I agree that a serial number would help with narrowing the date of your Colson-built bike.
In later 1933 and 1934, Colson had paperwork showing 26" balloon tire motorbikes.
Specifications list 7" cranks for the 28" bikes; 6+1/2" for the 26".
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I find the 24-tooth chain rings, like yours, more convenient, with the moderate grades, maybe not so much for foothill areas.
I believe that there is even a bike club with a logo the resembles the Colson Flyer head badges.
I believe 2+3/16" badge holes, with screws, similar hole
spacing as some Huffman and A&S bikes.