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Discussion Starter · #1 ·
So I'm building a new ride and everything was working well with a new 24t granny and a slightly used xtr chain...then I decided to try a lower gearing and put a new 20t chainring on and I couldn't even get out of the parking lot because the chain skipped so much.

20t seems pretty common, and I'm just wondering whether the small chainring size/#teeth amplify chain wear issues that much, and how common skipping problems arise on 20t rings, even with a new chain and ring together.

Other explanations of the problem?
 

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Former Bike Wrench
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You don't mention what crank you put the 20t on. If its one that has a 64/104 four bolt pattern and your using something like the Action Tec 20t that is made for those, it often requires a little metal work on the bolts. Otherwise the chain will not sit all the way down on the ring at each bolt and skip
 

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Discussion Starter · #4 ·
I did check the chain wear with a gauge and it seems fine

the chainring is on a 58mm bcd spider and the vuelta ring seems to have plenty of clearance between the bolts and the chain

having checked those, I'm not sure what the explanation is
 

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meh....
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IPA Rider said:
I did check the chain wear with a gauge and it seems fine
new ring and old chain, if it skips there's not much else it can be other than the chain. measure it with a good ruler/scale from pin to pin around 12" apart, see what you get. gauges schmauges.
 

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Vaginatarian
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it will be very noticable because as the chain wears it lengthens, the radius on a 20t is very tight wrap a worn chain around a small gear and the links no longer fit the teeth. put a new chain on , if it doesnt cure the problem you'll use it anyway
 

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Discussion Starter · #7 ·
dan0 said:
it will be very noticable because as the chain wears it lengthens, the radius on a 20t is very tight wrap a worn chain around a small gear and the links no longer fit the teeth. put a new chain on , if it doesnt cure the problem you'll use it anyway
this is what I was thinking, and wasn't sure just how sensitive 20t rings are to chain wear and associated slippage.

although if they wear together...
 

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Vaginatarian
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IPA Rider said:
this is what I was thinking, and wasn't sure just how sensitive 20t rings are to chain wear and associated slippage.

although if they wear together...
what is the 20 made of
I have an action tec ti 21t and its holding up pretty well
 
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