Correct Ride Height

Ever since the first drive for IVA, the suspension has been jacked up to comedy height so the indicators passed the minimum height test. With all the engine problems, sorting the ride height out has been at the bottom of the list but on Saturday we found time to address it.

According to the Dax manual, the correct ride height for a De Dion is 5.25" front, 6.25" rear. Ours was wound up to 6.75" front and 7.5" rear. The height wasn't really noticeable in normal driving but on heavy braking the nose pitches forwards alarmingly and it was vague and wallowy in the corners.

We set about winding the spring seats down and re-measured. With the fronts as low as they would go we managed 5.5". Perhaps with a little more time it will settle even lower so I'll keep an eye on it. The rears we set to 6.5" to maintain the 1" rake from rear to front.

Changing the ride height of course completely knackers the camber and toe at the front so we made a string box round the car and adjusted it back to spec. 0.25° negative camber and 0.25° toe in. Rear toe was unchanged, rear camber is not adjustable.

We made the changes and went for a short drive and it was immediately apparent something was wrong. The steering wheel was way off centre and the car darted around as if it had somehow shed 500kg. Good for racing perhaps, not good for a bumpy road. We quickly returned home and rechecked everything - turns out somehow we had managed to put 1° toe-in on the front! No idea how we managed that. Corrected to 0.25° and its now nice and stable. We decided to check the damper settings while we were at it and the rear was too soft, should be 10 clicks from softest and I had it at 2 clicks.

The car isn't completely transformed but is definitely far more stable over bumps, the steering rack height was set for the "true" ride height, not the IVA ride height so the bump steer has been reduced. The increase in damper rate on the rear has made it more stable under hard acceleration on a bumpy surface but the front seems to have lost a bit of directness. The initial turn-in is a bit sluggish but once your in a corner it feels very good and stable even if you're on/off the throttle (so long as your not jabbing at the pedal like a maniac of course). I think perhaps the front could take a click or two harder on the dampers, or maybe I need to check tyre pressures. but generally it feels very good and its just small tweaks now to find the optimum.

This is it now at the correct(ish) ride height. More pictures to follow.