NE London Bike Polo: Wednesdays: Mitchison Road N1 / Weekends:Hackney Downs E5

Rik speaks the truth.

If I were still fixed, I'd be running a bolt-on hub/sprocket... all thread-based polo hubs turn to butter pretty quickly (in my experience).

Interesting,

http://www.velosolo.com/shopdisc.html

They seem to be planning to sell a 22 tooth bolt on cog. I might look at that if they start selling it.