Tod
The basic requirement is that the control arms run should downhill from
their inner pivot point on the cross member to the outer ball joint at the
base of the strut. If these are near horizontal at ride hight then they
will go above horizontal on bump. General opinion on this list is they
should only get to horizontal on full bump. The further above horizontal
the control arms, go the worse the geometry becomes. Bump steer happens as
the control arms above horizontal will pull the lower end of the struts
toward the center of the car under bump, but the steering tie rods do not
shorten, so the wheel turns out, i.e. bump steers.
If you have this problem your options are:
1 Restore to original hight. (Nah)
2 Lower the outer end of the control arm by inserting a spacer between it
and the lower strut mounting point. Popular in the US, rarer here,
but you can buy the spacers kits from (Errol?)
3 Raise the inner control arm pivot point by re locating its bolt in the
crossmember up ward. The '67/8 cross member already has the bolt located
higher than later models as these had a lower front end from the factory.
The top end of the strut, which you know can adjust camber, is not
significant in the bump steer problem. Negative camber will help the car
turn in better, once again, given all other front end geometry is set
suitably. Caster is a similar story.
Of course all front end geometry must be checked, i.e. caster, toe in,
camber.
----- Original Message -----
From: "tod matthiesson" <[EMAIL PROTECTED]>
To: <[EMAIL PROTECTED]>
Sent: Friday, 4 May 2001 22:04 PM
Subject: front end (long)
> Hi all, I am trying to find the best ride height for a 1600 that is suited
> for street driving that doesnt cause the bane of all lowered 1600's bump
> steer. The best way to compare is to measure the distance
> from centre hub to guard lip so if youve got a tape measure handy could
some
> of you post your measurements for comparisons, could u also list the
struts
> etc you are runin. I beleive mine is way too low at the front and this
> combined with the offset lower control arm bolts has made a mess of the
> geometry ie lots of bump steer.
> The current setup is 240k struts, lowered springs(unknown brand) and
sports
> inserts(unknown brand), offset lwr control arm bolts.
> The heights (guard to hub centre) are:
> Front Left: 310mm Rear Left: 320mm
> Front Right: 305mm Rear Right: 315mm
> Does anyone know the stock heights as im pretty sure the rear of mine isnt
> far off stock. I am thinking i may try putting the stock control arm
bolts
> back in and obtaining some 180b offset strut tops but im not sure if this
> will give a suitable amount of camber, anyone?. I recentley replaced the
> steering box with a 120y unit as mine was very sloppy due to the excessive
> bump steer id guess, i also replaced all the tie rods, but i havent
replaced
> the idler arm/bushings could this be another factor adding to the bump
> steer? I think i will need to obtain some strut spacers to correct the
> geometry otherwise. Thanx in advance.......Tod
> _________________________________________________________________________
> Get Your Private, Free E-mail from MSN Hotmail at http://www.hotmail.com.
>
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