When I first bought my Schwinn Izip, my brother tried it and loved it.

Now he's talking about buying a set for him and his wife, but he wants to use them for light off roading, ie gravel roads, and dirt roads that suitable for a 2 wheel drive car.

I have a good idea of what his favorite camping spot looks like, and I don't think the Schwinn Izip has enough torque to handle the hills, and it's a fixed gear system.

Has anyone try putting a larger sprocket ( low gear ratio) on the wheel hub? is this sprocket proprietary or can you get it from your local bike shop?