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

[Thaleia]

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:





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?

[grinch]

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

[reckless toboggan]

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...

[SumJongGuy]

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..

[evdog]

Bend it back, reassemble, post for sale on CL.

[Ted Striker]

^^^ ha ha, evil.

I'm reading threads on mtbr, bikeradar, pinkpink etc

Well, that's your problem right there.

[bfree]

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.

[Ted Striker]

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.

[grinch]

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

[toast2266]

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.

[Name Redacted]

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.

[SumJongGuy]

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.

[Jonny Snow]

Bend it back carefully. It's not going to crack.

[beaterdit]

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.

[Dantheman]

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.

[dannynoonan]

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

[Thaleia]

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)

[Dantheman]

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.

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.

[Thaleia]

IIRC, Giant ran the same from designs from 2011-2013 so any of those years should work.



Rear triangles are typically the same size across all frame sizes.

Thank you.

Haven't had any luck finding a suitable swingarm used. Giat Canada is offering me a new replacement for CAD 412. Call me crazy but I'm going to go ahead and order it.

Thanks all for chiming in. Expensive way to learn not to be a bonehead.

[Dantheman]

Giat Canada is offering me a new replacement for CAD 412. Call me crazy but I'm going to go ahead and order it.

No brainer. That's, what, like $20 USD?

Honestly though that's a bit weak. That thing is taking up space in a warehouse somewhere and costing them money every minute it sits there in all likelihood. They should sell it to you for the scrap value+shipping. You sure won't get rolling again for cheaper than that, though.

[grskier]

No brainer. That's, what, like $20 USD?

Honestly though that's a bit weak. That thing is taking up space in a warehouse somewhere and costing them money every minute it sits there in all likelihood. They should sell it to you for the scrap value+shipping. You sure won't get rolling again for cheaper than that, though.

It's worth what someone will pay for it... and it probably has that number next to it in uber database so.. guess what.

But yeah, totally agree on sentiment and the fact that is the cheapest way to get rolling again.