Increased caster on rear wheels....

[ZROSSA]

Howdy all,

 

I am about to weld in the rear camber plates on my 260. I can get abot 5-8 ml extra caster by welding a little further back. Is there any advantage to doing this? Increased stability in a straight line perhaps? Or do you think it would make the car more difficult to turn in? This car will be mainly used for targa style rallys and fast road playing. Front tires are 245/45/17 and rear are 275/40/17. Front spring rates are 250lbs, rears are 275lb....and it's a 2+2. Open diff at this stage.

 

Cheers, Douglas

[m4xwellmurd3r]

Don't you mean camber? Caster has nothing to do with the rear wheels. Caster effects your steering on the front wheels. it's what causes your wheels to return to center on their own. if you had zero caster, your car would be horrible to drive I would think. I know the higher your caster angle, the less responsive your steering feels, and I know this first hand with my bug. we had to increase the caster to make up for the suspension geometry when we lowered my bug. the downside is the steering feels more sluggish. my dad's ghia (which basically uses the same exact front end/steering) didn't have the increased caster, and the steering felt very direct and responsive.

 

caster on the rear wheels as far as I know, has absolutely no effect on anything. in fact, I don't think you can add caster to the rear wheels since you'd end up tweaking your lca

[tube80z]

Unless you change the rear control arms to a different design you can't change the angle of the rear struts without putting the suspension in a bind. Ideally you'd install everything to make sure you don't have a bind and then tack in the plates.

 

Cary

[ZROSSA]

Thanks for the replys,

 

I had forgot that the design of the control arm basicly makes the suspension movement work in only one dorection. Dont want any binding!

 

Douglas

[260DET]

The strut could be bent where it goes into the lower housing if you wanted to move the strut top for some caster, but that would have other implications perhaps affecting squat as well. I don't know of any rear suspensions that are adjustable for caster but I bet its been done with race cars.

 

Might be an idea to tack the strut tops in and get the alignment checked before permanent welding, I'd suggest like you think a bit of caster may help rear end stability but who knows? 2+2 bus with its longer wheelbase should be fairly stable anyway.

[JMortensen]

The strut could be bent where it goes into the lower housing if you wanted to move the strut top for some caster, but that would have other implications perhaps affecting squat as well. I don't know of any rear suspensions that are adjustable for caster but I bet its been done with race cars.

Unless you change the arc that the rear control arm swings on, bending the strut is not going to eliminate the bind. If you bend the strut, it will be at a fixed angle, moving perpendicular to the top. So you might have one spot in its travel where there was no bind, and relatively little on either side of that sweet spot, but the further you got, the worse the bind would be.

 

In order to move the top back you need the control arm to articulate and allow for no bind all the way through. In other words, you'd need a rear A arm and toe link setup instead of an H arm. See this thread: http://forums.hybridz.org/showthread.php?t=129154

 

Might be an idea to tack the strut tops in and get the alignment checked before permanent welding.

This might be a good idea when welding camber plates in with a stock arm, just to ensure no side load on the strut.

[260DET]

Unless you change the arc that the rear control arm swings on, bending the strut is not going to eliminate the bind. If you bend the strut, it will be at a fixed angle, moving perpendicular to the top. So you might have one spot in its travel where there was no bind, and relatively little on either side of that sweet spot, but the further you got, the worse the bind would be.

 

In order to move the top back you need the control arm to articulate and allow for no bind all the way through. In other words, you'd need a rear A arm and toe link setup instead of an H arm. See this thread: http://forums.hybridz.org/showthread.php?t=129154

 

 

.........................

 

Of course, you are right Jon, thanks for the correction.

 

Bend struts for camber, not caster.

[ZROSSA]

Thanks again guys. I remember having read something about rear wheel caster in one of Carol Smiths books years ago. I havent really followed this up though and have welded in the stock position.

 

Douglas