|
|
Thread Tools | Display Modes |
#1
|
|||
|
|||
Fractured front cog?
Sorry guys, it looks like my web host has gone offline.
Here are some photos that work: Try these links: http://www.ucl.ac.uk/~ucgadak/fracture1.jpg http://www.ucl.ac.uk/~ucgadak/fracture2.jpg http://www.ucl.ac.uk/~ucgadak/fracture3.jpg Thanks! Jack "Daniel Kelly (AKA Jack)" wrote in message ... Dear Bikers, I fear my bike has a fracture in its front cog. I first noticed something was wrong when I heard the front cog hitting against the front derailleur once every revolution of the pedals. It turned out the front cog was actually bent and so "wobbled" as it rotated, relative to the front derailleur. Closer inspection showed that the front cog was a little loose and could be jiggled a little. The join between the front cog and the right pedal was clearly loose. I took the right pedal off and found a little crack in the front cog. Some photos are he http://www.xlk.org.uk/forum/modules....view_album.php Is this a fracture? If so, how dangerous is it? Can I ride my bike with this fracture? Do I need a new front cog & right pedal? Thanks, Jack -- rec.bicycles.off-road is moderated by volunteers. To find help solving posting problems, or contact the moderators, please see http://rbor.org/ Please read the charter before posting: http://rbor.org/rbor_charter.txt |
Ads |
#2
|
|||
|
|||
Fractured front cog?
Daniel Kelly (AKA Jack) wrote:
I fear my bike has a fracture in its front cog. I first noticed something was wrong when I heard the front cog hitting against the front derailleur once every revolution of the pedals. It turned out the front cog was actually bent and so "wobbled" as it rotated, relative to the front derailleur. Closer inspection showed that the front cog was a little loose and could be jiggled a little. The join between the front cog and the right pedal was clearly loose. I took the right pedal off and found a little crack in the front cog. Some photos are he http://www.ucl.ac.uk/~ucgadak/fracture1.jpg http://www.ucl.ac.uk/~ucgadak/fracture2.jpg http://www.ucl.ac.uk/~ucgadak/fracture3.jpg Is this a fracture? Yes. If so, how dangerous is it? Not very. Can I ride my bike with this fracture? Probably, but it may cause shifting problems or chain rub. Do I need a new front cog & right pedal? You need a new crank, but there's no reason to think you need a pedal. It seems you're a bit confused on the usual terminology. The part you refer to as the front "cog" is more commonly called a chainring or chainwheel. The part you refer to as the "pedal" is actually the crank. In this case the chainrings are permanently attached to the crank (though not as permanently as one might wish!) Higher-quality cranks generally have the chainrings bolted to them, so you could replace the chainrings without buying a new crank, but yours is not like this. The pedal is the part you actually put your foot on. It screws into the crank. Sheldon "http://sheldonbrown.com/glossary" Brown +------------------------------------------+ | The generation of random numbers is | | too important to be left to chance. | | -- Robert R. Coveyou | | Oak Ridge National Laboratory | +------------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide http://captainbike.com http://sheldonbrown.com |
#3
|
|||
|
|||
Fractured front cog?
It looks to me like the break is right at the spline which transmits all the
pedalling torque to all three rings. If this opens a little bit while you are pressing hard on a pedal, the whole thing could slip or collapse. Don't pedal very hard until you get it replaced--the sooner the better. |
#4
|
|||
|
|||
Fractured front cog?
It looks to me like the break is right at the spline which transmits all the
pedalling torque to all three rings. If this opens a little bit while you are pressing hard on a pedal, the whole thing could slip or collapse. Don't pedal very hard until you get it replaced--the sooner the better. |
Thread Tools | |
Display Modes | |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Fractured front cog? | Badger_South | General | 9 | July 6th 04 11:16 AM |
Fractured front cog? | Daniel Kelly \(AKA Jack\) | Mountain Biking | 3 | July 5th 04 08:42 PM |