Whose numbers these are
Most of our products ship from partner suppliers, and the specs, compatibility lists and descriptions on those listings are the supplier's statements. Treat any spec or fitment list as the supplier's claim unless the listing says we checked it ourselves. When a listing says it fits a bike, that is the supplier's claim, not a guarantee. If we do not know something, we say so rather than guessing. Send us a photo first and we'll tell you what we think.
Start with the label, not the marketing
The wattage on a motor is a marketing number. What matters is on the rating label of your controller and battery: voltage (and what it reads fully charged), amps (continuous vs peak), and connector type. Photograph them before ordering anything electrical.
The three things that must match
- Voltage platform. Your battery's charged voltage must sit within what the controller accepts. A 13S (48V) pack charges to 54.6V; a 14S (52V) pack charges to 58.8V. Not interchangeable. A charger must match the pack, not the motor.
- Current. The battery's BMS continuous discharge rating must be at or above the controller's max current. Continuous, not peak. A pack that trips its BMS cuts out on climbs.
- Connector. It has to mate physically and be rated above your continuous current. This one is fixable with an adapter, so it's the easy problem of the three.
Read the full tire marking
The first number alone is not enough. Match the full marking on the sidewall of the tire you have now, and the size of your rim, to the listing. Motorcycle-style sizes such as 70/100-19 end in the rim diameter in inches. Inch sizes such as 20x4.25 on fat tire e-bikes give a nominal diameter and the tire width in inches. If you are not sure, send us a photo of your sidewall before you order.
Not sure? Send a photo.
Email us your bike's make, model and year, plus a photo of the part label or tire sidewall and the connector. We'll tell you what fits, including telling you not to buy something. That answer is free and it saves us both a return.
Disclaimer
We stand behind what we publish, but you are responsible for confirming a part suits your specific configuration. Bikes get modified and model years change mid-run. Installation is at your own risk, and working near a charged battery is genuinely hazardous. If you're not confident, use a qualified shop.
Charger safety
Match the charger to the pack. Never use one whose output voltage doesn't match your pack's configuration. Avoid universal chargers: the CPSC specifically warns consumers against them, and we don't sell adjustable-voltage chargers. Don't charge unattended or on a flammable surface, and never charge a swollen or crashed pack. General guidance, not engineering advice for your build.