[NeillSlater]

astonished to hear that there are issues here,as the 14 tooth difference between the 2 chainrings(53-39) is practically nothing.generally on a TSR you want the large chainring to have 58 teeth as with 20 inch wheels 58 tooth chainring and an 11 tooth sprocket you have around 7 metres per complete chainring revolution in top gear.on a standard road bike i.e. 700 c wheels 52 tooth chainring and 11 tooth sprocket you have 10 metres in top gear..
so you can see 53 teeth is No use whatsoever on a TSR with 20 inch wheels.
it sounds like you are using a double front mech.
possibly try a triple front mech.a standard triple front mech has a capacity of 27 teeth.

[Roger Cantwell]

I have an adaptor bracket which I will probably never use, as I run my TSR as a 1 x 9 (or a fixie, or with a 3-speed hub gear). It would probably fix your issue, although it is a bit clunky. It’s a design fault, same as the rear RH dropout being too thin for a RD mounting bolt, so you always need a washer under the RD. British engineering!

[Author]

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