Originally Posted by
joey buzzard
The problem isn't generally a lack of low gears on 20" or 16" bikes but rather gaining more gear inches. If I could run s 9t or 10t on my cassette as my highest gears on my 20" bike I could use a 53 or 54 up front and a 36t would be perfectly great for tackling any mountain roads. In fact I'm currently riding 53t. 11t-36t and I'm climbing the steepest roads in Spain's highest mountains every day with ease.
Interestingly, 53-36T on 20" gives about the same lowest gear, 1.08m of development, as I have on my Brompton, 1.03m, albeit with the hub getting involved. In my case, that lowest gear is needed for the steepest inclines in Rwanda. The gear is hardly usable, though, in a continuous manner, rather just in surges like within a turn. For a continuous use, some sort of ratchet mechanism would be needed, to prevent the bike from rolling back when the torque from feet is reduced within the turn of the pedals.