Spring & Shock length?
Discussion
When designing suspension (dual wishbone in my case), is it generally better to have longer shocks and springs, or can short ones do the job just as well? Obviously they have to be the right length for any pre-existing mount points, but if designing a suspension from scratch, with the freedom to locate the mounts in a variety of places, is longer better, worse, or no difference? I'm asking because at some point it looks like I'm going to have to redesign the suspension on my kit.
Thanx, Pum.
Thanx, Pum.
Interesting stuff so far - thanx.
I spoke to some spring/shock suppliers at the Donnington Kit Show recently, and for an existing suspension they were saying if I specify the shortest and longest length between mount points (ie: when the suspension is at the extremes of its travel) then they can supply a generic adjustable shock that will probably do the job. I guess that is based on assumptions that my unspecified requirement are not very usual, which is probably true. WRT spring rates, they suggested looking at corner weights and picking likely springs, and then changing if necessary on a semi-trial-and-error basis, as springs are not too expensive, which sounds fairly OK to me.
From what you chaps are saying, for my new suspension design, it sounds like one approach for me is to work out the up/down range of travel of my proposed bottom mount point, and the max and min height I could place the top mount point, and then ask the suppliers what best spring/shock lengths would fit that range of possibilities; sound sensible? I'm not looking for the ultimate race setup, but rather something that will work decently for road and trackdays. From what you're saying the required travel will impose a minimum length (ie: shorter shocks and springs can do less travel). Beyond that, shorter may give a more convenient design, but longer is probably better for geometry, heat dissipation, etc.
GreenV8S: Good point re: geometry most important. Am I right in assuming that the more leaned over the shock/spring is to the direction of suspension movement, the worse that is geometry-wise?
BTW, this is a project for the future rather than something I'm doing now, and I'm planning on reading some of the suspension design material mention elsewhere before getting into this properly. I'm asking now because the body will be off the chassis for only a short time longer; after the body is fixed on, chassis mods (eg: for suspension changes) become more difficult, so I'm trying to get a quick basic idea of the issues.
Thanx, Pum.
>> Edited by Pum on Friday 11th November 17:38
I spoke to some spring/shock suppliers at the Donnington Kit Show recently, and for an existing suspension they were saying if I specify the shortest and longest length between mount points (ie: when the suspension is at the extremes of its travel) then they can supply a generic adjustable shock that will probably do the job. I guess that is based on assumptions that my unspecified requirement are not very usual, which is probably true. WRT spring rates, they suggested looking at corner weights and picking likely springs, and then changing if necessary on a semi-trial-and-error basis, as springs are not too expensive, which sounds fairly OK to me.
From what you chaps are saying, for my new suspension design, it sounds like one approach for me is to work out the up/down range of travel of my proposed bottom mount point, and the max and min height I could place the top mount point, and then ask the suppliers what best spring/shock lengths would fit that range of possibilities; sound sensible? I'm not looking for the ultimate race setup, but rather something that will work decently for road and trackdays. From what you're saying the required travel will impose a minimum length (ie: shorter shocks and springs can do less travel). Beyond that, shorter may give a more convenient design, but longer is probably better for geometry, heat dissipation, etc.
GreenV8S: Good point re: geometry most important. Am I right in assuming that the more leaned over the shock/spring is to the direction of suspension movement, the worse that is geometry-wise?
BTW, this is a project for the future rather than something I'm doing now, and I'm planning on reading some of the suspension design material mention elsewhere before getting into this properly. I'm asking now because the body will be off the chassis for only a short time longer; after the body is fixed on, chassis mods (eg: for suspension changes) become more difficult, so I'm trying to get a quick basic idea of the issues.
Thanx, Pum.
>> Edited by Pum on Friday 11th November 17:38
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