Twisted Sister.... Er Alloy Swing Arm?

[nzralphy]

Hi All

Has anyone ever twisted their alloy (Beta Rev3 not that this matters) swing arm. We have one that makes the rear wheel cant over to the RHS at the top. Quite a lot - perhaps 30mm. The bike frame looks good.

I was figuring on cold setting by either; removing the wheels and swing arm hard wear, clamp the bike - on it's bash plate - to the large steel workshop welders table, slip two large (lets call them huge) pieces of tube up the legs, and heave one up while one is heaved down..... or remove the swing arm and clamp the pivot end to the same table and use the same process.

Any thoughts or preferences?

[feetupfun]

I've found you can keep things under control better during the straightening if you leave the axle in place - this reduces the risk of the arms being bent sideways.

Another thing is that to do the bending you can usually use a bar positioned under one arm and over the other rather than a bar on each arm.

Some bikes you can get the bar in position with the wheel still in place but for some others you will need to make a spacer up to replace the wheel so the axle can be left in place tight.

Depending on how difficult it is to clamp the bike down, it may be easier overall to make a fixture to hold the swingarm and swingarm axle while you straighten the swingarm. Last one I did the frame and the swingarm were both twisted so I made a fixture that clamped the bike via the swingarm axle ends so I could straighten both the frame and swingarm at the same time.

[nzralphy]

Hi All

Has anyone ever twisted their alloy (Beta Rev3 not that this matters) swing arm. We have one that makes the rear wheel cant over to the RHS at the top. Quite a lot - perhaps 30mm. The bike frame looks good.

I was figuring on cold setting by either; removing the wheels and swing arm hard wear, clamp the bike - on it's bash plate - to the large steel workshop welders table, slip two large (lets call them huge) pieces of tube up the legs, and heave one up while one is heaved down..... or remove the swing arm and clamp the pivot end to the same table and use the same process.

Any thoughts or preferences?

Well that was easy. A little too easy to be honest. It was so soft/easy..... and thus i think i have found the reason Beta have gone back to a central shock on the Evo. It ain't strong!

It bent because the last owner ran the bike with a stuffed shock.

We did not remove the swing arm. Removed the wheel and clamped the bike to an immovable steel beam across the bottom of the foot pegs. Using a 1.8m piece of 100x50 timber and approx 1/2 my body weight, we tweaked it back to perfectly square. Done.