Cracked Dropouts

[Twitch-119]

I can get the crack welded, but will it hold? It looks like its in a really wierd place, think it was dropped by someone with the wheel off, but dont care how it happened anyway, just care how i'll get it fixed, it is a Onza Cleaner if that helps?

Cheers for the help, and sorry if its a crap photo

Twitch x

[Dan Clark]

Is it definitely a crack and not just a scratch in the paint? Especially given that it's been resprayed.

Doesn't look like a crack to me anyway.

[Matt Vandart]

Do you know the history of the frame, that looks like it has been repaired before to me.

[Twitch-119]

Yeah been mine from new, definatly a crack, and I got another couple of pic's a minute ago:

Twitch

Forgot this one in last post

[Stanners]

You could weld it BUT it can potentially weaken the area around the weld...aluminium - when its cracked - its cracked. Maybe better to leave it for abit, keep an eye on it and save up for a new frame. Can you get warrenty on it??

[Twitch-119]

BALLS!! what about a gusset? and it has been sprayed so does warranty cover it, its from tartybikes, and over a year old... so I guess not, oh well, run ti till' it breaks I guess, cheers anyway

Twitch

[Matt Vandart]

Ah I see you been rubbing the paint off, in the first pic it looked like it had been welded then ground back must be the light.

I would definately have that welded.

If you find someone that is good at tig welding that'll weld tidy and will give you more time to save up for a new frame.

Note to everyone else in the world.

It is possible to weld your cracked aluminium frame, when they crack again after welding it is because the welding is shit or the design is shonky.

[craigjames]

Ah I see you been rubbing the paint off, in the first pic it looked like it had been welded then ground back must be the light.

I would definately have that welded.

If you find someone that is good at tig welding that'll weld tidy and will give you more time to save up for a new frame.

Note to everyone else in the world.

It is possible to weld your cracked aluminium frame, when they crack again after welding it is because the welding is shit or the design is shonky.

Or that the weld is essentially a small cast area (if not heat treated) and as such is brittle, less ductile, lower tensile strength and is prone to cracking again.

[Stanners]

Or that the weld is essentially a small cast area (if not heat treated) and as such is brittle, less ductile, lower tensile strength and is prone to cracking again.

What he said ^^^^^

I had a downhill frame that cracked....had a beautiful weld put on it.....went out did a few drops and the tube ripped from the edge of the weld because the heat made it so weak in that area. Just ride it till it breaks.

[Twitch-119]

Just wanted to say cheers everyone, ride it till it/I die/s

Twitch

[Krisboats]

It's quite a common place for that dropout toi go. The weaker mech hanger doesn't support the narrow section of the frame and eventually it cracks. There is a very easy fix that'll prolong it's lifespan for a long time, and luckily it's very easy to do!

Get yourself a piece of 5-7mm thick steel, cut it out to the same shape and size as the mech hanger and simply replace the weak metal hanger with your new one. I did that to my t-rex sometime last year and it's still going strong now. I'm well over 200lbs too ;)It seems to be enough to distribute the forces evenly across the dropout and stop the crack from progressing.

Think i made mine with a peice of shopping trolley from work and an angle grinder. It's not like it'll cost you much time/effort to make one up. I didn't even file the edges of mine after grinding

[Matt Vandart]

Or that the weld is essentially a small cast area (if not heat treated) and as such is brittle, less ductile, lower tensile strength and is prone to cracking again.

Agreed to an extent, I wouldn't say it is 'essentially a small cast area' it is an area with undissolved alloying additions and therefore not the same chemical composition as the original parent metal.

It is possible to dissolve these alloying additions yourself if you're careful as the process consists of heating to the required temp and quenching it in water something that can be theoretically achieved with common garage tools.

The weld will naturally age over the course of a few weeks and then remain stable.

Obviously if your frame is T6 condition alloy and the manufacturer has actually followed the above heat treatment with a further process of heat precipitation, thus restoring the frame to the 'T6' condition rather than just used 'T6' tubing and welding it, then it will quite possibly if not definately crack due to the differential in properties between the welded area and the parent metal.

I have in the past converted 26" freeride bikes to 24" by shortening the chainstays I had them for a few years and as far as I know they are still going strong, these were not heat treated but welded with high Mg content filler rods and were 6ooo series aluminum alloys which tend to be crack happy thus the choice of using high magnesium filler rods.