Steering shaking at speed - not wheel balance

[IanJ]

If you want a definitive answer, I would suggest asking the tyre fitters to check the balance of the (now) rear wheels before mounting the new tyres: first using a stud plate and then using a centre cone...

[Z3MCJez]

Check the wheel isn't buckled. You might find it balances perfectly in a spinning direction, but that it's shaking left to right when attached to the car.

 

Jez

[Paul Deslandes]

Interested to read Grim Reaper's story on bump steer. Having looked at quite a few cars now, it would appear that unless the rack plate height varies between builds (unlikely), they will all suffer from bump steer as the rack is 9mm too low. Doing as GR has done and packing the rack up by 9 - 10mm, fixes the problem and makes the car a whole lot more comfortable to drive on bumpy/uneven surfaces.

 

If you want more details, see here.

 

Paul

[charlie_pank]

I've had to take wheels back 3 times to get them correctly balanced before.

[Grim Reaper]

Apparently the rack plate height has changed through the years, initially all was OK, then it was lowered for some reason, now same low height but supplied with different rack mounts.

Caterham even sell 3mm thick plates (and say you need 3 of them) to correct it.

Now if that isn't taking the piddle and making money out of us I don't know what is.

I'd have expected them to supply the shim plates FOC or at postage cost at the very least.

Admitting there's something wrong with it yet making us pay to put it right

[Paul Deslandes]

you just have to regard 7 ownership as a learning experience 😬

 

Interesting about the rack height changing. I'd assumed that must be the case and that engineering has somehow lost sight of such details. It almost ought to be a factory recall to sort it as the handling transformation is quite remarkable.

[Jason Plato]

in addition the uprights have changed in recent years with the addition of the 8mm spacer between bottom of upright and lower wishbone - the later uprights have a longer thread to allow for the spacer , 1997 uprights do not .

[oldbutnotslow]

Just a thought. Check the lower wishbone spherical joint for play.

Jack up the car and standing facing the front wheel get hold of the two wing stays and lift upward.

If there is movement either the bearing is worn and needs to be replaced or

the spacer has worn and the special half nylock need to be tightened up

 

Often this will not show up in an MOT as either the weight is on the wheels or the tester is under the car when checking the joints/bearings etc in which case either way it wont be obvious.

 

Also check the top wishbone rod ends for play

Grant

 

Edited by - oldbutnotslow on 11 Jul 2013 11:41:15

[Chris Cardwell]

My steering wheel vibration was cured by changing . . . the engine mounts

[zetec]

Its a shame i didnt get this responce when i posted this.

Ive had/ got the same, it has almost gone but ive changed the rear radious arms, cOmplete top wishbone conversion etc & its only at really high speeds

[CaterBram]

Part of the problem with steering vibration is that it can be caused by a multitude of sins