Thursday, August 28, 2008

Hum Cycle

Predictions on this blog have talked about how style, speed and prestige will define the new electric vehicle.

The Hum Cycle is certainly charging into this future - on two wheels.

A small gang of entrepreneurs are kicking the shins of the venture capitalists and blazing the streets of Silicon Valley with their potent new Hum Cycle - an uncompromisingly sportissimo, all-electric motorcycle.

I met with Forrest Deuth, and Jit Bhattacharya - two young guys looking very pleased with themselves - and a small crowd of onlookers to see the new Hum prototype in the flesh.

Deuth - an alumni of Tesla motors - was careful to elaborate that this prototype would vary in many ways from their final product.

But still some of the most obvious features that the prototype has that we're likely to notice in the real thing are that which are missing: no clutch handle, and no gear shifter by the left footpeg. It makes the left-hand side of the bike look decidedly bare.

Apart from that at first approach from the front it looks very much like many other sport bikes - modern full-fairing, stiff trellis frame (which will later be replaced by a fully custom frame, according to Deuth).

Then you notice between the frame and down under the belly of the bike telltale patches of yellow. These are the Lithium-Ion battery packs that power the Hum. Them, and a whacking great electric motor, its cylindrical bulk nestling down where the gearbox would be in a
conventional machine.

The chain sprocket goes directly onto the motor, and drives via an oversize chain and back sprocket to the back wheel. Riders I talked to that day reported plenty of pull from the prototype motor. Plans are afoot for a different drive set-up to elide the oversize gearing, and a more powerful motor.

The bike has regenerative braking - this is configurable, and was dialled down today since conventional riders are not used to their mounts being so very responsive on relinquishing the throttle.

And of course you can't blip the throttle when you're at the lights - not that you'd get any noise if you did.

This machine is almost completely silent. The only thing announcing its approach is the chatter of the chain. The makers are talking about the possibility of a belt drive, if the relative gearing of the drive train allows it.

Deuth and Bhattacharya say they're pitching right at the sports market with their first production machine - it will be a high-performance bike, with a decent range, suitable for the ride to work or short touring/sport riding.

Its something both the green community and the motorcycling community will be eagerly awaiting.

Me too.


  1. > is completely silent

    This part's actually kind of scary. Sometimes the sound of a motorcycle is the only thing keeping drivers from running them over.

  2. I got a test ride on the HUM bike, so I figured I'd respond with riding impressions. First though, the disclaimer: this bike has absolutely nothing in common with the bike they'll eventually produce, except that they're both electric. This bike was put together from readily available parts to demonstrate to potential investors that an electric sportbike is a reasonable idea. That's their excuse anyway - I suspect that Forrest just wanted an electric motorcycle to ride!

    Getting moving on the bike couldn't be simpler - just turn the grip and it goes! Electric motors should have maximum torque when stopped, but the bike was pretty soft off the line - it felt like the motor controller was limiting output up to about 10 mph, at which point the bike really took off. Acceleration was quite brisk up to 30-40 mph, but by the time I hit 60 it felt more like a typical car in acceleration. Forrest claimed the motor put out about 20 hp peak, but it felt like a motorcycle with 30 hp. Very similar to a Ninja 250 (which is no slouch) in performance, really.

    It was really nice when getting moving to not have to use the clutch - it's a pretty ideal bike for filtering to the light between cars at lights and lane-splitting on the freeway, both of which I got to try since my test ride was at rush hour. Cornering on a freeway offramp was a bit scary because the fairing dragged where they'd spaced it out to cram a few more batteries in, but the smooth throttle modulation was very confidence-inspiring.

    I think that if they build, as planned, a real all-out sportbike with 4x the power, no artificial limitations (don't limit torque to prevent wheelies!), and top-shelf components, it will be a total blast in the twisties, where the very smooth and direct control will be super confidence-inspiring when turning the throttle at extreme lean angles. It'll also be a surpisingly nice commuter, if the riding position isn't too punishing. Unfortunately, it won't be cheap, since they'll have to target the exotic bike market first given current component costs, and it won't be an only bike, due to range (80-150 miles depending on riding style, probably). I doubt I'd buy one due to price, but the success of Bimota, Benelli, MV Agusta etc. show that there are a lot of people out there willing to drop a very large pile of money on an exclusive bike, so I suspect they'll get plenty of buyers. I'm just looking forward to getting an opportunity to test-ride the final result!


Hi, thanks for leaving your thoughtful on-topic comment!