Zac,
I did some measurements on the weekend regarding this very subject. One of
the guys from the Club came around in his '68 and I did some comparos. As (I
think it was Derek) said once, the height of the lower control arm pivot is
higher on the old ones - causing less bump steer when you lower the
suspension.
I couldn't work this out for a long time. When I did my SR conversion I got
a reversed crossmember from SSS. When I put it all together I had heaps of
bumpsteer. The bloody thing had the pivot even lower than my old cross
member!!! Buyers of exchange crossmembers take note!
Anyway, I've had a good look at it and these are the figures I came up with.
Peter's '68 has the pivot 40mm up from the bottom edge of the crossmember.
This seems to be ideal (his is dumped and has no bump steer). My original
one has it at around 30mm, and the one I got from SSS (currently in my car)
has it at 25mm - worst of the lot! I've currently heated and bent my
steering arms to compensate, but these will have to go before I get it
engineered.
It would appear to be no big deal anyhow. I'm just going to grind off the
weld, slot the crossmember upwards and reweld it at 40mm (I'm actually going
to do some bump steer tests with the springs out to get it spot on - but I
suspect it will come out to approx 40mm). Shouldn't be too hard to improve
on the crap welds that I got from SSS!
If you want to bring your crossmember around we could do the two in the same
day. No big deal. Bit of grinding, bit of welding - bye bye bump steer!
'later
PL
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]] On Behalf Of Zac Campbell
Sent: Wednesday, 14 June 2000 11:50
To: [EMAIL PROTECTED]
Subject: RE: Suspension (longish)
thanks Derek, shall look into it. what does a 68/69 x-member go for?
bumpsteer spacers sound cheaper...
-----Original Message-----
From: [EMAIL PROTECTED]
[mailto:[EMAIL PROTECTED]]On Behalf Of Derek Franklin
Sent: Wednesday, 14 June 2000 8:44 AM
To: [EMAIL PROTECTED]
Subject: Re: Suspension (longish)
Zac,
wouldn't be surprised if both are true - the car's been lowered without
correcting
the geometry at both ends. Probably some toe-out at the rear causing the
unstable
feel, and the front wandering under brakes sounds like bumpsteer or
something
loose in the front end. Slot rear x-member and fit 68/69 front x-member,
maybe
bumpsteer spacers, might want to see about abjustable t/c rods and something
to tune the front camber as well.
DF
>its too low that why. You need bump steer spacers
>> >
>> >Zac,
>> >I think you might be experiencing the back end wanting to steer itself
>due
>> >to toe in or out & too much negative camber at the back caused by the
>> >lowering.
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