Advice needed about a crack on my frame

[Accy cyclist]

I noticed today that a crack has appeared on my bike frame, it's where the seat stem sits, and it's about an inch long. I thought the frame was carbon fibre but someone i saw out today said that it's made from light alloy. What can i do to stop it from spreading or is it irreparable?

 

[ianrauk]

pic?

Is it carbon or alloy?

 

[Accy cyclist]

pic?

Is it carbon or alloy?

It's alloy


56 cm size frame
54 cm centre seat tube to stem tube
80 cm stand over height of frame
7005 alloy frame
shimano sora gear set
Look Peals
Ritchley Crank 170 mm crank lenght
8 cassette , 3 sprocket crank outer 52T

 

[ianrauk]

Alloy will be a whole lot easier to repair then Carbon.
Get the bike to a LBS to see what they have to say.

 

[Accy cyclist]

Alloy will be a whole lot easier to repair then Carbon.
Get the bike to a LBS to see what they have to say.

Ok thanks, i'll take it down tomorrow. Hopefully it's repairable and it wont be too expensive...fingers crossed.

 

[screenman]

I would say that carbon is a lot easier to repair than alloy, but then I have played with both materials unlike a lot of people who have not.

Just found this great list of how to repair alloy frames.


1) Disassemble the bike to the frame;
2) Remove any finish with a chemical solution;
3) Take the frame to a heat treater and have it annealed (this means that the metal is taken to a "zero temper");
4) Weld it with the appropriate rod using the appropriate technique;
5) Reanneal the frame (since the welding makes the frame hard again);
6) Immerse the frame in a molten salt bath solution for the correct time;
7) Place the frame in an aging room for the appropriate amount of time;
8) Check the frame for proper alignment and to make sure that none of the tubes have deformed;
9) Immerse the frame in a phosphate bath (or other cleaning solution);
10) Primer and paint;
11) Reassemble the bike.

 

[marzjennings]

How old is the frame? Could it still be covered by a warranty?

Mine cracked in about the same place, but way past the end of the warranty and so I sent it in to get repair. Cost about 250, but I get a new seat tube a respray and some new parts.

There's not much you can do yourself so as mention, either take it to your LBS or contact the manufacturer directly.

 

[Paul J]

If its an alloy or a steel frame to stop it cracking further drill a small hole at the very botton of the crack. Steel frame easily welded with a mig welder. Alloy would need someone with a tig welder and is a little trickier. Any car body shop would be able to repair a steel frame.

Comes down to if it is within warranty.