The Helix Race Carbon e*spec brings e*thirteen's highest strength-to-weight MTB crank design to e-bikes, built for the Bosch CX Gen4 / SX / Brose S Mag / TQ HPR50 (26mm offset) motor interface in a 155mm arm length.

Highlights

  • Ultralight carbon layup, ASTM 5 approved for e-MTB use
  • Spindle interface for Bosch CX Gen4 / SX / Brose S Mag / TQ HPR50 (26mm offset)
  • 26mm offset, 186mm Q-factor on this motor interface
  • Moulded crank boots for rock-strike protection
  • Self-extractor system for easy fitting and removal

Built for the e-MTB motor, not bolted on

e*thirteen machines the spindle interface specifically for Bosch CX Gen4 / SX / Brose S Mag / TQ HPR50 (26mm offset), rather than adapting an MTB crank, for a precise fit and the strength-to-weight ratio the e-MTB class demands.

Compatibility & fit

Fits e-bikes running the Bosch CX Gen4 / SX / Brose S Mag / TQ HPR50 (26mm offset) motor only — check your motor before ordering. Pairs with e*thirteen's Helix Race e*spec direct-mount chainring (sold separately). Fitting is a job for the Tune workshop if you're not confident pulling an e-bike motor unit.

e*thirteen covers the Helix Race Carbon e*spec crankset for 10 years against manufacturing and material defects, plus a discounted crash replacement policy. For warranty support, return the product to Tune Cycles and we'll manage the claim with e*thirteen's Australian distributor. This is in addition to your rights under the Australian Consumer Law. Keep your proof of purchase.
  • Carbon arms, ASTM 5 approved for eMTB use
  • Fits Bosch CX Gen4/SX, Brose S Mag, TQ HPR50
  • 26mm offset, 186mm Q-factor
  • 155mm arm length
Brande*thirteen
ModelHelix Race Carbon e*spec
Motor fitmentBosch CX Gen4 / SX / Brose S Mag / TQ HPR50 (26mm offset)
Crank arm length155mm
Offset26mm
Q-factor186mm
MaterialCarbon
RatingASTM 5
ColourBlack
SKU DTW-ETG-CS5HRA-118
Barcode # 4711280346776
Brand e*Thirteen