j2eDX
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| posted on 25/3/07 at 01:58 AM |
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Setting up Ride Height
So I am in the process of designing my suspension with f1 style spring/shock configuration. What's a good ride height for a 3-wheeler? I'm
thinking of 3-5" ride height. Lets say I have finished w/ the suspension. I have the chassis sat on a platform with my prefered ride height. How
can I setup the pushrod length, bellcrank ratio, spring/shocks angle so that the car sits at my preferred ride height. For most of you guys, is it a
trial & error thing?
[Edited on 25/3/07 by j2eDX]
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nitram38
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| posted on 25/3/07 at 04:36 AM |
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You don't want much!  
Once you have your suspension set up, work out what type of cam/lever/pivot setup you need and where to locate that.
I usually mock this up using a coilover shock with spring.
Tack weld/bolt the pivot in place and check the angle of the cam in relation to the bones.
Tack your shock in place.
Leave the push rods until last, so that they can be made at any length you choose.
Using rod ends with left and righthand thread, means that you can adjust them by simply releasing a lock nut each end and just rotating the rod.
Remove the shock and check the pivot/pushrod by jacking the car up and lifting/lowering the wheel.
Once you are happy, weld the pivot/shock mount in place.
Just do it step by step or alternatively model your setup in solidworks in 2D and see how it moves.
 
Description
 
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[Edited on 25/3/2007 by nitram38]
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JB
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| posted on 25/3/07 at 07:16 AM |
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Ride Height
I have a ride hieght of 120mm and it doesnt catch on speed humps.
You have your coil over which is a set length. You need to decide how to proportion the travel. EG a 150mm stroke metal to metal, do you have 75mm
bump and 75mm compression? I went for more bump travel on mine because the bumpstop effects the travel. So my 130mm are set at 70mm bump tavel and
60mm droop.
The important thing to realise with your pushrod, bell crank and damper is that everything should work in a straight line otherwise you get bending
loads on the bell crank. In the photo above this can only be a straight line at one particular position in the suspension so you choose that position
and except the variance else where.
I like big bell cranks that give a 1:1 motion ratio, this reduces angles and gives more damper movement and lighter springs, both a good thing.
When mounting the coilover make sure the mount goes in a strong place on the chassis, where lots of tubes join, not in the middle of an unsupported
member.
Also remember that the pivot point on the bell sees twice the loads when compared to the coil over and pushrod mounts. Specify the pivot bolt
appropriatly.
Ride Height setting. This is done with springs. If you alter the pushrod to alter the ride height you will alter the designed position of the coil
over stroke. There will be only one rate of spring that will give you your desired ride height with out having a spring that rattles loose on full
droop or needs lot of preload, both a bad thing. This is where spring design gets fancy with helpers etc. Eibach do a good range but at around £100 a
go..............
Have a look HERE and the next page after this to see how I
did it.
[Edited on 25/3/07 by JB]
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