Ride height

[paul jacobs]

I'm currently re-setting the ride height of my 2001 ex-academy S3, and whilst it is common knowledge that a good height is fr. 120mm and rear 135mm, the difficulty I'm having is getting the front low enough, because the body of the Bilstein shock abosrber is too long, in other words, when adjusted with the spring seat platform and the correct length springs, as low as it will go, which is about 155mm measured in the middle of the front suspension arm bolt head, it is riding on the bump stops. 

It seems to need a shorter shock abosrber, but these things are standard, and at this moment I don't want to shell out hundreds for new ones of the correct length.

Does anyone have any suggestions?

BTW, I'm not worried about sump clearance as I do  not have one that hangs below the chassis rails.

[Jonathan Kay]

Are you now or have you ever been widetracked? Discussed here.

Jonathan

[Dave J]

depending upon tyres being used etc, 120mm is quite low. 

135mm under the chassis / front engine mount is quite common when using 13" 185/60/13 and should also provide circa 75mm under sump / gearbox and level ish wishbones.

 

[paul jacobs]

Thank you both.

Jonathan, the car has never been wide track, and as far as I'm aware the Bilsteins are standard issue circa 2000.  However the old thread is interesting.

Dave, I'm not worried about the sump clearance as their is so little below the chassis that it isn't a problem, but getting the rake right is difficult.  I can raise the rear, but then it will look ridiculously high, to get the differential required.  Previously the nose was up in the air!

[Wales South AR]

but why try and get down to 120mm ?, set the dampers for optimal wishbone angles. 

what tyres does it have ?

do the dampers have extension pieces ?

 

[paul jacobs]

Hi Alan, it doesn't necessarily need to be 120, that's' more of a target, but I think I do need to drop the front so that it's lower than the back, and because of the length of the shock absorber body, it is difficult to do this without running out of compression, before the bump stops come into play.  I would have thought there should be at least a couple of centimetres of rod showing?

The Bilsteins do not have the extension pieces, but appear to be bog standard 2001 issue.  The wheels are 13" but I don't feel that is really very important given the difficulty of getting the nose down more, otherwise the back end is stupidly high.

[Dave Rayner]

Hi Paul, give Andy a ring at PGM as when he set up my car on Bilsteins he had to machine another groove in the body for the circlip to get the extra adjustment

Dave

[russjones]

Not quite sure if I have your point but if you have adjustable dampers then the dampers are likely to have snap rings that you can reposition to allow a different range of adjustment, at least mine did

[paul jacobs]

I've already moved the spring seat down a groove, ( which I also had to have machined Dave), and this is the point,, the further the springs are moved down, the less movement there is left for the piston to work, and it then virtually or actually sits on the bump stops.  Have a look at yours Dave, and see if that is the case as well?

[garybee]

Post deleted

[F111C]

I purchased from eBay a brand new but second hand set of r400 dampers with the idea of taking out the wide track spacer to fit on my old narrow track chassis but the body of the damper was too long so I purchased from Caterham a new pair of dampers listed as live axle dampers although I have dedion and they fit ok but I wanted to use the adjustable platform from the r400 dampers ,but I had the same issue that there is not a groove in the damper body low enough to fit the platform so at the moment I am running without adjustment at the front and the ride height is a little higher than I want but not too bad.

[paul jacobs]

If you find a local machine shop, they will put in a groove or two.  I paid a rather high 60.00 for 2 grooves in each, but the point is that if you drop the platform down to a lower groove, it will bottom out, or at the very least sit on the bumpstop rubbers, which means the spring isn't working properly.

Anyway, it seems there is no easy answer, I am putting on considerably stronger springs, to compensate for less movement, so when it is all back to together will report back here on whether it still works -  or not.......

[Simon.Rogers]

And then the springs won't match the damping forces and you will bounce down the road.

 

It really needs a combined approach.

[p.mole1]

Hi Paul,

Are you sure you have the correct dampers? I had all sorts of problems with my car when I bought a set of Nitron, there are a few different lengths of dampers depending on year and track width. I have a 1995 car on 14" wheels with 60 series tyres. I am running a ride height of 150 mm at the front  I could go slightly lower but I would be on the bump stops. The car seems to handle fine and I wouldn't be to concerned over the ride height as long as you have the the required rake.

[paul jacobs]

The dampers are Bilsteins, as supplied when the car was new, but to me look too long.  If I run the correct rake, the back end is too high and looks ridiculous, but it is the bump steer issue that I am really trying to eradicate.

i've had a brief run with the stiffer springs, and they aren't half as bad as I feared, quite easy to live with on bumpy roads.  I will continue to play around, rack spacers are next on the agendas, do Caterham or anyone else sell them, or do I have to make them up myself?

Simon, I did send you an email, but it may have gone into your junk filter.  Do you have slightly less expensive dampers in your range?

[Simon.Rogers]

Hi Paul

No email.  

Check out my buyers guide here.  https://www.meteormotorsport.com/wp/wp-content/uploads/2017/07/Caterham-Suspension-Recommendations-July-2017.pdf

[MereCat]

I guess mine is running too low then...!? 65mm front( bottom of sump)  and 135mm rear ( bottom of A frame  centre) on billies and 13" wheels.  Not fitted the Meteor Nitrons yet though so will look at link when do...anyone else at this height?

[p.mole1]

Hi Paul,

I run my car at 150 165mm F/R but on 185/60 14 tyres so it looks ok. With regards to bump steer mine is terrible but I am in the process of sorting it out, be careful and measure it.Not all racks need lifting, mine needs lowering!. I am having to lift the track rod ends also adjust everything first, camber, castor and toe then check for bump steer a few mm makes a big difference.

[paul jacobs]

Thanks for the bump steer comments.  I did note your thread and how you were tackling it.l'm starting with the rake, getting the toe right, then will space the rack up until the track rods are level, then see where I go if it is still bad.  Maybe actually start to measure things!