Short 155mm alloy crank arms for eMTBs with a Bosch, TQ or Avinox motor, or a 2025 Specialized Turbo Levo 4. 5DEV machines them from 7075 billet in San Diego and shaped them to cut down crank strikes on rocky, technical climbs.

Highlights

• 5DEV lists them for Bosch, TQ and Avinox motors and the Gen 4 Specialized Levo
• 155mm crank length
• 7075-T651 aluminium, CNC-machined from billet
• IS spline drive, 192mm Q-factor
• 490g (155mm, 5DEV figure)
• 8mm hex crank bolt with a built-in 16mm self-extractor cap

Fitting

Fitting eCranks is a separate workshop service and isn't included in the price. The Tune workshop can fit them to your pedal-assist eBike and confirm your motor's crank interface first. Each arm is held by an alloy steel crank bolt (8mm hex, 40Nm) with a billet aluminium self-extractor cap (16mm hex, 2Nm), so the same 8mm hex takes the arm off again. Use a torque wrench.

5DEV eCranks by motor

5DEV makes a separate eCrank for each motor interface. Its current eCrank range includes:

• Shimano EP8 (5DEV says its EP8 cranks also work on EP801): R-SPEC EP8 eCranks and Titanium EP8 eCranks
• Bosch, TQ, Avinox and the 2025 Specialized Turbo Levo 4: R-SPEC Bosch/TQ/Avinox eCranks and Titanium Bosch/TQ/Avinox eCranks
• Specialized Turbo Levo and Kenevo, first three generations (Brose motor): Specialized Brose eCranks and Titanium Specialized Brose eCranks
• Specialized Turbo Levo SL and Kenevo SL (SL 1.2 motor): SL eCranks with the SRAM DUB spline
• Fazua Ride 60: ETOR eCranks

Options

Both options are the same 155mm R-SPEC arm; only the finish changes.

Compatibility & fit

• 5DEV lists these for Bosch, TQ and Avinox motors and the 2025 Specialized Turbo Levo 4.
• 5DEV doesn't say which Bosch or TQ motor models or generations they fit. Check your motor's crank interface with our workshop before ordering.
• Q-factor 192mm (5DEV doesn't say which motor it's measured on).
• For a Gen 1–3 Levo or Kenevo, or any Specialized SL model, 5DEV makes separate eCranks.
• No chainring is listed with the arms.