Will a little excess camber on one side cause car to drift in opposite direction?

[DaveInLA]

1989 BMW 325is, RWD

The camber on the front driver side is -1.3. On the passenger side, it's -2.1. Car was involved in some sort of collision on the passenger side before I owned it, but no obvious damage to suspension components can be seen.

Anyway, I had the car taken in for an alignment a short while ago. The toe was adjusted so that it's a little positive now, but the camber was left alone [in these cars, only front toe can be aligned, nothing else]. Before the alignment, the steering wheel had to be pointed about 5-10 degrees to the left for the car to go straight [ie, car drifted a little to the right if steering wheel straight]. After the alignment, it's now the reverse but much less [
My question is if the difference in camber [very high on right side] could cause the car to do this.

 

[mechtech]

Also see if eccentric aftermarket strut bolts can be obtained. They are around $20.00.
If you drive aggressively a lot, you wil actually get better handling AND better wear with a little moe neg camber.
For normal driving, I'd stick with around -1 deg, though.

 

[Gary Allan]

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Usually caster has more effect on pulling

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I would rather say that caster has more of an effect on "drift". In the traditional (antiquated by today's standards) front end the caster was set to have the car drift to the left, IIRC. I normally equate "pull" with the wheel wanting to turn on its own in that direction (hands off). With caster adjustments, no turning of the wheel would be required for it to drift in that direction, just an infrequent and minor realignment on the road. I believe that the driver side was more positive (it's been a very long time).

 

[DaveInLA]

Spec caster for this car is in the -1.0 range, so I'm okay with the -1.3. The -2.1 is a bit high, but I know a lot of people who track these cars run camber that high (or more). I wouldn't mind it too much if both wheels were aligned the same (ie, both -2.1), but I think the asymmetry is what's causing my car to drift to one side. Annoying. Also, the tires I just got rid of that I got from the previous owner were worn on the inside, especially in the R front tire. It was dramatically more than the L front tire.

I'll look into the camber plates, but they're expensive (in the range of $300). I've never heard of eccentric strut bolts.

Why would caster have an effect on drift if the car is pointed straight? Caster only matters when a car is turning, right? Anyway, both of my front wheels are a little short on caster (in the 6-7 range, spec is 8), but it's equal on both sides. The camber plates I'm looking at can adjust caster as well.

 

[ChrisW]

A solution thats rather crude would be to enlarge the upper strut mount holes to move the strut around so you can change camber (thats if you have this type of strut setup). Similar to a camber 'plate' and its practically free. Except that a camber plate would yield more consistent results.

 

[jamesn]

its only crude to oval the top bolt mounts and adjust the camber that way if you dont use JB weld to take them in place.

 

[Gary Allan]

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Caster only matters when a car is turning, right?

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Caster is responsible for stability ..or rather stated, ill set caster can upset stability. Drag a table with "casters" on it. The point of contact trails the axis. Try doing it backwards and see how easy it is to keep the wheels straight.

Older cars with bias tires had neg caster. The mans wanted figure light steering. Dampening was provided by the bias tire "pinch".

 

[RH+G]

Your car is not drifting to the left cause of the camber. The toe is off. The diffrence in camber would make your car drift to right. It always pulls to da side of the lower camber. Camber and Caster are two totally different things. What were your caster readings??

 

[Gary Allan]

The toe is off.

Toe will never cause a pull. It will either "plow" or wander. Now if you're saying that in the wandering (toe out condition) one cycle causes more of a reaction to one side, then I'll go with camber being a contributing factor.

 

[TheLoneRanger]

Dave, it obviously has in your case. (Usually caster has more effect on pulling). It's a compromise, but reducing the toe-in closer to 0 might stop the drifting to the left.

A better solution would be to install adjustable camber plates. They'll adjust from about +1* to -3.5*, which would compensate for any frame/suspension misalignment you might have. They'll also have a caster adjustment, which is probably off too.....

