Cranksets

No matter your skill level or experience on the bike, there's no better way to enhance your training and racing performance than by riding with a power meter. And for all of you Dura-Ace fans out there, we've combined our extremely light power sensors with a Shimano Dura-Ace crankset to give you the most accurate and precise power meter available. The development of Power Cranks began with our Human Performance Team looking at riders in realistic scenarios on the bike. Historically, power meters have been validated by two different methods—one is by measuring the produced torque by applying a static, linear load to a crankarm or chainring, while the second uses a power generating motor to pedal the bike. Well, cycling is neither static nor linear, and humans apply power much differently than a machine. So, we found that neither of these methods answers the "real-world" accuracy question. To get the best test for accuracy, in all types of riding scenarios, we built our own cycling treadmill, the WinMill, to measure power output to a known truth. This new benchmark lets us evaluate accuracy under all riding conditions—seated versus standing, various power and cadence levels, different weights, and a myriad of gear. This data acquisition process is our gold-standard for testing power meters, and through our testing and external validation from the Locomotion Lab in Boulder, Colorado, Power Cranks have been proven to have the highest accuracy in real-world scenarios (+/- 1.5%). The Dual-Sided S-Works Power Cranks utilize separate strain gauge systems to individually measure the effort produced by each leg. This maximizes the accuracy of your total power numbers, plus it helps you to better understand your performance as fatigue increases and when you're recovering from injury. And with class-leading temperature compensation firmware and waterproof enclosures, Power Cranks are easy to live with. Calibration is only required during seasonal-type fluctuations in temperature, and the included wrench makes battery swaps a breeze. - +/- 1.5% real-world accuracy tested on the WinMill and validated by the Locomotion Lab in Boulder, CO - Independent, dual-leg power measurement - Works with ANT+ and Bluetooth devices - Easy set-up and diagnostics with the Specialized Power app. (iOS and Android versions available) - 52/36T chainrings

In certain disciplines, the single-ring drivetrain reigns supreme. Championing simplicity, strength and durability, the SRAM RED 1 AXS power meter meets the demands of triathletes, time trialists and cyclocross racers. The power meter features improved aerodynamics thanks to direct mount aero chainrings with fully integrated power, and the tighter gearing range is perfect for racing and flatter terrains. - Single-ring drivetrain simplifies functionality - 48T and 50T variants have fully integrated power into a direct mount aero chainring - 36-46T variants have spider-based power - Chainrings can be easily changed without requiring recalibration of the power meter - Power readings are accurate within +/-1.5% and aren't affected by climate conditions during a ride - Power balance measures left and right legs separately - SRAM X-SYNC wide-tooth, narrow-tooth chainring technology provides maximum chain control - Laser-etched chainring finish is more durable - DUB bottom bracket adds durability and simplicity - Non-aero chainrings can be installed with a single tool, making gearing changes a breeze - Bottom bracket not included - BB Compatibility: All SRAM Road DUB BBs - BB Spindle Interface: DUB - Chainring material: Aluminum - Crank arm material: Carbon - Power Meter Type: ANT+ and BLE

The SRAM RED AXS power meter breaks with tradition — and breaks through to new levels of performance. SRAM reengineered road gearing: reducing front chainring size and adding more range to the rear cassette. They also maintained a 13-tooth delta on all chainring pairs, ensuring precise shifting for any setup. This results in more useful gearing and better shifting across all configurations. These power meters are also designed with Quarq's premier DZero power measurement technology fully integrated into the crankset. Welcome to the pinnacle of the power meter. - X-Range gearing technology gives you more range and a smoother gear progression, so you're always in the right gear - Integrated power measurement - Power meter is fully integrated into the chainring set for lighter weight - Power readings are accurate within +/-1.5% and aren't affected by climate conditions during a ride - Power balance measures left and right legs separately - Improved front shifting performance for crisp and accurate front shifts - Unique chainring shape results in a lighter weight, stiffer, more durable crankset - Integrated chainring design significantly reduces weight - DUB bottom bracket adds durability, simplicity and broad compatibility - Speeds: 12 - BB Compatibility: All SRAM Road DUB BBs - BB Spindle Interface: DUB - Chainring material: Aluminum - Crank arm material: Carbon - Power Meter Type: ANT+ and BLE - Bottom bracket not included

