Can caster be adjusted on the r/h wheel??

[Nick_Micouris 0]

Hi

Just returned from Elite in Essex, nice place. They told me that my Caster was out on the right wheel and that it could not be adjusted...

The value before their alignment is actually different to the final one, which makes me think it was adjusted..... :roll:

Is it really true that you cant adjust it from the right??

Cheers

Nick

[PhatVR6 0]

you can't adjust caster. not unless you run eccentric top mounts.

 

You could have a bent wishbone you know, check it out.

 

edit: Caster, not camber, sorry.

[dr_mat 0]

Yep, agreed. The only adjustment you *can* do to the camber angle is on the ball joint mounts. There's three screws in slots that can be moved in and out relative to the wishbone. You don't get much adjustment though, I couldn't tell you how much.

IIRC it's the castor angle that can't be adjusted at all.

How much do you mean when you say it's "out"?

[Nick_Micouris 0]

PhatVR6, Thanks for that.

I guess the top mounts are getting on a bit and that will have something to do with it too. Still the original suspension.

[Kevin Bacon 5]

I think Phat is talking about *Caster*, not Camber. Eccentric TMs, AKA "Pillow ball" alloy top mounts are for running serious neg camber and/or Caster. They're just big round plates with several holes round the circumference for moving the bearing to. Caster if IIRC is the north to south alignment and Camber is the East to West alignment.

 

Caster is sometimes desirable to adjust to stop the front wheels "Trolley wheeling" when they try to flap from side to side......but we're talking predominantly racing settings here....

[Nick_Micouris 0]

the caster readings now are:

Right 2 - 01'

Left 3 - 13'

[dr_mat 0]

Yep, kev. The VR6's high castor angle is what keeps the delights of torque steer at bay..

Sorry, I'd misunderstood the question, due to reading Phat's post and assuming we're talking about camber!

My statement was correct tho - you can adjust camber (bottom of the wheel moves in/out relative to the car), but cannot adjust castor (bottom of the wheel moves fore/aft relative to the car). If it's too far out, there's likely a reason for this - probably wishbone or bushes.

But then, how accurate are the gauges they used? It's a bitch to measure accurately.

[jedi-knight83 0]

hi, i recently had my camber / castor set up and mine is out aswell although the tracking and the camber are pretty much spot on. the castor changes when the other things are set but it cannot be changed by itself....only by moving the camber and tracking (and then those will be out)

 

From what i can tell by a little research and driving...the castor is not so important...as long as the tracking and camber are spot on you wont feel that the castor is different.

[dr_mat 0]

.. weeellll ... mechanically speaking, if the castor is different from one side to the other, the steering will pull to one side.

But other than that there should be no ill effects, no.

[jedi-knight83 0]

from what i understand and the basic research i have done...it wont pull to one side on a perfectly flat road...its only when the wheel is turned one way or the other that the difference will be noticed but the difference of a fe degrees wont be that noticeable to be honest.

[Nick_Micouris 0]

tbh I barely notice any pull in the steering. I It drives fine - its just the normal VR6 paranoia etc :lol:

[dr_mat 0]

if the castor is out on one side but not the other, that wheel will sit at a different physical height from the other one (albeit only very slightly) relative to the rest of the car. As the car's weight settles, it pushes down equally on both wheels, but the one with more castor will be pushed *back* towards the rear of the car with more force than the one the other side. That will of course be transmitted across to the other wheel, resulting in the steering turning slightly - at rest. Of course, it may all turn out to be more or less irrelevant compared to the other forces on the system, I couldn't say for sure, but the physics says it pulls to one side.

[jedi-knight83 0]

ah, that makes sense. so if the right wheel has a greater castor angle than the left....which way will the steering tug?

[Nick_Micouris 0]

so what do you think has put the castor out? strut tops?

[dr_mat 0]

(btw - the castor angle on the front suspension is what induces the self-centreing. Without castor, the wheels would just sit where you left them. Torque steer would rule the system. The castor angle on each wheel induces a wheel-turning force of tangent (theta) * weight on wheel. So you can see that if you alter the value of theta from one side to the other, you get a different force, and your self-centreing doesn't any more.)

[dr_mat 0]

erm, the wheel that has a greater castor angle is the side the steering will pull to.

As for what might change it over time, the most likely culprits are the lower suspension parts, not the upper ones. But like I say, the system is a complete git to measure accurately, so be very careful to make sure they know what they're saying when you start thinking something's wrong.