Bicycle Mechanics - clunking in high gears

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MoxMonkey
09-06-07, 08:06 PM
hi everyone,

i've recently broken out an old sekine road bike that's been sitting in our garage for ages, I had a local shop do a complete tune up and replace the rotted tires that where on it but another problem has come up and i'm not exactally sure what's causing it

when riding in high gears (mainly 10th gear but now 9 is starting as well) and pedaling heavy to get some speed there is a fairly loud clunk that sounds like the chain loses it's tension and then snaps back on about once ever revolution

i'm not exactally sure what's causing this but if i had to guess i'd assume crank wear but any suggestions would be great

Sheldon Brown
09-06-07, 08:19 PM
hi everyone,

i've recently broken out an old sekine road bike that's been sitting in our garage for ages, I had a local shop do a complete tune up and replace the rotted tires that where on it but another problem has come up and i'm not exactally sure what's causing it

when riding in high gears (mainly 10th gear but now 9 is starting as well) and pedaling heavy to get some speed there is a fairly loud clunk that sounds like the chain loses it's tension and then snaps back on about once ever revolution

i'm not exactally sure what's causing this but if i had to guess i'd assume crank wear but any suggestions would be greatMost likely chain/sprocket wear.

See: http://sheldonbrown.com/chains

Sheldon "Chains" Brown
MoxMonkey
09-06-07, 08:21 PM
oops i forgot to mention I also had a new chain put on when it was being tuned up but yah i figured it was wear so much for a cheap bike that would last me for a little while lol

rushlink
09-06-07, 09:50 PM
It could be your freewheel/casette slipping. You are either gonna need a new freewheel, cassette, or hub (I think those are the right terms)...

Other than that, i'm not sure what could cause the problem. You might want to take it back to that bike shop, and ask them what the problem is. Most bike shops don't ''test ride'' the bikes, or if they do, it is just brief, nothing that might cause wear and tear, such as accelerating hard in high gears.

If you feel the chain slipping, take a look @ it, try to see where the chain is slipping, then relay that information to the bike shop you took it to, i'm sure they'd be glad to take a look at it for free :)

~Rushlink

Oh one more thing... It could be the derailler slipping off, ask them to take a look at that too.