chopper frame failures, what do you see most?

[emzdogz]

Was wondering, some of you all who have lots of experience with choppers and/or hardtailed bobbers (whether XS or another kind): have you seen a frame actually break? what was the weak spot?

Just wondering what kind of stuff, or what points would be most vulnerable. I mean I know it would vary a lot from welder to welder and bike to bike - but still is there any one spot any of you have seen fail more than others? axle plate area? or bottom rails where they join front frame?

I started thinking about this when reading in another thread whether someone thought a particular frame would be strong.

Trying to think of the worst thing a rigid frame bike would have to endure. Worst I can think of is hitting a really hard bump or pot hole, putting lots of pressure on axle plate area. or?

thx

PS I'd like to say, too, that I'd prefer to hear from people who LIKE choppers, lol, and not just have this be a "damn them damn choppers" fest

 

[vonyinzer]

Most old frames (that I have seen) crack around the neck (especially ones with aggressive rakes/stretches) or at the backbone where the rear legs meet it.

A modern built frame, that is designed correctly, uses the correct material, and is welded by a pro shouldnt crack at all.

 

[Punkskalar]

I see more failures from improper axle plate spacing than anything. If the frame warps when you weld it, and you have to "spread" the frame to get the wheel and spacers in, then it will crack. Same goes for if you have to "squeeze" it to get it together.


Poorly done necks seem to be a problem as well...

 

[OakBehringer]

I'm not an experienced welder or fabricator by any means, but I have been reading up on it A LOT lately as I plan on focusing on the craft a lot over the next couple years. One thing that I have noticed a lot is improper gusseting, specifically behind the neck, where people are putting a single gusset in the middle of the two tubes. Gussets have to be on the sides of tubes to absorb pressure without causing cracks.

 

[bloodthirstysystem]

i would be more worried about a neck breaking than a hard tail! if your hard tail fell off you may have a chance of surfing the bike until it stopped..

some guys keep the swing arm and weld top rails to it to make a shitty hard tail, i'm surprised those can ride around without problems

 

[emzdogz]

thanks for all the responses.

 

[emzdogz]

I see more failures from improper axle plate spacing than anything. If the frame warps when you weld it, and you have to "spread" the frame to get the wheel and spacers in, then it will crack. Same goes for if you have to "squeeze" it to get it together.

hmm, I wonder if I should worry. Before I tightened the nut on my axle bolt there was about a 1/8 gap on the brake side. But it went away right away as I tightened. I guess the whole wheel and everything just needed to shift over that way (towards the head of the bolt).
Everything seems just right and when torqued the wheel spins easily by hand. When it's all tightened up the hole for cotter pin is right under one of the holes in the castle nut. I'm using 3/4 washers (lots of them) as spacers. They have to take the place of a. thinner axle plate compared to width of stock swingarm plates, plus I'm making up for the absence of the stock chain adjusters. My FINAL spacer on the threaded end (sprocket side) is made of the last half of one of the stock chain adjusters - cut off and rounded. That way I get that "smaller" hole at the very end by nut - like stock.

wow did that last part make any sense?

 

[tadd442]

hmm, I wonder if I should worry. Before I tightened the nut on my axle bolt there was about a 1/8 gap on the brake side. But it went away right away as I tightened. I guess the whole wheel and everything just needed to shift over that way (towards the head of the bolt).
Everything seems just right and when torqued the wheel spins easily by hand. When it's all tightened up the hole for cotter pin is right under one of the holes in the castle nut. I'm using 3/4 washers (lots of them) as spacers. They have to take the place of a. thinner axle plate compared to width of stock swingarm plates, plus I'm making up for the absence of the stock chain adjusters. My FINAL spacer on the threaded end (sprocket side) is made of the last half of one of the stock chain adjusters - cut off and rounded. That way I get that "smaller" hole at the very end by nut - like stock.

wow did that last part make any sense?

Perfect sense.....1/8" should be fine.

 

[emzdogz]

thanks! I think it is OK, too.