Offering all the precision and functionality of the DURA-ACE power meter, the ULTEGRA FC-R8100-P power meter comes in a more affordable package. Scientific training requires accurate measurement and user-friendliness, and the new ULTEGRA R8100 power meter has both. Its dual-sided measurement is accurate within 1.5% and zero offset calibration is a quick and easy process. Perhaps most importantly, its long battery life, easy recharge, and ANT+ and Bluetooth®LE connectivity makes using and recording your workouts easier than ever. Integrated, waterproof, and rechargeable Li-ion battery - Up to 300+ hours (TBD*) of ride time * Depending on ANT+/Bluetooth®LE settings Accurate data collection - ±1.5% (TBD*) strain gage accuracy throughout the entire calibration range * Depending on ANT+/Bluetooth®LE settings - Proprietary strain gauge Possible to start quickly - Simple zero offset calibration with switch on transmitter Active temperature compensation - Software automatically compensates for temperature changes

Every innovation in Quarq's DZero platform represented the 10+ years of Quarq's advances in power meter technology. This same platform is now combined with XX1 Eagle DUB CARBON TUNED crankset—lightest, stiffest, and strongest to date, and X-SYNC 2 chainring—providing significantly quieter performance with better mud clearing and extraordinary durability. Ready to power every ride. - Bluetooth low energy technology and ANT+ wireless data transfer - MagicZero: automatically checks and recalibrates your power meter as you ride (no need to manually calibrate) - AxCad: no cadence magnet required - 10K Temperature Compensation - Battery: CR2032, 200-hour battery life, change without tools - OmniCal: swap chainrings without affecting accuracy - 2-year warranty - IPX7 waterproof rating - Accuracy: within 1.5%, measuring both legs

We’ve fit the same outstanding stiffness, durability and weight savings of the eeWings mountain cranks into the slimmer road bottom bracket standard. This includes road, gravel and cyclocross configurations. - eeWings All Road 170mm, 172.5mm or 175mm - 30mm Spindle - 10 Year Warranty"

Take flight with the eeWings from Cane Creek. These titanium cranks are designed to keep up with the rigorous demands of the most aggressive trail and enduro mountain bikers—though they will benefit any rider who puts a premium on durability, stiffness and weight. - eeWings Mountain 165mm, 170mm or 175mm - 30mm Spindle - 10 year Warranty

The new Super Record 12x2 Speed crankset: an intense concentration of innovation that results in the greatest possible stiffness and precision in derailing, whilst providing a dedicated aerodynamic “super design." The new carbon fiber Super Record 12x2 Speed crankset has been made lighter on the inside through Campagnolo Hollow Technology, which uses the Ultra-Torque bracket system with a titanium axle to transfer all of the force the athlete applies to the pedal to the drivetrain. The new Super Record 12x2 Speed crankset can be installed on any type of frame, whether or not it is being used with disc brakes because it optimizes the chain line on the frame with a rear hub flange measuring 130, 135 or 142 millimeters, without affecting the Q factor, which remains constant at 145.5 millimeters thanks to the new hand crank design. The use of ceramic Cult bearings leads to obtaining the smooth ride that the Campagnolo brand is known for. The innovative design of the outer chainring ensures faster, quieter derailing owing to the contoured pin. The symmetrical design of the inner chainring teeth allows improved stability with chain crossovers. The double wheel sizing standards (112 and 145 millimeters) combined with the eight fixing screws, optimize weight and stiffness through the increased use of carbon fiber. The varying number of pins for each of the three chainring combinations (34/50, 36/52, 39/53) facilitates upshifting due to the optimized free strokes associated with each combination. The special drains on the inside of the outer chainrings optimize performance when downshifting in dead spots.

Triathlon. Time Trial. Cyclocross. Some disciplines are made for 1x. And while SRAM's X-Range 2x set up has integrated much of the simplicity of a 1x system, there are still times when a single ring is best. The SRAM RED 1 crankset offers the most demanding racers the right mix of features—aerodynamics, durability, and simplicity. - Single-ring drivetrain simplifies functionality and reduces weight - 48 and 50t variants feature direct mount aero chainrings for better aerodynamics - Non-aero chainrings can be installed with a single tool, making gearing changes a breeze - SRAM X-SYNC wide-tooth, narrow-tooth chainring technology provides maximum chain control - Laser-etched chainring finish is more durable - DUB bottom bracket adds durability and simplicity - Can be upgraded to a power meter - Version: D1

