Folding Bikes - Downtube 2007 H hairline crack

Hi guys,

I have have the above bike since August 2007. I like a stretched ride and I'm 6' 0" so I had the seatpost above its minimum insertion point. As I weight over 90kg (14.5 stone) the pressure resulted in a hairline crack on the frame just where the seatpost inserts. Silly of me I know!

What I needed to know was can such a hairline crack (which is has now spread completely full circle) be repaired by an alumnium welder?

Advice much appreciated.

Sorry to bump up this thread but can anyone help?

well if you, or whoever is fixing is a good welder then yes. but you would have to do a good job of it to prevent it cracking again.

You might get the answer you seek in this thread from last year, mulleady:

http://www.bikeforums.net/showthread.php?t=363772&highlight=barneybarney

Or, email Yan with pix. He's got (had?) some DT IX FS frames to move, be an easy rebuild. They're sweet urban bikes - be a shame to be without it.

Was that the cause of the squeak we heard yesterday?

Or, email Yan with pix. He's got some DT IX FS frames to move, be an easy rebuild.

Was that the cause of the squeak we heard yesterday?

thanks all for your advices.

No Snafu the squeak went away lol, I think the bird may have died lol!

I'm talking about the front suspension downtube with 8 speed hub gears that I bought off Yan de Man in august 2007. FS is fine!

Aha! Aplopogies. Well, you might still get a frame transplant? Perhaps?

Did you ask Yan if he has some spare frames, you could buy for a resonable price?

Regards

I read on another thread that aluminium can be welded but needs the same grade of metal to bond. I can't swear to this as I'm not a man of the weld.

Maybe go to a proper Metal Works and ask them. I went to a place in South London (see attached pics) and a jolly chap gave me loads of advice.

Aluminium can absolutely be welded, but whether a hairline crack all the way round a thin walled tube can be welded strongly enough, and still had the interior smooth for the seatpost I don't know. I'm fairly sure the best welders could do it, but how expensive might it be?

I'd drill the crack to keep it from propagating, then weld or attach a larger diameter tube onto the outside.

I think that you might have to heat treat the whole frame if you weld it.