Camber Adjustment in Upright

[Terry]

I am working on the suspension for our '06 car. In the past our team has adjusted the camber by placing shims between the chassis and the suspension mounts. This of course is not a very elegent solution.

I have heard that some teams build camber adjustment right into their uprights. I was wondering if anyone has some advice on how to do this. Do you design the upright with an adjustable mounting position? And if so, how do you make sure that it won't migrate as the supension is placed in a driving situation.

Any help or other ideas would be very much appreciated!

Terry Vermeer

[Agent4573]

We went with the camber adjustment in our upright last year. What we did was made a camber bracket for the rod end to go into, that had ridges machined on the bottom of it. Our upright had matching ridges machined into the top of it, and the two peices just bolted together. I believe each ridge that we moved adjusted our camber .3 degrees.

[CMURacing - Prometheus]

somebody (i believe) has said it on here before, but it may have been in real life that i heard it. shims are definitely the way to go, believe it or not, but don't just use a bunch of bandsawed pieces of aluminum plate. get the right stock, and machine the shims to the right size. real racecars (and race mechanics) use shims for suspension adjustment because of repeatability.

another way to look at it is this way: we're designing cars for a weekend autocrosser. the customer may or may not be mechanically inclined. if you sell a series of camber adjustment shims with the car, and anodize them different colors for varying amounts of camber (say, blue for neutral, red for +-1 deg, etc), its idiot-proof.

having said that, our shims were outboard (on the upright), between the spherical bearing housing (also on the upright) and the upright itself.

[clausen]

I think there is another similar thread on here that isnt that old.

A common method of adjusting camber at the upright involves making a large clevis of some sort to which both a wishbone pickup and the steering pickup are connected. If you shim this block then you can change camber without needing to re-set the toe. This is nice but I think it should just be used for small adjustments. If you're doing some experiemnting with large variations in camber then if you use shims at the upright you're also going to be making changes to the scrub radius and the KPI, hence the camber change with lock.

The name of the game with testing is to, where possible, isolate your variables as much as you can.

[tal]

Paul

I agree with your view on making large changes with these shims and the additional variables you introduce by changing your scrub (increased + camber >> decreased scrub). However your KPI shouldnt change because all your ball joints are remaining in place; the drawback of adjusting camber with a rod end or chassis shims is that you are changing your KPI, and suspension geometry...but your scrub is for the most part staying the same.

[adrial]

As Agent4573 said, the Rutgers car used small ridges for camber adjustment. However, each ridge resulted in a 0.15 deg camber change.

For next year, we will be going to inboard shims primarily for manufacturing reasons.

[clausen]

Originally posted by tal:
Paul

I agree with your view on making large changes with these shims and the additional variables you introduce by changing your scrub (increased + camber >> decreased scrub). However your KPI shouldnt change because all your ball joints are remaining in place; the drawback of adjusting camber with a rod end or chassis shims is that you are changing your KPI, and suspension geometry...but your scrub is for the most part staying the same.

Hi, I wasn't actually sure if KPI was relative to the ground or relative to the hub. What I mean is that the angle between the camber angle and the KPI angle should remain constant, because this the one that actually matters as far as KPI's effect on camber change with lock. IE if you have 3 degrees KPI and 3 degrees neg camber then you arent going to get any camber change with lock that results from the KPI.