The problem is always the friction drive part of it. Anything that relies on a friction drive is always gonna get upset by water on tyres - not to mention it will eat knobbly tires for breakfast and vibrate itself to **** at any speed.

It really depends on what you want from the machine. If you want an all weather all surface rig then its better to go chain or belt (which means ditching those wonderful wheels). If you want something for sunny days and road work - then the friction drive/roller drive would be fine. You pays your money and takes your choice as it were..

The other option is electric drive with hub motors - but that still means losing the 3-spokes and means you have to find somewhere to put the batteries which for any decent speed/range will not be small in size or weight...

Its a conundrum really - you have to balance needs with what you are willing to change/remove and also whether you will be able to live with the limitations involved..

hope that helped

Jemma xx