The 5Dev R-Spec Shimano Steps EP8 eCrank Arms are billet machined from 7075-T651 aerospace aluminum, the same alloy spec that handles the sustained torque loads a Shimano motor puts through the drivetrain on long technical climbs. What Our Gearhead(R) Experts Are Saying:"On a Shimano EP8 or EP801 build, the 155mm arm keeps the pedal arc clear through rock sections where stock crank length forces a line choice. The terrain opens up when that variable is off the table."