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Crush tube and wishbone bracket
multanen - 17/1/08 at 02:16 PM

I bought some poly-bushes from Rally Design. I wonder if their crush tubes are 1 or 2 mm too long for Locost, they are 46mm. I know 1-2 mm isn't much, but exact wouldn't require hammering.

My calculation (I don't have the brackets yet!): If bracket is 51mm outside and
the walls are 3 and 3, then the crush tube should be 51-3-3=45mm. If the bracket is 50mm outside (Gibbs), then 50-3-3=44mm ... right?
...Or is 46mm really the correct length for book/common wishbone crush tube?

(EDIT: last sentence ends "crush tube", not "brackets"

[Edited on 17/1/08 by multanen]

MikeRJ - 17/1/08 at 02:37 PM

How do you know the crush tubes require hammering in if you don't have the brackets yet?

Remember that crush tube length is also dependant on the length bush tube and the width of the "top hat" sections of the bushes.

multanen - 17/1/08 at 08:25 PM

quote:
Originally posted by MikeRJ
How do you know the crush tubes require hammering in if you don't have the brackets yet?

Well I'm not going to hammer anything for sure (it would stretch bracket "open", in to a V-shape... not good. Just a light tapping should be enough).
I think I'm going to make my wishbones and brackets by the Gibbs book. In the drawings crush tube is 44mm long. So 2mm has to go.
By the way, in the Gibbs book crush tube length equals the bracket inside width - this makes sense to me.

Maybe there are drawings somewhere, or even a ready made bracket, for 46mm crush tube... Since Rally Design is supposed to sell zillions of these and nobody has ever complained. Or people just hammer them down by force. Probably latter.

snapper - 17/1/08 at 09:01 PM

Carefully grind off a couple of mm or get an engineering shop to use a flat bed grinder.

To big is never a problem with metal, to short is.

Also you can releve the polly bushes if needed, but i would have brackets made to to fit.