Alloy eCrank arms shaped for current full-power eMTB motors: Bosch Gen5 CX and PX, Avinox M1/M2/M2S, Qore (Brose) Drive3 and the Specialized Levo 4. Short lengths from 150mm give more pedal clearance.

Highlights

• Type 2 arm shape for Bosch Gen5 CX/PX, Avinox, Brose Drive3 and Levo 4
• Cold-forged alloy left and right arms
• 150, 155, 160 and 165mm lengths
• 530g for a 160mm set (Praxis figure)
• Replaceable M24 alloy main bolt with built-in self-extractor, 8mm hex, 50Nm

Fitting

Fitting eCrank arms is a separate workshop service and isn't included in the price. The Tune workshop can fit them and confirm your motor and spindle first. Praxis specifies a torque wrench with an 8mm hex for the M24 main bolt (50Nm). The bolt comes pre-installed and doubles as a self-extractor, so the arm comes off with the same 8mm hex. Praxis's manual says to re-check the torque after about the first 100km.

Which Praxis eCrank type fits?

Praxis sorts its eCranks by the motor's spindle and the arm shape. Its fit guide (April 2026) matches them like this:

• Type 1: older Bosch Gen4 CX (BDU37) and SX (BDU31), Yamaha PW-X, Giant SyncDrive Pro
• Type 2 (MTB): Bosch Gen5 CX (BDU38) and PX (BDU34), Avinox (DJI) M1/M2/M2S, Qore (Brose) Drive3, Specialized Levo 4
• Type 3 (MTB): Brose S-Mag, TQ HPR50/HPR60, Fazua Ride 50, Bafang M800, SRAM Powertrain
• Type 4 (narrow road/gravel): Brose S-Mag, Fazua Ride 50, TQ HPR50/HPR60, Giant E+ BBSS
• Type 5 (road/gravel): TQ HPR40
• Type 6 (ETOR alloy spindle): Fazua Ride 60 and Maxon AIR-S (MTB and road/gravel), Mahle M40 (MTB)
• Specialized Turbo-ISIS: Gen 1–3 Levo, Kenevo, Vado, Como (asymmetric arms)
• M30/SL1.1: Specialized SL 1.1 motor

Options

Every option is the same alloy Type 2 arm set; only the crank length changes. A carbon Type 2 set in 155mm is listed separately.

Compatibility & fit

Praxis shapes Type 2 arms for these eMTB motors, all with an ISIS-spline spindle. Q-factors Praxis quotes for the alloy arms:

• Older Bosch and Yamaha: Praxis's Type 2 page says these arms also fit older-generation Bosch and Yamaha motors, and quotes a 176mm Q-factor on Bosch Gen4 CX/SX. Its fit guide, though, matches Bosch Gen4 CX (BDU37) and SX (BDU31) and Yamaha PW-X to Type 1 arms. On an older Bosch or Yamaha, check your motor's crank interface with our workshop before ordering.
• Not for Brose Mag family, TQ, Fazua, Bafang, SRAM Powertrain, Mahle or Maxon motors (Types 3–6), Specialized Gen 1–3 Turbo models (Specialized Turbo-ISIS) or Specialized SL 1.1 (M30/SL1.1).
• Praxis lists Type 2 for MTB use.
• Left and right arms only. No chainring is included.
• Unsure what your bike has? Check your motor's crank interface with our workshop before ordering.