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  1. #1
    Join Date
    Jan 2016
    Posts
    185

    Oh God, rebending part of an aluminium rear triangle? pls help..

    Fuck I'm dumb.

    I'm in the process of swapping in new bearings on all suspension pivots on my 2012 Giant Trance. While pressing in the large lower bearings on the rear triangle I bent the two tabs that stick out of the triangle to accommodate the bearings. They are about 4 mm off now.

    You know what's coming..

    I'm reading threads on mtbr, bikeradar, pinkpink etc and the consensus is if I bend it back it is extremely dangerous to ride again since the aluminium will be weakened.

    I love this bike, it's traveled all over Ontario, Quebec, Utah, Colorado etc with me. I've lovingly upgraded everything on except the rear shock which I was planning on doing next. I know it's not new, hell it's a 26 er - don't judge lol, but yeah I'm gutted. I'll try to leave my feelings out of this.

    Do you all agree it's a write off? Is there any saving grace in the fact that the bent areas will be clamped together where the triangle attaches to the frame by a massive pivot bolt?

    Here's a pic:

    Click image for larger version. 

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    So the triangle above is shown upside down - you can see the bottom tabs are both leaning inward slightly. You might suspect there is a crack on the left side but it's an old scrape.

    What do you think?

  2. #2
    Join Date
    Sep 2009
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    in the trench
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    7,359
    It’ll probably break. Aluminium does that. I wouldn’t be surprised if giant gives you a swingarm or frame if you sId you have a crack/wink wink

  3. #3
    Join Date
    Dec 2011
    Posts
    4,242
    Quote Originally Posted by grinch View Post
    It’ll probably break. Aluminium does that. I wouldn’t be surprised if giant gives you a swingarm or frame if you sId you have a crack/wink wink
    Yup.

    Tell them you were just riding along...
    Quote Originally Posted by XXX-er View Post
    the situation strikes me as WAY too much drama at this point

  4. #4
    Join Date
    Mar 2012
    Location
    The Bull City
    Posts
    2,590
    Troll Craigslist for a donor swingarm or frame... roached neglected same model. Might find use for other parts as well once you have the donor parts bike..
    Go that way really REALLY fast. If something gets in your way, TURN!

  5. #5
    Join Date
    May 2012
    Location
    san diego
    Posts
    1,213
    Bend it back, reassemble, post for sale on CL.

  6. #6
    Join Date
    Mar 2008
    Location
    the ham
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    5,463
    ^^^ ha ha, evil.

    Quote Originally Posted by Thaleia View Post
    I'm reading threads on mtbr, bikeradar, pinkpink etc
    Well, that's your problem right there.

  7. #7
    Join Date
    Jan 2007
    Location
    SnoqWA
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    2,385
    I'd probably try and re-bend it. Unless that's already a crack starting on the right side (just below the reflection).

    Like you said, it's somewhat supported once assembled. Also seems like there shouldn't be much bending load there. Forces should be more in-line with those tabs.

    Lastly, consider chance of injury if it breaks on a ride. I sure wouldn't do it for something like a fork or handlebars, but less risk behind the seatpost IMO.

  8. #8
    Join Date
    Mar 2008
    Location
    the ham
    Posts
    5,463
    That's actually my feeling too. It's only 4mm.

    The question is cold or put some heat on it? Annealing would probably yield the best result, but also has a bigger potential for fuck up.

    You should pm big steve / geezer steve (or whatever handle he's going by now). He's an expert on this sort of stuff.

  9. #9
    Join Date
    Sep 2009
    Location
    in the trench
    Posts
    7,359
    Definitely make an effort not to scratch/scar it up when you try and bend it back. Big wrench or vide marks will limit your options on replacing it. Same with heat. No heat marks

  10. #10
    Join Date
    Dec 2007
    Location
    Hell Track
    Posts
    7,914
    Bend it back (gently). If / when it cracks, it probably won't lead to a catastrophic crash. And yeah, once it's cracked, talk to giant about getting a replacement.

