caster

[Trangieboy]

Please don`t laugh,but i have a `98 4wd rodeo.It has bugger all straightline directional stability(steering correction all the time).I asked my local `Bob jane` blokes to shim more caster into it but they reckon they can`t put any more on as it will effect the camber?? It has around 2deg pos. caster on the left and around 2.5deg on the right.
My question is is it possible(surely it is) to shim more caster into the front while retaining 0 deg or so camber.The caster should be same both sides right ?? How much caster could i run(it has power steering and the steering is very light at present)??
An interesting thing about the 4wd rodeo front geometry is that the wheels go postive camber in bump and negative in droop.Great design hey !!

Thanks for any ideas,Mal.

[Wojtek]

Hi,

I really can't comment if there is any latitude on your car to be able to set more positive caster without effecting camber angle. I don't know this model that intimately, or enough to know that the common range is. Sorry.

But, you could try going for about -0.5deg camber, which should allow to dial in some more caster.

I understand that the front suspension on your car uses a short-long double wishbone configuration wth a torsion bar, shock absorber and roll bar.

I'm not sure if the lower arm is a double pivot, or single with a seperate radius arm. Some models use an adjustable radius rod to adjust caster.

The pocitive camber gain on bump may most likely be due to the high ride height of your car, so it may first add positive camber followed by negative change further up the bump curve.

If this is the case, the only practical (from a modifications point of view) way to fix this is to lower the ride height.

Hope this helps.

Regards,
Wojtek.

[Trangieboy]

Thanks for the reply Wojtek.The rodeo has no radius rod on the bottom,just a normal double pivot wishbone.Camber/caster adjust is done with shims behind top wishbone pivots.Same as HQ holden`s,ect.
Is it standard practice to `stagger`the caster slightly in order to provide slight `pull` to the left ?? ie more postive on LH side ??
Do you think up to 1/2 deg. negative camber is still OK as far as tyre wear goes ??
Thanks again,Mal. :)

[Wojtek]

Hi Mal,

Yes, caster stagger is common practice to counter act the "pull" caused by the crown of the road.

Camber... hhhmmm.. haven't really had too much experience with your car... I think that could be right for a "factory spec"... I'd probably want to start with around 0 camber... but you'll need to experiment a little to find what you like, including your tyres.

Wojtek.

[jgevers]

Hi,

Although I am not familiar with your vehicle, I would expect -0.5 degrees static camber will be fine. However if you run 'toe out', you might find that the inside edge wears quicker.

Could your power steering pressure be to high? Could you experiment with washers in the pressure circuit to reduce assistance?

Regards,

Job