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-   -   Suspension (lowered) issue (http://986forum.com/forums/showthread.php?t=12371)

jbboxsters 07-25-2007 10:48 AM

Suspension (lowered) issue
 
On my 02 Boxster S with lowered suspension the rear tires (and maybe the front but to a far less degree) have the camber off enough that it is visible from the rear of the car that the inside of the tires are going to wear much more than the outside. The tire store told me there is no camber adjustment and the only correction was to raise the car back up. Does that sound correct? The reason the car was at the tire store was because the rear tires were completely worn down on the inside edge only. I just purchased the car and was told it was lowered by a very reputable customizer.

Thanks,

Jerry :confused:

insite 07-25-2007 11:09 AM

Quote:

Originally Posted by jbboxsters
On my 02 Boxster S with lowered suspension the rear tires (and maybe the front but to a far less degree) have the camber off enough that it is visible from the rear of the car that the inside of the tires are going to wear much more than the outside. The tire store told me there is no camber adjustment and the only correction was to raise the car back up. Does that sound correct? The reason the car was at the tire store was because the rear tires were completely worn down on the inside edge only. I just purchased the car and was told it was lowered by a very reputable customizer.

this is very common. the problem is that our rear toe changes significantly as we modify camber. when you lower the car, proper camber settings would make the car pidgeon toed. the correction is to purchase a set of toe steer arms from either Tarrett Engineering or The Racer's Group. i think there is a slightly used set on rennlist right now for $300.

jordan986 07-25-2007 11:18 AM

my boxster is lowered and I got the camber adjusted in the rear.. I cant see the 02 s not having room for adjustment in the rear. I have heard from the factory there is not much room for adjustment in the rear but there is some. That being said I sugest you take it to a different shop (perferably on that knows porsche) and have them do something with it. Depending on how much it has been lowered you may need to get adjustable rear strut mounts for more adjustment.
http://www.pelicanparts.com/catalog/shopcart/996M/POR_996M_SUSprf_pg3.htm

let us know how it goes :cheers:

insite 07-25-2007 11:22 AM

Quote:

Originally Posted by jordan986
I cant see the 02 s not having room for adjustment in the rear. I have heard from the factory there is not much room for adjustment in the rear but there is some.

the real problem is that the factory toe links are too short. the toe eccentrics can't toe the car out enough to meet spec with normal camber on a lowered car. the problem effects many cars. i've personally aligned quite a few with this problem.

jordan986 07-25-2007 11:30 AM

Quote:

Originally Posted by insite
the real problem is that the factory toe links are too short. the toe eccentrics can't toe the car out enough to meet spec with normal camber on a lowered car. the problem effects many cars. i've personally aligned quite a few with this problem.

hmmm maybe I should have a look at mine! So your saying the degree of correction is not enough from the factory, is it just some cars that suffer from this problem or all? Depending on the lowering can the factory toe links be sufficient or is it necessary to change them no matter how low?

racer_d 07-25-2007 11:49 AM

Quote:

Originally Posted by jordan986
hmmm maybe I should have a look at mine! So your saying the degree of correction is not enough from the factory, is it just some cars that suffer from this problem or all? Depending on the lowering can the factory toe links be sufficient or is it necessary to change them no matter how low?

If your car was set as "factory delivered" this wouldn't be an issue. Since you, or the previous owner, lowered the car, you are now on the slippery slope of modifications. Will new $300 arms be the answer? perhaps. Will learning to live with tires that wear out a few thousand miles early be ok? We all make compromises.. now its time to decide on yours ;)

That said, having an appropriate amount of negative camber will improve the car's handling with the trade off of potentially higher tire wear.

porsche986spyder 07-25-2007 12:13 PM

I see 2 factors comming into play here. 1) how low are your going exactly? 1.5" or 2", etc...??? 2) What size rims are you using and what is the rims offset from the center of the cars hub? These 2 will be different from most everyones car, so many different people will have more than one answer for their car having or not having enough negitive camber. It all just depends on your setup.

insite 07-25-2007 12:29 PM

Quote:

Originally Posted by jordan986
hmmm maybe I should have a look at mine! So your saying the degree of correction is not enough from the factory, is it just some cars that suffer from this problem or all? Depending on the lowering can the factory toe links be sufficient or is it necessary to change them no matter how low?

racer_d is right...to an extent. many boxsters, including my own, don't have enough toe adjustment even for the RoW M030 suspension, which is a factory option. porsche986spyder is right in that the degree of the issue is heavily dependant upon the amount your car is lowered.

