Springs

[Andy Sykes]

So I needed some shorter springs for the front of the car so orded some shorter ones

So now I'm confused they are the same poundage but the coil DIA is much smaller



It's got the wheel were I want it but surly they can't  be right?



Cheers Andy

[spanners]

spring height, wire size,  number of coil turns, helix angle and coil overall diameter all come to bear, if you cut the original spring down say to half its existing height, it would more than double in poundage. very rough guide, if you add the coil rate to the springs, say 150 lb, it should drop by 1". or put them on the bathroom scales in a press or pillar drill and compress them 1" for a 150lb reading. tho it may not work due to the angle of the spring tails stopping them sitting squarely, or if installed on the car the term "sticktion" comes into play to further confuse things, ie, damper and bush resistance etc, i would say they were o.k, but just from the photo, the original spring looks to be a monster.

[Andy Sykes]

Ok thanks that makes sense the bigger ones are. 7" the small ones are 3 " 2.25" DIA

[dannyboy]

are you sure its not a valve spring? 

[spanners]

Andy, with short springs the only thing to watch out for is adequate travel in bump and droop, again roughly twice the droop versus the bump travel, and spring retention in droop also so they wont fall off the perch, then adequate bump stop clearance if external or on the damper shaft, most shocks will be destroyed by bottoming, tho it is possible to have bump stops internal to the damper by special order.

[Andy Sykes]

Thanks they have external bumps stops as soon as I fitted them I realised I'm going to have the limit the down award travel as like you say the springs will come of the perch, I think I will only need 2" of travel.

Cheers Andy

[spanners]

Just use a tender spring under the main spring, you can even tune these to taste, either just strong enough to support the main spring, or up the poundage to suit low speed bump and ride pre the aero loadings come on , tho this will be overkill for drags i would think, given a good racing surface.

[Andy Sykes]

is that what they call a helper spring ?

[spanners]

is that what they call a helper spring ?

others may..