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Old 01-17-06, 12:30 PM   #1
broomhandle
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Cracked Head Tube, To ride, or not to ride....

i somehow have cracked my head tube on my mountain bike. its 7005 alum. it is a hairline crack, but is this safe to ride? im thinking no. but the crack is very faint. here are some pictures...

anybody have any thoughts?
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Old 01-17-06, 12:38 PM   #2
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I have no specific knowledge of frames or metalurgy, but I concur with your gut feel. I wouldn't ride it.
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Old 01-17-06, 12:39 PM   #3
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You could ride it, but you wont enjoy it as much because you will be always in the back of your head be afraid to do anything that would make the crack worse. I had a small crack in my carbon steerer tube on a pair of SIDs, glued it back together and rode it for a couple months... the crack never got any bigger, but trust me all you can think of when your riding is "is it gonna break? is it gonna break?" Makes for some very frustrating rides!

I'd bite the bullet and just not ride it, a new frame is cheaper than a new skull!

-Andrew
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Old 01-17-06, 12:40 PM   #4
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eeep.
I might put a hose clamp on that and ride it on the street, but definately NOT off road.

I'd be wary about using the front brake too.
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Old 01-17-06, 12:42 PM   #5
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If the crack was to a weld holding the top tube or down tube to the head tube, it could lead to a catastrophic frame failure and likely injury to you. With such a crack, I would retire the frame immediately. Your crack does not look like it will lead to a frame separation failure. Your crack looks like it will lead to a trashed headset. By the time it steers "funny" the headset, frame and maybe the fork will be trashed. I would keep riding it for now and retire the frame if the crack opens up, if the crack gets or if the sterring gets "funny".
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Old 01-17-06, 01:07 PM   #6
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thats what i thought, i didnt want to loose any teeth, or smash my head. dang, and i liked that frame!!! o well.... thanx guys!
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Old 01-17-06, 01:09 PM   #7
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No, don't ride it.
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Old 01-17-06, 06:03 PM   #8
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If your riding on the street, it's unlikely to suddenly fail, though you need to mark the end of the crack and watch it for growth.

I would be VERY hesitant to do any technical riding. It's not worth the risk.

Is it under warranty? Now would be a good time to have a lifetime frame warranty.
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Old 01-17-06, 06:20 PM   #9
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No. Never ride with cracked xxxxx tube.
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Old 01-17-06, 08:20 PM   #10
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How old is the bike?
What make is the bike.
It may be covered under warranty.
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Old 01-18-06, 01:05 AM   #11
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Absolutely not!!!!!!!!! Aluminum once it exhibits fractures anywhere it is toast.
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Old 01-18-06, 01:34 PM   #12
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Quote:
Originally Posted by Alphonso
How old is the bike?
What make is the bike.
It may be covered under warranty.
the bike is a 2000 alfton made with 7005 easton elite alum.

im bum-ed out, i loved that bike. Mount Tam did this to the bike. haha o well..
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Old 01-18-06, 07:54 PM   #13
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well, anybody know a good inexpensive frame? lighter the better....
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Old 01-18-06, 08:13 PM   #14
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Hey wait. It is fixable.
I take it that you don't know how to weld, but look up some industrial welders in your yellowpages and they should do it for about 10-15 bucks if you do all the prep yourself.

Strip the headtube and sand away all the aniodizing/gloss 1" away in each direction of the crack. take a 1/8 inch drill bit and drill a hole at the very head of the crack (in the middle of the headtube). Then, using a file or a dremel tool, file a V groove over the crack about 1/16" deep all the way across the length of the crack.
Take it to the weld shop and ask them to TIG or heliarc weld the crack, preferably with a similar alloy rod your frame is made of.
Once they weld it up, you can grind it down if you want, or leave the weld as a "scar" (TIG welds are generally very beautiful).Have the headtube faced if necessary, toss in your headset and go ride, worry free about catastrophic failure from that one crack.
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Old 01-18-06, 09:36 PM   #15
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Don't ride it. Warranty? Replace it? Have local framebuilder ^maybe^ fix it?
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Old 01-18-06, 09:42 PM   #16
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Quote:
Originally Posted by broomhandlde
i somehow have cracked my head tube on my mountain bike. its 7005 alum. it is a hairline crack, but is this safe to ride? im thinking no. but the crack is very faint. here are some pictures...
I'd say ride it. It was damaged not by any sort of road hazard or fatigue, but by (probably improper) headset cup installation.

The nature of this particular crack is that if it gets worse, the symptom will be a gradual loosening up of the headset, as the upper race may start to be able to wiggle in the frame. No way will this cause any kind of a crash unless you keep riding it way after it becomes noticeably loose, and probably not even then.

If you want to keep the frame, it might be a good idea to drill a "stopper" hole at the very bottom of the crack. This would be a small hole, maybe 1/16" or a bit larger, to keep there from being a sharp bottom to the crack. The place where the crack ends can act as a stress riser.

Think about tearing a cellphane bag...when you try to tear a straight, undamaged edge, it's almost impossible. Once a tear begins, however, it's unstoppable.

Sheldon "Might Still Have Some Serious Miles Left" Brown

P.S., another poster referred to an issue with a carbon steerer. That's not a good comparison. Steerer breakage is relatively common, and frequently causes grisly crashes. (Personally I don't trust even undamaged carbon steerers.)

Head tube failure, however, is just about unknown, aside from the type of damage your bike received during headset installation.
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Old 01-18-06, 09:50 PM   #17
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The "stopper" hole is the 1/8 hole I referenced to in my post. I would still just get it welded up to have the peace of mind that the crack isn't going to creep out any further.
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Old 01-19-06, 11:14 AM   #18
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the head set is loose, it swings around.

ive called a few alum frame builders, and they said it would be really expensive to repair it.

i have a friend who does tig welding.... we will see.
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Old 01-19-06, 12:10 PM   #19
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Quote:
Originally Posted by broomhandlde
the head set is loose, it swings around.

ive called a few alum frame builders, and they said it would be really expensive to repair it.

i have a friend who does tig welding.... we will see.
Those aluminum frame builders are jerks. Go to a Cletus and Deke's welding and fab shop and they'll do it for lunch money. This is a really really simple repair that doesn't require any specialized knowledge of bike frames. Just prep the crack as described, zip it up, and go ride.
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