Madness or genius? you tell us...

How do you make an electric bike that will do 50mph? You bring together two hub-motors, a backpack full of lithium-ion batteries and - we assume - some clever electronic jiggery-pokery to make it all work and you get this:

The builder says it has two-wheel drive from the pair of motors, which must make for a very different ride feel from a conventional bike, and three power settings for 20, 30 and high-40s mph speeds.

The set-up uses a 72-volt battery. If you’ve seen videos of exploding lithium-ion batteries, fret not: these use lithium iron phosphate chemistry, which doesn’t quite have the energy density of the batteries in your laptop, but can take a higher power draw and has a longer service life.

The nutter engineering wizard behind this machine can be found though his Facebook page. His custom-built e-bikes cost between $2000 and $5000

If the videographer and the venue, California’s Mulholland Drive, seem familiar, that’s because YouTube user rnickeymouse, shot a famous clip of a cyclist getting rear-ended by a motorbike in the same place.

Our official grumpy Northerner, John has been riding bikes for over 30 years since discovering as an uncoordinated teen that a sport could be fun if it didn't require you to catch a ball or get in the way of a hulking prop forward.

Road touring was followed by mountain biking and a career racing in the mud that was as brief as it was unsuccessful.

Somewhere along the line came the discovery that he could string a few words together, followed by the even more remarkable discovery that people were mug enough to pay for this rather than expecting him to do an honest day's work. He's pretty certain he's worked for even more bike publications than Mat Brett.

The inevitable 30-something MAMIL transition saw him shift to skinny tyres and these days he lives in Cambridge where the lack of hills is more than made up for by the headwinds.