Rear Camber Adjust - Does It Affect Rear Toe?

[Munkyb0y]

Hey guys, ive got a question I couldn't specifically find the answer to.

Is toe affected when adjusting rear camber on an R33 GTST, using adjustable rear camber arms (upper arms), like these? >>

If it is affected, how much would it change vs camber?

Does that makes sense?

ie. I adjusted the rear camber myself, adding about 1 degree positive. From my measurements & calculations, around -1.8 deg >> to -0.8 deg. (possibly off, but moved + towards zero some amount)

18 inch wheels, so lip to lip, rim height measures 495mm.

Cheers

[V28VX37]

Is toe affected when adjusting rear camber on an R33 GTST, using adjustable rear camber arms (upper arms), like these? >>

As far as I know, yes. Camber and toe are normally adjusted together when doing an alignment. I'd suggest dropping by at a wheel joint and getting them to measure it for you?

[Marcus89]

Last time I got a wheel alignment I asked about this and was told it would affect toe. By how much I have no idea

[colourclassic]

It will almost certainly affect toe, and using my logic: adding negative camber will increase toe-in, subtracting negative camber (as you've done) will increase toe-out.

Did you adjust both upper arms for camber?

The change in toe would be minimal but you'd want to verify it by taking it to a shop.

Edited September 25, 2013 by colourclassic

[GTSBoy]

It will almost certainly affect toe, and using my logic: adding negative camber will increase toe-in, subtracting negative camber (as you've done) will increase toe-out.

Did you adjust both upper arms for camber?

The change in toe would be minimal but you'd want to verify it by taking it to a shop.

I would have said the exact opposite. Assumnig you do not change the lengths of the radius/traction arms, then shortening the upper arms (adding neg camber) will effectively push the front of the wheel outward. This is because the traction arm stops the front of the upright leaning inward with the rest of it as the neg camber is increased.

Logically, in order to increase neg camber without causing toe out, you would also need to have adjustable traction arms that you could shorten at the same time.

As to how much.....well, toe is measured in mm and camber in degrees, so it would be hard to come up with a relationship that made sense without going and measuring everything carefully. But I would estimate that because the traction arms are about 45° to the upper arm, then you'd get about 1/sqrt(2) change in toe angle with each change in camber angle. Or about 70% of the camber angle change might turn up as toe change. Might be a bit less, depends on how close to 45° that arm is, and also the influence of the tie rods/toe rods at the rear. What might actually happen is that the traction arm bushes end up soaking up a lot of the force and so you don't actually see so much angle change but you do increase the binding load in the traction arm bushes.

[colourclassic]

I would have said the exact opposite. Assumnig you do not change the lengths of the radius/traction arms, then shortening the upper arms (adding neg camber) will effectively push the front of the wheel outward. This is because the traction arm stops the front of the upright leaning inward with the rest of it as the neg camber is increased.

Logically, in order to increase neg camber without causing toe out, you would also need to have adjustable traction arms that you could shorten at the same time.

As to how much.....well, toe is measured in mm and camber in degrees, so it would be hard to come up with a relationship that made sense without going and measuring everything carefully. But I would estimate that because the traction arms are about 45° to the upper arm, then you'd get about 1/sqrt(2) change in toe angle with each change in camber angle. Or about 70% of the camber angle change might turn up as toe change. Might be a bit less, depends on how close to 45° that arm is, and also the influence of the tie rods/toe rods at the rear. What might actually happen is that the traction arm bushes end up soaking up a lot of the force and so you don't actually see so much angle change but you do increase the binding load in the traction arm bushes.

Good point, I was assuming you adjust the traction arm with the upper arm when adjusting camber to compensate for rake/caster changes? If that was the case then the HICAS linkages would dictate toe. If in fact you only adjust the upper arm, then your theory would be correct. Any suspension experts out there?

Edit: It looked like he does have adjustable traction arms, hence my logic stated above.

Edited September 25, 2013 by colourclassic

[Munkyb0y]

Yes, i thought as much re: toe being affected one way or the other..

Just wasnt sure.

It will almost certainly affect toe, and using my logic: adding negative camber will increase toe-in, subtracting negative camber (as you've done) will increase toe-out.

Did you adjust both upper arms for camber?

The change in toe would be minimal but you'd want to verify it by taking it to a shop.

Do you mean both sides (driver and passenger) equally? Yes.

I adjusted both sides to about 7-8mm below zero camber. (495mm / 8mm) x (INV)tan = 0.89 degrees.

Of course i did this at home, and didnt use precision measuring tools, but it looks good to me.

However, toe is much harder to measure and gestimate, so I should prob get this looked at anyway.

[colourclassic]

Do you mean both sides (driver and passenger) equally? Yes.

I adjusted both sides to about 7-8mm below zero camber. (495mm / 8mm) x (INV)tan = 0.89 degrees.

Of course i did this at home, and didnt use precision measuring tools, but it looks good to me.

However, toe is much harder to measure and gestimate, so I should prob get this looked at anyway.

No, I meant did you adjust both the 'camber' and radius/traction arms on both sides? It looks like both your upper arms are adjustable on each side. The Nissan multi-link is a pretty complex setup, and adjusting just one parameter changes the whole suspension dynamic; toe, caster, camber etc.

Edited September 25, 2013 by colourclassic

[Munkyb0y]

no thats not a photo of my car. Just showing which type of adjustable arms i was using.

i only have the one that bends around the coilover. as in the 2nd pic.

i dont think there is any adjustment in the other arm in stock form.

ive had my camber adjusted a while ago, and the guy had it spot on. but since then it's been lowered a little more and it was bugging me, hence the home adjustment.

[colourclassic]

no thats not a photo of my car. Just showing which type of adjustable arms i was using.

i only have the one that bends around the coilover. as in the 2nd pic.

i dont think there is any adjustment in the other arm in stock form.

ive had my camber adjusted a while ago, and the guy had it spot on. but since then it's been lowered a little more and it was bugging me, hence the home adjustment.

Ah! That explains it then. If you only have adjustable camber arms, and non adjustable traction arms, then GTSboy is right, your toe has increased inwards.

[Munkyb0y]

yeah but I'm pretty sure you can rectify that by adjusting the hicas (lock bar) rods.

also, i'm pretty sure i can feel more rolling resistance now. so thats what made me think maybe toe was not zero anymore.

[colourclassic]

Correct

[Munkyb0y]

FYI for future searches.

I had the rear alignment done.

My calculations were a little out. I had -1 degree on the passenger side, -1.2 degree on the drivers side.

The toe had hardly been affected. Was sitting on zero. I suspect it was previously just under zero.

So i guess adding positive camber = increase in toe out??

Anyway, new rear alignment is -0.8 deg, 0 toe. I think that's reasonable for street driving.

Cheers for the help guys!