Ever thought about going fixed? It's a traditional winter favourite over in the parallel road bike universe, but something of a niche off-road. We know of about half a dozen people who regularly ride off-road without the ability to coast, and we rather suspect that that's the lot. But leaving that aside, here's an interesting way to go about it. The ISO-cog is a rather novel idea, allowing you to take a front hub and convert it to use as a rear hub, with a sprocket attached to a standard 6-bolt disc mount.

The parts are custom manufactured in England by a leading international aftermarket motorcycle gear and sprocket engineering company with over 70 world champions riding its products. Blanks are machined from solid EN36 chromoly steel stock. Teeth are precision milled and the cog drilled to very tight tolerances before undergoing heat treatment.

You can do something similar with a BMX sprocket and a pillar drill, but you're unlikely to get quite as neat a result. Take a look at www.londonfixiebike.co.uk and see what you think.