Bill Lehman

I ran the Schattenbaum DE at NJMP the last two days. Both circuits used are clockwise courses. My car is a Cayman running R888 tires. During one session I noticed that the steering wheel was at about a 10 degree angle off center while running down the straight. After returning to the pits I noticed that the PSM, which had been on, was "disabled". After a lot of inspection, we found that the left rear wheel had severe toe in. The car had recently been aligned and I had measured 0 toe on that wheel after the alignment. With some help, we got the eccentric on the toe rod loose and managed to get rid of the toe in and using "eyeball" aliignment now seem to have a little toe out. The eccentric was very tight and it seems unlikely that it moved. Everything appears straight and there is no noticable play. Although there is now a little toe out and a little steering wheel angle in the other direction, the PSM is happy and the car is tracking reasonably straight. Assuming the eccentric did not move, does anybody have any idea about what could have caused a sudden change in toe? It looked like the front edge of the tire had moved about 3/8" inboard judging by the fender well. I didn't hit anything.

Larry Herman

How's the camber eccentric Bill? If that moved, then it would change your toe and may not be as noticeable.

Darren

Why would you want 0 rear toe? I'm guessing that would be diabolical under the brakes. I agree with Larry that one of the adjustments might have moved. But setting it to 0 makes me think they don't know what they are doing anyway. So either something moved or the alignment shop f'd up.

d15b7

larry beat me to it; a relatively small change in camber on a strut car can make for a big change in toe! i bet the camber slipped somehow, and threw the toe way off...

good luck!

todd
ReidSpeed

Bill Lehman

I got a chance to to get under the car today while switching back to street pads and tires. I couldn't tell where the camber eccentric bolt was originally set but without loosening the nut, I was able to move it with moderate effort using a combination wrench. The bolt head was in an inboard position so I'm thinking that the camber did move. What is the torque # for the camber bolt? Darren suggested that 0 toe was incorrect. What should rear toe be for a street/track car? Larry, do you need a test dummy for the alignment clinic?

kurt M

If this were my car I would take the car back to the shop where the line work was done and get it redone. This time with more care taken to torque and check the nuts and bolts. They messed up and could have caused you more harm that was done. All the fastners need to be checked.

Larry Herman

Bill, I have a car arranged for the clinic, but if it changes I'll let you know. Of course, you could always throw $$$ at me.

As far as torque, I don't know because I have to use box wrenches to tighten them. I put a 1' extention pipe on mine and tighten the crap out of them. As far as the toe spec, I do not have that handy, but I would feel that 3/32" per side would be in the range.

insite

0 toe in back on a cayman is fine. usually i have them set it JUST a tad toe in & run zero up front. FYI, if you run slicks, it's possible for the toe link eccentrics to move. tarret engineering makes an assembly that locks them in place. basically, the toe links are replaced w/ double adjustable rod type links & the eccentrics are locked at full extension.

in this case, it sounds like your camber eccentric moved. FYI, the torque spec for that fastener is 81ft-lb. this is a common mistake by an alignment shop because this fastener is difficult to tighten with the wheel on and the diagonal in place. this was laziness on the part of the shop.

the 3/32" per side quote from larry may be a tad much toe in for a cayman.

Darren

I'd just be nervous about running 0 rear toe, if you get any deflection on braking you'll get toe out which is always exciting. I can drive a car with messed up camber, front toe out, in whatever. Rear toe out? Its scary as crap.

Larry Herman

I just checked the specs for a 986 and it calls for 5' +or- 5'. That is essentially a range of 0 to 2/32s toe in. Like Darren says, especially on the track I'd rather have some toe-in.

insite

the boxster's rear suspension geometry results in toe-in deflection under braking. on tighter tracks (fastest turns < 100mph) & auto-x, i prefer zero toe front & rear. on tracks with transitional sections greater than 100mph, i like about 1/16" total rear toe in & still zero up front.

on a lot of cars, people like to use a bit of toe out up front to sharpen turn-in. i have tried this w/ the boxster; the car hunts excessively on straights & braking gets pretty hairy. i like zero toe up front in all conditions.

insite

one more note: the rear subframe to which the control arms mount can flex over bumps. this results in camber loss & can cause snap spins over uneven pavement in corners. if you experience this (or prefer not to), consider installing a jack bar to stabilize the lower control arm locations. mantis sport sells a decent one; they're also easy to make. search for 'lower stress bar' here or on 986forum.

Larry Herman

Did the search & can't find it. Please point me in the right direction. Thanks.

NJcroc

I believe he means this product,Ernie over at mantis has some great stuff

http://mantissport.ca/tabid/55/ProductID/5/Default.aspx

insite

that's the one. ernie & stan make some great parts for boxsters & caymans; they campaign the yellow 007 cayman in PCA. i have that exact lower stress bar on my car; it really solidifies the back of the car, especially over bumps.