Changing springs and dampers

[Chris71]

I've taken the plunge and bought a set of road spec springs and dampers for my RSA, the next question is how to fit them? The car is running adjustable platforms, so on Caterham's advice I'm retaining those and using the damper spacers which bring it in line with the road spec.

Can anyone give me an idiot's guide as to what is involved in the operation? Also, does anyone know exaclty which C-spanner I need for the old (2001) Bilstein competition dampers. Finally, are there any other tools beyond the usual sockets etc. that might come in handy?

Chris

[fergus]

You'd better pop over once you've got them, and we can fit them in about 1 hour!

[Chris71]

We fitted the new springs and dampers after a slight struggle with some ingenious homemade spring compressors and the difference is quite dramatic. There is slightly more sensation of the suspension loading up as you enter a corber, but the turn in remains sharp and there's still little in the way of perceptable roll. The ride still isn't limousine like, but it's compliant enough to retain its composure on just about any surface (where before it would crash and skip over the bumps) but the biggest changes are in its handling. Curiously the first thing I noticed was improved steering feel - I swear you get more slip angle feedback (although that might just be a function of the front tyres working better now they're actually on the ground). The fact the handling is now more composed and the feedback improved means you can lean on it more comfortably and this does tend to highlight the inherent understeer a bit more. However, when you manage to overcome that the breakaway now seems to be rather more progressive. I think for a mere mortal such as myself it would probably be more fun on track with the current setup, as well as being much improved on the road.

There were only two slight downsides. One, the new springs (from Caterham) didn't fit the adjustable platforms on the old Caterham/Bilstein race dampers, so we had to go with the standard mounts. Two, the lower ride height is now causing my somewhat modified exhaust mounting to ground on the worst bumps. Other than that I'm pretty chuffed.

[gedG]

It may be different on yours, but on mine the upper platform and the lower locking ring were interchangable. one was machined to suit 2.25ID springs and the other for 1.9ID springs.

[Incorrigible]

I've got some second hand platforms if you want them

[Chris71]

gedG said:

It may be different on yours, but on mine the upper platform and the lower locking ring were interchangable. one was machined to suit 2.25ID springs and the other for 1.9ID springs.

Ah, that's definitely worth checking in case we missed something there.

Have to say (exhaust withstanding) I'm not in a hurry to change the ride height otherwise. The new setup has smoothed off the car's more alarming traits and doesn't really seem to affected it's positive attributes.

Actually the only thing I can think of is it seems to be very slightly more sensitive to camber changes now, particularly on roads where one side has sunk. Presumably the geometry could do with a check once the new ride height has settled? Again, though, I'm splitting hairs, and the old suspension's ability to send me airbourne was a much more grave concern.

[fergus]

gedG said:

It may be different on yours, but on mine the upper platform and the lower locking ring were interchangable. one was machined to suit 2.25ID springs and the other for 1.9ID springs.

The problem is that the 1.9" i/d springs don't fit over the outside of the threaded collar. The lockring is not the issue, as the whole threaded platform rests on the lockring when it's moved down the damper body to the lower of the 3 (or 4?) possible locations. I think 2.25" springs would be required to facilitate use of the moveable spring perch.

[Incorrigible]

What's the shock part no? Standard spring should be 75511 1.9 id nd the standard adjustble platfors should work with them.

[Chris71]

Will dig out the invoice and take a look.

Can't say I'm too worried with the unadjustable setup though. It's a massive improvement on the road - subtle at first, but you rapidly realise that in all the places you'd have to slow down due to the surface previously you can now really throw the car around. It's really brought the car alive. Out again a couple of times over the weekend and loving it.