Clausager says the GT had longer and stiffer springs to the roadster, and
the later GT springs were also used on the V8. The change in numbers
occured in 72 when both types were increased in length by 1/2", to stop
springs settling too low, which mainly occured on export models lashed down
on ships for long periods. With the rubber bumper cars the roadster springs
were used on the GT as well. However you will see below that the factory
workshop manual says the GT springs were *shorter*, not longer, although
obviously stiffer. Some time ago I bought what were described as
'rubber-bumper roadster' springs which had a shorter free-length but gave an
almost identical ride-height (as far as you can compare the results of used
and new springs) but now I'm thinking they were completely the opposite -
that is 'chrome-bumber GT' springs.
>From the Factory Manual the early roadster had a coil diameter of 3.238in, a
free height of 9.9in, and free coils of 7.5. No 'spring weight' is given
but interestingly it gives a static length at 1030lb of 7in. Since the
unladen weight is given as 1920lb, the kerbside weight as 2303lb and the
weight distribution as 1127lb front and 1176lb rear I don't know where
1030lb comes in - any guesses? However it may be the answer to the
perennial question "what is the ride-height of an MGB?", another clue to
which is a stated minimum ground clearance of 5".
The early GT had a coil diameter of 3.28in, free height of 9.1in, free coils
of 7.2, and a static length at 1193lb of 6.6in. The GT weight specs are:
unladen 2190lb, kerbside 2401lb, front 1162lb, rear 1239lb.
The post-72 roadster and rubber-bumper GT (not V8) had a free-height of
10.2in, static length at 1030lb of 7.24in (i.e. plus 1/4" as opposed to the
plus 1/2" of Clausager), and free-coils of 7.5. No coil diameter given,
possibly unchanged.
The post 72 chrome-bumper 4-cyl GT and all V8s had a free-height of 9.32in,
static length at 1193lb of 6.84in, and free-coils of 7.2. Again no coil
diameter.
For the rubber-bumper cars I don't have unladen weights but kerbside is
2394lb roadster, 2446lb GT. Front is 1216lb roadster and 1198lb GT, rear is
1178lb roadster and 1248lb GT.
Clausager makes reference to a further roadster change in November 72 but
says as they were interchangeable it must have only been a part-number
change. However the factory workshop manual has an additional set of
figures for what it describes as 'later' roadsters of 10.2in free-height,
static length at 1030lb of 7.44in, and free coils of 9 - a significantly
different specification. The factory parts catalogue makes no reference to
a third part-number for roadsters.
I haven't put these figures in tabular form as when I receive tables in
emails the spacing is all to pot even if I convert it to a
non-proportionally spaced font. Seems like a worthy addition to the web
site though, plus specs for rears.
Note: The factory kerbside for GT and roadster plus driver and passenger is
plus 353lb, so all those over 176.5lb or 12 stone 8 lb complaining of
sagging springs - now you know the reason why! Me? I'm 12 stone 5lb. For
the rubber-bumper cars the allowance was reduced to 150 lb or 10stone 10lb.
PaulH.
----- Original Message -----
From: Ptegler <ptegler@gouldfo.com>
To: <mgs@autox.team.net>; <mgbgt@egroups.com>
Sent: Thursday, January 25, 2001 8:22 PM
Subject: front springs
> Anyone have any idea what the difference is in the
> 62-74 Roadster front springs - AHH6451K
> and the 62-74 GT front springs - BHH1077
>
> yes.. I assume it has something to do with
> vehicle weight, but I'm wondering about
> free length, rating, installed length, etc.
>
> thanks in advance
>
> Paul Tegler ptegler@gouldfo.com www.teglerizer.com
|