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Crack in bike frame head tube..... is it terminal?


ph5172
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I have a crack in the head tube of my mountain bike. I marked it and it hasn't got worse in 20 or so miles. 

Alloy framed

Its not from a fall so must be some form of stress crack

its not an expensive bike and a few years old mainly used for road cycling 

the question is..... will it be worth trying some quick steel putty or is it a scrapper? Apparently alloy welding wouldn't be worth it   

i would rather keep my teeth!!

 

 

 

IMG_2999.JPG

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14 minutes ago, Yellow Bear said:

Perhaps a jubilee clip round may help relieve stress - not pretty but cheap.

 

Great minds..... the only ones I had were a little thick because of the frame it slipped off or scraped so they stopped the forks turning properly 

IMG_3001.JPG

Edited by ph5172
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The way that crack has propogated, it may have been caused by a poorly machined (too tight) bearing housing and been started by the forcing in of the bearing race at manufacture. Welding might be an answer, but then the bearing housing would need reaming for the correct fit of the bearing as it would most likely be distorted by the heat.

If you are going to go the jubilee clip route, it would be worthwhile filing back the weld at the bottom of the gusseting so that you can get a greater surface area for the clip to sit on.

Best answer is probably to find a secondhand frame and transfer all your bits across.

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You could try welding it yourself with "Lumiweld".

https://www.ebay.co.uk/itm/Lumiweld-5-Rod-Kit-Low-Temp-Aluminuim-Repair/260531563568?hash=item3ca8e42c30:g:3~oAAOxyJX1TCfx3

This is low temperature welding that you can do yourself, ideally with a MAPP-gas torch, although you can use propane.

I have used this very successfully on the motor-bikes, repairing castings and even brakes.

I would drill the end of the crack first to stop it spreading, file a groove in it to give the Lumiweld some area to adhere to then pull the crack together with a stainless Jubilee clip and weld up to the clip - the Lumiweld will not stick to the stainless - remove the clip then finish off welding the un-welded bit.

As Tribsa wrote above, it will almost certainly need some fettling to allow the bearing to fit

Total cost probably less than £30

 

Edited by amateur
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The frame is done, Is it a hardtail or full sus? if it's a hardtail used good frames can be picked up for £100 up over and a good full sus for £500 up over so not worth messing about with a temporary fix.

Look at Pinkbike for frames

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Thanks for all the ideas. 

It's just a 'normal' mountain bike I bought a few years ago (and haven't ridden that much to be fair)  

for the sake of £300 or so as much as it pains me I'm going to consign it to the scrap heap - I don't have the technical knowledge to move all the components over, and to be honest I don't think the value would warrant the time. 

I will strip off as much as I can before I clearly mangle and dent the frame and the scrap man takes her

Thanks for saving me from a broken shoulder or a new set of teeth !

 

Edited by ph5172
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16 hours ago, TIGHTCHOKE said:

I bet Ditchman could sort it out!:rolleyes:

im with amateur......another is "laser brand".....use MAPP gas.........ive used it several times on outboard motors and castings.....it only works on aluminuim...if its an alloy you might have a problem...tried it on a "alloy" casting of a sthil chainsaw................DIsASTER...........

 

if yor guggle laser brand you will see a video...

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Could be worse than new teeth. A kid I went to school with had his frame snap as he was riding along and it rammed a testicle into his body. He had to have surgery to put it back in it's proper place. 

Nice. 

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