really uneven rear tread wear? - 986 Forum - The Community for Porsche Boxster & Cayman Owners

FUHRIUS · 03-29-2005, 10:02 AM

just burned through the my rear pilot sports...bought the car at 24k miles with lots of tread, put 4k on it so far, and I can't believe how fast they've gone. fronts looking good.
the rears are really worn on the insides and less so on the outsides. is that common on boxsters, or do I have a set up issue. I'm wondering if my 21mm wheel spacers are contributing to the problem...

Perfectlap · 03-29-2005, 10:24 AM

when was the last time the car had an alignment?

FUHRIUS · 03-29-2005, 10:55 AM

service records indicate in was done about two years ago, at 14k mies.

YellowJacket · 03-29-2005, 11:11 AM

Rumour has it that Boxster rear tires just don't last (I'm guessing due to the tons of negative camber). I had heard consistently 15k miles out of the rear tires.

That being said, mine are almost-new, and I have put 7k on them so far. I fully expect them to last quite a bit longer than 15k. But I drive like an old lady most of the time. :-)

Brucelee · 03-29-2005, 11:18 AM

Alignment, tire pressure, driving habits, wheel balance, quality of tire.

All impact tire wear to a tremendous degree!

Perfectlap · 03-29-2005, 11:30 AM

just my experience, when the tires start to go they go quickly. I check my tire pressure with each gas tank 32F and 34R. (It was the other way around with my old car) and usually do custom alignments where negative rear camber is maxed out. But with this Boxster I decided to stick with Factory specs. I figure Porsche would know better than me.
Accelerating hard/often from a stop (red lights) will significantly eat into your rear tread life.
Your car sounds like it was tweaked often, did the previous owner go beyond Factory specs?
From reading the Porsche reviews on TireRack.com 24k sound like you got your miles worth. Some reviews complained about only getting 15K out of PS's.

RandallNeighbour · 03-29-2005, 12:03 PM

I noticed that due to the positive camber of the rear wheels as I see them on my boxster from the back, it would just make common sense that the inside edge of the tires would probably wear more than the outside edge.

With this in mind, I plan on having the rubber knocked off my wheels and mounted on the other side. I have dreamed up this strategy to rotate tires that are unidirectional. Thus, the inside of the left tire become the outside of the right tire.

My mechanic told me that if I didn't wait forever to do it, it would extend the life of my oh-so-expensive tires. Thought I'd post this for others to consider.

If you know why this would not work, do post it here so I can have my common sense realigned and balanced, not my Boxster

Subanez · 03-29-2005, 02:10 PM

For your birthday, Yellow Jacket, you ought to drive not like an "old lady," but like a speed demon!

HAPPY BIRTHDAY!

Lux · 03-29-2005, 02:33 PM

The Boxster has a lot of weight on the rear tires. On top of that, you're probably running a lot more negative camber due to your lowering springs. These two things add up to fast tire wear.

I wore out my rears in 10K miles at stock height. Unfortunately, as a daily driver, a lot of my miles are straight and on the freeway. A lot of negative camber is good for the twisties but bad for straight line.

I don't know what the factory camber settings are, but if you do a lot of straight line driving I would suggest no more than 1.5 degrees negative. Due to the Boxster using a Mac strut design, this might not be possible when the car is lowered.

-

Perfectlap · 03-29-2005, 03:24 PM

which tires did you wear out in only 10K miles? wow, that's way less than a year's driving for me.
The funny thing is, ever since I bought this car I drive about twice as much as I did with my Miata.
I think I rarely averaged more than 7K a year with the Miata and since buuying the Boxster in November I have already driven nearly 4K. Lots of weekend miles

Adam · 03-29-2005, 05:34 PM

My pilot sports still look ok. I tried to do a burn out once or twice and just got a bunch of wheel hop. I even get wheel hop on the 1-2 shift lots of times. I guess IRS is good for corners...not so good for peeling out

Perfectlap · 03-29-2005, 05:58 PM

why does the Boxster's rear wheel hop? I noticed in one magazine's(R&T?) 0-60 test they complained about "ridiculus amounts of rw hop".
I noticed this on another Boxster taking off during an Atuocross way before I bought mine and thought it was driver error. None of the rear wheel drive cars ever displayed this,better drivers?

Lux · 03-29-2005, 06:25 PM

Quote:

Originally Posted by Perfectlap

which tires did you wear out in only 10K miles? wow, that's way less than a year's driving for me.

I have Yoko AVS Sports. I probably could've gone a few more miles but with the rain I was seeing at the time it was getting dangerous. Regardless, it'd be pretty much the same for all high perf tires. All of you getting 15K or so out of your tires, make sure that you check the inside tread as the outside can look fine. Tires are something you don't want to penny pinch.

I'd recommend swapping the tires side to side every 5K miles for max mileage. If you have directional tires, then that means having them unmounted and then remounted/balanced.

-

Schwarzer Kater · 03-30-2005, 07:20 AM

That's common for RWD vehicles......they go out fast and uneven. Even worse because you can not rotate due to the difference in wheels.

UKBXSTR · 03-30-2005, 10:55 AM

Agree with Lux - lowered suspension and excessive spacers all lead to increased tyre wear.

My Mich Pilot Sports are wearing better on the Box than the Contis did on a BMW 330 DIESEL (which lasted 9k miles in normal driving). Put Yokos on the BM and they were like new after 5k miles.

I'm reckoning on 14-15k on my rears and i do drive it pretty hard, but no track days or autocross

graybeard · 03-30-2005, 12:16 PM

When I asked the service guy about the correct camber on my car he told me .5 was the factory setting sure looks like more than that, but who am I to say.

A sure sign of bad alignment is tire cupping. Easy to watch for this just run your hand along the inside edge of the tire, if adjacent treads feel uneven there is an alignment problem. The tires will go fast from this point.

FUHRIUS · 03-30-2005, 01:36 PM

it's all ringing true...
My car is lowered 1 inch from stock s height, I run 21mm spacers in the back for a better look, I do mostly straight line 'round town driving, the engine mods that were done to this car beg for me to goose it at almost every chance I get...and the result is a set of pilot sports that have completely petered out after about 9k miles.
As I reflect on it, I'm not sure I'd change any of the above just for a little better tire wear...these are the reasons I dig my boxster in the first place!

Now it's time to figure out what my next tires will be...but I don't see any reason to abandon the pilot sports.

Adam · 03-30-2005, 02:38 PM

Quote:

Originally Posted by Perfectlap

why does the Boxster's rear wheel hop? I noticed in one magazine's(R&T?) 0-60 test they complained about "ridiculus amounts of rw hop".
I noticed this on another Boxster taking off during an Atuocross way before I bought mine and thought it was driver error. None of the rear wheel drive cars ever displayed this,better drivers?

Axel hop is a common character trait of cars with Independent rear suspesions. Solid rear axel cars are better for launhes( stangs, camaro's etc etc)