Flywheel | June 27, 2022
Featuring the top 5 used vehicles of the week and exploring how to make sense of ebike power and torque ratings
Welcome to Flywheel, a weekly exploration of the used side of owned micromobility. Each newsletter will highlight five of the most interesting used vehicles being sold in the market followed by an observation of trends emerging in the industry.
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This week’s features are a mini commuter, a long-tail cargo bike, a folding fat-tire, and two urban cruisers/commuters. The observation of the week explores how to make sense of ebike power and torque ratings.
Top 5 Vehicles of the Week
The Riese & Müller Tinker Vario is a class-1 mini commuter e-bike that’s a great portable option for everyday urban riding. Despite its small stature, the Tinker Vario rides as smoothly as larger commuter ebikes (largely due to its 20” wheels, Enviolo continuous hub gear with Gates belt drive, and front fork suspension) while still being compact enough to fit into the trunk of a car or next to you on public transit. The powertrain features Bosch’s 50Nm Performance CX motor and a 500Wh Bosch battery pack, giving riders plenty of torque and range for most commutes. This listing has a fair bit of mileage at 1800 miles, but it seems to be well taken care of and regularly serviced. This listing is also very well authored, with the seller providing information on where the vehicle was bought and serviced. These are useful details that allow buyers to verify vehicle health and ownership information and give buyers a go-to for all future maintenance. Listing can be found here.
The Tern GSD S10 is a class-1 longtail cargo bike and my personal favorite cargo bike. The GSD S10 actually has a shorter wheelbase than most longtail cargo bikes, which combines nicely with its small 20” tires and low center of gravity to make it much more agile and maneuverable than the average cargo bike. It can even be fit into most cars because its handlebars fold down. The GSD S10’s powertrain features Bosch’s 85Nm Cargo Line Motor and 400Wh battery pack. Although this provides a relatively low range, the motor torque is more than sufficient for the average rider to tow two kids or potentially even a second adult passenger on flatter routes. This listing has a higher usage than most used ebike listings at 3187 miles, but this is still a relatively low mileage given what Bosch motors and battery packs are rated for. The seller is also including a front rack, passenger seat, and passenger foot pegs. Listing can be found here.
The Luna Eclipse is a class-3 budget fat-tire folding ebike. Selling new at $1,400, the Luna Eclipse has a number of features that defy its price tag. The powertrain consists of a 500W Bafang geared hub motor and 672Wh battery pack, the vehicle has full suspension, and the drivetrain uses a Gates CDX belt drive that’s almost never found on ebikes in this price range. One interesting thing that Luna does with the Eclipse is that it actually uses its double power motor controller to run 1000W through the 500W motor. This combined with motor’s 80Nm torque rating allows the Eclipse to have some of the same acceleration and torque as scrambler style e-bikes (i.e. Super 73 and Juiced) while using motors and batteries that are half as powerful and half the cost and size. This listing is virtually new, with only 50 miles of usage. Listing can be found here.
The Bulls STURMVOGEL E EVO is a class-1 urban cruiser that stands out as a premium build ebike that feels similar to riding a pedal bike. The STURMVOGEL’s powertrain features a 250W Brose motor and a ~650Wh battery pack, with the Brose motor being a particularly exceptional feature on the STURMVOGEL. The Brose actually uses an internal belt as opposed to direct-drive gearing, which reduces vibrations in the motor unit and makes the assist so smooth that many reviewers say that they often forget the bike is actually electric. It’s also a motor with a 90Nm torque rating, which is way more torque than the average urban ebike and is actually more akin to something that’s found on a performance e-mountain bike. One con with this vehicle is that its transmission is manual, unlike the automatic shifters we’ve seen on most ebikes released over the past few years. This can make it a bit difficult to bring the STURMVOGEL up to its max speed, especially considering that the motor also draws fairly low power. This listing is in excellent condition with 150 miles ridden, and was only used sporadically as the seller’s second vehicle. Listing can be found here.
The Analog Motion AM1+ is a class-1 commuter designed for riders looking for a single-speed fixie style ebike. This ebike is engineered for agility; the narrow chassis, forward leaning rider position, and feather-light weight of 34.5 lbs allow riders to lean and turn on a dime. Even the battery is shockingly light at ~2lbs and is portable enough to slip into your backpack or carry as a spare. Although the battery is only rated for 125Wh, it combines nicely with the 250W motor and light weight of the bike to give riders a range of ~15 miles at a top speed of 15.5mph. The AM1+ is an upgraded version of the AM1, featuring disc instead of rim brakes and a few other minor accessory improvements. Disc brakes aren’t really that much better than rim brakes for this vehicle given its low weight and speed, so it’s usually not worth the extra $200 to buy a new AM1+ over an AM1. However, this specific listing has a very low mileage and is selling for a lower price than the average AM1. Listing can be found here.
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Observation of the Week
Making sense of ebike powertrain performance ratings
On this week’s observation, I wanted to discuss about an excellent question/pain point I recently received from Flywheel subscriber Robin Sloan on how to make sense of ebike powertrain performance ratings:
“I find that I have a difficult time making sense of power and torque ratings and what they would actually feel like. I have only test-driven two bikes total, which were very different, but not enough to give me a comprehensive sense of what X Watts or Y Newton-meters feels like -- it might not be possible to put into words, or a chart, or anything -- but I will just say as a shopper, that's something that's vexing me currently!”
At a high level, motor power ratings tell you very little about the performance of an ebike. Power ratings are used as an attempt to provide an electric analog to horsepower, as power is an indication of how much work a motor can do. However, electric motors are limited by heat dissipation, which is really a factor of how long a motor is on and the ambient temperature. This means that even if a motor is rated as 250W, it is capable of and often runs significantly higher power for short increments of time (i.e. when accelerating from stop, going up an incline). The power rating of a motor is also dependent on the motor controller and battery pack, so the same 250W motor could run very different power levels based on what motor controller and battery its connected to.
Torque is a better metric to compare motors, since its a measure of the force a vehicle expends onto the road and ultimately gives an idea of the acceleration of the vehicle. However, a singular torque rating isn’t particularly useful either because the work that a motor can do, or its power, is actually a product of torque and motor RPM. Ultimately, to be able to effectively assess the performance of different motors or vehicles, micromobility manufacturers need to publish torque vs RPM curves that can be overlayed and used to compare the power different motors can output at different RPMs. The automotive industry publishes similar torque vs RPM curves, and these charts are a critical tool when benchmarking the performance of cars against one another.
That being said, a torque vs RPM chart alone doesn’t help consumers understand what riding a vehicle actually feels like. Therefore, its equally important that manufacturers also publish practical examples of the work their vehicles can output. A great example of a manufacturer that did this is Boosted Boards, which used to publish its vehicles’ grade capability. Grade capability is a spec that indicates the % incline a rider can climb given a certain payload (i.e. a 170lb person can climb a 20% grade at 15mph).
Until this happens, a consumer’s best way to assess performance of vehicle powertrains is unfortunately limited to test riding vehicles and looking at reviews from other riders to see if the vehicle is adequately suited to their use-case and needs.
As an aside, this conversation also points out how regulations governing the max power or max torque of micromobility vehicles don’t really make sense. Regulators should really be governing mass and max speed. Mass and speed determine momentum, which can be thought of as an object’s resistance to stop. This is ultimately the most important thing to consider when defining the safety of a vehicle, especially in the context of those around it.
That’s it for this week. Thanks again for joining, see you next week!
- Puneeth Meruva
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