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Old 2015-07-11, 10:35 AM   #1
bristlecone
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bent aluminum frame, game over?

UPD'd then uni went bouncing 300-400m down steep rocky slope. Frame no longer aligned with bearings (a few cms off, but can be forced into place).

The internet seems to tell me that once you bend an aluminum frame, it's game over as aluminum is weakened by this, and would be weakened still further by trying to bend it back. For muni riding it seems I need to get a new frame.... ?



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Old 2015-07-11, 11:15 AM   #2
Monomalist
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Aluminum tubing can be straightened after being deformed without weakening significantly if it hasn't been stretched. My concern would be getting it back to the original shape. If it's not restored to original shape you'll stress the bearings, and possibly end up with handling issues. Even if you have access to the tooling to straighten the frame, I think you would spend more time, energy, and money with less than perfect results. If it were me, I'd buy a new frame and use the old frame for a project, or sell it to someone for a project.
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Old 2015-07-11, 12:04 PM   #3
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Quote:
Originally Posted by bristlecone View Post
UPD'd then uni went bouncing 300-400m down steep rocky slope.
Look on the bright side. Luckily it was the uni and not you going down that slope.

Aluminium quickly becomes stiffer with work so it would not necessarily be weaker if the deformation is not excessive which it does not appear to be.

However any dent is always going to be a weak point where a collapse could start again. Unless you can fully return it to the entirely convex original shape it won't be as strong. Without access to the inside of the tube I doubt this is possible.

BTW Aluminium can be dramatically reshaped without fatigue when heated to the temperature that makes oil smoke. However such heating would anneal the work hardening that came from the tube manufacturing process so it wouldn't be a good solution for this problem.
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Old 2015-07-11, 10:11 PM   #4
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Contact Unicycle.com

Contact Unicycle.com and tell them about this. They will be surprised I'm sure.
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Old 2015-07-12, 07:54 AM   #5
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Quote:
Originally Posted by bristlecone View Post
uni went bouncing 300-400m down steep rocky slope.
Wow, have you got a photo of where you fell off?
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Old 2015-07-12, 11:45 PM   #6
Killian
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I agree with Richard, I'd contact UDC and see what they have to say about it.

If they won't warranty it or give you a deal on a new frame, I'd probably just ride it as long as it wasn't SUPER difficult to get the bearing into the frame.
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Old 2015-07-13, 01:59 AM   #7
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...just throwing out another perspective.

For me anyway, if I had came out of that scratch free, or even a few cuts or bruises, it's (for me anyway,) definitely worth the $165.
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Old 2015-07-13, 02:26 AM   #8
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IMO for bouncing that far it's impressive that it survived as well as it did. You could heat it up and straighten it and see what happens. It will obviously never be as strong again but there's a good chance that you could get quite a bit more use out of it before having to purchase another frame.
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Old 2015-07-13, 09:04 AM   #9
bristlecone
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Wow, have you got a photo of where you fell off?
Along ridge in foreground, a glacial moraine close to the angle of repose. However as demonstrated, angle of repose for glacial till > angle of repose for rolling unicycle.



Incidentally it's an odd thing to watch, a unicycle bouncing down a hill for an extended distance. All kinds of crazy angular momentum and random bounces going on. I'm just glad no-one was near. Will definitely be more aware of people far below on mountainsides. I'm used to worrying about kicking off rocks, but unicycles...

Last edited by bristlecone; 2015-07-13 at 09:08 AM.
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Old 2015-07-14, 11:47 PM   #10
frillneck
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However as demonstrated, angle of repose for glacial till > angle of repose for rolling unicycle.
Yeah, an acute observation! Looks like a very nice place to go for a ride!
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Old 2015-07-15, 09:56 AM   #11
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Incidentally it's an odd thing to watch, a unicycle bouncing down a hill for an extended distance.
If only you had a video camera following it.
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