Parabolic Paradox
Discussion
Hey all,
I'm posting in the hopes that someone else who has travelled this road will be able to offer some advice.
I'm currently restoring a RB MGB roadster of 1977 vintage. Aside from the usual replacement of rusty sills etc, one of the main jobs was to lower the ride height and replace the suspension. So I've gone with parabolics and telescopic spax dampers at the rear.
First problem was that the springs add 2.5 inches to the ride height, quite the opposite effect to what I wanted! They appear to be subtly different in length to the originals, which seems to jack things up a little. A few things on the internet about this, so I'm going to try swapping them for the CB versions and see if that helps. Anyway, that's really an aside.
It was also apparent that the damper attachment points are around 2" too far apart. I wondered if this was because of the increased ride height, so I've tried it with the original springs - still about an inch away.
Now the car is basically stripped down to a shell, sans engine and gearbox, which would obviously make it settle a bit; but by 2 inches? Even then, the dampers would be at full extension at rest, which surely can't be right? They'd be topping out all the time.
I've checked all the part numbers etc and everything looks ok.
So, assuming the replacement springs are ok, I seem to have a choice of compressing everything to make the dampers fit, and assume it'll all be ok when the car is built back up; or I can flip the bottom bracket back to its original position which will put the damper attachment points 1.5" or so closer together. Does anyone have any feel for how much the car will settle when everything is back in it?
I'm posting in the hopes that someone else who has travelled this road will be able to offer some advice.
I'm currently restoring a RB MGB roadster of 1977 vintage. Aside from the usual replacement of rusty sills etc, one of the main jobs was to lower the ride height and replace the suspension. So I've gone with parabolics and telescopic spax dampers at the rear.
First problem was that the springs add 2.5 inches to the ride height, quite the opposite effect to what I wanted! They appear to be subtly different in length to the originals, which seems to jack things up a little. A few things on the internet about this, so I'm going to try swapping them for the CB versions and see if that helps. Anyway, that's really an aside.
It was also apparent that the damper attachment points are around 2" too far apart. I wondered if this was because of the increased ride height, so I've tried it with the original springs - still about an inch away.
Now the car is basically stripped down to a shell, sans engine and gearbox, which would obviously make it settle a bit; but by 2 inches? Even then, the dampers would be at full extension at rest, which surely can't be right? They'd be topping out all the time.
I've checked all the part numbers etc and everything looks ok.
So, assuming the replacement springs are ok, I seem to have a choice of compressing everything to make the dampers fit, and assume it'll all be ok when the car is built back up; or I can flip the bottom bracket back to its original position which will put the damper attachment points 1.5" or so closer together. Does anyone have any feel for how much the car will settle when everything is back in it?
As I recall when I fitted parabolics to my rubber bumpered GT there were spacer pieces between the clamps and the leaves. Moving these from top to bottom allowed some adjustment of ride height. Also there is an amount to settlement that occurs after the first few hundred miles. So it may be worth running it for a bit, then relaxing the torques in the leaf bushes, then retorquing after bouncing it a few times.
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