At last weekend’s Tweedlove Festival, an Orange Phase MX Strange – their name for any bikes under early stage prototyping – was attracting its fair share of attention thanks to the drivetrain it was sporting. Correction – the powertrain – it was sporting. Indeed, the Phase MX was home to the latest prototype from Intradrive, a Gearbox Powertrain manufacturer based in Edinburgh, Scotland. It is an 8-Speed system that combines the motor and transmission into one unit, inside a housing that shares the same fitment as a Shimano EP8 Motor.
Intradrive 8-Speed Gearbox eBike Motor
Intradrive Ltd is looking to secure further investment to fund the final push to market for its innovative 8-Speed powertrain. We got a quick look at an earlier prototype at EuroBike, again on an Orange Phase MX, but this latest one is a little smaller; only by around 5-10%, but importantly it allows for better integration with the Shimano frame bracket, resulting in much cleaner lines. It now has a much wider gear ratio, too.
While the competing 7-Speed powertrain from Valeo offers a 450% gear range, Intradrive’s 8-Speed System delivers a 470% gear range. And, it is a lot more pleasing to look at, largely due to the fact that it is around 50-60% smaller.
A 470% range is a way off the range offered by the widest 12-Speed Drivetrains and Transmissions available today, but is wider than most 11-Speed Drivetrains.
I am comparing apples with oranges here; clearly, the combination of a gearbox and transmission into one single, sealed unit, has a number of advantages over any transmission that relies upon a rear derailleur. I’m sure you don’t need me to tell you those are indisputably vulnerable to rock strikes, but on eBikes, they are also vulnerable to poorly timed gear changes, often unable to shift under the high loads that come with a motor.
A number of boutique brands have dabbled in the use of a gearbox – Deviate and Instinctiv spring to mind. While a gearbox has low maintenance appeal, and the advantages of reduced unsprung mass, the additional drag that comes with the spur gears has hindered the transmission’s widespread uptake. On an eBike, that additional drag is sort of a moot point. Arguably, you aren’t going to notice it when you’ve got the support of a motor.
Moving on to more reasonable comparisons, let’s just marvel at how Intradrive has managed to squeeze an eBike Motor and an 8-Speed Gearbox into more or less the same footprint as a Shimano EP8 Motor; the latter having no transmission, of course. It is heavier, as you might expect – claimed weight is 4.5 kg without cranks.
The production Orange Phase MX runs the Shimano EP8 Motor, so serves as a nice comparison.
It does, however, require use of a chain tensioner to allow for the chain growth that occurs as the rear wheel is pushed through its travel.
Ahead of the Tweedlove Festival, we sat down with Intradrive Founder, Mark Ravilious, to learn more about the company, the system’s innovative technology, and what the next steps are before this powertrain makes it to market.
Headquartered in Edinburgh, Intradrive is made up of a team of five, and the company is majority employee owned.
Founder Mark is a mechanical engineer, who has previously been involved in developing wind turbine technology. He also has a bunch of practical experience in welding and fabrication. Then, there’s Craig Gault, the System Engineer who joined in 2020; he is another trained Mechanical Engineer with previous experience in the robotics industry. Jonathan Nicholson is the team’s third Mechanical Engineer, with over 15 years experience in the wind, wave energy and energy storage sectors. Finally, we have Steven Shand (the founder of Shand Cycles), coming in as the Business Development Manager, and Peter Slotwinski, the Project Manager with an electrical engineering background.
All involved are keen mountain bikers, and share the goal of making a durable powertrain that is built to last, is maintainable, and has a minimal environmental footprint. Indeed, Intradrive has adopted a circular economy model, drawing inspirations from the likes of Fairphone and Patagnoia.
Details on the powertrain’s novel technology are thin on the ground, which is reasonable to expect given that Intradrive’s motor unit hasn’t yet made it into the market. However, we can tell you that, as with any gearbox, the Intradrive’s drive unit uses hardened steel spur gears are protected from the elements within a sealed, oil-lubricated enclosure.
The patent-pending sequential gear change mechanism uses an electric actuator housed inside the gearbox to achieve rapid and consistent shifting performance. Power is then transferred to the rear wheel via a heavy duty chain, or a belt like the Gates Carbon Drive seen on the Phase MX Strange. We are told the steps between gears are relatively consistent at around 18-20%.
Intradrive plan to furnish OEM customers with the full eBike package; the combined motor-transmission unit, a 500 Wh or 630 Wh battery, display and controller, speed sensor and shifter. The batteries match the capacity of Shimano’s offerings, and they use the same mounting system, but importantly, they are not actual Shimano batteries; they would be incompatible.
Intradrive’s powertrain has a peak power of 500 Watts, translated to the rear wheel via a heavy-duty single-speed chain and sprocket, or a belt system like the Gates Carbon Drive shown throughout. As shown here, it runs a 56mm chainline.
While the Valeo eBike Motor-Transmission offering boasts an auto-shift function, the latest prototype of the Intradrive’s powertrain does not. Mark says this can be implemented, however, if the demand arises.
We asked Mark about what engineering challenges are still to be overcome prior to production. He says, “All the major technical challenges have been overcome. Most of the work now is testing to validate lifetime, and building supply chain”.
Clearly, the Intradrive’s powertrain lends itself well to eMTB, but we wondered how versatile the system would be in regard to use in other applications. We asked Mark what kind of bikes he expects the powertrain to perform best for. He says, “eMTB, eCargo… e.g., anywhere where durability and low maintenance in heavy duty use is important. However. our drive is suitable for many applications including commuter bikes”.