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[Closed] Chainlines

Posts: 21643
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[#1835342]

If a triple with a 135mm back end works with a 50mm chainline, would it be fair to say that a triple with a 130 back end would work with a 47.5mm chainline?

Mate wants me to have a look at his hybrid later and work out why the front mech wont swing in enough to get the granny ring even when he brings the limit screw all the way out. Thought I might measure the chainline and see if that's playing a part.


 
Posted : 27/07/2010 9:03 am
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Is it possible that he has a recent front mech with an older chainset, the newer mechs seem to be designed around the wider chainline needed to prevent the cage catching on wider tyres.Have been able to effect a bodge on some by swinging the mech in at a slight angle, not the perfect solution, but may help.


 
Posted : 27/07/2010 8:50 pm
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Cheers. Had a closer look at his bike tonight. It's got a 135mm rear end with a triple up front running a 47.5 mm chain line. It's running SRAM shifters and mechs with 1:1 actuation but he can't get the granny ring as the front mech bottoms out on itself. Can't tweak it with screws or adjusting the angle. It just doesn't want to play.

The front mech really does stop a long way off from the frame. I'm thinking of trying a shimano front mech rather than trying for a wider BB. 47.5 should be okay for the chain line.


 
Posted : 27/07/2010 10:32 pm