I have always had a 32-34t ring on my bike with 18-21t cogs. I could use a 64 BCD 26t ring with a 16t cog for the same effect. it seems like the main reason for 30t + rings is memetic inertia from when we used 3x cranksets and just used the middle ring position. why are singlespeeders afraid of using smaller rings?
pro for smaller rings:
more clearance from ground- never any reason to put your rings closer to trail features.
lighter (meh)
more frame clearance- frame designers could make frames with shorter chainstays and room for fat tires without resorting to drastic frame designs like elevated chainstays
64 or 96 BCD and various direct-mount crankset designs could make replacing rings cheap and easy.
cons for smaller rings
drivetrains wear out faster with fewer teeth (maybe not a big deal if they can be replaced cheap and easy)
pro for smaller rings:
more clearance from ground- never any reason to put your rings closer to trail features.
lighter (meh)
more frame clearance- frame designers could make frames with shorter chainstays and room for fat tires without resorting to drastic frame designs like elevated chainstays
64 or 96 BCD and various direct-mount crankset designs could make replacing rings cheap and easy.
cons for smaller rings
drivetrains wear out faster with fewer teeth (maybe not a big deal if they can be replaced cheap and easy)