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My Bicycle chain skips when it's on the smallest gear and there's too much pressure on it. Anyone got any ideas?

i am speaking of the rear cassette. it and the entire rear wheel is months old, so i don't think its a worn out freewheel. Ive adjusted the derailer numorous times with no luck.

rowerwet5 years ago
the smallest gear in the back is the one you use the most, it will wear out first.
You could have a tight chain link, which causes the chain to hiccup every once and a while under high load.
MRM1 (author)  crazybuilders5 years ago
I dont think this is the problem either, as i already broke a chain due to this skipping (it was particularly violent). so i have a spanking new chain and the problem persists. but only on the smallest (last) gear.
It's worn down, definately. If you already broke your chain on it, you need to replace the sprocket (it's cheap, $20,- and you're done) It's always best to replace both your sprocked ánd the chain at the same time, because you could be creating the same problem again with a worn out chain on your new sprocket :)
MRM1 (author)  SchizoDuckie5 years ago
nope. as i mentioned i just bought the sprocket and the chain. It was the rear derailleur. it was worn out. it was causing the chain to skip down, and eventually off the sprocket. the chain broke because of this, it jumped the sprocket and got stuck and i pulled the chain while pedaling and it snapped.
MRM1 (author)  MRM15 years ago
my bad i didnt mention the new sprocket. i just thought i did.
goodgnus5 years ago
Have you adjusted the limit screws on the derailer? Inspect the frame near the smallest gear, is there wear on the frame? If so the limit screw on the derailer might need adjustment as the chain might be trying to jump off? It's hard to say without seeing the problem. Check this page to see how to determine if your sprocket/cassette is worn out: http://www.sheldonbrown.com/chains.html, the page is titled Chain Maintenance but further down the page it shows worn sprockets. You mentioned the rear wheel is new but is the cassette new as well?

As PKM says, make sure the # of speeds on your shifter matches the # of cogs on the cassette.

You may need to make a visit to your LBS (local bike shop) to have it inspected by a mechanic. They probably won't charge you to tell you what's wrong.
kwschofi5 years ago
"PKM" and "crazybuilders" have offered excellent advice. Here are a few more: If the chain skips to the next gear, then you need to keep working on derailleur adjustment and check the smoothness of cable movement inside the cable housing. If the chain "pops" and stays on the same gear, it is most commonly a worn out or "shark-finned" gear. If you're confident it is not the gear, check the chain... typically you install a new chain at the same time you install a new cassette. Finally, check the alignment of the derailleur hanger. If the derailleur hanger is bent it will give you maddening problems.
PKM5 years ago
The same happened to me, it was a worn sprocket (the bike wasn't very old, I just abused it). Check that the shape of the teeth is still right (flat top, semicircular gaps between- if the gaps are oval or the teeth are pointy your sprocket needs replacing. Consider the derailleur may be bent, in which case it's possible no amount of adjusting will fix it. Alternatively, if the cassette has more gears than the derailleur is designed to cope with (replaced 6-gear wheel with 8-gear wheel, for instance) the end gears might not work properly (but you only see the problem with the smallest one).