springs for f56

13522 Views 18 Replies 9 Participants Last post by Ryephile, Nov 20, 2015

oliverdf

Discussion Starter · Oct 25, 2014

http://www.nm-eng.com/337/0/0/3107/nm558846-nm-eng-rs-alpha-spring-kit.html#popUp

im so getting these springs..

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stevens

· #6 · Sep 16, 2015

Which is why if you get different bump stops and shave your top mounts you will get the full travel wtih the lowered look, common thing to do when lowering BMWs

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stevens

· #9 · Sep 18, 2015

Ryephile said:
That's a major myth generated by people unwilling or unable to understand the design of the damper. You can't create extra travel, the damper has mechanical limits and trying to force it beyond those limits is how you damage them. The shorter bumpstop is simply a steeper slope to its compression curve and less overall compressibility, making large bumps even more abrupt feeling. The bumpstop still must prevent the damper from reaching its mechanical limits.

The only correct way to get "full travel" is to use correctly designed dampers that move the stroke such that there's the same droop and compression amounts re-positioned around the new ride height. That is of course making a gross assumption that the kinematics [camber, caster, and toe curves, roll centers and axis] will be effective at the different ride height.

Hello Ryephile, im going to start by saying im no expert in suspension but just some basic logic from what I said earlier (happy for you to correct me). By using shaved top mounts (circa 8mm on bmws of the e9x series) combined with shorter bump stops, this pulls the damper closer to the top strut housing (increasing the travel lost by the lowering springs as you have gained 8mm back from the drop) and having the shorter bump stops allows the lowering spring to be fitted keeping astehtics but effectivly allowing the full travel of the damper. Or at least thats how I understand it

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stevens

· #11 · Sep 18, 2015

I have not seen the Fxx mounts so again just using the ex car as an example, so there may not be an option to shave them and gain the travel. If not then I agree that lowering with original dampers is not ideal.

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