Bump steer

[OpulentPete]

Evening team!
Last weekend I replaced ALL of the front suspension:

- New coilovers from KTR
- New genuine strut top mounts and swivel bearings
- New lower wishbones incl bushes and ball-joints
- New track rod ends

The reason was Three-fold, it's done 115k miles, the spax springs were painfully hard, and the derbyshire roads have completely shagged everything suspension based.
Before doing this refresh i was experiencing a significant amount of bump steer, e.g. going over ruts in the road i would feel a distinct pull.

Given the both the track-rod ends and the lower ball joints had distinct play in them I expected this to fix the issue, the wheel bearings show no signs of play at all, and both sides now feel completely rock solid when pulled/shaken when up on the lift.
I had the tracking done to 1 degree tow in, and the camber is currently set to 0 degrees.

However, the bump steed persists.

Any ides??? the rack mounts don't appear to be worn

 

[JamesBryan]

You're naturally going to worsen the effect of bump steer when you lower a car.

You could fit a correction kit, but they're not that cheap.

It must drive terrible with that alignment! Are you sure you have 0 camber and 1 degree of toe in?

I'd suggest you get it set up with -1.5 camber and 12mins of toe out.

 

[OpulentPete]

Sorry i got that backwards!!!!, 1 degree of camber and 0 degrees toe (I've seen ALL sorts of recommendations.... absolutely all over the place)

I've had a few of these and never known lowering to increase bump steer - its not mad low either.

 

[White16valver]

My understanding is that bump steer can be caused when the suspension is compressed and the steering runs out of available movement - e.g. if the steering rack arms/rods are horizontal on a standard car, they have X degrees of movement up when the suspension compresses, but if it's lowered and your arms/rods are therefore already angled up Y degrees from horizontal, you only have (X-Y) degrees of movement available.

(I think??)

I believe that one option is to lift the rack up off the mounting points, to make the arms horizontal again (as per what James said above), but I'm not sure if it's possible on a Clio??

 

[OpulentPete]

I haven't lowered it recently - it's sat at the same height it's been for at least a year - the bump steer has increased significantly in the last couple of months, this is the main reason i have swapped the suspension for new.

 

[Martin.]

Parallel toe is fine, but I think -1 degree camber isn't enough. I'd make that at least 1.5, not that I can see it affecting your drive too much.

Have you looked at your arb bushes? They could be shagged. and possibly causing it to tug under load.

 

[BaileyWolves]

@Martin yes I just did all suspension springs top mounts ball joints ect and only felt totally complete when I upgraded the arb bushes deffo a good shout

 

[OpulentPete]

Have you looked at your arb bushes? They could be shagged. and possibly causing it to tug under load.

I haven't no, didn't think to look at them when i swapped the suspension around, i'll get a set ordered, cant do any harm either way.

However I have bigger issues now as someone ran a red light in derby and bumped my right rear side-on, its killed the bumper, luckily no body damage but I think the rear beam is tweaked :-( - Off to meet with him now (He passed hit test on Tuesday.... ! )

 

[obcuz]

Bump steer sounds least of your problems now!
The rear shocks can also have some effect, I am not sure why, but have seen this posted before and must admit since I fitted new rear shocks, the bump steer is minimal now compared how it was before.

 

[1985michael182]

What spacers are you running?
Wider track means you dont run in the natural tramline on the road.
I have role centre and bumpsteer kit on mine and it still pulls on the roads because of the track width. Nature of the beast it's a track car

 

[1985michael182]

Check your rack bushes aswell