Cranks could break

davidsis

New Member
Mar 14, 2008
11
0
0
I was rideing on the beach and my crank broke. Could have gotten hurt if I was on the street. I was pedaling to get it started, and it just snapped. Probably good idea to inspect for crackes because there was a dark spot that looked like it was cracked for awhile before it snapped

Do not know how to post pictures hope this is okay

YouTube - Broken crank
 
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Jemma Hawtrey

New Member
Dec 29, 2007
288
2
0
Essex, UK
The fact you have noticed a 'dark spot' might indicate a stress fracture failure from vibration...

could be the engine is setting up a resonance that is travelling back through the drive system and stressing the metal of the cranks - considering the stress a crank is usually under they wouldnt be made of very strong or tempered metal...

just a thought

Jemma xx
 

Dave31

Moderator
Staff member
Mar 1, 2008
11,204
29
38
Aztlán, Arizona
I've never had a crank break, but I have had a pedal break and had a very bad crash. This was before my bike was motorized.
 

Bikeguy Joe

Godfather of Motorized Bicycles
Jan 8, 2008
11,843
236
63
up north now
I broke the crank on my Next bike- I was trying to do a burn out (no engine, just me). The third time I tried to "lay a patch" the crank broke off of where it's mounted to the sprocket. I welded it and it seems fine now.
 

sisdavid

New Member
Mar 31, 2008
257
0
0
Daytona Beach
I got lucky that it did not cut me. When me and my brothers were kids, and into BMX. My brother broke some Shimono 600 cranks the aluminum ones, and cut his leg so bad that he had to get 5 stiches.