Robin hood 2b rear coil over mod

[John Timmins]

Hi all sorry to use your brains mine is frazzled , converting rear sierra suspention to coil overs spax adjustable , what spring lbs on rear and front, I have problem when I jack car up so wheel off the floor the spring on the coilover becomes loose ,I have lowered the top insert in chassis down the ride height is to high the springs I have are 350lbs on front 300lbs on rear hope you can help me I'm  stuck regards john

[Pintogogo]

when you jack car up spring will become loose as shocker is compressed when wheel on floor

 

[RallyChris]

The new springs supplied recently by GBS with a set of Gaz coil overs for a 2B are 325lbs for the rear. Shock is 16” open, 10.5” closed fyi. The rule of thumb when setting the position of the top spring mount is that you want the shock absorber (inside the coilover) to be compressed by 1/3 of its working range at the normal ride height of the car. The remaining 2/3 travel is therefore available for bump compression.

What I plan to do on my build is to make a fixed dummy shock that is 1/3 compressed length and then set the wheel up at the desired height relative to the bottom of the chassis. The top mount will then be fitted at the required height to match up to the dummy shock. If you try doing this setup with a spring in place and/or weight of the car sitting on the suspension then you could end up chasing your tail as you can’t directly control the nominal length of the shock absorber.

Edited August 26, 2022 by RallyChris

[John Timmins]

9 hours ago, RallyChris said:

The new springs supplied recently by GBS with a set of Gaz coil overs for a 2B are 325lbs for the rear. Shock is 16” open, 10.5” closed fyi. The rule of thumb when setting the position of the top spring mount is that you want the shock absorber (inside the coilover) to be compressed by 1/3 of its working range at the normal ride height of the car. The remaining 2/3 travel is therefore available for bump compression.

What I plan to do on my build is to make a fixed dummy shock that is 1/3 compressed length and then set the wheel up at the desired height relative to the bottom of the chassis. The top mount will then be fitted at the required height to match up to the dummy shock. If you try doing this setup with a spring in place and/or weight of the car sitting on the suspension then you could end up chasing your tail as you can’t directly control the nominal length of the shock absorber.

Thank for the info I will be trying this today