MOST cars can handle M030 RoW with no problem. MANY cars can handle the Eibach with no problem. i have seen NO cars that can handle the H&R springs without a problem.

the factory camber spec in back should be around -1.6 to -1.8. tires will wear fine at these settings. my personal car will have WAY too much toe in unless i'm running at least -2.4 degrees of camber. it just so happens that my particular car was on the upper end of the camber spectrum from the get go (i can get up to
-3.2 degrees in back and -1.7 degrees up front with no camber plates).

other cars are camber challenged in that they can't ever seem to get more neg camber than the factory spec. it's the 'slop' (tolerance stack-up in engineer speak) that causes this.

the only solution is aftermarket toe links, which still may not entirely cure the problem (although they will greatly improve it). it all depends upon your particular car.

to determine your car's minimum neg camber (rear), you set the toe links to full toe out. you then adjust the camber until you have zero toe (changing the camber changes the toe). when you have zero toe, you measure your camber. this is the minimum negative camber that your car is capable of as it is currently set up. on most cars at factory height, this will be in the -1.4 range. you run into problems with tire wear at and beyond -1.9 degrees.

jordan986 07-25-2007 12:51 PM

hey thanks for clearing that up for me hope it helps jbboxsters as well. I'll have to get that checked asap thes cars are not the greatest on tire wear no sense in adding to it... even if I have to buy arms it'll still be cheaper then replacing tires earlier then necessary!

thanks again :cheers:

jbboxsters 07-26-2007 06:11 PM

Quote:

Originally Posted by porsche986spyder
I see 2 factors comming into play here. 1) how low are your going exactly? 1.5" or 2", etc...??? 2) What size rims are you using and what is the rims offset from the center of the cars hub? These 2 will be different from most everyones car, so many different people will have more than one answer for their car having or not having enough negitive camber. It all just depends on your setup.

I have 18" Kinesis rims with 285/35/18 ttires, the hight to the top of the rear wheel well is aprox. 25.75". I don't know what the stock height is supposed to be, but it appears that the lowering was done by just installing lowering springs, but I am not sure how I would know for sure.

jbboxsters 07-26-2007 06:21 PM

According to the sheet that I received from the tire store (generic name to protect the innocent) the rear camber was set to -1.65 right and -1.91 left. The spec was -2.00 to -1.00. the toe was set to 0.25 right and 0.07 left. The spec for toe was 0.00 to 0.17. With that info it would appear that the alighment was in spec (or very close) and the tires are visibly at an angle with the bottm of the tire sitting further out than the top. Using a level it appears that the top of the tire is in about 0.6-0.8" off vertical level.

insite 07-27-2007 03:45 AM

Quote:

Originally Posted by jbboxsters
According to the sheet that I received from the tire store (generic name to protect the innocent) the rear camber was set to -1.65 right and -1.91 left. The spec was -2.00 to -1.00. the toe was set to 0.25 right and 0.07 left. The spec for toe was 0.00 to 0.17. With that info it would appear that the alighment was in spec (or very close) and the tires are visibly at an angle with the bottm of the tire sitting further out than the top. Using a level it appears that the top of the tire is in about 0.6-0.8" off vertical level.

first off, if your car is lowered, it was done with springs. second, the camber spec is NOT -1.00 -> -2.00, it's -1.33 -> -1.9.

-1.6 -> -1.7 is a good goal. your left and right settings are VERY different from one another. they should be nearly the same. your toe difference is significant, too. the shop did a crappy job with your car. take it back and complain.


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