I found that the both my rear tires on my 08 C4S are wearing unevenly with the inner side taking a beating. Initially I thought it was alignment, but the dealer informed me that this is in fact how the C4S are aligned for handling purposes.

Before I pick up new rear tires, I just wanted to confirm that this is normal? The fronts are fine. Should I get the car aligned so that they wear evenly after I pick up new tires, or is it best for the car/handling to leave alignment as is?

 

May be too much negative camber which causes the wheels to tilt inward contributing to tire wear on the inside edge of the tires. The link below will answer all your wheel alignment questions.

http://www.tirerack.com/tires/tirete...e.jsp?techid=4

 

Sounds right on par. I have 325's on the rear and need to regularly swap the rears around (Left Rear to Right and vise versa) otherwise I'll be bald on the inside. Just normal wear because of the Negative camber.

 

Are you a C4S as well? How many miles do you switch the rears from left to right to balance out the camber?

 

I'm a C2S. However, I know a handful of C4S guys and their rears wear much the same as mine (All depends on Driving style). I usually have them swapped around once per year. I don't track my car, normal driving with a little give & go, I'll get about 25K-35K.

 

So has anyone aligned their rear to eliminate the negative camber and uneven wear? Dealer told me that the cars are aligned this way for better handling, but I just wanted to confirm that.

 

Yeah. What he said.

It's pretty much universal you are going to get 2 sets of fronts to a set of rears on a 911. They come from production with close to 2 degrees of neg. camber, and it does wear the inside shoulder faster. The camber allows the car to "climb" onto the sweet spot of the contact patch during hard cornering, and does increase handling. All of that camber should not be taken out, but you can have some of it removed. Doing so will give you about 20% of the rear lifespan back. Just remember to actually get down (yes, as in lie on your back and slid under the rear of the car) and look at your inside shoulders once in awhile to see where your wear is at. I get calls all the time from people that have nice looking tires outside, and are showing cords inside.

Call me if I can help.

 

Thank you Damon. That's the response I was looking for. Wasn't sure if I should or should not remove the negative camber for the sake of tire life, but it sounds like it's there for a reason so I'll leave it untouched and just eat the cost of rubber. I did in fact find the uneven wear, unexpectedly, while lying on my back underneath the rear of the car.

Looks like I'll be getting new tires soon, and will definitely call you for a quote.

 

My experience also 2 sets of rears for one set of fronts. 12 years 50000 miles 996 99 Cab. Leave the camber alone it could save your life!

 

Unless your rear camber is actually off, which I doubt, Porsche Engineers spent countless hours figuring out the exact degree at which to run. I understand that you might not be use to seeing negative camber on rear wheels, but this is how road sports cars run. Most drivers don't adjusting the tire pressure every time you drive the car, Porsche runs negative camber to help increase the patch between rubber and asphalt. I'm not sure you're aware how negative camber works, take a look at the tirerack guide posted above. Please don't protrude my response as rude, as that is not my intent. I just really don't want you "correcting" Porsche's Engineers because the tires appear inverted and wear heavily in the back. It's the way it's suppose to be!! Just flip rears and enjoy the car.

 

No offense taken - thank you for the insight. I am coming from an audi equipped with quattro, and wasn't sure if the 4s all-wheel drivetrain was supposed to run in similar fashion.

I'm not used to seeing negative camber, and my thought was initially that the alignment was off. This is my firs p-car, and although I've had it for almost 4 years, I'm still learning about it as it's not my DD. Now that I know that negative camber is in place for a reason, I won't be adjusting anything. Instead, I'll be happily purchasing a new set of rears.

 

I thought our tires were directional? Can you actually rotate them?

 

They are directional, sorry, perhaps my explanation wasn't clear, you need to remove the Tire off the rim and swap the tires, do NOT swap your tires & rims!

 

They didn't say owning a Porsche would be cheap! Glad to help.

 

Perfect! VERY clear now.