[mlifxs]

Hey folks,

I was on Whiteline's site looking at their bushings and noticed they have a front tension strut bushing which can be used to adjust castor.

There's not a ton of direct discussion of castor on our site. Mostly "it's not adjustable" or "use camber plates that have castor adjustment". So this option seemed interesting, or, at least different.

Here's a link to the product
http://www.whiteline.com.au/product_..._number=KCA430
there is an install pdf on the page to see how it works.

Anyway, curious about any knowledge or opinions from our suspension experts.

[ajsalida]

Those are cool, did not know they made them. I think you'd affect toe and camber though, not just purely caster.

[mlifxs]

Originally Posted by ajsalida

Those are cool, did not know they made them. I think you'd affect toe and camber though, not just purely caster.

do you mean lose negative camber if castor is improved?

[mike-y]

caster is on a different axis of the suspension than camber is. if you increase front caster, static camber is not affected, but you do increase the negative camber gain on the outside wheel/tire as the wheels are turned.

so usually this is a good thing, though it's only 0.5 degrees of additional castor. You'd have to take some measurements with a camber gauge (or do some calcs) to see how much additional negative camber it adds at X steering angle.

if you are upgrading bushings, it might make sense to throw these in, but camber plates would probably give you more adjustment as well as being easier to adjust.

[ajsalida]

Originally Posted by mlifxs

do you mean lose negative camber if castor is improved?

No I mean that, from the installation diagrams, it appears these affect camber caster and toe at the same time. It is not clear exactly how. IOW it is not a pure caster mod.

The tension strut sits at roughly 45 deg angle to the bottom of the hub, relative to straight ahead. Making that slightly longer or shorter via an eccentric in the inboard point the angle of all three measurements changes. Or at least it looks that way.

To increase caster only you'd need to find a way to tilt the top of the strut straight back at the top (via camber/caster plate) or push the bottom straight forward at the hub. At the bottom it is constrained by the other link and the tie rods, so it is going to rotate/tilt in some more complex way.

[mlifxs]

thanks guys. Sounds like a camber/castor plate is a more robust solution.

[ajsalida]

Originally Posted by mike-y

caster is on a different axis of the suspension than camber is. if you increase front caster, static camber is not affected, but you do increase the negative camber gain on the outside wheel/tire as the wheels are turned.

so usually this is a good thing, though it's only 0.5 degrees of additional castor. You'd have to take some measurements with a camber gauge (or do some calcs) to see how much additional negative camber it adds at X steering angle.

if you are upgrading bushings, it might make sense to throw these in, but camber plates would probably give you more adjustment as well as being easier to adjust.

Of course this is true in theory if you have a means of adjusting caster independent of camber or toe, but this mod is not capable of that. It just makes a link in the suspension longer or shorter, and that link is not aligned to any of the 3 variables. I agree camber caster plates are a better solution.

The rear susp has what are called camber and toe links, but if you've ever adjusted them yourself it is obvious they affect each other.

[mike-y]

right, but they would only affect toe if you didn't get an alignment after the install, and you should always have the car aligned after changing suspension pieces. Any toe change would be adjusted back to your original setting.

It may slightly affect static camber very slightly, but since it's on a different axis than the lower control arm, the effect would be minimal.

either way, I think we both agree that there are other mods to do to the suspension that would be more beneficial than these bushings, and also offer more adjustment.

[ajsalida]

Yep. I am having a hard time looking at the install diagram and telling what all it would affect, but clearly not just caster.