E. thirteen Helix Race Carbon e*spec BOSCH SX Brose S Cranks The pinnacle of ultra-light e-bike crank performance Engineered to match the performance of elite-level e-MTBs, the Helix Race E*Spec Carbon Cranks combine the highest strength-to-weight ratio in their category, with a wide range of motor compatibility and progressive arm lengths. At just 330-357 grams, they're light enough for trail and all-mountain, while still maintaining the strength needed for high-intensity laps at the local bike park. ASTM 5-rated and offset-optimized for fit and Q-factor tuning, these cranks are designed to perform, giving riders the stiffness and efficiency, low weight, and compatibility for virtually any high-performance e-MTB platform. Features Carbon construction combines ultralight performance with an advanced carbon fiber layup and molding design for increased strength ASTM 5-rated durability for aggressive e-MTB use, including bike park and shuttle days21. 5mm offset Bosch(R) SX, Brose(R) S-Mag, DJI(R) Avinox, TQ(R) HPR50 and Specialized(R) 2. 2 & 3. 1 motor systems Progressive arm lengths available in 155mm, 160mm, and 165mm for ground clearance and modern fit Note:chainring sold separately, pairs perfectly with e. Thirteen Helix Race e*Spec Chainring TECH SPECSMaterial Carbon Fiber Crank Lengths155mm, 160mm, 165mm Motor System Compatibility Bosch(R) SX, Brose(R) S-Mag, DJI(R) Avinox, TQ(R) HPR50 and Specialized(R) 2. 2 & 3. 1 motor systems Weight (165mm)Bosch SX, TQ, DJI, Specialized (21. 5mm offset): 357g | E. thirteen | Helix Race Carbon E*spec Bosch Sx Brose S Cranks 165Mm Offset Blk 21. 5Mm Offset