The Bike Blog

Ellsworth have created a couple of nice looking bikes that use a continuously variable planetary (CVP) drive as a rear hub. This is a device which allows you to change gear in a continuous movement - there are no distinct gear ratios. The video above explains how it works better than I can. You can get your hands on it for $3995 with the belt drive, or $2995 with an old fashioned chain drive.

The Revopower is a petrol-engined hub that fits onto your existing bike wheel. It allows you to travel at up to 17Mph, and will cost $499 -$599.

The petrol tank slips into your water-bottle holder, and a throttle is fitted to the handlebar. RevoPower is expected to launch sometime in 2007.

Personally I think that if you don’t like pedalling, then you should get a moped.

Sussex Enterprises have created a chain-less drive system for use on bikes that they claim maintains an efficiency of 94%. The main advantage of this is that it requires virtually no maintenance, and that it looks pretty cool.

I wonder whether it would be possible to integrate this into the frame of the bike, so that you can’t see any of the components at all? I suppose that would be fine until you needed to get inside to repair something.

There’s a review here of the NuVinci variable gear hub. This is a fancy little invention that doesn’t change between several gears, but gradually alters the gear ratio with a handle bar twist-grip.

It allows you to adjust to exactly the right ratio for the hill that you’re climbing, rather than find the gear closest to the ideal. I think it’s better suited to laid back tourers than racers or off-roaders, but could make cruising effortless.

I’ve got an internal hub on my everyday bike, and I love it. The only problem is that they can be a pain to service, and the mechanism makes it harder than usual to get the back wheel off - a pain if you get a puncture a long way from home.

I would advise that before you buy something unusual, that you find out where you can get it fixed.