Most 700 wheel size bike use a cassette with a smallest cog of 11t. The other solution to adjust the transmission to the smaller wheel size, instead of only increasing the size of the chainring, is to reduce the size of the smallest cog to 10t or even 9t.

Moving from 11t to 9t is equivalent to moving from 50t to 61t.

Companies making race small wheel bikes like Moulton use a 10t cog.