Quote:
Originally Posted by Megator
Maybe get the guys who installed your friends kit to look at your? or take some measurements off of his kit?
Assuming everything is in good working order wouldn't too much preload on the rear give a crappy bouncy ride since you need to overcome whatever preload force the spring is already exerting outwards before compressing it?
Ie at 190N/mm a preload of 40mm gives a preload force of 7600N or roughly 775KG. Assuming 1/4 the weight is on each rear wheel (say 400KG) and a spring motion ratio of 0.6 (then the "weight" on the spring is roughly 670KG ) the the spring is still pushing the car upwards with 100KG of force which needs to be overcome before the spring compresses due to any dynamic forces.
I imagine the numbers work out so you have some compression of the shock at rest but not much this means you have no or very little extension travel which would seem to make the car handle like crap over potholes. It also means bumps are not absorbed as the body will be lifted before the spring can be compressed further, again leading to a crappy ride.
The damper settings would not affect the ride much as they do not work unless the spring allows the suspension to move.
This is just my thought experiment and I have no real world experience setting up suspensions. A quick check would be to jack the car and see how much the suspension drops by. If it is less than your friends this might be the culprit no?
Can the experts tell me if I am way off?
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It looks like you're getting confused by Ohlin's terminology too. When they say "40mm of pre-load" they don't actually mean the spring is compressed 40mm at neutral ride height. If that were true the spring would basically never move under normal operating conditions since the weight of the car only compresses it by about 16mm on its own.
What Ohlins means is that the space between the top of the rear adjuster and the top of the spring needs to be 40mm in order to preload the spring by a small amount (let's say 5mm) to prevent it from coming loose/popping out under the droop allowed by the damper body at the length settings for that they also recommend. I agree it's not very straight forward.