rear tire wear

When I had the clutch T/O bearing and pressure plate replaced at 41K mi. ( due to broken Pressure plate spring ) my inde noted 3mm of thred depth remaining on the tires. Now at 46K mi. Last week I noticed the tires on both sides L & R have worn to the cords at the very inside edge. I can't see how removing the trans can screw up the rear alignment or can it? OR have the tires finally given up... the wear has been uniform thats why I ask.

Normal and nothing to do with removing the trans.

When I changed mine a couple of thousand back, the only real wear was on the inside edges of rear ones. I presume that is the normal wear pattern for these cars owing to the allignment of the rear wheels. I was thinking of trying to get more wear from them this time by taking the rear from the rims and reversing them around on the same rims on the rear after about 10000 miles. I believe that the rear tires dont see more than 15000 miles under normal wear. I suppose thats one of the cons when driving these cars. I do not track my car. After saying that, I do not molicuddle it during street use. I drive it in and out of the corners and love it..

You have to remember, that as the tires really do appear visually appear to wear evenly, unless you used a tread depth gauge across the full width of the tire, you really do not know, especially if the tire is unidirectional & asymmetrical, then it is even harder to judge correctly. It is very common for these cars to wear on the inside corners with their negative camber, and as they do, the negative camber increases, which causes the inside wear to accelerate, so the last few mm, especially if the middle was already only at 3mm on the 285 - 18s you have on the car (wider is harder to measure and see the inside corner) they were already border line 5k miles ago. If you have very expensive tires (Like N3 PS2s) on your car, it is likely worth the money to have the alignment readjusted for the rears after 10k miles from new to readjust the camber and extend tire life. Ahsai is 100% correct. Normal, and nothing to do at all with the service. Ou are just due.

When my Evo's were near new, the rear alignment was done in Nov 2011 and the negative camber was set at the least allowable minimum for the Turbo. (pry could have gone 1/2 or 1 degree more conservative to help tire life, but car was at the dealer, so no go.) I got about 7-8K miles out of them. The tires wore well and are great for a DD. As the insides were thinning out, I had them switched. That was 3K miles ago. I can pry get another 3K miles out of em, but need to have a rear set ready to mount. Fronts still look like 75% tread. That said, total miles pry about 12-15K miles on the rears. that's wearing them until they are quite low. FWIW, kook evo's show tread wear 280, sumi's 300. that's better than others, but it's still a low number if you're looking for an high mileage tire. Kumho Ecsta SPT shows a 320 TW. (Michelin and Pirelli are 220 TW)

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If the car was lowered to the ground with the transmission out this can upset the alignment. This is probably what happened. My Boxster went in for an RMS and due to parts unavailability the tech (at a dealer) had to take the car off the lift. This upset the aligment and the tire wear previously even went then because quite uneven with the wear concentrated at the edges. After new tires were fitted and a proper alignment done (in which the before numbers clearly showed rear toe to be out of spec) tire wear became even once more and has remained so over countless sets of rear tires over the last 265K miles though not without a few alignments. My 03 Turbo had its transmission replaced under warranty and the techs left the car on the lift while the transmission was out and the new one (from the factory) was installed. All this time the engine was supported by an engine jack stand (a tall one). Afterwards the alignment was unaffected. After fitting new tires you need to get the car properly aligned. Do not fear camber. Fear incorrect toe. For a good alignment the fuel tank should be full, all dead weight (junk like the dead batteries you've been meaning to drop of at the recycling center) removed from the car, and the spare tire (if one fitted) and toolkit properly installed. Some places like to use ballast to mimic the weight of the driver and some do not. I've had the Boxster aligned both ways and I can't notice any difference. The Turbo has only been aligned without any ballast. Be sure to get a before and after printout of the alignment readings.

1. When's the last time you got an alignment? 2. Do you have lowering springs or Coilovers on your car?

15 to 18k is normal, and the inside edges almost always go first due to the camber. It takes a bit of effort to get down there and see it, which is why it catches some off guard when it happens.

not lowered its stock. driven like it should be, just caught me off guard i know they were way low i've been waiting for BFG's new rival to hit the market. and i took a closer look and saw it. thanks for the replies. It did not bother me It seems normal just wanted to get more opinions.. Thanks

You never answered when the last time you got an alignment was. Reason being is if your toe is not in alignment, it can also accelerate your inner tire wear. Some members actually set the toe a little bit out more from the factory specs to get better rear tire wear(inner portion) along with running lower rear tire pressure.

I have had similar problem in my 2002 c4s. i installed adjustable lower control arms (RSS) and to correct toe in. tires seem to be wearing evenly over the last 10k mi

O sorry May 15 2010 @ 1325 pm. By the dealer. The car had 23800 miles on it. I installed on all 4 corners Michelin PS2's N rubber, the date code of the tires is (3008) a bit old for being installed in 2010 whatever,.... the car now has 46325 miles.

damon I did order from tire rack do i win a prize ?

