Crush tube size

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trucked
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Crush tube size

Post by trucked »

After much google search and looking to find any sort of answer i havent found anything that concrete.

Is there a rule that you guys go buy as to the thickness of a crush tube?

ie i can get a 16mm od tube with a 2mm wall which makes it perfect for a m12 bolt but i get the feeling its a little on the light side for 4wding.

I dont have access to a lathe to cut my own so am looking for a easier option when it comes to making them

Any help is apreciated
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chrome
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Re: Crush tube size

Post by chrome »

that will be fine so long as the bolt can get past the seam of the tube,
it takes a shitload of force to crush a tube that is stufffed solid with a bolt
DIRTY OLD HILUX
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Swamped
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Re: Crush tube size

Post by Swamped »

I'm pretty sure thats the size of the crush tubes samurais use in their leaf-spring bushes at the chassis end. Depends on application but should be strong as for a crush tube.
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churchill
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Re: Crush tube size

Post by churchill »

Made them that size before and they work well. I also have aftermarket shocks that use thin wall pipe as crush tubes so a machined on should be fine.
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tomsoffroad
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Re: Crush tube size

Post by tomsoffroad »

I use 30mm hollow bar for steering box crush tubes and other applications. 12.5ish mm ID. Way overkill but its what I've got lying around :mrgreen:
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De-Ranged
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Re: Crush tube size

Post by De-Ranged »

The general rule of thumb for cert is the wall thickness should match or excede the wall of the structure its protecting.... so on a hilux chassis 3.5mm min
There are a few specifics to do with suspension mounts that state a specific size
There is no mention of thickness for rubber bush suspension mounts
I've got lengths of heavy wall line pipe and carbon hollow that I use

Cheers Reece
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mudlva
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Re: Crush tube size

Post by mudlva »

do the destruction test

cut a length of tube to match what you will be doing
slide a bolt through it and clamp the head into your vice
with a good washer on either end fit the nut and start tightening. keep going until either the tube crushes or you strip the bolt and nut threads

if the threads strip first then technicoly the tube is sufficiency strong
if the tube crushes then its not

that's been my working theory

if its to go into a road legal / certed vehicle then best to have a word with your cert chap, better to be safe than sorry
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tomsoffroad
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Re: Crush tube size

Post by tomsoffroad »

mudlva wrote:do the destruction test

cut a length of tube to match what you will be doing
slide a bolt through it and clamp the head into your vice
with a good washer on either end fit the nut and start tightening. keep going until either the tube crushes or you strip the bolt and nut threads

if the threads strip first then technicoly the tube is sufficiency strong
if the tube crushes then its not

that's been my working theory

if its to go into a road legal / certed vehicle then best to have a word with your cert chap, better to be safe than sorry


Pretty sound thinking there :D
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trucked
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Re: Crush tube size

Post by trucked »

thanks guys that gives me a much better idea on what i need.
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