The SRAM RED crankset leverages a pivotal design innovation: smaller chainrings and a wider cassette range. This leads to smoother and faster shifting up front and more useful gearing for today's riders. The new configurations improve cadence and efficiency while also delivering shifts that are crisp, clean and quick-every time. Features - X-Range gearing technology gives you more range and a smoother gear progression, so you're always in the right gear - Improved front shifting performance for crisp and accurate front shifts - Unique chainring design results in a lighter weight, stiffer, more durable crankset - DUB bottom bracket adds durability, simplicity and broad compatibility - Power upgradeable Specifications - Speeds: 12 - BB Compatibility: All SRAM Road DUB BBs, GXP/PF GXP 68mm - Chainring Size: 46/33, 48/35, 50/37 - Crank arm length: 165mm, 167.5mm, 170mm, 172.5mm, 175mm - Chainline: 45.0mm - BB Spindle Interface: 24mm, DUB - Chainring material: Aluminum - Guard: No Guard - Bolt Circle Diameter (BCD): Direct Mount (DM) - Crank arm material: Carbon

- Single-ring drivetrain simplifies functionality and reduces weight - Direct mount chainring - SRAM X-SYNC wide-tooth, narrow-tooth chainring technology provides maximum chain control - DUB bottom bracket adds durability, simplicity and broad compatibility - Can be upgraded to a power meter

Designed specifically for use with H11 groupsets. Full Carbon crank arms and spider are hollow for maximum stiffness and minimal weight. Utilizes USB ceramic ball bearings. Light weight hard anodized alloy chainrings and alloy chainring bolts. Utilizes Campagnolo's Ultra-Torque crank system. - Ultra-Torque axles couple together in the middle of the BB shell via a Hirth Joint that self centers the crank. This results in a very light weight and stiff system that transfers power to the pedals without power loss - Features Campagnolo X.P.S.S. (eXtreme Performance Shifting System) featuring geometrically optimized chainring teeth. Optimized when mated to a full Campagnolo drivetrain - USB ceramic bearings increase smoothness and decrease rolling resistance, weight and the need for maintenance. USB bearings are 50% smoother than standard Campagnolo bearings - Ultra-Torque system have both drive and non-drive side bearings pre-installed - Double standardized bolt circle diameter allows for use of standard, mid-compact and compact chainrings - Required for use with H11 Ergopower shift levers, the crank spider is shifted outward to adjust for 135 and 142mm hub spacing while maintaining the Q-Factor - Requires use of Ultra-Torque bottom bracket cups

- Optimum Power Transfer - Best Balance For Lighter Weight (-7G) And Efficiency - New Designed Crank Arm - Maintains High Rigidity And Reduces Weight - Hollowglide - 4-Arm Construction Crankset - Adapted For Race Specific Disc Brake System - Shorter Length Of Rear Center With O.L.D. 135mm - Redesign The Gear Teeth Profile To Fit Wider Gear Pitch - 50-34T/53-39T/54-42T/55-42T/52-36T - Iconic Design - Chain Line: 43.5

The Shimano Dura-Ace FC-R9200 crank performs two vital functions; transferring your pedaling effort into the drivetrain and ensuring the fastest, most precise front shifting available. With HOLLOWTECH II crank arms to ensure light weight and Shimano's class-leading chainring designs, the FC-R9200 won't let you down. - Optimal balance of stiffness, strength, weight and rotational performance - HOLLOWGLIDE structure cuts weight yet maintains strength for better power transfer and quicker, more precise front shifting - 148mm Q-factor - 44.5mm chainline

The new Record 12x2 Speed crankset: a new hole-free design for the right-hand crank that optimizes aerodynamics. The new carbon fiber Record 12x2 Speed crankset with unidirectional finishing guarantees continuity with the finishing of the entire groupset, whilst maintaining the Ultra-Torque bracket system on the steel axle to ensure perfect transmission of power. The new Record 12x2 Speed crankset can be installed on any type of frame, whether or not it is being used with disc brakes because it optimizes the chain line on the frame with a rear hub flange measuring 130, 135 or 142 millimeters without affecting the Q factor that remains constant at 145.5 millimeters. The innovative design of the outer chainring ensures faster, quieter derailing owing to the contoured pin. The symmetrical design of the inner chainring teeth allows improved stability with chain crossovers. The double wheel sizing standards (112 and 145 millimeters) enable reducing the weight through greater use of carbon fiber. There are eight fixing screws for increased structural stiffness. The varying number of pins for each of the three chainring combinations (34/50, 36/52, 39/53) facilitates upshifting due to the optimized free strokes associated with each combination. The special drains on the inside of the outer chainrings optimize performance when downshifting in dead spots.

