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MUSELK 1T4 Wiring Harness
1T4 waterproof cable · display, throttle, 2 brakes · 137 cm

MUSELK 1T4 Wiring Harness for BBSHD

A waterproof 1T4 cable that links a Bafang BBS01, BBS02 or BBSHD motor to the display, the throttle and two brake cutoffs. At 137 cm it is the longest of the three BBSHD harnesses here, and it is compact and light enough to carry as a spare.

  • FitsBafang BBS01, BBS02, BBS02B, BBSHD
  • Length137 cm (53.93 in)
  • BranchesDisplay, throttle, two brakes
  • BuildWaterproof, compact, lightweight
  • ColorBlack
Made for
  • Builds where a 51-inch harness comes up a few inches short
  • Tourers and bikepackers who want a light spare harness in the kit
  • Riders replacing a damaged UART BBSHD harness on a budget
Pass if
  • Bafang CAN-bus kits, which use different wiring
  • Buyers who want every connector's pin count published before ordering
  • Tandems or long cargo bikes that need far more than 137 cm
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The extra three inches that rescue a tall-stem build

MUSELK's 1T4 measures 137 cm, or 53.93 inches, from end to end. The other two BBSHD harnesses here both run 51 inches, so this one gives roughly three inches more. That sounds trivial until you are holding a display branch that stops just short of the mount, with the bars turned to full lock pulling the cable tight.

The builds that run out of length are predictable:

  • Tall stems and riser bars on commuter and cruiser conversions, where the cockpit climbs well above the head tube.
  • Large frames with long downtubes, where the motor sits further from the head tube.
  • Swept-back bars that pull the display position rearward, away from the split point.
  • Frame bags that fill the main triangle and force the cable to route around them.

Three inches does not solve every case. A long-tail cargo bike or a tandem may need an extension cable on the motor side. But for a standard frame that is just slightly too big for a 51-inch harness, the MUSELK is the simple fix, and on a normal frame the spare length coils neatly under a velcro wrap at the head tube.

Measure with the bars turned. Run a string from the motor's main plug along the downtube, around the head tube, to the display mount, then turn the bars to full lock both ways. Add a few inches for a relaxed loop. That number, not the frame size, decides which harness fits.

Fitting the motor itself to wide 100 mm and 120 mm shells is covered in the BBSHD fat bike guide.

Tech specs

By the numbers

SpecValue
BrandMUSELK
Cable type1T4 handlebar harness
Compatible motorsBafang BBS01, BBS02, BBS02B, BBSHD mid-drives
SystemUART display generation (1T4 layout)
Length137 cm (53.93 in)
Display branch1
Throttle branch1
Brake branches2
WaterproofingWaterproof cable
SizeCompact and lightweight
ColorBlack
DurabilityHigh-strength build for long-term use
Motor power rangeAny BBS-series power; the harness carries signals, not motor current
In the boxOne 1T4 cable

Finding a dead branch by elimination before buying a new harness

A new harness fixes a damaged harness. It does not fix a bad throttle, a stuck brake lever or a failing display, and all of those produce symptoms that look like harness trouble. A few minutes of elimination at the bike tells you which part to replace, and whether this cable is the right purchase at all.

Work through the handlebar parts one at a time with the battery on:

  1. Unplug both brake leads. If assist comes back, a lever switch or sensor is stuck closed; replace the lever, not the harness.
  2. Unplug the throttle. If a phantom surge or an error disappears, the throttle is the culprit.
  3. Wiggle the harness at the head tube and near the motor plug while watching the display. Flicker or cutouts point to broken wires inside the jacket.
  4. Inspect every connector for green corrosion, pushed-back pins or water inside.
  5. Swap the display if you have a spare. A communication error that persists with a known-good display points back to the harness or the motor plug.

Two symptoms point strongly at the cable itself: problems that change when you move the bars, and several handlebar parts failing at once. The throttle, both brakes and the display all share this one cable, so a single break can take them all down together.

  • Display dead and throttle dead together: suspect the harness or its motor-side plug.
  • Only the throttle dead: test the throttle first.
  • No assist with a lit display: test the brake cutoffs first.

Faults that start inside the motor belong to the BBSHD controller guide.

Range check

Its spot in the range

BBSHD mid-drive kit models by type, September 2026. Highlighted: MUSELK 1T4 Wiring Harness.