Slightly OT: Are there different alignment specs for 18 vs. 17 in wheels? My 18s had the inside corners worn off very quickly. I changed to 17s for other reasons, never got around to having an alignment. Now approching 20K miles later, the 17s have worn perfectly uniformly accross. Of course they are narrower (255 vs. 285).

I looked at 2002 alignment specs: C2/4 with 17" and 18" wheels Camber = -1.2*, toe = 0.15* C2/4 with 17" and 18" wheels with low suspension Camber = -1.7*, toe = 0.15* C4S and turbo Camber = -1.4*, toe = 0.15* Summary is: 17" and 18" wheels have the same specs but are different based on standard suspension/ride height vs. low suspension/ride height The only way lowering the vehicle to the ground would affect the alignment would be if the lower suspension tie bar was removed. (Probably was if the trans was being pulled). This could allow the lower suspension pickup points to move. Otherwise putting the car in the air and putting it back on the ground will not affect the alignment.

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while I agree with the second 1/2 of this - I have yet to get 15-18k out of a set of tires...maybe 10! and OP - your comment about driving like it should be...you know that means turning the wheel and having the weight off center - ALOT! right I am wearing out my tires on the outside edges with as much camber as I can muster out of the stock suspension (even on street )

my fronts are good, but my rears are wearing out in the middle, P zeros...that came on it when I purchased it a few months ago. Any ideas? new P car owner

I love trying to drift this thing but she is not happy that way. In my vett ton's more power & torque she steps out at will its fun in either always done in a safe way ofcourse

Is there any advantage to having a little more postive camber to help on the tire wear? Not tracking the car.

buy a Camary if tire wear is your priority Porsche's like rubber....they like good rubber, and they chew it up and spit it out, and ask for more - buy good sticky tires and smile each time you replace them knowing how fun your car is and knowing you are NOT getting 20-50k miles out of a set of boring a$$ tires on a boring a$$ car I went through 8 tires last year - and I smiled my a$$ off!!

OH - you can flip some tires on the rims...I do that with my R888's evens out the wear - not all tires can be flipped

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Actually wear concentrated in the center is normal. I do not know why. At first with my Boxster I thought the tires were over inflated but over time I found that reducing the tire pressure didn't seem to matter. Then I thought the tires were under inflated and growing at high speed. Well, again over time I found a few psi higher didn't make a difference. The tires just wear in the center first, though not real bad. Noticeable but not excessive. If the car is driven aggressively on the street the right rear tire -- USA cars anyhow -- can wear faster. This is from lack of LSD which allows the inner less loaded tire to spin under sharp right turns with throttle. The important thing is the tires wear evenly at their inner and outer edges. This is a toe adjustment issue not camber. Get behind another Porsche and watch the rear tires as the car goes down the road. The tires are flat on the ground, the camber is almost gone. At the end of one alignment the alignment shop (Custom Alignment) in Mountain View told me my Boxster rear tires had a lot of camber but it was not out of spec, just at the max. alllowed. I asked about the effect this would have on tire wear -- I was having the car aligned because new tires had just been installed -- and was told there would be no compromise in tire life nor in the car's feel or handling. Having my doubts I agreed to accept the car with the excessive camber and found over the miles the shop was right.

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There is a common misconception that negative camber is the main culprit in causing inner tire when in fact having negative toe can increase more tire wear on the insides. You'll definitely want to retain negative camber or what is at least specified by the factory to retain good grip levels or you might as well be driving a Camry. Negative toe is generally synonymous with camber since the lower your car is the more negative camber and toe your car will have. Fortunately for our cars, there are adjustable toe links available to dial out some toe if one is lowered beyond a certain point to correct this.

I have to agree, toe is MUCH more influential on tire wear than camber.

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Most likely cause is rear tire psi set at factory spec (44?) & car is normally driven with minimum load of driver only & no luggage. If this is the case try setting 4psi lower, makes a big improvement in comfort too. Also wear could be caused by previous owner "jackrabbit" starts from stopped.

thanks for all the good info

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is the correct answer!!

Or you can save your tires by driving less. Why DD with expensive tires? Save the tread for fun driving.

No one noticed the OP got 23k miles out of an older set of PS2s? That's awesome! They are only rated for 15k miles when staggered sizes. Nice alignment for sure! I hope mine go that long!

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I was about to say, the man was just due.

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I guess a lot of us had missed that info as it wasn't part of the original post. I've grown accustom to people wanting to have their cake and eat it too on here so it doesn't surprise me.

Man, that is so true. I mean, it's a 911. How can so many expect to get Camry wear, BMW ride, Cadillac sound systems and Porsche handling out of a tiny sports car? I can't stop the grin every time I drive mine. 15k miles on sticky tires is fine with me. If you want more wear, then compromise the handling and get all season tires. Lifes too short for mediocre.

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+1 on this. It's a common misconception that camber is wearing your rear tires. It is excessive toe-in that causes the wear. More negative camber helps the toe wear just the insides, but properly aligned rear tires should get 20,000 miles. It's not the camber. For example, I run -3.0 rear camber on my Boxster (my main track-day squeeze) and 1.5mm toe-in on each side. My rear street tires wear perfectly evenly.