Originally Posted by MoxMonkey

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