24 could be made anywhere, with a labour force that is not even trained to put together motorcycles. “As a result, we are very anticomplexity. Anything that puts a failure point onto the bike we wanted to get rid of. Water cooling was something that could fail, so we got rid of that. Even a transmission is a point of failure; you have to put oil in and it fails, so we sized the bike to the very specific use case so it doesn’t require that. “It was completely optimised to a level that would be impossible with a petrol engine. It looks like a motorcycle and it has standard components – suspension, wheels, brakes – but everything about the frame and the chassis is different because we had pretty much free reign and we optimised it purely for handling and performance.” The power to perform The team worked with QS Motors to develop a custom air-cooled motor; a 72 V brushless DC unit, rated at IP67, which delivers 6500 rpm. That is coupled to a direct belt drive with a 4.7:1 ratio, giving a lot of torque but without a transmission and maxing out at 27 kW, which, Tran says, is “more power than you ever need” on this type of bike. The motor also employs flux weakening at the top end, reducing torque at high speed by allowing the motor to rotate a little faster. Most modern electric motorcycles have some sort of system such as this to help with the top speed, and given the choice of direct drive, it was especially important on Ryvid’s machines. The battery uses the same P58 cells that are found in Zero Motorcycles’ range. These are high-quality lithium-ion nickel manganese cobalt pop cells, which have very fast charging capabilities and a very high power-to-weight ratio. The unit’s total capacity of 4.3 kWh delivers 50–70 miles of range, which is the target distance for this type of bike. One of the most innovative parts of the Ryvid drivetrain, however, is not what is in it, but how it is mounted. The size of a traditional petrol engine requires it to be fixed in position on the frame, with slack built in to compensate for belt or chain stretch from the relative movement of the wheel on the swing arm; not the case with this compact electric solution. “We designed that out completely, because the motor is part of the swing arm,” reveals Tran. “It moves with the swing arm, so we’re able to stretch our belt to the exact specs and not have to compensate for the movement. That makes it basically zero maintenance on the belt–it’ll run for 60–70,000 miles before you need to replace it.” This solution has also enabled the team to design out the squatting effect often experienced on a motorbike, which tends to shift the centre of gravity and affect handling and acceleration. Tran adds: “The anti-squat design effectively counteracts the force of the wheel and the bike stays completely level throughout acceleration.” In innovation, copying is a form of flattery and, on that basis, Ryvid has clearly done things right because the new Can-Am Pulse and Origin bikes, which have recently been launched, follow the same route of having the motor built into the swing arm. No doubt, over time, other manufacturers will follow suit but, as Tran proudly claims, “Ryvid was first!” The air-cooling solution is another innovation Ryvid has pioneered on its bikes, helped by Tran’s background in aviation. The team clocked up hours and hours of computational fluid dynamics work on aerodynamic solutions and the result is a precision-designed airflow regime, which aims to keep the battery and motor at optimum temperature for the bike’s full range. “The design is enabled by the simple electric drivetrain because there is nothing to get in the way,” explains Tran. “We have custom fins that pop up in the direction of airflow. The battery has an inlet at the front, the air goes through the casing and out of small vents on the side, then it comes right through the side panel and tucks into the motor. “The motor casing was designed with special cooling fins that are upright, and they catch the air. Essentially, we cool the battery, then cool the motor, and then it shoots out the back and does some pretty interesting aero effects. If we max out at full throttle the whole time, the motor will never overheat–and that was the simple design requirement.” May/June 2025 | E-Mobility Engineering The battery is designed to be compact and removable
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