Suspension
Suspension
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SL500

Original Poster:

469 posts

294 months

Monday 24th January 2011
quotequote all
I have recently replaced the springs, bushes etc. On my Cerb including installing the group buy steering rack mod that included new track rod ends and rack lifting spacers. I have had the car set up but the steering now seems very jittery and the steering wheel is now very light and seems to bump steer even more than before.

Before I attempt to play with camber tracking etc. Has anyone on here had the same problem and cured theirs?

Cheers

Paul

Ireland

3,517 posts

243 months

Monday 24th January 2011
quotequote all
How wide are your front tyres?

Anything wider than the 225s can make it twitchy.

Also are the UJs on the steering column tightened properly?

itiejim

1,822 posts

234 months

Tuesday 25th January 2011
quotequote all
I had exactly the same symptoms when I fitted the kit just before the end of the summer - an anti bump steer kit it is not.

I suspect that removing the under rack spacers will help a lot but it's still on my "to do" list before I put the car back on the road in the spring.

Erich Stahler

2,878 posts

299 months

Tuesday 25th January 2011
quotequote all
SL500 said:
I have recently replaced the springs, bushes etc. On my Cerb including installing the group buy steering rack mod that included new track rod ends and rack lifting spacers. I have had the car set up but the steering now seems very jittery and the steering wheel is now very light and seems to bump steer even more than before.

Before I attempt to play with camber tracking etc. Has anyone on here had the same problem and cured theirs?

Cheers

Paul
Not surprised you have changed the geometry! dont think spacers under the rack sound like a very good idea!

jammy_basturd

29,778 posts

241 months

Tuesday 25th January 2011
quotequote all
I think the crutch of that anti-bump-steer kit was that we need to measure the bump steer before and after to make sure it is having a positive effect.

ridds

8,372 posts

273 months

Tuesday 25th January 2011
quotequote all
Lots of things to consider:

Tyre pressures
Side wall profile
Tyre Width
Wheel offset
Ride height
Steering UJ's, they need to be TIGHT!
Rack back-lash

What was the Geo set to? 0.5° variation in front Toe can have a HUGE effect on tramlining etc.

Is it definitely bump steer issues you have? The kit helped my car no end.

SL500

Original Poster:

469 posts

294 months

Tuesday 25th January 2011
quotequote all
Yes it is bumpsteer as the steering woggles from side to side and feels too light on a bumpy road. I have had it set up by a TVR specialist who knows his stuff. I will ring him anyway, but I do also like to sus these things out myself. All part of the car fun!
I am not sure what toe in/out he has set the wheels at.

I am thinking about adding some negative camber to the fronts. Not sure if there is a facilty to alter Caster. I will check this weekend as I cannot remember.

Jimii

182 posts

206 months

Tuesday 25th January 2011
quotequote all
Rack back lash adjustment will take the light feel away

Edited by Jimii on Tuesday 25th January 22:57

itiejim

1,822 posts

234 months

Wednesday 26th January 2011
quotequote all
ridds said:
Lots of things to consider:

Tyre pressures
Side wall profile
Tyre Width
Wheel offset
Ride height
Steering UJ's, they need to be TIGHT!
Rack back-lash

What was the Geo set to? 0.5° variation in front Toe can have a HUGE effect on tramlining etc.

Is it definitely bump steer issues you have? The kit helped my car no end.
Ridds, did you fit the rack spaces too?

Edited by itiejim on Wednesday 26th January 06:07