SRAM Eagle 90 Transmission eMTB Crank Arms – Bosch

SRAM Eagle 90 Transmission Crank Arm Assembly – Bosch eMTB

Forged aluminium crank arms built specifically for Bosch-equipped eMTBs and the SRAM Eagle Transmission drivetrain. Available in five lengths — 150mm, 155mm, 160mm, 165mm, and 170mm — so you can properly dial in your pedal stroke and ground clearance rather than accepting whatever came on the bike.

What It Does

The Eagle 90 crank arms are designed around a Bosch ISIS spindle interface, making them compatible with Bosch CX BDU37 (Gen 4) and BDU38 (Gen 5) motor systems. SRAM's removable Gap Cap system is included, helping keep the drivetrain interface clean and protected. SRAM quotes a weight of approximately 490g for the 160mm Bosch version with cap fitted — treat this as an engineering estimate.

Technical Insight

• Forged aluminium construction for strength and impact resistance
• Bosch ISIS spindle interface — not compatible with non-Bosch motor systems
• Compatible with Bosch CX BDU37 (Gen 4) and BDU38 (Gen 5)
• SRAM Gap Cap system included
• Five crank lengths: 150mm, 155mm, 160mm, 165mm, 170mm

Sizing Guide

Crank length affects pedal clearance, power delivery, and comfort. Shorter lengths (150–155mm) suit riders prioritising ground clearance on technical terrain or those with shorter leg proportions. Mid-lengths (160–165mm) are the most common trail and enduro choice. Longer arms (170mm) suit riders used to road-influenced fit. No official SRAM sizing chart was supplied — consult your fitter or the Torque Collective workshop if you are unsure.

Why Torque Collective Stock This

A significant portion of the bikes through our workshop run Bosch motors, and crank length is one of the most overlooked fit variables on an eMTB. Having the full range of Eagle 90 arms in five lengths means we can replace or upgrade without compromising drivetrain compatibility or forcing a rider into the wrong fit.