  11. #11
    Join Date
    Oct 2007
    Location
    Scummit
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    7,674
    Talk to Giant and see if you can get a reasonable replacement before you try to bend it. If they can't help, then maybe try to bend it. But as you've read, aluminum isn't meant to be bent twice.

  12. #12
    Join Date
    Mar 2012
    Location
    The Bull City
    Posts
    2,590
    LOL@ all the comments about claiming warranty issue with vendor while not disclosing or outright lying about the cause of the damage. Hope your customers and business associates treat you with the same shady actions. Here's a thought, just tell the customer service exactly what happened and ask what your options are. You'd be amazed how much more willing people are to work with you and make you happy when you don't try to screw them from the start.
    Go that way really REALLY fast. If something gets in your way, TURN!

  13. #13
    Join Date
    Sep 2017
    Posts
    610
    Bend it back carefully. It's not going to crack.

  14. #14
    Join Date
    Nov 2005
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    Land of Brine Shrimp and Magic Underwear
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    5,819
    I'd give it a go. HOWEVER, chances you're gonna get it perfect are slim to none. Even a very slight misalignment there will cause it to start eating bearings. Frequently replacing them is a pain, and may further stress the weakened area. Best route would be to try to source a rear triangle from Giant but it's an old model, they might not have any.

    Good luck.
    There's nothing better than sliding down snow... flying through the air.

  15. #15
    Join Date
    Oct 2003
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    slc
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    9,671
    Quote Originally Posted by beaterdit View Post
    Best route would be to try to source a rear triangle from Giant but it's an old model, they might not have any.
    Summer before last I got a warranty replacement frame for my 2011 Reign. It's worth asking for sure.

  16. #16
    Join Date
    Feb 2012
    Posts
    14
    Quote Originally Posted by beaterdit View Post
    I'd give it a go. HOWEVER, chances you're gonna get it perfect are slim to none. Even a very slight misalignment there will cause it to start eating bearings.
    This. Except that I bet you can get it pretty straight if you own a vernier caliper or similar. Tweak until it's the same distance edge to edge at both ends of the bearing bore. It's supported as others have said so less likely to just break on you.

    If it does crack, good lesson on bearing press usage, I guess. Don't ask for warranty.

    Sent from my SAMSUNG-SM-G930A using Tapatalk

  17. #17
    Join Date
    Jan 2016
    Posts
    185
    Thanks everyone for chiming in. I have rebent the tabs and am putting everything back together.

    I have contacted Giant (Canada), explained honestly how the damage happened, and asked if they have any options for me. If they can source a swing arm I will buy one. I have also tracked down one from 2011 (my bike is 2012) so that *might* be an option.

    Worst case scenario is no dice with Giant and I can't find a suitable replacement - if this is the case I will remove the good bits (carbon bars, stem, high end components etc) and make this my camp site / beater bike.

    The few people who said that riding this won't be a big risk - I tend to believe you but I'm a pretty heavy guy and ride hard and fast - I can't see myself getting comfortable at speed on this bike anymore. It will always be in the back of my mind and holding me back. What a shame. Again, completely my fault so I'll own it.

    I'll be asking Giant, but curious if anyone here has any views:

    Do I need a 2012 swingarm or is there a range of years that are applicable?

    Also - are swingarms sized based on frame size? (I recall seeing a single post somewhere that said the swing arm on a S, M, L, XL are actually the same size.. Sounds odd but I'll need to confirm)

  18. #18
    Join Date
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    Quote Originally Posted by Thaleia View Post
    Do I need a 2012 swingarm or is there a range of years that are applicable?
    IIRC, Giant ran the same from designs from 2011-2013 so any of those years should work.

    Quote Originally Posted by Thaleia View Post
    Also - are swingarms sized based on frame size? (I recall seeing a single post somewhere that said the swing arm on a S, M, L, XL are actually the same size.. Sounds odd but I'll need to confirm)
    Rear triangles are typically the same size across all frame sizes.

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