Harrison: Commodore adjustable radius rods

Merv and Sharon · #1 (**permalink**) 11-30-2011, 02:37 AM

One of the difficulties with the Commodore (VS) front suspension on the Harrison (and others I suspect) is that the Radius rod ("Z" bar) is not adjustable so that caster variations are difficult when wheel alignment is attempted. There are adjustable rods available and I was wondering if anyone had experience with these?

http://www.whiteline.com.au/docs/bul.../069_rr207.pdf

sambo · #2 (**permalink**) 11-30-2011, 03:44 AM

Merv, I haven't set my caster yet but I was under the impression that it was done by shortening the rearward-most spacer or crush tube on the upper control arm to lay it back. Do these adjustable radius rods achieve the same thing by moving the lower arm (or its arc) forward somehow?

Krait · #3 (**permalink**) 11-30-2011, 07:45 AM

Merv,

Like these?

Short discussion on this thread.

Cheers

Merv and Sharon · #4 (**permalink**) 11-30-2011, 12:15 PM

Yes Paul with a shimming process but Geoff where did you get those ones? That is what Fulcrum Suspensions suggested to me.

Merv and Sharon · #5 (**permalink**) 11-30-2011, 12:40 PM

Found your source Geoff.

Merv and Sharon · #6 (**permalink**) 12-01-2011, 11:39 PM

These are the ones that should suit Harrisons with the Commodore front end: Whiteline W82567 Front Caster correction - radius rod complete assembly

hsv300 · #7 (**permalink**) 12-01-2011, 11:42 PM

Merv are you thinking about getting these?

Merv and Sharon · #8 (**permalink**) 12-02-2011, 02:47 AM

Maybe. I like the idea of having things adjustable. I originally found that I had +3.5 caster each side and had this adjusted, to the extent possible, with the current set up, to +1. Car feels to have sharper turn in and does not seem to have lost straight line stability. The suspension guy I am working with suggested the adjust adjustable rods. I will keep evaluating the setting I have now first.

sambo · #9 (**permalink**) 12-04-2011, 02:19 PM

Merv, what problems were you experiencing with +3.5 caster? Warwick suggested something like 7 or 8 for caster, mind you I have a power rack.

Merv and Sharon · #10 (**permalink**) 12-04-2011, 10:38 PM

Paul I found the steering a bit heavy and now it is lighter and not as susceptible to road undulations.

Merv and Sharon · #11 (**permalink**) 12-05-2011, 03:15 AM

7-8 sounds a lot, although with PS you should not feel the heaviness, but tyre wear? This is an interesting thread on caster and FF cars

Are 9.5 degrees of caster too much? - FFCars.com : Factory Five Racing Discussion Forum

sambo · #12 (**permalink**) 12-05-2011, 03:51 AM

Good reading there Merv, thanks. Will probably go for around 6 degrees of caster to start with, in fact that number rings a bell rather than 7-8. It's written on a piece of paper "somewhere" after I last spoke to Warwick. I think he said zero toe front and rear as well.

sambo · #13 (**permalink**) 12-05-2011, 03:57 PM

Just a thought - you've got some pretty lethal track weapons up there in QLD, what settings are the quicker Harrisons running?

Merv and Sharon · #14 (**permalink**) 12-05-2011, 06:31 PM

I would not classify mine in that category as it is set up as a street car. Rear camber is about +0.5 and front is about +1.20. Toe-in is minimal at the front (1mm total).

gjkrv8 · #15 (**permalink**) 12-05-2011, 09:59 PM

On the CR we run the following:

Seems ot handle ok:

FRONT:

Camber 1.0 to 1.25 deg negative

Castor 6.0 to 8.0 deg positive

Toe in 2.5 to 3.0 mm TOTAL

Rgds

gregg