Had my car on the road and done about 1500 miles, But only just started to push it past 80-90%% and its very skittish on high speed bumpy roads. The back end of the car seems to wonder around following the road and I get a lot of feedback through the steering and vibration at high speed. Even on motor ways the steering wheel sort of vibrates. Now a little bit is fine but a few people have drove it and people who have followed have made a few comments so I thought that a setup may be required.

The skittishness I thought might be the damper setting? They where set on 3 clicks (can some one confirm this is correct and is it, turn fully anticlockwise then 3 clicks clockwise? ) it seems to ride ok at normal speeds and speed bumps etc.

My car has level wish bones, slightly higher ride height at the rear, 3 clicks front and back. Not sure what the front alignment is like but 1.5 neg camber and 1mm toe in is what it was originally set too (i Think? What ever MNR said)

Any Suggestions?

What Tyre Pressures are you running ?
Also have you checked the rear toe-in ?

How much rear tow in? and camber on rears?

im running 15 inch tyres on about 18- 20psi.

are you running the fully rosejointed mnr chassis or the poly-bushed one? id imagine the vibrations are from the lack of give in the rose joints but a good setup should cure rear end bounce!
what spring rates are you running front/rear?

Try 15 psi front 16 psi rear.
Rear toe-in same as front or slightly more, it is very important that neither of the rear wheels have toe-out.

Toe and camber should be set with the drivers (or if you normally run two up driver and passengers) weight on board.

After that you should look to setting the corner weights.

After a basic setup if the car is "loose" at the rear eg oversteer either stiffen the front by changing the springs or fitting a front anti-roll bar or fit softer rear springs.

quote:

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Originally posted by daniel mason
are you running the fully rosejointed mnr chassis or the poly-bushed one? id imagine the vibrations are from the lack of give in the rose joints but a good setup should cure rear end bounce!
what spring rates are you running front/rear?

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quote:

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Originally posted by britishtrident
Try 15 psi front 16 psi rear.
Rear toe-in same as front or slightly more, it is very important that neither of the rear wheels have toe-out.

Toe and camber should be set with the drivers (or if you normally run two up driver and passengers) weight on board.

After that you should look to setting the corner weights.

After a basic setup if the car is "loose" at the rear eg oversteer either stiffen the front by changing the springs or fitting a front anti-roll bar or fit softer rear springs.

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quote:

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Originally posted by umgrybab

quote:

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Originally posted by britishtrident
Try 15 psi front 16 psi rear.
Rear toe-in same as front or slightly more, it is very important that neither of the rear wheels have toe-out.

Toe and camber should be set with the drivers (or if you normally run two up driver and passengers) weight on board.

After that you should look to setting the corner weights.

After a basic setup if the car is "loose" at the rear eg oversteer either stiffen the front by changing the springs or fitting a front anti-roll bar or fit softer rear springs.

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Rear toe in is for front wheel drive cars. With a rear wheel drive you need a slight toe out to compensate for the pull on the rear suspension in the opposite direction.

The way you say its fine at regular speed but skittish at high speed makes me think you have an over damped set up.

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Ill stick with MNRs settings unless a decent setup specialist opens in north east. Ive turned my clicks to 5 on rear and it rides better i was nearly flat in 4th before breaking today on a bumpy poorly shaped road and it wasnt wondering at all.

Be sure your rears are toeing IN. Never ever ever have them toeing out.

Should you want to see what a car handles like with a kit with rear wheels toeing out (on track)

Go to my YouTube and see the handful my car was before I realised.

www.youtube.com/trackdaynova

It's the video aptly named 'Rear Geometry Problem'

I have a similar problem with my car at speed so keen to hear any findings you make on this. I have firmed up the dampers a few clicks but it started peeing down during my test run on Sunday.

I have heard playskool motorsport in County Durham are very good for suspension setups

Sdh, im booked into kenny browns in hillington for suspension setup tomorrow. Will let you know how he fares.

Hi johnny I had all the baseline settings done at Kennys and he was pretty good. Are you getting the corner weights done or just a basic setup? All the settings on mine are ok, my weaving issue is definitely a damping/spring rate or ride height issue and I'm working through them.

wheres kennys at?

Sorry Kris, probably a bit far for you, Kenny Browns is in Hillington just outside Glasgow.

I'm just back from getting full suspension setup and corner weighting.

The good news is the car only weighs 494kg

The bad news is my four protech shocks are grubbed and could do with being replaced

Yellowcab - I was reading this post today with interest as I have recently bought an MK Indy with slight high speed instability and wondered how you adjusted the rear toe in on yours as I don't think it is easy to adjust on an MK Indy.

Also where did you get your geometry checked? I live in Leicestershire which I think is close to where you live and I was wondering where is the best place locally for that sort of thing.

Hi mate,

I ended up buying some rose jointed rear wishbones, in order to alter my rear geometry - the alternative is shimming the rear to eradicate any tow-out at the back end.

I got mine setup at Pro-Comp, over in Birmingham, well worth the trip

Yep - I'm out Hinckley direction

Hope you get sorted?

Sounds like I need to take a trip to Procomp. They get very good reviews on this forum.

Will keep an eye out for you around Hinckley