Dura-Ace crank crack.
08-30-04, 11:58 AM
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Dura-Ace crank crack.
Does anyone know if the Dura-Ace 7401 crankset (8-speed) had a known failure at the "web" between the arm and the spider?
During bike inspection I discovered a small 4mm crack in this area. Looking at the arm I can see the stress point in the machining. I'm not too worried (the bike is about to become a winter bike I'll try to clean up the crack with a file) but it is weird that I cracked the rear hub and the crankset in the same season...
During bike inspection I discovered a small 4mm crack in this area. Looking at the arm I can see the stress point in the machining. I'm not too worried (the bike is about to become a winter bike I'll try to clean up the crack with a file) but it is weird that I cracked the rear hub and the crankset in the same season...
08-30-04, 12:15 PM
#2
Aluminium Crusader :-)
There's a few scary broken crank stories on this thread.
https://www.bikeforums.net/showthread...3&page=1&pp=25
I'd definitely be chucking that crank.
I've had a crank failure which was near catastrophic, and I was only going about 13mph! I was riding out of the saddle, then BANG..... I managed to "de-knacker" myself, take off a lot of skin, and mess up my shoulder. I was so spooked by it, that I wouldn't get out of the saddle for about two months. I will never ride on "iffy" cranks again.
If you think about it, there's not much worse than breaking a crank or pedal when you're sprinting off the seat at high speed, applying hundreds of pounds of down-force. Just think about it: all that down-force at 35mph, then BANG!!! Nothing support you weight
At least if you break a chain you still have your weight supported.
https://www.bikeforums.net/showthread...3&page=1&pp=25
I'd definitely be chucking that crank.
I've had a crank failure which was near catastrophic, and I was only going about 13mph! I was riding out of the saddle, then BANG..... I managed to "de-knacker" myself, take off a lot of skin, and mess up my shoulder. I was so spooked by it, that I wouldn't get out of the saddle for about two months. I will never ride on "iffy" cranks again.
If you think about it, there's not much worse than breaking a crank or pedal when you're sprinting off the seat at high speed, applying hundreds of pounds of down-force. Just think about it: all that down-force at 35mph, then BANG!!! Nothing support you weight
At least if you break a chain you still have your weight supported.