The XX1 Eagle Fat Bike DUB crankset has been re-examined and re-engineered. Featuring SRAM’s DUB technology, this design simplifies the relationship of the spindle to the bottom bracket. DUB-powered cranksets mean simplicity, compatibility, and durability. - SRAM DUB technology creates a lighter, stiffer and stronger crankset - Carbon-tuned lay-up crank design provides extreme stiffness and light weight - Included direct mount X-SYNC 2 chainring provides significantly quieter performance, with better mud clearing and durability - Chainring is designed specifically for Eagle chains and drivetrains - DUB compatible bottom bracket sold separately - Fat bike frame compatible - BB Included: No - Chainring BCD: SRAM Direct Mount - Crank Intended Use: Mountain - Number of Chainrings: Single - Drivetrain Speeds: 12, 11, 10 - Spindle Interface Type: SRAM DUB - Chainline/Hub Compatibility: 170/177 Hubs

The XX1 Eagle Fat Bike DUB crankset has been re-examined and re-engineered. Featuring SRAM’s DUB technology, this design simplifies the relationship of the spindle to the bottom bracket. DUB-powered cranksets mean simplicity, compatibility, and durability. - SRAM DUB technology creates a lighter, stiffer and stronger crankset - Carbon-tuned lay-up crank design provides extreme stiffness and light weight - Included direct mount X-SYNC 2 chainring provides significantly quieter performance, with better mud clearing and durability - Chainring is designed specifically for Eagle chains and drivetrains - DUB compatible bottom bracket sold separately - Fat bike frame compatible - BB Included: No - Chainring BCD: SRAM Direct Mount - Crank Intended Use: Mountain - Number of Chainrings: Single - Drivetrain Speeds: 12, 11, 10 - Spindle Interface Type: SRAM DUB - Chainline/Hub Compatibility: 190/197 Hubs

The XX1 Eagle DUB crankset has been re-examined and re-engineered. Featuring SRAM’s DUB technology, this design simplifies the relationship of the spindle to the bottom bracket. DUB-powered cranksets mean simplicity, compatibility, and durability. - SRAM DUB technology creates a lighter, stiffer and stronger crankset - Carbon-tuned lay-up crank design provides extreme stiffness and light weight - Included direct mount X-SYNC 2 chainring provides significantly quieter performance, with better mud clearing and durability - Chainring is designed specifically for Eagle chains and drivetrains - DUB compatible bottom bracket sold separately - Boost Compatible - BB Included: No - Chainring BCD: SRAM Direct Mount - Crank Intended Use: Mountain - Number of Chainrings: Single - Drivetrain Speeds: 12, 11, 10 - Spindle Interface Type: SRAM DUB - Chainline/Hub Compatibility: 141/148 Boost Hubs

True competitors are always looking for a performance advantage—a relentless pursuit of equipment that is lighter, stiffer, stronger, and more durable. To create the best drivetrain possible, we re-examined and re-engineered our crankset design. Our all-new XX1 Eagle CARBON TUNED crankset is our lightest, stiffest, and strongest to date. DUB technology enhances this by simplifying the relationship of the spindle to the bottom bracket and redefining the measure of durability. DUB-powered cranksets deliver simplicity, compatibility, and durability. - DUB technology delivers the lightest, stiffest, and strongest crankset available - SRAM CARBON TUNED crank technology provides extreme stiffness and low weight - The X-SYNC 2 chainring provides significantly quieter performance with better mud clearing and extraordinary durability - New colorway is matched to work with XX1 Eagle AXS-enabled componentry

True competitors are always looking for a performance advantage—a relentless pursuit of equipment that is lighter, stiffer, stronger, and more durable. To create the best drivetrain possible, we re-examined and re-engineered our crankset design. Our all-new XX1 Eagle CARBON TUNED crankset is our lightest, stiffest, and strongest to date. DUB technology enhances this by simplifying the relationship of the spindle to the bottom bracket and redefining the measure of durability. DUB-powered cranksets deliver simplicity, compatibility, and durability. - DUB technology delivers the lightest, stiffest, and strongest crankset available - SRAM CARBON TUNED crank technology provides extreme stiffness and low weight - The X-SYNC 2 chainring provides significantly quieter performance with better mud clearing and extraordinary durability - New colorway is matched to work with XX1 Eagle AXS-enabled componentry

The XX1 Eagle crankset features a special hollow internal architecture, combined with SRAM's Carbon Tuned technology to provide extreme stiffness and low weight. An X-SYNC 2 chainring offers significantly quieter performance with better mud clearing and extraordinary durability. As a part of the SRAM Eagle ecosystem, this crankset was developed for a superior 1x drivetrain experience. - SRAM DUB technology creates a lighter, stiffer, and stronger crankset - For use with a Cannondale Ai frame interface - Carbon-tuned lay-up crank design provides extreme stiffness and low weight - Included direct mount X-SYNC 2 chainring provides significantly quieter performance with better mud clearing and durability - Chainring is designed specifically for Eagle chains and drivetrains - Use with SRAM Eagle chain for optimum performance

