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170 mm Square Taper Single Crankset, 44T with Chainguard (generic)

The typical hub-motor e-bike has a single front chainring on a square-taper crankset, and when a crank arm strips or the chainring wears hooked, the replacement is a generic 170 mm alloy crankset with a 44T or 46T ring and a plastic chainguard. These are sold by many sellers and are functionally interchangeable. The important checks are square-taper bottom bracket (not Octalink or Hollowtech), crank length, and chainring size; keep the same tooth count to preserve your gearing. A square-taper crank puller is needed for removal.

Replacing a stripped crank arm or worn chainring on a hub-motor e-bikeBikes with a square-taper bottom bracketBudget repairs

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Key considerations

Confirm square-taper spindle; note whether the old crank used a JIS or ISO taper (JIS is common)
Keep chainring size close to original to avoid chainline and derailleur issues
PAS magnet disc must still fit on the spindle next to the crank
Needs a crank puller and a 14 mm socket or 8 mm hex

Pros

Cheap and available
Chainguard protects pant legs
Direct fit on most budget e-bikes

Considerations

Generic quality and finish
Not for mid-drive motors
Taper variants

Features & specifications

Crank length	170 mm
Chainring	44T

Specifications are manufacturer-published figures or our own notes; confirm on the current listing before purchase.

Compatibility notes

Square-taper bottom brackets on hub-motor or non-motor bikes; not for Bafang mid-drives or ISIS/Hollowtech systems

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Similar alternatives

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Cranksets

Shimano BB-UN300 Square Taper Bottom Bracket

The UN300 is the sealed-cartridge square-taper bottom bracket Shimano sells as the successor to the long-running UN55 and UN26, and it is the right replacement for the creaking, gritty bottom bracket on most hub-motor e-bikes. It comes in several shell widths (68 and 73 mm are common) and spindle lengths, so you need to measure or read the old unit. Installation needs a splined bottom-bracket tool. Once in, it is a fit-and-forget part — which is exactly what you want on a commuter that gets ridden in the rain.

Best for: Fixing a creaking or loose bottom bracket on a square-taper bike · Pairing with a new square-taper crankset · Hub-motor e-bikes with standard threaded shells

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Pedal Assist Sensors

12-Magnet Cadence PAS Sensor, Dual Hall (generic)

The 12-magnet cadence sensor is the standard pedal assist pickup on hub-motor kits: a magnet disc that slides onto the crank spindle and a small sensor bracket that mounts against the bottom bracket. Dual-hall versions sense pedaling direction, so assist stops when you back-pedal. Twelve magnets give faster response than the old 5- or 8-magnet discs. Most use a 3-wire lead with either a Julet waterproof plug or a small SM plug. Installation is the fiddly part: the crank usually has to come off, and on some bikes the disc needs to be the split type.

Best for: Replacing a broken or intermittent PAS disc on a kit bike · Upgrading a slow 5-magnet sensor to 12-magnet response · Builders who want assist to cut when back-pedaling

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E-Bike Chains

KMC Z7 Chain (6/7/8-Speed)

The KMC Z7 (formerly labeled Z51) is the standard replacement chain for 6-, 7- and 8-speed drivetrains, which covers most hub-motor e-bikes. It is an inexpensive chain that includes a reusable quick link, so installation needs only a chain breaker to size it. On an e-bike the chain carries only your pedaling load with a hub motor, so a basic chain like this lasts well; with a mid-drive you should step up to an e-bike-rated chain. Measure your old chain for length and replace the freewheel if the old chain was badly worn.

Best for: 7-speed hub-motor e-bikes · Budget drivetrain refreshes · Riders who want a quick-link install

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