Suspension set-up

[PACR]

I've fitted my adjustable spring seats -

Any advice on a good starting point for ride heights? (Standard springs, widetrack, 14" wheels).

 

'Raising the rear reduces understeer' - I assume lowering the front will have the same effect. Is this right? It's easier to lower the front but it's very near to the bump stops at present.

 

I've got a trackday at Llandow on Saturday so will try and get a nice neutral set-up with ride height tweaks to get the ballpark settings and then do a flat-floor measured set-up later. I figure on needing 4 sets of bathroom scales - lower wheels onto the middle of a plank spanning the scale and block the same height as the scales. Scale should then give half load reading. Argos do scales for a couple of quid - might have to use that 16 day money back guarentee! How close (kgs tolerence) should you aiming for when doing the loadings?

 

Piers

 

 

[philwaters]

Piers,

 

As a starting point before a flat floor I would set the ride heights to the recommended levels for your spec car. It is the 'rake' of the car that effects the level of under/oversteer and this should be set to around 15mm to begin with. If you haven't changed tyre profiles then this should leave your suspention geometry correct and any flat-flooring will have a small efect - small adjustments are normally all that are required. If you have changed profile (say from 70's to 60's) then you might need to check your steering rack height - this can cause bump steer.

I'm sure Peter will be along soon though.

 

 

Phil Waters

Zetec is in and running wink.gif

[Peter Carmichael]

Piers,

 

Lowering the front is not the same as raising the rear. There is a very particular rear steer aspect of the rear geometry that is linked to the angle of the radius arms. You affect the angle much more by altering the rear height rather than the front.

 

Altering the front is *not* easier. Every time you touch the front end, you have to reset the toe. The back end only has adjustable height. It is much easier to muck around at the back of the car.

 

Front lower wishbones level and 15mm higher at the back (loaded) is a good starting point.

[PACR]

Cheers!

 

I wasn't thinking about toe changes with the front end - it's just easier to reach the adjusters with the spanner and allen key (new SVA complient collars) at the front. I'll set it up as suggested and take the tools along for tuning.

 

Piers