Not sure what the alignment specs are for your car, but around -1* camber is about right for a street driven car. The -2.1* is not all that bad, but might cause some inside tread wear.....

 

[DaveInLA]

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The toe is off. The diffrence in camber would make your car drift to right. It always pulls to da side of the lower camber. Camber and Caster are two totally different things. What were your caster readings??

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The toe is +0.14 on the R and +0.13 on the left (toe in, meets specs), so they're pretty even. The caster is actually low in both wheels, 6.2 R and 6.4 L (should be in the 8 range).

As far as the camber goes, the right wheel is more negative ("higher") than the left. Wouldn't that cause the right wheel to wander to the inside (ie, to the left like my car), kind of like how a motorcycle rider leaning to one side will turn toward that side?

Anyway, my car doesn't pull the steering wheel to one side. If I angle the steering wheel a tiny bit, it'll drive straight without trying to go in one direction. It's just that the wheel isn't centered properly.

 

[Tosh]

Perhaps a body shop or BMW specialist could strategically beat on something to even out your alignment?

 

[Gary Allan]

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The toe is +0.14 on the R and +0.13 on the left (toe in, meets specs), so they're pretty even.

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Someone update me (and I really mean update me). Aside from the steering wheel being straight ..why would toe be different on one side or the other? Total toe in is, in this case, +0.27. If it's on one wheel only ..the wheels will automatically distribute this between them. The tire with all the static toe would not be in the static toe position when moving. It would have its +.13 or +.14 while in motion.

Have they managed to over complicate this too

(or is the term "refinement and enhancement appropriate in this situation)? As in (visions of Monty Python and the Holy Grail while reading how to pull the pin and count on the Holy Hand Grenade) "The camber must be set to xxx when the toe is a +.14 WHILE the other wheel is set to +.13 with a camber setting of xxx..

 

[thrace]

The difference in camber and caster could cause drift. The camber setting could cause slight drift to the left but should be very minor. The caster would drift slightly to the right. Do you have rear wheel alignment specs? If the thrust angle is off, it could be more important than these small camber and caster differences.

 

[DaveInLA]

The drift to the left is very minor. It used to be prett significant to the right side before the alignment, but I figure that if I'm going to pay $50 for an alignment, it has to be done right. But if it's from the camber, then there's nothing the shop can do (camber not adjustable).

Rear wheel alignment is not adjustable per BMW. Thrust angle is -0.07, which is within spec (-.25, +0.25).

 

[Hirev]

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Anyway, my car doesn't pull the steering wheel to one side. If I angle the steering wheel a tiny bit, it'll drive straight without trying to go in one direction. It's just that the wheel isn't centered properly.

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Caster needs to be the same on both sides of the car to avoid the tendency to pull to one side WITH THE STEERING WHEEL CENTERED.

 

[CoosBayDave]

See if a product called EZ-Cam is availiable for your car. Our car, like most unibody cars now, only have toe in/out adjustments. Made a world of dif here.

 

[Gary Allan]

" quote:Anyway, my car doesn't pull the steering wheel to one side. If I angle the steering wheel a tiny bit, it'll drive straight without trying to go in one direction. It's just that the wheel isn't centered properly.


Then the alignment tech didn't center and lock the wheel before setting the toe. He was lazy. What you're describing has nothing wrong with the alignment ..and everything wrong with the technician.

I also agree with HIREV ..except I'll add "with hands off on a non-crown road".

 

[DaveInLA]

Thanks, I think I'll take it back to the shop to see if they can get the steering wheel centered properly this time.

Still, I feel that a 0.8 difference in camber between the two wheels is a bit too much. Hopefully I'll be able to find some way to adjust that.

 

[Gary Allan]

Dave, when it's on the rack, place a weight that is about your mass in the driver seat. See what the riding height gets altered ..and what subsequent altered readings that you get with that in place.

I'm not acquainted with your frontend ..but "back in the day" if you had a large(r) driver ..or towed (or whatever), to get a true alignment, you had to simulate that "outside of factored" element into the process.

Good luck.