How we choose a part

Every part on this page has to clear three doors before it goes on a shelf. Door one is voltage: controller, display, and battery all have to agree on nominal pack voltage — there is zero tolerance here, unlike wattage, which is mostly a heat-dissipation rating rather than a hard electrical limit. Door two is current: a controller's rated amperage only needs to sit at or above what the motor and battery can push; buying a higher-current controller and dialing it down in software is a normal, safe move, the reverse is not. Door three is protocol: a controller and a display have to speak the same language at the data layer — KT, No.2 UART, APT, and Bafang UART/CAN are not interchangeable even when the physical plug looks identical, and "it plugs in without an error" is not the same as "it communicates."

Once those three line up, two more checks decide whether a part actually threads onto a given bike: the connector (shell shape plus pin order — an outwardly identical 9-pin motor plug has been documented wired differently across brands, and even across production batches of the same model) and physical size (a higher-current controller is a bigger box; a 35A-class unit commonly needs an external mounting bracket that a 20A-class unit never does). We list what we can confirm for each of those five checks per model below, and mark anything we could not verify instead of guessing at it.

Source: controller+display technical briefing (engineering handoff notes, sections C–E) · our Bafang kit teardown notes §2, §5.

Bafang UART controllers

These are Bafang's own conversion-kit-side controllers — the UART half of Bafang's protocol split. Bafang's CAN-protocol controllers are built for sealed OEM bicycle platforms and are a separate line, not listed here. Every row below carries an explicit UART tag in its own portal spec line, not an inference drawn from the model name alone.

Source: parts catalogue (our parts catalogue, Bafang distributor catalogue, UART-tagged Controller rows) · our Bafang kit teardown notes §2.2 (protocol split).

Bafang displays

All seven displays below report UART or CAN explicitly on their own portal spec line — protocol here is read, not inferred. Bar-clamp diameter is not published at this line of the Bafang distributor catalogue for any of these, so that column reads NA across the board; confirm on the physical unit before ordering if clamp size is the deciding factor.

Source: parts catalogue (our parts catalogue, Bafang distributor catalogue, Display category).

Harnesses & extension cables

Two families live here: the 1T4/1T5 main harness that fans a controller's EB-BUS output out to the display, throttle, and both brake levers, and 9-pin motor extension cables that lengthen the run between a hub motor and the controller. A harness carries no protocol logic of its own — it just follows whatever the controller and display on either end are already speaking — so the "protocol family" column below reads NA on purpose for most rows, not because the data is missing.

Source: parts catalogue (our parts catalogue — EB BUS Cable, Motor Cable, and Cable/Harness rows across the Bafang, Amazon, and EcycleMD listings) · our connector library.

Sensors, throttles, brake levers

Pedal-assist (PAS) and torque sensors are sized by bottom-bracket shell width, not by voltage or current — a 68mm-shell sensor and a 100mm-shell sensor are not interchangeable even within the same product family. Brake levers on this page are the cut-off type: squeezing the lever opens or closes a small signal circuit that tells the controller to stop driving the motor. That logic comes in two opposite flavors — normally-open (NO) and normally-closed (NC) — and wiring the wrong one in is a real hazard, not just an inconvenience: either the bike gets no power at all, or worse, the motor keeps driving while the brake is squeezed. We mark a row unverified rather than guess which logic a given listing uses.

Source: parts catalogue (our parts catalogue — Throttle, Cadence Sensor, Torque Sensor, Wheel Speed Sensor, and Brake Sensor/E-brake rows) · our connector library (brake NO/NC logic).

Hub motors & wheels

Bafang rows below are bare motors, sold to be laced into a wheel; EBikeKit rows are factory-laced complete wheels. Dimension strings in the "physical size" column are transcribed directly from the Bafang portal's own spec line — we translate the diameter symbol and the multiplication separators for readability but do not decode each number's meaning field-by-field, since not every digit's role is confirmed in our records. Treat them as a comparison fingerprint between motors, not as fully labeled dimensions, until bench-confirmed.

Source: parts catalogue (our parts catalogue — Hub Motor rows, Bafang portal and E-BikeKit exports) · our Bafang kit teardown notes (dropout/OLD terminology).

E-BikeKit parts

These come from the E-BikeKit portal, which publishes far less spec detail per item than the Bafang portal does — no voltage, current, or protocol name on any of the six listings below. That is not a gap in our extraction, it is what the vendor's own product feed contains. The "connector" values below describe the battery-side option named directly in each listing's title.

Source: parts catalogue (our parts catalogue, EBikeKit distributor catalogue, Controller and Display categories).

Universal self-learning electronics packs

These three are generic controller+display kits built around a self-learning wiring routine rather than a locked, motor-specific program. The standard action across this family: power on the display, pick an assist level above zero, then briefly short the controller's dedicated learning-wire pair — the wheel spins on its own as the controller cycles through phase/Hall combinations. If it spins backward, disconnect the learning wire and re-short once to relearn. Never twist the throttle while the learning wire is connected.

Source: parts catalogue (our parts catalogue — AMZ-B07RRWWJQQ, AMZ-B0B31953Y6, AMZ-B0GS52F76V) · research on self-learning controller wiring and protocol-family mapping.

In-house stock parts

This is a fixed, non-restocked batch of factory electronics pulled from documented factory bills of materials, not a generic aftermarket run. Rows below are exact factory replacements for the model line(s) named in "fits which bikes," sold as a same-model swap rather than a universal part.

Source: in-house parts inventory log (electronics section) · factory bill-of-materials deep-read (six-model electrical spec table) · controller+display technical briefing (engineering handoff notes).

What we don't stock

Three categories are off this page on purpose, not by oversight.

• Batteries. Pack chemistry, BMS matching, and charge-port wiring sit in a different risk and liability category from a controller or display swap, and a wrong pairing here is a fire-safety issue, not just a compatibility one. Route a battery need to a dedicated pack-rebuild shop or the bike's original brand.
• Closed or encrypted CAN-bus OEM electronics. Bosch, Shimano, Yamaha, Specialized, Trek, and VanMoof mid-drive systems, Super73's proprietary CAN platform, Aventon's ACU-generation electronic pairing lock, and some 2021-and-later Rad Power models run a handshake an aftermarket controller or display cannot join — plugging in without an error is not the same as communicating. Route these back to the original brand's dealer or service network.
• Complete mid-drive conversion kits. We do carry Bafang's own BBS-family replacement controllers (see the UART table above) for bikes that already have a BBS01/BBS02/BBSHD mid-drive installed, but we don't sell a from-scratch crank-motor conversion kit — the bottom-bracket fit, chainring interface, and torque-sensor pairing involved make this a frame-specific job better handled as a full kit purchase from a mid-drive specialist.

Source: controller+display technical briefing (engineering handoff notes, closed-CAN platform list) · how-we-diagnose.html Step 0 hard-blocker list.