Mtn bike help! Also, aluminum welding. 

"PowderHound" (PowderHound) 03/27/2015 at 15:49 • Filed to: None

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My bike, 04ish stumpjumper is Fawked. The weld on the hollow link for the rear shock has cracked dead down the middle. Does anyone know if I can simply get this welded? It's aluminum so I hear that welding can make it weaker from the heat and just won't work. That and scouring the Internet for a replant are my only options short of buying a new bike.

Terrible pic but I was in a rush.

bob and john > PowderHound 03/27/2015 at 15:52

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dont. just replace it.

RamblinRover Luxury-Yacht > PowderHound 03/27/2015 at 15:53

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If you had access to an acetylene torch to locally anneal it afterward, I'd say knock yourself out. However, it's likely better to replace it.

PowderHound > bob and john 03/27/2015 at 15:55

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Part is impossible to find. I'm on the lookout for one but it's looking like I have to buy a whole new bike

PowderHound > RamblinRover Luxury-Yacht 03/27/2015 at 15:55

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It's a part that not made anymore… unless I get lucky and find one, I'm replacing the entire bike

bob and john > PowderHound 03/27/2015 at 15:57

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talk to your local bike shop. they should be able to get one.

RallyWrench > PowderHound 03/27/2015 at 15:58

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A bike that old will be hard to find the part for. They obsolete that stuff pretty quick in some cases. Welding would be a temporary fix until it broke around the new weld, and might affect the geometry & fit. Look for a beater used bike to scavenge, or start looking for new ones.

Lumpy44, Proprietor Of Fine Gif > PowderHound 03/27/2015 at 15:58

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Provided you know someone who knows the intrinsic pain in the ass of aluminium welding it should be fine.

Replacement is still probably your long term best bet. I think there was steel ones you could buy as replacements too.

Lumpy44, Proprietor Of Fine Gif > PowderHound 03/27/2015 at 16:00

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Provided you know someone who knows the intrinsic pain in the ass of aluminium welding it should be fine.

Replacement is still probably your long term best bet. I think there was steel ones you could buy as replacements too.

Bird > PowderHound 03/27/2015 at 16:00

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It could be fixed...but seems like a poor design to begin with. If I'm looking at it right, the area where it cracked is under repeated tension right? If you try to have it fixed, I would have them add an extra piece of aluminum perpendicular to the weld to act as a bridge over that weld. It would add a few ounces, but in the even the new weld fails, it would prevent catastrophic failure of the whole part.

PowderHound > RallyWrench 03/27/2015 at 16:00

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Figured. Everything I own is breaking this year. Fuck

PowderHound > bob and john 03/27/2015 at 16:01

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That's where it was when they found out. They looked. I think I'm just fucked.

PowderHound > Lumpy44, Proprietor Of Fine Gif 03/27/2015 at 16:03

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I'll have to be on the lookout for a steel one. I think this bike being so old the parts are impossible to find. Anything I do find will most likely be pricey and at that point I should almost just buy a new bike

bob and john > PowderHound 03/27/2015 at 16:04

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ahhh poop.

I would recommend trek, they are really good with warrenties like tht.

RamblinRover Luxury-Yacht > PowderHound 03/27/2015 at 16:06

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Well, in that case, you *can* get it TIGed, and then anneal the aluminum in the area afterward. TIG is extremely localized heat that with most alloys will leave the area brittle, but I suspect they didn't worry too much about relieving stress the first time - probably why it cracked there. If you get it welded and then annealed it shouldn't be worse than it was.

To anneal, you take an acetylene torch, soot up the surface, and then heat the workpiece until the carbon *just* burns off... basically. That means that all the stress lines and weaknesses in the aluminum for the weld get to blend into the surrounding metal. Only downside - that leaves it softer, and to harden it back up to be strong, it can help to hit it some with a hammer.

Lumpy44, Proprietor Of Fine Gif > PowderHound 03/27/2015 at 16:06

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I had a Big Hit 26' that came with an aluminium swing that broke, found one from a 24' that sort of fit as long as the tires weren't too knobby.

I got the whole parts bike for 80 bucks from some kid leaving College so it was a good deal.

PowderHound > Lumpy44, Proprietor Of Fine Gif 03/27/2015 at 16:09

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I'm finding some things on Betd but they are about $160 without shipping. Why must everything I do be so expensive?

DasWauto > PowderHound 03/27/2015 at 16:09

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It can be welded but the part would be best off being annealed afterwards.

That said, I believe Specialized has a lifetime warranty on their frames, which you might be able to argue includes this component. I'd suggest checking in with their customer service/warranty departments to see if they could help you out.

Lumpy44, Proprietor Of Fine Gif > PowderHound 03/27/2015 at 16:11

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I know, all my favourite hobbies cost way too much haha!

whiskeybusiness NOW A DANGER TO CROWDS NEAR YOU > PowderHound 03/27/2015 at 16:16

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Either replace the frame and use the old parts, or better yet, sell all the parts and buy a new bike. Preferably hard tail to prevent further breakage.

DasWauto > Bird 03/27/2015 at 16:24

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That component shouldn't see too much tension (the upper bronze coloured piece in the above image). I'm thinking lateral forces applied to the wheel from cornering translated into a torsional load on that suspension link, which over time has fatigued that weld, ultimately failing in shear.

At 10 years old, I would argue that the bike has served him well though. I think the piece can be re-welded as is, adding a bridging piece wouldn't hurt but I don't think it's necessary either.

PowderHound > whiskeybusiness NOW A DANGER TO CROWDS NEAR YOU 03/27/2015 at 16:25

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Not a hard tail fan. But selling off the parts could be a good bet

PowderHound > DasWauto 03/27/2015 at 16:26

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I will try, but I think I saw a few things about it being so old that the part just isn't made anymore and can't be ordered. It used to be a service part.

whiskeybusiness NOW A DANGER TO CROWDS NEAR YOU > PowderHound 03/27/2015 at 16:30

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I've had tremendous success buying on the Pinkbike and MTBR forums, I can only imagine selling would be just as pleasant an experience. Although, if I remember, It does cost to list there.

PowderHound > whiskeybusiness NOW A DANGER TO CROWDS NEAR YOU 03/27/2015 at 16:35

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Awesome, thanks for the heads up on cost to list.

RallyWrench > PowderHound 03/27/2015 at 16:39

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I had to relegate my '04ish GT Ruckus to townie duty for similar reasons, I know the feels.

samssun > PowderHound 03/27/2015 at 17:22

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Messing around with the aluminum itself will be a pain. You could try making a nice blanket of JB Weld around it, if you don't mind hack fixes.

PowderHound > samssun 03/27/2015 at 18:08

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Hell. Yes. I'm going to JB weld it and run with only a rear brake. Let's see how long it takes before I 1. Can't stop or 2. my bike falls apart around me.

Squid > PowderHound 03/27/2015 at 21:08

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Take it to a fab shop and see if they can fab up a steel replacement part or TIG the part back together. . . If you don't have a good fab shop in your area you might be fucked and it might be time to get a new bike. . .