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chainset -

you could stay with what you have and just replace the cracked arm with a used one in good condition

the adaptor ring on the chainset limits the smallest inner chainwheel to 43T

you could keep the same T.A. arms and go with a design where the outer chainwheel mounts directly to the drive side crank arm
this is the Cyclo-Touriste pattern and permits chainwheel dentitions from 26T to 68T

the cycle's present chainwheel arrangement is termed the Professional -

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here is the Cyclotouriste -

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