Well the age old question of when were the suspension bolts tightened comes
to mind. If you are using rubber bushings the bolts need to be torqued at
ride height. With poly it doesn't matter. The second possibility is, are
the tops of the springs seated correctly. If they are on top of the
retainers instead of around them it will add a half an inch to spring
length. IME they like to slip out from around the retainers during
assembly.
My experience with 550# springs was just the opposite. I have two pairs of
them and they both sit lightly on the bumpstops when installed. I ended up
machining some spring spacers to lift them up to where they belong. In my
case, they are Vicky Brit. When I measure the springs all four are 1"
shorter than stock, this means a little more than 2" lower at the wheels.
It seems someone got their math wrong when the spec'ed the spring to be 1"
lower ride height. That said, my 1" lower rear springs sit exactly at stock
ride height but such is life I guess.
If you knew the free height of the 550# springs then it is easy to calculate
the change in ride height given some basic assumptions (like 500# static
weight on each wheel). Basically the wheel has a 2:1 advantage over the
spring so the wheels sees 500# static weight while the spring sees 1000#.
Simple math will tell you that a 480# spring will compress 2.1 inches. If
the stock spring height is 10.2 inches at 2.1" compression you get a
compressed length of 8.1" and a ride height of 13.5 inches by inspection.
Take the free height of the new spring subtract 1.8" which is the
compression of the stiffer spring and this will give you a compressed length
for it. Once you know the change in compressed length, doubling that will
give you the change in ride height. As I mentioned above, if the spring is
on the retainer, which is about 1/2 inch tall, the car will sit 1" higher
due to that slip up.
Hope this helps.
James Nazarian
71 MGBGT V8
71 MGB Tourer
-----Original Message-----
From: owner-mgs@autox.team.net [mailto:owner-mgs@autox.team.net] On Behalf
Of Paul M.
Sent: Monday, July 26, 2004 9:42 PM
To: mgs@autox.team.net
Subject: MGB front springs
I just had the front suspension rebuilt on my 1971
MGB, and had the mechanic install a set of 550lb
"blue" front springs at the same time. Despite the
fact that the new springs are visibly quite a bit
shorter than the stock springs, the ride height is
actually slightly HIGHER with the sport springs than
it was before.
My guess is that because of the increase in rate, the
car is not compressing the springs down as much, and
as a result, it sits up higher. Does this make any
sense? Has anyone experienced this before?
I ordered a set of the 480lb "red" springs and they
are being shipped directly to my mechanic, so I'll let
you guys know what happens, but any insight into
possible causes would be greatly appreciated.
Cheers,
|