Adjust wheel alignment after height adjustment?

[rollerdan]

Just want to be sure do i have to adjust the tracking after ive raised my coilovers up a touch?

 

[Rob]

As long as you literally just wound them up, touched nothing else, and undid no suspension components then no.

 

[Fred@BTM]

yup

 

[JackJack]

Yep.

 

[Rob]

Yep to me? Or to him?

 

[Dan@SJM]

Him. Height changes toe.

 

[rollerdan]

Cheers lads

 

[Rob]

Him. Height changes toe.

Unless a racing driver, you're telling me what's probably 15-30mm of height is going to make any difference to how the car drives?

The amount of toe added/removed would be so minor surely no one would notice and it'd probably still be within the the bounds of acceptable wouldn't it?

I'm genuinely asking, not just being a douche btw.

 

[Jay Payne]

yep changes it. Race car gained about 4mm toe out when we raised it at Outon the other day

 

[Adam G]

I'm no racing driver Rob but I can tell on track, the difference is quite noticeable when giving it some.

 

[Dan@SJM]

Unless a racing driver, you're telling me what's probably 15-30mm of height is going to make any difference to how the car drives?

The amount of toe added/removed would be so minor surely no one would notice and it'd probably still be within the the bounds of acceptable wouldn't it?

I'm genuinely asking, not just being a douche btw.

You do realise that 1mm of toe on a wheel makes a massive difference?

 

[Rob]

^^ Well I didn't. Hence asking!

I don't know a great deal regarding alignment, but I'm interested to learn.

 

[JackJack]

It's not just the feel etc that needs to be taken into account it's tyre wear too imo.

Yep was to Fred btw.

 

[Steven103]

yep changes it. Race car gained about 4mm toe out when we raised it at Outon the other day

...which given the amount of toe (even on a race car) you start of with, 4mm is a very big percentage.

As a side note toe changes for exactly the same reason bump steer or even roll steer occurs (I'm on about proper bump steer, not neccessarily "I hit something hard and the car changed direction") - the distance between the steering rack and the outer balljoint changes, but the length of the toe arm (call it what you want) doesn't so something has to give - since the steering rack nor steering wheel can move in this case it's the toe angle that has to "give."

On many purpose built competition cars (stuff where you start from scratch with the suspension design, e.g. single seaters) toe will not change at all with ride height because bump steer can be eliminated/minimised in the original suspension design by putting the steering rack in a clever place relative to the wishbones. Probably find there's an engine in the way if you tried to do this in a Clio... or most things FWD/FR/4WD to be fair.


Uneccessarily long post for what I wanted to say, as always.

 

[Dan@SJM]

^^ Well I didn't. Hence asking!

I don't know a great deal regarding alignment, but I'm interested to learn.

Sorry, was in the middle of work when I sent that, didn't mean it to be so blunt.

Well 1mm of toe out is what a fast road setup

 

[Chip-mk1]

Raised my car 15mm or so at Bedford to clear the larger tyres I ran that day and it threw the tracking out loads, felt horrible after and me and danlp6 had to do it by eye in the pits and then I kept tweaking it after driving it till it felt ok again.

Its a function of the steering geometry that these cars suffer from 'bump steer' where the wheels turn as the suspension compresses and expands, so absolutely vital they are tracked again once the ride height is changed.