Triple chain length

I have a Dawes Galaxy fitted with 9 cogs (11-32) and Shimano Deore triple chainwheel 26-38-48. I’ve reduced the 48 to 44 without shortening the 112 link chain. It works okay but I need to replace the cassette and chain. Should I shorten the chain and if so by how many links?

Pete Sutton, Chippenham

You could shorten it by two links but there is no need to. What concerns me is that if you have simply fitted a smaller outer ring, rather than the altogether smaller 22-32-44 chainring set, you will not be able to move the front mech down the frame – in order to maintain the recommended 2mm clearance between outer cage and outer ring teeth – because the deep inner cage still has to clear a 38 tooth middle. In that case the chain may, from time to time when upshifting, overshoot through the yawning gap that now exists between the outer ring and cage, ending up wrapped around the crank and pedal!

I recommend replacing all the rings in order to maintain correct adjustment and operation of the front mech. Then you would want to remove those two links, to avoid the chain running slack in some inner ring gears.

The chain on a triple should be just long enough to climb onto the biggest ring and sprocket combination without damage. I cannot predict how long that is without measuring the chainstays. It is easier for you to pull it tight around those two and then round up to the next even number of links. For example: if 108 links just fit big-and-big, you want 110; likewise if 109 just fits.

Chris Juden


This was first published in the October / November 2012 edition of CTC's Cycle magazine.