but I like the directional tread.

 

Some tires are "directional", some are "assymetrical", and some are both. If your tires are NOT assymetrical (marked with an "inside" and "outside" on the sidewall), then you can dismpunt and swap them side-to-side to extend tire life. BTW, my tires are wearing uniformally accross the tread.

 

Ok, so not all 993’s have this issue. Hopefully with my new alignment setup I’ll get even wear across the tread, but the damage has been done on my current tires. I’m going to contact Hergesheimer’s and look into a front tire rotation, by the way Hergesheimer’s is only 1.5 miles from my house. (Lucky me)
Thanks to everybody for all the replies.

 

If you stay with the allignment specs of Porsche, you will most probably continue to wear the inside of the rear tires faster than the outside. This is due to the negative camber specified for the car to facilitate better cornering. The more you drive at high speeds, particulary long highway driving, the faster you will wear down to the belt on the inside half of the rear tires. Good rear tires may get approximately 10,000 miles before replacement is needed. The harder compund tires will last longer, but you sacrafice traction. Fronts should last 2 - 3 times longer.

To eliminate this weer, the only alternative is to reduce the negative camber settings on the rears. This approach of coarse will effect the handling of the car.

 

When I installed 4 new tires in April, I had my car aligned, with K Toe and had this same tire wear issue. Both front and rear insides wearing (equally F&R), both outsides look fine. Went back for an alignment check and the alignment didn't change. BTW - my shop knows what's up with 993's and alignment issues, K-toe adjustments. Maybe it was the tire choice I made that had to do with it? Kumho Supra's.