02-19-2007, 12:42 PM
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#1
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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Tire Wear
I had my car aligned by the local dealer when I put these tires on the front 22,000 miles ago. Usually I'd suspect the car has too much negative camber or is toed out, but some have told me this is normal. What say ye?
__________________
1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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02-19-2007, 01:22 PM
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#2
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Guest
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Paul, I thought you drove your car hard! I say your tires lasted a lot longer than average. Go get some new ones! And don't worry about it. 
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02-19-2007, 02:02 PM
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#3
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Hi,
Hard to tell from just the pics. If most of your driving is straight-ahead Freeway driving, than I'd say you have an issue, but if you drive primarily in the twisties, given the mileage, I'd say there is no problem.
The stock Boxster has positive Toe and positive Camber (+5' ± 5' and +5' ± 30' respectively). So negative Toe and Camber can't be the issue. But what may be the culprit here is the allowable difference L to R for both Toe and Camber (-1° 20' ± 30' and 20' respectively). This sort of looks like the case to me, as if the tires are fighting each other. I'm also assuming that you don't travel with excess weight in the front? In any event, 22k mi. from the fronts is about in the middle of the normal wear range...
Happy Motoring!... Jim'99
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02-19-2007, 02:28 PM
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#4
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Registered User
Join Date: Apr 2006
Location: Chicago
Posts: 585
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How many total miles on your car?
Not saying this happened to you but after only 15,000 miles on the odometer of my 02 S the toe at all four corners was out of spec along with the front caster.
I would highly suggest that you have the alignment checked right after you throw on new rubber.
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02-19-2007, 03:03 PM
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#5
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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Quote:
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Originally Posted by MNBoxster
Hi,
Hard to tell from just the pics. If most of your driving is straight-ahead Freeway driving, than I'd say you have an issue, but if you drive primarily in the twisties, given the mileage, I'd say there is no problem.
The stock Boxster has positive Toe and positive Camber (+5' ± 5' and +5' ± 30' respectively). So negative Toe and Camber can't be the issue. But what may be the culprit here is the allowable difference L to R for both Toe and Camber (-1° 20' ± 30' and 20' respectively). This sort of looks like the case to me, as if the tires are fighting each other. I'm also assuming that you don't travel with excess weight in the front? In any event, 22k mi. from the fronts is about in the middle of the normal wear range...
Happy Motoring!... Jim'99
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The wear is on the inside of the tires.
Here's the "after" readings from the alignment I had done 22,000 miles ago:
Camber: Left 0 degrees 12 minutes Right 0 degrees 2 minutes
Caster: Left 7 degrees 52 minutes Right 7 degrees 44 minutes
Toe: Left 0 degrees 2 minutes Right 0 degrees 3 minutes
I used these tires to drive 7000 miles to the last two Parades and back, but the rest is mainly in the twisties. Both trunks were fully loaded for the Parade trips.
BTW my rear tires always wear out with the same pattern every 15,000 miles. During the same alignment the rears were set at:
Camber: Left minus 1 degree 40 minutes Right minus 1 degree 42 minutes.
Toe: Left 0 degrees 5 minutes Right 0 degrees 6 minutes
Total toe: 0 degrees 11 minutes
Thrust angle: 0 degrees 0 minutes
The car has 57,000 miles...
__________________
1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
Last edited by Paul; 02-19-2007 at 03:07 PM.
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02-19-2007, 03:27 PM
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#6
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Registered User
Join Date: Apr 2006
Location: Chicago
Posts: 585
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Quote:
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Originally Posted by Paul
The wear is on the inside of the tires.
Here's the "after" readings from the alignment I had done 22,000 miles ago:
Camber: Left 0 degrees 12 minutes Right 0 degrees 2 minutes
Caster: Left 7 degrees 52 minutes Right 7 degrees 44 minutes
Toe: Left 0 degrees 2 minutes Right 0 degrees 3 minutes
I used these tires to drive 7000 miles to the last two Parades and back, but the rest is mainly in the twisties. Both trunks were fully loaded for the Parade trips.
BTW my rear tires always wear out with the same pattern every 15,000 miles. During the same alignment the rears were set at:
Camber: Left minus 1 degree 40 minutes Right minus 1 degree 42 minutes.
Toe: Left 0 degrees 5 minutes Right 0 degrees 6 minutes
Total toe: 0 degrees 11 minutes
Thrust angle: 0 degrees 0 minutes
The car has 57,000 miles...
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My vote is have the alignment checked. Excessive weight in the front could give you enough camber to wear out the tires in this fashion. Combine this with out of spec toe and it gets worse. Out of spec caster through a lot of sharp twisties could also give you a similar wear pattern. Regardless of the likelihood of any of these, I still think it would be peace of mind to have the alignment checked with new rubber and before you set out for a long journey.
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02-19-2007, 04:50 PM
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#7
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by Sammy
My vote is have the alignment checked. Excessive weight in the front could give you enough camber to wear out the tires in this fashion. Combine this with out of spec toe and it gets worse. Out of spec caster through a lot of sharp twisties could also give you a similar wear pattern. Regardless of the likelihood of any of these, I still think it would be peace of mind to have the alignment checked with new rubber and before you set out for a long journey.
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Hi,
Agree. You should always have a 4-wheel alignment done everytime you add new rubber, even if it's just to one axle. Misalignment on the other axle will affect the tire wear on the other...
Happy Motoring!... Jim'99
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02-19-2007, 04:55 PM
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#8
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Porsche "Purist"
Join Date: Aug 2003
Location: Wisconsin
Posts: 2,123
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I wonder if the car is supposed to be loaded (weight of driver and passenger) when the car is aligned?
In my case (250 +130)= 380 lbs plus luggage....
__________________
1998 Boxster with 7.8 DME, 2005 3.6 liter/325 hp, Variocam Plus, 996 Instrument panel
2001 Boxster original owner. I installed used motor at 89k.
1987 924S. 2002 996TT. PST-2
Owned and repaired Porsches since 1974. Porsche: It's not driving, it's therapy.
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02-20-2007, 06:21 AM
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#9
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Registered User
Join Date: Apr 2006
Location: Chicago
Posts: 585
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Quote:
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Originally Posted by Paul
I wonder if the car is supposed to be loaded (weight of driver and passenger) when the car is aligned?
In my case (250 +130)= 380 lbs plus luggage....
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I've seen cars aligned with the weight of the driver but nothing to represent a load in the trunks. I would recommend that when you get the alignment done that you ask them to align the car with you in the drivers seat. I wouldn't recommend trying to reproduce your "loaded" weight in the trunks.
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02-20-2007, 06:34 AM
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#10
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Registered User
Join Date: Sep 2005
Location: Minneapolis/St. Paul, Minnesota, USA
Posts: 3,308
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Quote:
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Originally Posted by Sammy
I've seen cars aligned with the weight of the driver but nothing to represent a load in the trunks. I would recommend that when you get the alignment done that you ask them to align the car with you in the drivers seat. I wouldn't recommend trying to reproduce your "loaded" weight in the trunks.
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Hi,
Good point, but also be sure to have a Full tank of Fuel and the spare and tools in the front at minimum. If you always drive with a greater load than this, then that should be present for the most accurate alignment (with the caveat that if you change this gross weight at any time, the alignment, feel and possibly tire wear will change as well, maybe imperceptibly so, but it will)...
Happy Motoring!... Jim'99
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