A light spare harness in the frame bag for long tours

MUSELK describes this cable as compact and lightweight, easy to carry. For a day ride that hardly matters. For a week of bikepacking on a BBSHD fat bike, or a long commute through winter slush, a spare 1T4 is one of the few electrical parts worth carrying, because a single torn harness stops the whole handlebar side of the system.

The failure that strands riders is usually mechanical. A crash twists the bars and yanks the harness across the stem; a bag strap rubs through the jacket over a few hundred miles; a zip tie cuts in at the head tube. Without the harness, the display will not power on, and on most Bafang setups the motor will not run without it.

  • Pack it coiled in a zip bag so the connectors stay clean and dry.
  • Carry side cutters and a few zip ties for the swap.
  • Practise once at home. Knowing which plug goes where is faster than learning it in the rain.
  • Cap the connectors or grease them lightly before storage to keep corrosion off the pins.

On the bike, protect the main harness at the spots that wear first. A short length of spiral wrap where the cable passes the head tube stops rubbing from the fork crown and frame bag. Keep the split point high and dry, close to the bars, so spray from the front tire does not sit on the joints.

The waterproof jacket handles rain. Mud packed around a connector is a different matter, so rinse and dry the joints after a wet ride rather than leaving grit to work into the seals.

Other options

Also worth a ride

Fully documented connectors1 E-Mangue 1T4 Wiring Harness
E-Mangue 1T4 Wiring Harness
E-Mangue's 51-inch 1T4 lists an 8-pin controller plug plus 5-pin and 3-pin handlebar plugs, labelled for UART kits.
  • Wiring and programming
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Built for special bikes2 Zeekpowa 1T4 Wiring Harness
Zeekpowa 1T4 Wiring Harness
Zeekpowa's 51-inch 1T4 is aimed at trikes, cargo and tandems and names gear-sensor use for its cutoff ports.
  • Wiring and programming
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Test the throttle first3 E-Mangue Thumb Throttle
E-Mangue Thumb Throttle
E-Mangue's 3-pin female thumb throttle is the cheaper fix when only the throttle branch has gone dead.
  • Plug-in control part
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Checking fit yourself when the documentation is thin

Of the three BBSHD harnesses here, MUSELK publishes the least detail. It gives the length, the waterproof build and the four branches: display, throttle and two brakes. It does not list the pin count of each connector, and its wording about fitting BBS01, BBS02 and BBS02B controllers as well as hub controllers is broader than a Bafang 1T4 layout supports.

Read that last claim narrowly. The 1T4 layout belongs to Bafang's UART BBS-series systems. A hub-motor controller that uses the same Bafang connectors may accept it; a hub controller from another maker will not. Check the plugs, not the marketing.

  • Choose MUSELK when your measured route is just over 51 inches, or you want a light spare.
  • Choose the E-Mangue 1T4 if you want the 8-pin, 5-pin and 3-pin counts confirmed before you order.
  • Choose the Zeekpowa 1T4 for trikes and cargo builds where you plan a gear sensor on a cutoff port.

To confirm fit without a spec sheet, compare photos of the connectors against the plugs on your own bike. The display branch should mate with your UART display's 5-pin plug, the throttle and brake branches with 3-pin Bafang-style connectors, and the trunk with the motor's main cable. If your display is a C961, C965, DPC18, 500C or 850C, you are in the right system.

If the connectors on your display look different, you may be on Bafang's CAN-bus system, and the BBSHD display guide helps identify it.

Build Q&A

Fitment Q&A

How much longer is this than the other 1T4 harnesses?

It measures 137 cm, about 53.9 inches, against 51 inches for the E-Mangue and Zeekpowa harnesses. That is roughly three extra inches.

Will it work on a hub-motor e-bike?

Only if that system uses the same Bafang connectors. The 1T4 layout belongs to Bafang's UART BBS-series mid-drives, so check the plugs before ordering.

How do I know my harness is the problem?

Unplug the brakes and throttle one at a time and wiggle the harness while watching the display. Faults that change when you move the bars, or several parts failing at once, point to the cable.

Is it waterproof?

The cable is waterproof. Keep connectors fully seated and rinse mud off after wet rides, since grit is what wears the seals.