Retrofit a new chain ring

[idahomtman]

I have a recumbent bike with a Durabi crankset 32/43/52 TX 165mm. I would like to be able to ride up hills a little more easily. Is it possible to replace the 32 with a 27? How difficult is this and what other considerations are involved in changing this chain ring?

[cyclerUK]

Firstly you need to know the "BCD" (bolt circle diameter) of the crankset.
http://sheldonbrown.com/gloss_bo-z.html#bcd
The BCD can also be measured from the centre of the crankpin to the centre of a mounting bolt x 2 = diameter.
Probably the smallest chainring that will fit yours is 30T. A 27T may have the mounting holes nearer the centre.<br />
You would have to change the whole crankset if this is the case or optionally put a bigger cassette at the back.?<br />
If you do decide to fit a new crankset then also consider longer (170/172/175mm) cranks.<br />
This will give you a bit extra torque but will depend on your leg length etc.