coilover, how much to adjust

[uk-rich]

i need to firm my suspension up slightly (get minor rubbing on big bumps, on the arches)

 

 

i have hks hypermax 3's, which have adjustable height platforms as well as the adjustable spring seats

 

so i if was to compress the spring say 10mm would that make alot or a little to the stifness of the ride

 

i'm happy with the rebound setting (adjusted at the top of the shock)

 

cheers

[uk-rich]

awaits for mr wilsons input

[Chris Wilson]

If you compress the spring 10 mm the ride height will go up by the ratio of the damper to wheel function, it won't make the spring stiffer. It's NOT the correct way to stop rubbing, not at all!

[uk-rich]

ok, but what is the point of having adjustable length dampers, i though that is how you adjust the ride height

[Chris Wilson]

OK, I see what type you have now, the lower stem, BELOW the spring seat, can be changed in length, right? You can raise or lower the car like that, yes, without affecting the spring preload, and by using the spring seat adjusters you can alter the spring preload, but that will ALSO affect ride height, so you may be able to compensate on the stem length. Adding preload to the spring rather than using a stiffer rate spring has additional effects, which you probably don't want, like reducing droop travel of the spring until it's near fully relaxed. traction will suffer.

 

You really want tyres and rims that don't have a clearance issue throught full normal extension and compression...

[uk-rich]

OK, I see what type you have now, the lower stem, BELOW the spring seat, can be changed in length, right? You can raise or lower the car like that, yes, without affecting the spring preload

 

yes that is correct

 

 

Adding preload to the spring rather than using a stiffer rate spring has additional effects, which you probably don't want

 

but would it have the effect of slightly "increasing" the spring rating ?

 

 

You really want tyres and rims that don't have a clearance issue throught full normal extension and compression

 

 

it only catches on the hardest of bumps

[Tricky-Ricky]

I also thought that pre loading springs, increased the spring rate ? as well as increasing the ride hight on adj spring platform suspension.

[bodilx6]

Does anyone know of some writeup including general concerns of how to setup suspention and what the different settings does in real life driving?

 

For example the preload, rebound and so on.

[Chris Wilson]

ftp://ftp.chriswilson.tv/penske_shock_manual

 

It's for very high end race shocks, but toward the end is some good info on setting up dampers.

[uk-rich]

so the answer is yes, compessing the spring will have the effect similar to stiffer springs

[Chris Wilson]

so the answer is yes, compessing the spring will have the effect similar to stiffer springs

 

Not quite that simple, it will only do this once the shocks are fully extended, or length artificially limited. A lot of single seaters and very stiffly chassised sports GT cars run with the springs pre loaded and the shocks stopped from opening fully by anti droop stops.

[Chris Wilson]

You should be using the bump stop rubbers to control final movement over really severe bumps. You need to see when they come into play, with the springs off the dampers.

[uk-rich]

Not quite that simple, it will only do this once the shocks are fully extended, or length artificially limited.

 

i fully understand what you are saying here chris, but what is the point on having adjustable length and adjustable spring platforms then