Bafang M620 Ultra

The offer

What Bafang M620 Ultra actually is

Bafang M620 Ultra is one configuration from Bafang, made in China, filed here as a mid-drive. The family is M, generation Catalogue. Torque-sensing Ultra mid-drive. 1000 W nominal, peak around 1500 W in retail listings, 160–170 Nm, about 6.7 kg.

In the box, as this record has it: M620 motor, Controller, Display, Crank hardware. Still required before the bike moves under its own assist: Matching bottom-bracket shell, High-current battery. A cheaper advert for the same family name is not this list. If the battery, the charger or the throttle differs, it is a different configuration and it gets a different page.

A full-power mid-drive. Not a 250 W street motor.

The price on the card is the maker’s published figure in USD, or Maker list when no figure was published. Allowances for a missing pack, a charger and workshop time sit in the complete-cost band. They are not a second product and they are not a promise that a random pack will talk to this controller.

The bicycle

The frame this motor is asking for

Bafang lists Bafang M620 Ultra against Mountain, Cargo bicycles, for Hills, Load carrying. Wheel sizes on the card: 700c, 26, 27.5. The mechanical interface is BSA 68–73 mm. Brakes are disc.

A mid-drive takes the bottom bracket’s job. The shell width, the thread or the press-fit standard, and the chainstay clearance decide it. The bike’s own gears then multiply whatever the motor puts into the chainring, which is why a modest continuous rating can still climb if the shell is the right one.

Pedals stay. This configuration is a bicycle with assistance, not a motorcycle conversion. Sensor on the card: combined. Cut-off on the card: not stated. Throttle: not fitted.

The numbers

1000 W is not the whole story

Continuous rated power for Bafang M620 Ultra is 1000 W. Claimed peak is 1500 W. Torque is 160 Nm. 160–170 Nm depending on the listing. Motor mass is 6.7 kg. System mass, once the named parts are on the bike, is M620 motor, Controller, Display, Crank hardware.

Peak is a short claim. Street rules, including the Great Britain check on this site, use continuous rated power and the speed at which assistance stops. A controller that can be unlocked does not change the record of the motor as sold. Bafang M620 Ultra is filed in the Off-road class: Above street classes. Private land and closed courses.

Off-road on this site means the published rating sits above the ordinary street classes. It is for private land and closed courses unless a specific controller is sold as a limited street version. That limited version would be its own page.

Pack and charger

The motor is not a finished electrical system

Bafang M620 Ultra is sold as a motor. Voltage class is 48 V. Energy in this offer: no watt-hour figure in this offer. No battery model is invented to fill the gap. The complete-cost band holds an allowance so a finished bike can be budgeted without pretending a pack was included.

The charger follows the pack, not the motor slogan. Budget the charger once the pack model is fixed. Similar voltage, a connector that happens to fit, or the word universal is not a match. The controller in Included controller expects the pack the manual names.

If you already own a pack, the workshop question is the continuous discharge rate, the connector pinout and whether the battery management system will talk to this controller. Those three are not on a watt sticker.

Mid-drive

How Bafang uses this layout

Mid-drive. Bafang M620 Ultra sits at the bottom bracket and drives a chainring, so the bicycle’s gears become the motor’s gears. Climbing in a low gear is the point. Spinning a tiny ring on the flat, at the motor’s expense, is how chains and cassettes die early.

The shell on this record is BSA 68–73 mm. Press-fit, a worn cartridge, or a carbon shell with a hopeful adapter is a workshop measurement, not a yes from the listing. Chainline is the quiet failure: the chain climbs, the stay rubs, the clutch chatters.

The sensor is combined or otherwise not a plain cadence switch. Treat the manual’s description as the one that counts.

The workshop

A workshop path, written as a sequence

Bafang M620 Ultra is a workshop install in this record. Doing it yourself does not rewrite the path into a pass. It means the documented route was not the one you took, and the result stays conditional until someone competent has seen the bike.

Warranty as published: Maker warranty. Term is on the invoice.. Labour in the cost band is separate from the offer. A brake service the bike already needed, a new chain, or a hanger alignment is not folded into Bafang’s price to make the total look neat.

The sensible order is measure, then mount, then connect, then the first assisted roll in the stand. Connectors are keyed for a reason. The torque arm, the axle nuts and the connector boots are one inspection at the end, not three trips.

After it is on

The first month, and the parts that wear

Chains and cassettes wear faster because the motor can hold a high torque in a small gear. Shift before the load spikes. A worn cassette is a workshop line, not a reason to suspect the motor first. Keep the chainring that shipped with the kit until you have a reason, in writing, to change the ratio.

Keep the named charger with the pack you actually fitted. Store the pack cool, part-charged if it will sit, and not in a hallway that is your only exit. Bafang’s display, if one is included, is paired to this controller generation. A screen from the next family is not a spare.

My Garage on this device can hold the configuration, who fitted it, and what was still open. That note is for you and for the next workshop. It is not a certificate. If a later notice lands on this configuration, the record is where it should show.

Read next to it

• Bafang BBS02BBafang · Mid-drive · Off-road
• Bafang BBSHDBafang · Mid-drive · Off-road
• Bafang BBS01Bafang · Mid-drive · 25 km/h
• Bafang rear hub 250Bafang · Rear hub · 25 km/h

From the library

• What a conversion kit actually includesA motor wheel and a complete system are not the same product. The page should say which one you are looking at.
• Watts, torque, and the sticker that does not mean rangeContinuous watts, peak watts and newton-metres describe different moments. Mixing them is how a listing looks twice as strong as the motor you will live with.
• Speed classes, from 25 km/h to off-roadThe class is a property of the kit as sold. The road you may use it on is a property of the country, and sometimes of the state or the canton.
• Bottom brackets: 68, 73, and the shells that are not BSAA mid-drive does not sit beside the bracket. It becomes the bracket. Width and thread are the fit.
• Cadence sensing and torque sensingOne motor notices that you are turning the pedals. The other notices how hard. The ride, the wiring and the price all change with that choice.
• Cargo bikes and longtailsThe motor is the easy part. The chain, the brakes and the length of the frame are the job.