Bicycles

Shift Drive is an ebike belt drivetrain that can shift gears

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Veer's (currently ) two-speed Shift Drive system is compatible with traditional wheel hubs and frames
Veer
Veer's (currently ) two-speed Shift Drive system is compatible with traditional wheel hubs and frames
Veer
The belt stays straightly aligned at all times, as the cog elements swivel underneath it
Veer
A spring-loaded tensioner wheel takes up belt slack as needed
Veer
The Shift Drive system's individual swiveling cog elements (silver) are clearly visible in this image
Veer
Shift Drive could conceivably also find use on non-electric bikes
Veer
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For vehicles like ebikes, belt drives offer a smoother, zero-maintenance alternative to chain drives. The Shift Drive system takes the technology further, by allowing riders to shift between two gears – plus it works on unmodified bicycle frames.

Currently the subject of a Start Engine investment-seeking campaign, Shift Drive was created by California-based belt drive manufacturer Veer.

The setup incorporates the company's existing Split Belt. Unlike traditional drive belts which come pre-made in the form of an uninterrupted loop, the Split Belt starts out as one long strip. Once it and the rest of the Veer drivetrain have been installed on the bike, the two ends of that strip are riveted together so that it then forms a loop.

The big advantage of this system lies in the fact that when the Split Belt eventually wears out, it can just be pulled apart and replaced with another that's simply put in and looped up.

By contrast, in order to allow for the replacement of a conventional pre-looped belt, a bike must have a removable section built into its drive-side seat stay. Otherwise, there would be no way of getting the new belt onto the drivetrain in one properly tensioned piece.

Another disadvantage of traditional belt drives is the fact that because they can't incorporate derailleurs, the belt drivetrain itself can only offer a single gear ratio. In order to provide more gears, a third-party hub or bottom bracket gearbox must be added to the mix – although that adds weight, complexity and expense.

The Shift Drive system's individual swiveling cog elements (silver) are clearly visible in this image
Veer

Shift Drive instead utilizes a rear cog that incorporates several separate sprocket-toothed elements arranged side-by-side to form a ring. Each element can independently swivel 180 degrees relative to the underlying cog body, in order to place either a taller or shorter side of itself directly beneath the belt.

By having all of the elements sequentially swivel in the same direction, it's thus possible to increase or decrease the diameter of the cog – or at least, the part of it that the belt engages. A clutched-spring tensioner wheel located below the cog automatically takes up the belt slack as needed.

It's difficult to describe how the system works in written words, but you can see it in animated two-geared action in the video at the end of this article, starting at the 01:18 mark.

A spring-loaded tensioner wheel takes up belt slack as needed
Veer

Veer founder Sean Hacking tells us that while an electronic micro-servo initiates each gear-shift, the actual swiveling of the segments is driven solely by the rotation of the hub. The shifts can be manually triggered via a handlebar-mounted remote, or they could be automatically triggered via a pedaling torque sensor.

What's more, Shift Drive can be used along with any third-party geared hub that has a standard 9-spline freehub body, thus doubling the total amount of gears available. That said, Veer is working on adding additional gears to the Shift Drive system itself.

Hacking says that the technology should start showing up on production ebikes – and possibly other light electric vehicles – as of next summer (Northern Hemisphere). Prospective commercial partners can get in touch with him via either the Start Engine campaign or the company website.

Source: Veer

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7 comments
PAV
All the showmanship was fun, but I still don't get what's so special, and what makes it better than a chain.
Glidedon
PAV , belt is more durable, less weight, less maintenance, pay attention next time.
Wild-Bill
The belt drive for a classic frame design, that I find really interesting. The gearing systems is of no interest as I use Rohloff's internal geared hub on all my rides and they can be easily converted to take a belt drive. I am not interested in electric drives at the moment but Rohloff hubs can be used with mid drive motors controlled by torsion sensors basically because one should not shift a Rohloff under load.
veryken
Total BS.. Adapting belt to shifting like a chain is ludicrous and stupid. His claims are hyperbolic and childish. It's one of the most laughable perverted useless concoctions ever.
YourAmazonOrder
That’s all fine and good but it isn’t electric! Think of all that deadly CO2 being produced by the cyclists! Maybe, if there was a place to strap a tree to the bike, so it can be carbon neutral? Or a couple of flower pots riding pillion? Or… a mask connected to a tank to capture the CO2 and sequester it long enough to be buried underground! We’ll get rid of all that nasty CO2 on this planet one way or another!
Captain Danger
Brilliant concept.
I wonder what the rpm limit would be for shifting? (it may have been mentioned in the video but I watched it at work and had it on mute)
The sprocket needs to shift 180 deg really quickly
at 60 rpm the unit is moving 360 deg / sec
if the shift needs to take place in a 90 deg window then it must unlock rotate and lock in 250 ms
That is not to bad and sounds reasonable for a bike, but on a faster unit running at 600 rpm that would only allow 25 ms.
some serious fast accell , decell and impacts. wear may become an issue.
But I like it. Need to keep this idea in my pocket , may come in useful when building custom machinery.

TechGazer
Couldn't they just push the sprocket segments outwards? At large extensions the torque would be uneven, but at smaller ones, maybe acceptable. The more segments, the less the difference from perfectly round. It would allow more steps across the range.

It doesn't seem like a significant improvement over the standard chain drive (and has drawbacks). The pedaled generator/electric motor system seems like it would make a much bigger difference in ride experience for the average rider.