You will only win at XC on a single speed if you are massively fitter than the rest of the field. Depends a lot on the course too. If it’s Big Up Big Down then you are stuffed as can’t pedal the descents. Flattish uppy/downy you might have a fighting chance.
As for Rik, and I have nothing but respect for the man, but he did build the trails with SS in mind, design the course and rides there most days, so I am not sure the unigear was the advantage….
I sat at the front of one of the Thetford Winter rounds with a lassie on a single speed, knew I could pick her off when I wanted too with a big ring sprint, and I did, so stayed for the chat.
But you would never beat a rider of equivalent fitness on a geared bike.
Anyway, I thought Single Speeding was about the beards and the beers, not the podium babes ?