Herne Hill Saturday Training

You obviously don't use a speedo.

Novice session average* speed 16-18mph
Intermediate session average* speed 22-24mph
Advance session average* speed 28mph

Based on last year.

*Bunch during general efforts.

I'm using one this year.

I didn't want to exaggerate, and TBH, the difference is probably less at this time of year. Advanced sessions have been rolling around at more like 25mph, but winding up ~5-10mph for the sprint.

Either way, 46x15 is fine for a novice session, init.