I'm just wondering what the difference is with the 4 seater 4 leaf springs.
Is the rate firmer or the camber higher?
Jack this was my recent experience.
I had the original saggy factory springs replaced on my +4 with 4 seater springs. Not because I had issues particularly with the ride or bottoming or the car not being level but the ground clearance was dire.
Both the regular 2 and 4 seater springs manufactured in the UK and supplied by BCC have the same spring rate I believe so offer the same ride quality. As only the camber differs the benefit of the extra height was appealing to me. However unlike others the 4 seater springs didn’t work out with my car. I only had them in for a single 20 mile run before reverting back to 2 seater springs.
My attempt at an explanation….
The issue I believe was the camber. It would appear that with the increased camber yes you gain bump travel and ride height but it is traded for a reduction in extension travel.
When I drove the car with the 4 seater springs the ride was comfortable and indeed very similar to the 2 seater but I could detect the subtle feel of the rebound rubbers making contact under the axle. The pics below might help. The top pic is the new 4 seater spring with the extra camber and below is the new 2 seater spring. In the top pic with the extra camber you can see that there is only about 4mm clearance under the U-bolt nut to the chassis return. In order to prevent the nuts making contact with the chassis and causing long term chassis damage the rebound rubbers had to be set so high that there was zero static clearance between the axle and rubbers (I’ve read that there should be at least 10mm). So consequently with my light weight 2 seater car and a 10 1/2 stone whimp at the wheel the axle was effectively riding on the rubbers with no or at least very little suspension extension travel. I suspect that it might have all been different with a heavier set up that applied a greater preload to the springs.
So now I’m back with a pair of regular 2 seater springs. The ride is still the same but with the extension travel has been restored, the car is level to within about 5mm (unloaded) and the ground clearance is so much better than the factory originals. An interesting exercise…….
PS – The spacer in the top pic is there only to adjust the ride height.