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how do you calculate rollover bar bends?
aerosam - 23/4/09 at 08:37 PM

Having looked around for a roll hoop, I simply cant find one to fit my +4" chassis. Closest thing I could find was from GBS/robin hood/kit parts direct who offered to cut a standard one and weld an extra 4" into the middle. But I'd rather have the whole thing made from seamless tube TBH.

So I'm going to have to make my own. I know the distance between centres has to be 42" to fit centrally on my suspension mounts, but does the tube shorten when you bend it? how do you work out where to accurately place the bends?

I guess I'm after an idiots guide really!


minitici - 23/4/09 at 08:44 PM

Performance & Protection will make you a bar.
Just send them the dimensions....

Linky

[Edited on 23/4/09 by minitici]


nitram38 - 23/4/09 at 08:44 PM

All benders differ in that they gain or lose as you bend. The only way to find out is to mark a tube, bend it and recheck the gain/loss etc.
Once you know this, you can add or subtract this measurement from future bends


wam builder - 23/4/09 at 10:34 PM

Really easy one mate! just make a template ie draw the thing out on a bit of plywood or cardboard, then bend one of the required angles. Mark the start point on the curve of the tube against the corresponding start point on the guide of the bender, then lay the tubing back down on top of the template and mark the required start point on the opposite corner still to be bent. This is the easy way, just remember to use a piece of tubing much longer than that which you require as it is much easier to start a bit in from the end and re-cut both ends to the required length thus fixing the height to something that pleases once the whole thing is fabbed up. Another tip is that a complete 90 may kink on the inside and flatten slightly on the outer dependant on the former used. So I now make rollover bars ALA westfield ie with a small bend midway up "12 degree bend" this then reduces the larger bend from 90 down to 78 and it makes the bar look less agri effect.


welderman - 23/4/09 at 11:22 PM

if your strugglin mate could knock one up for you and poss send it by tnt.

Joe


Peteff - 24/4/09 at 09:10 AM

They have some free software for the job. Link


James - 24/4/09 at 11:08 AM

Martin Keenan did mine for me.

Cheers,
James


aerosam - 25/4/09 at 05:33 AM

quote:
Originally posted by welderman
if your strugglin mate could knock one up for you and poss send it by tnt.

Joe


U2U sent, thanks!