Etwenty1 45 Report post Posted June 10, 2013 Is it necessary to have shocks shortened if fitting lowering springs? Thinking about lowering my PFL 325i and have some M3 e30 springs or some msport struts complete to use. Ive seen examples of m3 springs in 325i's that give a nice drop but i keep hearing about shocks "bottoming out". Is this fact, fiction or does it depend on how much a car is lowered? Also anyone know what spring rate a standard shock will handle ? Cheers Quote Share this post Link to post Share on other sites
e30ftw 398 Report post Posted June 10, 2013 You should shorten them for a couple reasons, Mainly to stop the shock bottoming out and also to keep the spring captive (Like when you raise the car, the shock does not extend out so long that the spring ends up loose in the perch) Depends on how much lower though. Up to an inch or two is usually fine. e30 stock height vs super lows is like a 3" + drop and you would definitely need shortened shocks. Quote Share this post Link to post Share on other sites
Etwenty1 45 Report post Posted June 10, 2013 (edited) You should shorten them for a couple reasons, Mainly to stop the shock bottoming out and also to keep the spring captive (Like when you raise the car, the shock does not extend out so long that the spring ends up loose in the perch) Depends on how much lower though. Up to an inch or two is usually fine. e30 stock height vs super lows is like a 3" + drop and you would definitely need shortened shocks. Ok, so to get them shortened it is a shop job with the shock assembled? does the captive part only apply to the rears due to the fronts being in a strut? and you shorten them by how much the drop is i guess? Edited June 10, 2013 by etwenty1 Quote Share this post Link to post Share on other sites
e30ftw 398 Report post Posted June 10, 2013 Ok, so to get them shortened it is a shop job with the shock assembled? does the captive part only apply to the rears due to the fronts being in a strut? and you shorten them by how much the drop is i guess? You can shorten them by how much shorter the actual spring length is. The captive part applies to both front and rear, if a front shock is too long, the shock can extend so much that the spring sits inside top mount and strut loosly. To shorten the shocks you need to take them to an engineer who can cut then machine a new end on the shock. They will shorten the insert part, then lathe / machine and tap thread on the end so it matches how the top was before it was cut (so you can attach the top mount on again). I used to get them done at a local auto engineer for $40 each, length cut should not matter as it involves the same amount of work cutting it and then re-machining the tip. Quote Share this post Link to post Share on other sites
_ethrty-Andy_ 2122 Report post Posted June 10, 2013 I used to get them done at a local auto engineer for $40 each, length cut should not matter as it involves the same amount of work cutting it and then re-machining the tip. Thats a good price. I remember pricing it up when i was 15 or 16 and found it was more economic to buy new shocks. Quote Share this post Link to post Share on other sites
