Picked this up secondhand a little while back and after three only rides noticed a crack in the top tube, just behind the headtube weld..
It's an alloy frame, US made so sending it back isn't really an option but I was wondering whether repair aluminium is ever really an option? The crack runs from one side, under the tube (which is a sort of V shape) and about the same distance up the other side...
Ex in my opinion but I have no experience or real world knowledge of this...
I'd scrape the paint off first and have a closer look.
Looks like a stray pube
For me I would call that an ex claim on your house insurance for a replacement?
we could weld that up stronger than it was no problem...
If you remove the paint you won't be able to see anything. I would mark it with a stanley knife at the uppermost point across the way and then monitor it to see if it gets any worse.
I would also be looking for a new frame, is it an intense?
Chances of it cracking in two are slim, still it would be messy if it did.
Everyone else reading this, always check all the welds and the area close to them when you buy a frame or bike, it's a bit of a pain but not as bad an losing out on your investment.
You might be able to buy a new front end or a damaged frame that has a front end that's OK.
For what it's worth, I hope that helps.
I'd remove the paint too, it may just be a crack in the paint rather than the tube underneath. Most cracked bikes I've seen have had an obvious crack in the tube under the paint if it's truly dead.
Chances of it cracking in two are slim
Ummm bollocks. This is really poor advice and possibly ruddy dangerous, I havn't joined in the Kasae bashing before but this is really quite a dickhead thing to say, what exactly do you know about fatigue to say this Kasae? I'll tell you, eff all.
Thats is a stage two crack, its growing, and it's going to end in fracture, and it will be messy(OK the crack in theory could arrest, but it probably won't). Don't ride it any more. You could try welding it, but if it was heat treated post weld then your weld will be pretty poor compared to the manufacturers original, but it's worth a try, just monitor the weld carefully after although I wouldn't do this, just accept it and get a new one. Paint looks in good nick, is it a new ish frame or has it been powder coated/painted?
Can't say I really fancy riding it so I think it'll be written off...
May scrape the paint off and see if I can see anything underneath - it was powder coated just before I bought it so I guess it could just be a crack in the paintwork.
Hmm maybe they powder coated it to hide the crack? Three rides seems a little short to grow a crack of that magnitude, unless they were 8 hour epics?
It's a salient lesson in one of several reasons not to buy a refinished powder coated frame.
Te frame is dead, so work the crack up nice and large so that it is near failure. Cover it up with tippex and build the bike up with cheap and left over parts. Then leave it locked up at the top of a steep hill, with good front but poor rear brakes. Wait for thief.
toys19 - MemberChances of it cracking in two are slim
Ummm bollocks. This is really poor advice and possibly ruddy dangerous, I havn't joined in the Kasae bashing before but this is really quite a dickhead thing to say, what exactly do you know about fatigue to say this Kasae? I'll tell you, eff all.
Thats is a stage two crack, its growing, and it's going to end in fracture, and it will be messy(OK the crack in theory could arrest, but it probably won't). Don't ride it any more. You could try welding it, but if it was heat treated post weld then your weld will be pretty poor compared to the manufacturers original, but it's worth a try, just monitor the weld carefully after although I wouldn't do this, just accept it and get a new one. Paint looks in good nick, is it a new ish frame or has it been powder coated/painted?
I think that what I said is accurate, the chances of the frame cracking in two are slim, first you would need to go through the rest of the top tube and then the bottom tube as well.
I also said I would be looking for a new frame and a few other things, however those don't fit your argument and you don't get to be right if you mention them and put what I said into context, so just ignore them!
In my opinion it would be very difficult for that frame to completely snap in two, but I would be looking for a new frame anyway.
You're a legend mate, in your own mind anyway 
What kind of frame is it and how harsh where the rides?
Yeah Kaesae I didn't disagree with the rest of what you said so I didn't feel the need to copy it, and do you think people cannot actually read your post just because I only selected a bit of it? I dont have an argument, what you stated falls over on its own, context or not. If the top tube fractured the lower tube would collapse pronto, with possible dangerous consequences, so once again you've recomended that something is "safe" when it patently isn't. The way you bandy about stuff like this is what reveals how little you know about engineering/science. I'm not a legend, I'm just a lowly metallurgist. But you are a fantasist of Walter Mitty proportions. Go to college.
The whole point of missing out the rest of my post was to reinforce your point or opinion.
