2012-06-30 Sat/Sun - Dunwich Dynamo DD20

Smaller wheel = less rotational mass, great for everything till you hit a big hill, even with the right gearing.

Good point.

Mind you, it descent brilliantly to the point of being able to do it no-handed on a bad road.

I wouldn't say the Brompton's that stable over the bumps, although I haven't come off it yet. It's quick on the downs, though -- I freewheeled (sorry fixie people) down so many hills because I was catching the race bike in front (and didn't want to be in the front for the climb back out).