Tips to remove some S2 Understeer

[robin]

Dezzy, as stated somewhere earlier up the thread, until you know for sure that the car is understeering when you're off the pedals I don't think you should go making radical changes to the suspension. I would expect you to be able to turn the wheel quite hard at 60mph or more in these conditions and get the car to turn in (what happens to the back end is another question!).

Unfortunately you need somewhere sane to test this out.

For low speed the hairpin at KH is probably as good a place as any. For higher speed stuff you really need somewhere with a load of run off so that if you spin you'll have plenty of tarmac to stop on.

That said, you do want the standard rear geometry.

The front toe should be standard (i.e. the tiniest smidge of toe out).

You want the front camber to be balanced side-to-side. If you end up giving it a drop more -ve camber at the front in order to get it balanced, that will be no bad thing, but remember the more -ve camber you add, the more the car will tram line on the roads and the more the inside edge of the tyres will wear (in a straight line, you're putting more load on the inside edge than outside edge).

Cheers,
Robin

[dezzy]

Thanks Robin. It's off to CLCM this week, firstly to get all my wheels balanced (because they're quite wobbly), but was going to get him to check my geo. However, do you think I'm better waiting til after Kames and KH next week? I'm doing Kames on Thursday and KH on Friday and could see how the car is on track. The other thing is that I'm getting my rear tyres replaced by Ronnie after the KH session, so am I better waiting til after that for the geo or does it not really matter?

Thanks,
D

[Cisco]

Dezzy,

When You take your car for geo make sure you ask them to check that the rear toe link inboard bolt torques. 50Nm required on each side.

There is quite a bit written on this in the various forums but I have a feeling that most people ignore this as the diffuser has to come off to check.

Last time I checked mine (before every 2nd track day) the LHS required re-torque/loctite.

Take care,

Frank

[robin]

The tyres have nearly no effect on the geo - they live on the outside of the suspension, while the geo adjustment is angles between the chassis and the hubs.

I say "nearly" because tyre pressures and tread wear will affect in a small way the height at each corner and thus the attitude of the chassis. This in turn will reposition the centre of gravity slightly and thus lead to a different amount of static compression at each corner; camber and toe change with compression.

*BUT* I would bet that within normal tyre pressure and wear variations, the error introduced will be smaller than the measurement error of the equipment you are using to set up the geo in the first place.

Cheers,
Robin

[dezzy]

Thanks Robin and Frank for the advice.

I think what I'll do is just get my wheels balanced this week (as they really need done), then do my trackdays next week, and wear out the last of my rears and get them replaced after KH. I'll see how the car feels round KH and then decide whether or not to get the geo checked. If I do, I'll just stick with standard settings unless I definitely feel understeer.

Cheers!

D