ypshan

I replaced the two rear tires and asked the service manager to give it some negative camber so the tires won't wear out on the outside. He wrote down MAX negative camber so the mechanics gave it as much as the Hunter machine would allow and still make it a "green" status.

Now the two rear wheels are really sticking out. I can tell by just looking at them.

I don't mind if this much negative camber can wear the inside of the tires out quicker as long as it improves handling.

Do you think I can lose handling by having too much negative camber in the rear? If so, I may have to go back and re-align the wheels again

Viken

Negative camber makes the tire go in at the top and out at the bottom. Where is the tire sticking out and how much negative camber do you now have.

ypshan

The tires are sticking out at the bottom. I asked him how many degrees but he couldn't tell me. Just the Max the machine allows while staying in green.

I did a very rough measure using a string and a heavy coin. When I put the string with the coin hanging right next to the bottom of the tire, I have about 1" space between the top of the string and the top of the tire. The radius of the tire is 25".

1/25 = 0.04

Since sin(2.3 degree) is roughly 0.04 as well, I figure that I have about 2.3 degrees of negative camber.

What do you think?

KPV

Shan,
If your measurements were correct, I concur on the math.
I am very surprised the tech could not give you a printout of the actual camber settings.
As a rule, the more negative camber the better the cornering ability. Without getting into all of the technical jargon concerning CG's, moments, lines of force, etc., suffice it to say that as a car corners, the outer tire flattens on the road providing a large contact patch.

PorschePhD

Man that is a ton for the street. A good -1 and -1.5 is fair for street use.

KPV

Porsche spec for the rear camber is:

USA Turbo=negative 1 degree, 25 minutes
ROW Turbo=same as USA
GT2=negative 1 degree, 50 minutes

PorschePhD

Ha....Someone get these damn numbers out of my head!! BTW that was front/rear I was talking about

Pierre

BTW, did someone manage to put more negative camber (than stock) on the front wheels? I'd need some, but my mechanics told me that the 4WD system makes it impossible... :?

--Pierre

Viken

It has nothing to do with AWD but it is next to impossible to change front camber with the stock suspension. On an ROW car, it would be -30' plus or minus 10'. If you want to go more than that, you need to get a different suspension which lowers your car more.

GreggT

Just my $.02 but any shop should give you a print-out of where all specs were when you brought it in........what OE range is.......what they left it at.

Mention your request for that when you bring it in......then add the print to your service log............see how the car drives, an then next time you will be able to request a change here/there (from before)...and, more importantly, know what they just did to your car.

I'm still working on various ideas of modifying rear control arms to help in quest to reduce rear negative.

Pierre

Thanks for the reply, Viken! My Turbo already has the H&R suspension, which is set pretty low. So, you say it should be possible to put more camber with that?
--Pierre

Ruiner

Mine were sitting at -1.5 and -1.8 when I replaced my rear tires. I had them adjust them to -1.1 and -1.2 (both were in the green).

Viken

Yes.

PorschePhD

Remember that the camber can be adjusted like Viken says, however a lot of dealers or shops in general will place an aggressive camber on it because the tires and wheels are over sized and they are trying to keep the tires from rubbing. Instead of rolling the fenders they will set more negative camber to roll the wheel in and avoid this.

DJF1

Take it to a race mechanic that has a good reputation to setup your car properly...Gee....Hunter gives you detailed camber, toe etc values...The "green" on the hunter machine underneath has the value in numbers visible at all times. Also the "green" is relative to which car the "mechanic" input at the start of the session as different setups are stored, if he made a mistake which is likely God knows what setup you have there... I would not trust an idiot like this with the work he did. Setup of the car is so important it can lead to a heavy accident if you push it and the car is unbalanced as it may surprise you with the handling.

Get your car properly balanced ( corner balance, alignement etc) and you will see the difference.