ShareRoller / OneMotor, a 750W friction drive

November 8, 2015

This is the most impressive friction drive I’ve seen so far. It uses a battery pack made from the very safe 18650-format cells that we love (found on safe and reliable cordless tools), and it has several very clever design features that I think will change a lot of peoples minds about what a friction drive is capable of. It provide 750 watts of power, which is the US legal power limit, and I have personally run a friction drive of my own design up to 1000W before it began to loose traction, so this is a very balanced design.

edit: as of October of 2018, the company is now called “OneMotor



More major cities are trying out a Bike Share program, where rental bikes are very cheap, and you can lock them up at racks that are scattered all over the city. Rent the bike in one place, and lock it up in another, while you only pay for the actual time you used it.

Bike Share Programs

The “Share” part of the ShareRoller is a reference to how many large cities are now using a “Bike Share” program. These are bicycles that can be rented very cheaply, and when you reach your destination, you simply set them into a nearby Bike Share rack, and you are only charged for the time that you used it. Having these bikes available in the congested cities will reduce the need for workers to drive their cars in, so it relieved a great deal of congestion.

The Netherlands is very “bike friendly”, but they actually have a lot of bicycle congestion. By having a program were each bike can service the needs of several people throughout the day, a modern city can have fewer cars, and also…fewer bicycles.



A bicycle parking structure in the Netherlands. Bike friendly? Oh yeah…I think so! Gasoline is about $8/gallon there.


And this brings us to the ShareRoller. The Bike Share bicycles are very robust and durable, in order to withstand years of abuse, and that means they are heavy. Many Bike Share bicycles are a single-speed, or at best a 7-speed…in order to simplify maintenance and repair. So pedaling one of them can get very sweaty, especially during a very humid summer! It’s no surprise to us that office workers didn’t embrace that user-model as much as the designers hoped they would.

This creates a dilemma. If the Bike Share bicycles had an electric power system added, the municipal program that administers them would have the added expense, maintenance, and repair headaches…which they were reluctant to take on. One issue is that renters often abuse equipment in a way that they would never do if the device was owned by them.

Psychologists call this the “tragedy of the commons”. If everyone “owns” something (a “shared” resource) then, no particular person is responsible for upkeep and care. For instance, if getting a flat tire on a Bike Share only means that you put one bike back in the rack, and just check out a different bike (at no extra charge), then…the rider has no incentive to avoid riding over nails and debris. Not that you would ride over sharp objects on purpose. Its just that…most people in that situation would ride without any extra care or concern.

So…we now find ourselves in a situation where these great programs are under-utilized because the bikes themselves are built like tanks. The bikes can take any abuse customers dish out, but how can they be made more usable so we can get more people to actually use them, instead of just talking about how great the program is?

The ShareRoller could have initially been rolled out as a friction-drive for the masses (and later, a variation designed for Bike Shares), but their initial push has been directly aimed at Bike Share programs, and I think that was a great decision.

By designing it to snap onto Bike Shares, it can then easily be adapted onto the publics personal bikes with almost no changes other than an inexpensive adapter to make it fit your individual model of bike. This also creates a situation where many people who are unsure, or unaware about electric bikes…they will see ShareRollers being used, and may even ask their friend to allow them to take a test-ride.



The initial primary market for the ShareRoller is all of the Bike Share bicycles, and there are quite a few out there already, with more on the way.


There are over 15 major cities that use the PBSC/Bixi “Share Bike” interface that ShareRoller was designed for (which is used in the USA, Canada, Mexico, UK, and Australia!).



The ShareRoller can be adapted onto just about any common bicycle frame, and here it is on one of my favorite commuters, the Electra Townie.




The ShareRoller will even attach to a kick-scooter, which can be folded and carried on just about any train or bus, for a very handy commuter transport solution.




This pic shows the ShareRoller about to snapped onto the locking lug that Bike Shares come with. This mounting/locking interface has been standardized in many major cities that are moving in this direction…the already existing market for the ShareRoller is huge!




Here, the ShareRoller is being shown with the yellow rubber sleeve that helps the drive unit maintain traction, even when occasionally running through an unexpected puddle.




This pic shows the very light and compact ShareRoller when it is completely folded up, next with the motor flipped-out, and then fully deployed onto a full-sized bicycle.




Another close-up to show the details when it is mounted on a kick-scooter. You can use the ShareRoller on a solid-rubber tire that is found on some fold-up kick-scooters, but I much prefer pneumatic tires to smooth-out sidewalk irregularities.




The central drive unit contains the controller, the motor (which also acts as the roller), and the small twin LED headlights. There are three different sizes of battery, so you can choose light, small, and less expensive, or…longer range. The packs are 6S / 22V, and each battery has a USB port for charging smart-phones or any other 5V device, like a GPS…


The device has been fully prototyped and endurance-tested. The designer launched an Indiegogo crowd-funding campaign to speed up the move into full production. But, don’t worry about if this innovative product will make it or not…he met his funding goal in the first four days!

