Stiff suspension = unstable at speed?

[jesus]

I set the newly refurbed dampers to (what I thought was) 22 clicks. It was as stiff as anything, handled well but felt extremely unstable on the motorway and there was literally no body roll.

I've turned them down a few times and there's a slight bit of body roll now and it feels better, however I've not had chance to test it on the motorway at speed yet.

Would the dampers being stiffer affect straight line stability? Tracking has just been done btw.

 

[Mrpete]

Mine seems slightly unstable at times (have cup dampers on original trophy springs) that's my thinking. How olds ur springs?

 

[Jonc]

I would imagine that if they're set that hard you'd have dialed out most of the compliance. That is the wheel would not be following/absorbing the dips and ruts and cambers in the the road and under certain circumstances, the wheel would loose contact with the road. Hard setting would only be suitable for track use where the surface tends to be even and smooth.

 

[jesus]

Springs are new Sportlines! On the Cup dampers with Trophy springs it was fine. Jonc that sounds about right, hopefully with this tiny bit of body roll I now have it'll be more sturdy!

 

[Rob Vox]

you had youirs depinned and refurbed then ? Mine are being done now and contemplating depinning

 

[hoolio]

I would imagine that if they're set that hard you'd have dialed out most of the compliance. That is the wheel would not be following/absorbing the dips and ruts and cambers in the the road and under certain circumstances, the wheel would loose contact with the road. Hard setting would only be suitable for track use where the surface tends to be even and smooth.

22 clicks is middle for diddle and what Renault had them pinned to so the first thing I would do is to check that. Zero them and then count all the clicks till it stops and then work your way back to half of that total. Check your tyre pressures and don't make too many assumptions until you have the tracking set up.
BTW I always thought the rear of mine became light at "interesting" motorway speeds. Also you may have got used to the softer ride of the cup dampers and the 'stiffness' is just the Sachs set up as they should be.

 

[Rob Vox]

I was thinking of asking that. 44 total then with standard being 50% @ 22 ?

 

[Luke335]

I don't think the dampers being stiff will make it unstable at speed on the motorway. A bumpy B road maybe. The slow lane is often rutted but this isn't really a damper thing in my opinion. Check damper settings as Hoolio said though. Wheel alignment would be my first guess. Do you trust the people that did it. I had mine done a couple of times at your average tyre place and they are often just not accurate enough. I had Mark Fish do it afterwards and the car was transformed. If they say its 'within tolerance' then forget it. That's not good enough on the Trophy.
Tyre pressures. Track rod ends. Bushes?

 

[jesus]

New TRE and bushes, tyres are brand new too. The place that did it was a motorsport place rather than a regular garage, however something doesn't feel right... back end feels like it could step out at any time when turning the steering lightly.

 

[Carbon Chaos]

Do you know what the alignment was set at ? toe in or toe out ? Most places make the error of putting toe in because most fwd cars have it.

 

[Luke335]

How are your tyres wearing? I did have a strange feeling like this after running too much pressure. They wore more in the centre and then it felt unstable.

 

[jesus]

I've not checked the wear actually. I am going to get a print out of the tracking setup so I can be 100% sure that it is/isn't right and then maybe find out where the problem lies.

 

[Jibber_Monkey]

What condition are your rear dampers in? Seized or sagging rear shock could easily cause these symptoms.

 

[jesus]

As far as I know they are fine - there are no obvious leaks and body roll is minimal.