Suspension fettling options

dunnah01

Member
Messages
648
The damper has a fixed length. If the natural length of the spring is longer than the distance between the platform nut and the top of the damper when fully extended, then the spring is pre-loaded when installed. As the platform nut is moved up the damper the pre-load will increase but so will the ride height of the car.

The effect of pre-load is to stop the damper compressing until the load on it is greater than the amount of pre-load plus a bit of friction. This doesn't change the rate of the spring or the amount it will compress in total (assuming the total load is greater than the pre-load) but it will change the characteristics of the suspension.

Cheers,

Simon
I'm still not sure I'm getting it. Most people want to lower their car a bit so this would effectively mean a reduction in preload during assembly as the spring platform is wound down. Once the weight is on the car any preload is overcome by addition of the car weight to the total spring load and the compressed length is the same as before. Preload would only have some effect if the weight of the car couldn't overcome the preload and the strut didn't allow any rebound, which would be pretty uncomfortable.
I'll have to get some coffee and maybe then it will click..
 

TimR

Member
Messages
2,656
I'm still not sure I'm getting it. Most people want to lower their car a bit so this would effectively mean a reduction in preload during assembly as the spring platform is wound down. Once the weight is on the car any preload is overcome by addition of the car weight
No...this is correct. ( I was right to say "rate " is linear but wrong to have said preload increases )
Lowering the ride height is the same as increasing the static sag...
This is done by removing preload. It isnt correct to say you will sit at the level of compression it started at when it comes to settle ( at rest AKA static sag) but it might.. This is a workaround that gets the car to sit lower under it's own weight- not to be confused with suspension "tuning" per se..!
The real way to change the set up is to install dampers with adjustable length. (This is what Simon was saying when he said they are fixed ) The allows ride height adjustment independently of preload, and independently of stroke ( ie- you have all the available stroke/travel ) So it doesnt change the static sag, or preload, or have consequences to the damping. Travel is also unaffected - Only ride height ( length of the telescope eye to eye) alters.
I m not going to guess at how the dampers work..It wont wont be progressive damping but they will be variable.... I'll bet they arent independent circuits though( rebound & comp ), which means there is crossover- something modern tuning design has either eliminated.Or in the case of bikes, comp in one fork, rebound in the other...The important compromise here to is that changing one side directly affects the other, like it or not...so there's that !

Im not explaining this very well, sorry..

Tim
 
Last edited:

TimR

Member
Messages
2,656
The locking rings' propensity to weld themselves to the threaded sleeves would encourage me to use the exact spanner size needed...not a version of one that fits "-ish". The wrong size will damage the castellations so that no one can do much with it once its butchered.
Likewise, .adjustables wont touch it and shouldnt really be considered IMO.
 

Evo Cymru

Member
Messages
688
Plan this winter is the drop the front ARB get it cleaned up and re-finished. I have new drop links from Euro Spares to install as well.

I am thinking maybe to uprate the ARB bushes while I am at it... I have seen an old thread by @CraigWaterman11 but I am not sure how far it went in the end. Are Powerflex poly ones any good or is there an option for an improved rubber bush on the market?

Excuse the thread drift but i was planning this as well - I was going to avoid Powerflex etc because of having to grease all the time (to avoid squeaks!) - unless anyone has a better experience?

Olly
 

FIFTY

Member
Messages
3,100
Excuse the thread drift but i was planning this as well - I was going to avoid Powerflex etc because of having to grease all the time (to avoid squeaks!) - unless anyone has a better experience?

Olly

Thanks for chiming in. Yes the powerflex or any polyurethane bushes need greasing regularly which wont be so bad for the front but if you decide the fit them to the rear they will be inaccessible due to the subframs as you know. Need to find some performance hardened rubber versions
 
Last edited:

Evo Cymru

Member
Messages
688
Yes rears would be a right pain! Let us know how you get on - broken wrist means I wont be doing mine for a while...!