My initial interest in friction drives several years ago was for local college-students, who couldn’t take their bicycle indoors at night, either because their was no room inside their rental, or they lived in an upper story dorm or apartment. With one of these, you can leave a cheap bike locked up outside, and bring the entire drive unit and battery inside to charge it. It pops on and off, quickly and easily.

Wireless Throttle

When I first viewed the video ride-review (link below), two things jumped out…the designer is incredibly smart and very articulate, and also…this kit needs a wireless throttle. Well, as I continued my research, I found out that the wired version in the video is the initial first version (V1), and the Indiegogo campaign is for the newest V2 with a bluetooth wireless throttle…I had a good idea that it would be upgraded eventually, but the designer has decided that this kit needs the upgrade before the unit goes into production…good choice!

Here is a link to their home web-page, and…

Here is a link to a video-review from Electric Bike Review (EBR) by Court Rye.

Here is a link to their Indiegogo campaign, which ends December 2nd, so if you want one, there’s not much time left to get “early bird” discount pricing.

Here is my friction drive from five years ago (2010), so you will understand that I am not just blowing smoke up your caboose when I say this is the best friction drive out there. I know what I am talking about here…

Update, October 2018

Based on feedback from customers, This company has come out with an upgraded version with a variety of sophisticated features. The new model is called “Onemotor


Written by Ron/spinningmagnets, November 2015



Grew up in Los Angeles California, US Navy submarine mechanic from 1977-81/SanDiego. Hydraulic mechanic in the 1980's/Los Angeles. Heavy equipment operator in the 1990's/traveled to various locations. Dump truck driver in the 2000's/SW Utah. Currently a water plant operator since 2010/NW Kansas


  1. Thanks for the review…are there significant downsides to friction drives? I’m not a hard-core biker, I just want to be able to ride more often than my oldness, or the hills around me, will allow.

    Also, what’s up with the handlebars in the picture in your forum post? Those are pretty awesome, and look like the solution to my needing a higher bar.

    • That was an experiment. I used a cheap set of BMX bars to raise the handles a few inches (I prefer the “Dutch style” upright seating posture), but I wanted my hands to be rotated down to a more comfortable position. I used two cheap quill-stems from my junk-heap to make near-vertical grips, and it suited me at the time. Easy and cheap to replicate if you want to experiment too…

      • Excellent, thanks! I, too, am constantly experimenting with bars and positioning. Maybe an article sharing some of your experiments? 🙂

  2. Interesting friction drive

    • I looked at those other two units and I think they are pretty good sounding also, but I doubt they are half the weight when you include the required separate battery. The ShareRoller weighs around 5-8 pounds including battery, motor and mounting hardware depending on how large a battery you choose. I could not find the battery weight or total weight listed on the other two models, but comparing the weight of just the motor to the weight of the entire system is not a fair comparison.

      ShareRoller has a smartphone app also, and as the article mentions, was designed for bike share bikes initially. It also offers a throttle which the other two do not have, as well as the option for pedal assist.

      I think an add on friction drive is a great idea all around and there is no need to dismiss one version versus the others.

  3. I agree that all of these 3 products have finally solved many of the early problems of the friction drive but if you look at more articles and videos of the other 2 products you will see that their systems weigh a combined 1.8 – 1.9 kg (about 4 lbs.) including battery and they both are pedelec because they have to be – they originate in the EU. And the onwheel version has a throttle which allows one to operate it without pedaling. But there is the important question of aesthetics and overall drive-ability of the bike with the system installed. The other 2 products are tucked under the bottom bracket of the bike and the only part that is easily visible is the battery while the share roller is much more visible and in my opinion makes the final overall look of the bike worse. And since the share roller is on the front wheel, it doesn’t drive as well as the other 2 systems because they are mounted to the rear wheel where they will get more traction, less slip. The share roller is on the front wheel which adversely affects the overall steering of the bike because it is mounted to a steering wheel. And the steering is again affected adversely further by the total weight of the share roller system whereas the other two have much less weight on a non steering wheel. And finally, the share roller is in the front of the bike and since adversely affects aerodynamics; the others don’t because they are tucked lower and behind other bike/rider parts.

    • So as I suspected, they are not less than half the weight of the ShareRoller, and it sounds like they only have one size of battery which must be pretty small if the motor and battery together weigh 4 pounds. The ShareRoller has three different size batteries to suit different user’s needs, and the smallest unit is 4 1/2 pounds. While Jeff has responded to many of your other points in his message above with reasons why the ShareRoller approach will work as well as or even better in some respects, I will say that the fact that there are three different systems out there suggests that this is a good idea whose time has come. I hope they are all successful.

  4. A few other key points to consider when comparing ShareRoller to Add-e/Go-e:

    – ShareRoller can also power kick scooters as well as tens of thousands of bike share bikes in 15 cities worldwide. This is a huge increase in versatility, and once you try a powered kick scooter you’ll wonder how you survived without one. And of course if you live in a city with compatible bikeshare it’s an enormous plus.

