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| Motor Bicycle Safety Share safety tips for motorized bicycles. Some of these bicycle engines will reach great speeds and need respect. |
Cranks could break
Discussion at Motorized Bicycle Engine Kit Forum in the Motor Bicycle Safety forum. I was rideing on the beach and my crank broke. Could have gotten hurt if I was on the street. ...  | 
04-28-2008, 04:15 PM
| | Motorized Bicycle Newbie | | Join Date: Mar 2008
Posts: 11
| |  Cranks could break
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
Last edited by davidsis : 04-28-2008 at 04:29 PM.
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04-28-2008, 04:39 PM
|  | Motorized Bicycle Elite Member | | Join Date: Dec 2007 Location: Essex, UK
Posts: 292
| | Re: Cranks could break
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 |
04-29-2008, 03:33 PM
|  | Moderator | | Join Date: Mar 2008 Location: Cuk Ṣon, AZ
Posts: 4,724
| | Re: Cranks could break
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. |
05-12-2008, 02:13 AM
| | Motorized Bicycle Elite Member | | Join Date: Mar 2008 Location: Daytona Beach
Posts: 225
| | Re: Cranks could break
Wow that video made me sound like Special needs Kermit the Frong. |
05-12-2008, 07:16 AM
|  | Godfather of Motorized Bicycles | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 7,121
| | Re: Cranks could break
__________________
If it ain't broke, and you mess with it long enough, it will be. |
06-05-2008, 11:47 PM
|  | Master Bike Builder & Forum Sponsor | | Join Date: Dec 2007 Location: Duvall, WA PNW
Posts: 2,685
| | Re: Cranks could break
Quote:
Originally Posted by sisdavid  Wow that video made me sound like Special needs Kermit the Frong. | The sounds and the picture of a broken crank are....well funny!   |
06-05-2008, 11:59 PM
| | Motorized Bicycle Elite Member | | Join Date: Feb 2008
Posts: 413
| | Re: Cranks could break
wow.. I have never seen that before. Wow !! That is a manufacturing defect for sure. |
06-06-2008, 08:55 AM
| | Godfather of Motorized Bicycles | | Join Date: Jan 2008 Location: Ashtabula county, Ohio
Posts: 7,121
| | Re: Cranks could break
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.
__________________
If it ain't broke, and you mess with it long enough, it will be. |
06-06-2008, 09:14 PM
| | Motorized Bicycle Elite Member | | Join Date: Mar 2008 Location: Daytona Beach
Posts: 225
| | Re: Cranks could break
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. |
06-06-2008, 09:57 PM
| | Master Bike Builder & Forum Sponsor | | Join Date: Dec 2007 Location: Duvall, WA PNW
Posts: 2,685
| | Re: Cranks could break
Yeah glad you didn't get hurt - that would be nasty. | | Thread Tools | | | | Display Modes |  Linear Mode | 
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