Description:

The ethirteen Helix Core espec Cranks offer high-end drivetrain integrity and a premium look at an exceptional value. Forged from tough 6066-T6 aluminum, these short 160mm crank arms drastically reduce pedal strikes on low-BB trail geometries while maintaining excellent pedaling efficiency. Featuring a 21.5mm offset for a compact, tailored Q-factor on standard ISIS spindle motors, they come complete with an alloy self-extractor system, steel pedal washers, and molded impact boots.

e*thirteen Helix Core e*spec Cranks for ISIS Spindle Motor Systems - 160mm, 21.5mm Offset, Black

The e*thirteen Helix Core e*spec Cranks deliver an exceptional e-bike drivetrain upgrade, combining high-end structural integrity and refined aesthetics at an extreme value. Engineered to withstand the relentless torque and punishing loads of modern e-MTB riding, these cranks ensure you never have to hold back on your next gravity run. By blending a value-conscious production layout with robust construction, e*thirteen provides privateers and daily trail riders with a reliable alternative to premium-priced models without sacrificing trail confidence.

This model is engineered for standard 24mm ISIS spindle motor interfaces, offering seamless compatibility with the market's leading e-bike platforms—specifically optimizing layouts for the Bosch SX, TQ HPR50, Brose S Mag, DJI Avinox, Yamaha, and Specialized 2.2/3.1 motor systems. Featuring a narrow 21.5mm offset, these cranks help maintain a highly efficient and compact stance width. Depending on your motor configuration, this offset achieves tight, tailored Q-factors: a precise 169.6mm on TQ platforms, 172.7mm on Bosch systems, and 186mm on Brose setups, striking an excellent balance between structural motor casing clearance and ergonomic pedaling alignment.

At an optimized, short 160mm length, these crank arms strike the ideal sweet spot between raw pedaling leverage and vital ground clearance on modern, low bottom-bracket frame geometries. Shorter crank lengths allow riders to maintain a fast, fluid pedaling cadence through rocky, root-strewn climbs, significantly improving technical climbing capability while minimizing the risk of high-speed pedal strikes. For ease of maintenance, the arms feature an integrated alloy self-extracting crank bolt system that makes routine home workshop servicing and installation quick, simple, and efficient.

Weighing 509g, these stealthy black crank arms are forged from high-strength AL 6066-T6 aluminum to ensure maximum durability against heavy rock strikes and accidental casing. e*thirteen packs this economic upgrade with premium attention to detail, including durable steel pedal washers to protect the spindle threads from high-load deformation and custom-molded composite crank boots that act as a resilient shield against trail debris. Fully engineered for aggressive trail duty, the Helix Core e*spec cranks are backed by e*thirteen's dependable 5-year manufacturer warranty.

Key Features

• Forged AL 6066-T6 Aluminum Construction: Delivers high-end durability, structural stiffness, and dependable trail strength at an accessible price point


• Optimized Short 160mm Length: Increases vital ground clearance on low-BB frame designs to eliminate pedal strikes while maintaining natural leverage and pedaling fluidics


• Narrow 21.5mm Offset Profile: Yields an ergonomic, tighter stance with optimized Q-factors across compatible ISIS motor casings


• Standard 24mm ISIS Compatibility: Designed for flawless integration with Bosch SX, TQ HPR50, Brose S Mag, DJI Avinox, Yamaha, and Specialized systems


• Integrated Alloy Self-Extractor: Heavy-duty self-extracting bolt configuration makes installation and routine drivetrain maintenance efficient and tool-free


• High-End Hardware Inclusions: Comes equipped with durable steel pedal washers and high-impact molded protective crank boots for maximum longevity

Specifications

• Model: e*thirteen Helix Core e*spec Cranks


• Crank Arm Length: 160mm


• Spindle Interface Type: 24mm ISIS Spindle


• Crank Offset: 21.5mm


• Realized Q-Factors: TQ: 169.6mm | Bosch: 172.7mm | Brose: 186mm


• Motor System Compatibility: Bosch SX, TQ HPR50, Brose S Mag, DJI Avinox, Yamaha, Specialized (2.2/3.1)


• Material: Forged AL 6066-T6 Aluminum


• Pedal Thread Interface: Includes Steel Pedal Washers


• Extraction Mechanism: Integrated Alloy Self-Extractor System


• Protective Hardware: Molded Composite Crank Boots Included


• Weight: 509g


• Color: Black


• Warranty: 5 Years

A durable, value-optimized alloy e-bike crank arm upgrade combining a rock-clearing 160mm profile with a compact 21.5mm offset, built for trail riders who demand high-end e-MTB strength and reliability without the premium price tag.