    – ShareRoller is a single, small self-contained package when removed, making it much easier to carry with you into an office or restaurant for example, or in a backpack to keep with you in case you get tired while riding and want to add assist. Plus the retracting motor assembly keeps the possibly dirty motor covered and protected when not in use.

    – ShareRoller has a more advanced traction system: Add-e/Go-e use sandpaper/griptape in order to grip in the wet. This is an old-fashioned approach, and dramatically increases tire wear. Plus, the sandpaper/griptape wear out and need to be replaced. ShareRoller instead uses a custom treaded urethane belt (that lasts the life of the motor) combined with it’s RainLock variable pressure system, to work well in the rain without significantly increasing tire wear.

    – While Add/Go-e’s mounting location under the bottom bracket is less visually obvious, it has a lot of negatives for an outrunner friction drive motor. First off, the motor is vulnerable to striking things you might ride over. Second, it will get pelted by dirt, mud, rocks, and debris kicked off by the front wheel. And while these motors can be cleaned, they don’t like to be run with dirt, grit, and other junk on and inside them. So not really an optimal spot to put a motor.

    – ShareRoller has three modes of operation instead of one (or two), including standard variable throttle, a unique ‘TailWind’ cruise-control system that doesn’t require pedelec sensors, and a full pedelec setup for those that prefer that method. And in addition to smartphone integration, ShareRoller also offers a wireless throttle
    module which allows you to control all three modes of operation without needing a phone. It looks like Add/Go-e offer just standard pedelec operation, and only a smartphone app to change settings.

    – ShareRoller offers built-in bright headlights and tail-lights, as well as a built-in USB charger.

    – ShareRoller’s quick-release split battery packs are unique in that they allow you to have a large capacity battery while still being able to meet the FAA and IATA carry-on Lithium battery limits.

    – Finally, Add/Go-e use the common ‘swing-to-engage’ method of friction drive, which while having the advantage of zero-drag when not in use, makes for ‘jerky’ motor engagement, as large RPM surges are needed to swing the motor into the tire, which then ‘bites’ when it hits the tire. This also adds to tire wear, as
    the motor is often spinning faster than the wheel when it engages. ShareRoller offers this same ‘Freewheel’ option for those that use the motor infrequently and prioritize zero-drag freewheel, but also offers a separate ‘Continuous’ engagement mode where the motor is always engaged with the tire, for smoother operation when using the throttle often, or when riding in TailWind mode. For many people this is a better solution.

    – Oh, and front-wheel drive is not really a traction disadvantage vs rear-wheel drive. There are many e-bikes that use FWD. The only time that front wheel power might slip is in climbing a slippery hill, but then in that situation having a front-wheel motor plus your legs would give you two-wheel-drive, which would provide even better traction than a rear-wheel-only power setup.

    – Steering impact is barely noticeable, and no different than having a handlebar mounted basket/rack, which are quite common on many bikes. Plus the weight of the ShareRoller (4.5-7.25lbs) is less than what is commonly put in front racks. And if the aerodynamic impact of a 8″x3″ cross section device is enough for you to notice, then you must be a tour de france rider!

    So there are a lot of reasons why the ShareRoller system would be preferred by many riders, but of course each person has their own set of priorities when choosing a friction-drive system.

    • Very good points Jeff. I wasn’t aware of a few of these and they do make me want to seriously look into your product. Just one last thing about front wheel drive. I run my electric bikes at high power (>2000w) and I have never been able to get as nice a ride or as much traction on flat pavement as I do with my rear wheel drive setups. For now, the product is well suited for the share markets and I completely understand the initial motivations of the product; maybe later down the road you can offer a rear drive version.

      • Thanks Nikola, glad it was helpful! I see your point regarding traction – certainly at some high power level FWD might start to slip more than Rear – it’s the simple physics of weight transfer on acceleration. However we haven’t seen any issues with traction even running up to 1,500 Watts (on admittedly heavy bike share bikes). So I could see if you had a bike with more rear-biased weight distribution then you might see it at the 1500-2000w power level. But certainly at the 750 Watt power level it’s not an issue on any bike type. We have explored a dual-mount capable setup (front or rear) that would enable simple seatpost clamp mounting for rear-wheel use. Perhaps we will even get this incorporated into V3 before production begins!

        • Wow, that would be great if there was a rear wheel mounting version. That would expand even further the types and kinds of bikes you could use this with to include bikes with unusual configurations of the front wheel….like short wheel base recumbents where the front wheel often does not have enough clearance above the tire for this to be mounted there. Although, recumbents usually do not have a normal seat post, so it might still require a custom mount. Maybe you could design a rear rack that mounts in the same way as most rear racks, but that has space beneath the rack for the ShareRoller. Then you could still also use the space above the rack for a racktop bag or to strap on a briefcase, milk crate etc.

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