Firstly mr mettalurgist let us look at the facts.
1) How many alloy frames have you owned, for mountain bikes and how many frames with cracks have you owned or seen people ride on?
2) If the frame has been out for 3 rides and it has not cracked in two, then what are the chances of it cracking in two, before the OP notices that the crack is getting worse?
3) We have no way of determining how long that crack has taken to form, in my experience, they either form and widen over a long period or due to intensive use.
I would be very surprised if that frame snapped in two, not from books or from being a mettalurgist but simply from hands on experience of people riding bikes with cracks.
As I said and will continue to say, the chances of that frame cracking in two are slim, however if it does it will be messy and I would be looking for a new frame.
That is my honest opinion on the frame, it's not simply me calling other people names to try and discredit them or trying to prove that I am in fact right!
Who needs facts when you have anecdotes? I admire your certainty 
I had a similer crack on one of my old downhill bikes.
I had a hole drilled at each end of the crack to stop it growing any further, then a gusset plate welded onto the side of the headtube, much like a lot of frames come with anyway.
It stopped that crack, but welding it puts stress in other places, so it wasnt too long until I got another crack in the top of it.
I would probably just get a new frame
I'd sell it to Kaesae - after all there's nothing really wrong with it. In the words of the Black Knight "it's just a flesh wound"
Well I'm liking Charlie's idea. Extreme honeytrap!!!
I'd put it out to pasture to be honest, I've had a steerer tube failure and was lucky to walk away, imagine if the headtube goes at speed you will be hitting the ground hard.
Maybe use as a light use commuter. My GT with a pretty severe crack in one chainstay has been ok for 4 years now as a occassional pub bike/commuter.
Scrap it, mate. Play safe.
Not a current speciality but one from the past. I would definitely agree that your crack is at present freely propogating through the parent metal. It's growing at a point of obvious stress & probably not all of the crack is visible. Continued flexing & stress will make the crack longer & more prominent....if ignored, to the point of failure of the top tube. Surface breaking defects like this are relatively common on highly stressed triangulated structures. IE nodal areas on oil platforms.
Can it be fixed ? definitely. But you then have to ask yourself, is it worth the outlay of doing the job properly & having the frame re painted. Then monitoring the area for subsequent signs of failure in the heat affected zones of the new weld.
Sorry to drone on....I'd be looking for another frame 
D.
So Kaesae you are going against 100 odd years of fatigue research, carried out using the scientific method, and using your experience with your mates instead. Cool. I won't batter you any more, I just felt it was my duty to highlight you and your "experience " on this thread in case the OP hadn't come across you before and thought you had something sensible to say.
personally i wouldn't ride that. seen too many frames snap with cracks
Ride it till it breaks.
I can't believe you are even asking the question...
But since you are, just ride it, the NHS is free - although I'd use a full-face helmet from now, as the Dentist costs.
I'd be scraping the paint off then if it is a crack i'd be drilling a couple of holes to stop the crack spreading. This is if it couldnt be welded.
Well, I scraped a bit of the paint away and it goes through to the metal so it'll definitely go on the scrapheap. Previous owner says it was in tip top shape before being powder coated so looks like I'll have to put it down to experience and write it off - should be able to get a few quid back from the shock.
Think I'll be sticking to new frames with warranties in future.
there are a world of possibvle results.
best result it is the paint and you ride forever on it.
worst result it cracks at a crucial moment during a ride resulting a nasty off and serious permanent injury.
most likely something in the middle happens; now it's up to you if you want to chance it being good or bad.
personally i'd be retiring it to the shed wall.
Im worried now - Ive got a crack in my a55, will I break in two ?
Some frame manufacturers dont recomend after market powder coating
because of the baking temps used during curing.
Having had a top tube go on me i wouldn't ride that again!
Im worried now - Ive got a crack in my a55, will I break in two ?
You've got a hole drilled in it (I've heard) so that should stop it from propagating.
Trimix
Definately, how soon just depends on how hard you get ridden!
toys19 - Member
So Kaesae you are going against 100 odd years of fatigue research, carried out using the scientific method, and using your experience with your mates instead. Cool. I won't batter you any more, I just felt it was my duty to highlight you and your "experience " on this thread in case the OP hadn't come across you before and thought you had something sensible to say.
100 years of scientific research, into mountain bike frames made of alloy? 
This topic has been closed to new replies.
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