Helmet fitting
 

Most of the helmets I've been trying on seem to be designed for people with an oval head shape (as viewed from above). My head is more circular in dimension. I either get slippage in the front and back, or painful tightness at the sides. The built-in adjustment only helps slightly. Any suggestions?

Normally this play is removed with pads. Put thicker ones in the sides and thinner ones in the front or arrange them in whatever combination gets even play all the way around. But, you've probably already tried this, so, you may have to experiment with helmet manufacturers to get one that has a basic shell shape that seems to fit your head. They are all a little different. I find that Bell fits my head well, while others often don't have the fore to aft distance I need.

According to legend, Oliver Cromwell and his followers wore Bell helmets.

I have the same trouble in that my head seems to be more round than normal. Bell helmets not only fit me perfectly, they are the only ones that fit me.

Well, we're in fine company then, aren't we. :) Now if we could just confirm that Thomas More used fenders, we could be sure that he was really a man for all seasons. :)