Have you ridden one? I’d love to hear more.
Yep, been out for a few rides with Geoff, and tried his bike on each occasion. It was always slightly different, as he’s an inveterate tweaker and inventor.
In brief – it’s short, steep angles, zero length stem with high bars, 29er wheels, relatively narrow rims with DH 29er tyres and motorbike tubes, run at about 5/6 psi!
Also (very) elliptical chainrings, pedals with a cam axle, so your crank length effectively changes during each pedal stroke. Full chainguard and mudguards, drum brakes, and gearbox hub.
Geoff likened riding it to balancing a broom on your hand – it only works with a long broom, therefore the short, high build of the bike. Lots of small incremental movements, give you lots of slow speed control.
Watch the film, and you see it looks like he’s wobbling around, but in fact that’s how the bike handles so well on rough ground at slow speed.
It’s quite counter-intuitive, but by ‘eck it works!
As he’s says, it’s much more like observed motor bike trials – getting from A to B, over rough terrain and obstacles – than balls-to-the wall downhilling.