Chain length relative to chain wrap?
06-12-20, 02:47 PM
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Chain length relative to chain wrap?
I'm changing the gearing of a bike, with new chain rings and a different freewheel. The gearing calculator gives the same chain wrap as the present drive train. Would I end up using the same length chain? Thanks.
06-12-20, 03:07 PM
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If the total number of teeth on the largest chainring and largest rear cog did not change, then you do not need a longer chain.
if the sum grows, you may need a longer chain.
if the old chainrings and cogs were worn, you may need a new chain.
if the sum grows, you may need a longer chain.
if the old chainrings and cogs were worn, you may need a new chain.
06-12-20, 05:35 PM
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New chain. Size it by your preferred method.
06-13-20, 11:47 AM
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Don't know how I double posted. I'm going from 48-36tx14-28t to 50-34tx14-24t. The calculator gave the same chain wrap for both set ups. I think it was 26t. Same bike
same chainstay length. Bike is blue. Just curious. Will replace chain anyway.
I looked at the calculator a bit and it looks like chain wrap on the derailleur is not directly correlated for a given chainstay leangth. But the my elementary school level math makes it look like the chain will actually have the same number of links after changing every thing else.
same chainstay length. Bike is blue. Just curious. Will replace chain anyway.
I looked at the calculator a bit and it looks like chain wrap on the derailleur is not directly correlated for a given chainstay leangth. But the my elementary school level math makes it look like the chain will actually have the same number of links after changing every thing else.
Last edited by bark_eater; 06-13-20 at 12:05 PM.
06-13-20, 01:36 PM
#6
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Your biggest ring increases by 2.
Your largest cog decreases by 4.
Difference in chain length required -2
ERGO- You could shorten your chain by 1".
I wouldn't bother. You obviously have enough chain wrap to handle to handle the difference without issue. Why risk doing damage?
Measure the chain to see if it's worn, although if using NEW rings & cogs, a new chain will probably at least make us feel better.
Your largest cog decreases by 4.
Difference in chain length required -2
ERGO- You could shorten your chain by 1".
I wouldn't bother. You obviously have enough chain wrap to handle to handle the difference without issue. Why risk doing damage?
Measure the chain to see if it's worn, although if using NEW rings & cogs, a new chain will probably at least make us feel better.
06-13-20, 02:03 PM
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Cool. The chain presently has less than 50% wear and well less than 1000 miles. I am interested in just trying out the new combination before cutting a new chain If I like the new gearing.
06-14-20, 03:28 PM
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1,000 miles isn't very much for a chain but it's more than zero so I'd expect the chain to have some wear elongation. When you install your old worn chain onto your brand new cogs and chainrings, the old chain is going to do it's best to wear in the new cogs to fit. My philosophy has always been new sprockets = new chain.
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