True competitors are always looking for a performance advantage—a relentless pursuit of equipment that is lighter, stiffer, stronger, and more durable. To create the best drivetrain possible, we re-examined and re-engineered our crankset design. Our all-new XX1 Eagle CARBON TUNED crankset is our lightest, stiffest, and strongest to date. DUB technology enhances this by simplifying the relationship of the spindle to the bottom bracket, and redefining the measure of durability. DUB-powered cranksets deliver simplicity, compatibility, and durability. - DUB technology delivers the lightest, stiffest, and strongest crankset available - SRAM CARBON TUNED crank technology provides extreme stiffness and light weight - The X-SYNC 2 chainring provides significantly quieter performance with better mud clearing and extraordinary durability - New colorway is matched to work with XX1 Eagle AXS-enabled componentry

The FSA SL-K carbon tandem cranks feature an asymmetrical modular compact 2 x 11-speed spider, 30mm spindle, and tons of adjustability. - Hollow carbon arms with UD carbon finish - Asymmetrical 110 A.B.S BCD achieves 4 chainlines (44,47,50,53) - English BB included - 104 BCD timing spider - 653 grams - Number of Chainrings: Single - Crank Intended Use: Tandem - Pedal Spindle: 9/16" - Rings: 38 - Spindle Interface Type: 392 EVO - BB Included: English

You have a lot of choices when choosing a crankset, and your choice says a lot about your personal style. SRAM designed the X01 Eagle crankset for riders who feel most stylish when they stand on top of the podium. This is a completely reengineered design, employing their proprietary CARBON TUNED lay-up technology. The new X01 Eagle is SRAM's best, toughest, and most aggressive Trail and Enduro crankset thanks to DUB technology, which features a better-engineered bottom bracket and a new spindle design. Together, these allow for a more uniform approach to bottom bracket fitment, better sealing against contamination—and define a new measure of durability. If you’re into that kind of thing. - DUB technology delivers the strongest, stiffest, lightest crankset available - SRAM CARBON TUNED crank technology provides extreme stiffness and light weight - Chainring technology is designed specifically for Eagle chains and drivetrains - The X-SYNC 2 chainring provides significantly quieter performance, with better mud clearing and extraordinary durability - Chainline: 66.5mm

This Hollow Carbon Crankset features reduced weight, and excellent stiffness. The K-force WE system is perfect for triathlon and/or time trial riders who want advanced technology without the bulk. - Lightweight hollow carbon arms with UD carbon finish - Maximum frame compatibility with a forged AL7050 BB386EVO spindle - Innovatively designed for a better ride, the variable thickness means that it’s reinforced at critical stressed areas and reduced in other areas for lighter weight - Chainring pins are AL7075 forged then 100% CNC 3D machined, to increase outer chainring stiffness and provide efficient up-shift pin design for full-power performance - AL7075 Torx T-30 alloy chainring bolts - Number of Chainrings: Double - Crank Intended Use: Road, Tri - Pedal Spindle: 9/16" - Rings: 50/34 - Spindle Interface Type: 386 EVO - Drivetrain Speeds: 11 - Chainring BCD: 110 - Weight: 534 - BB Included: No

Already a legend in its time, the SRAM RED crankset is now available with refreshed graphics to complement the SRAM RED eTap componentry. The SRAM RED crankset features a completely hollow construction all the way to the spider. Its hidden bolt pattern makes better use of carbon fiber to further improve stiffness and shed weight. As always, for seamless, flawless performance and Yaw compatibility, pair this crank with X-GlideR chainrings. - SRAM Road 11-speed compatible - Compatible with SRAM RED eTap components - Exogram technology uses a large, hollow cross section all the way to the spider, minimizing weight while maximizing stiffness - SRAM's stiffest crank ever - Hidden bolt pattern leverages the characteristics of carbon fiber while presenting a sleek appearance - Stiffer X-GlideR chainrings feature thicker construction and advanced shift timing pins and ramps, which are optimized for shifting with the Yaw front derailleur - Arm Material: Carbon - Chainring Material: Machined alloy - Weight: 557 grams (BB30 172.5mm 53x39 BB not included) - Compatibility: SRAM RED & SRAM Force Yaw Front Derailleur, SRAM RED 22 & PC1170 chains - Finish: Carbon - Bottom Bracket Compatibility: BB30, PressFit 30

The X01 Eagle DUB crankset is designed to be tough; ready for aggressive Trail and Enduro riding. The Carbon-tuned crankset paired with DUB technology simplifies the relationship of the spindle to the bottom bracket. DUB-powered cranksets mean simplicity, compatibility, and durability. - SRAM DUB technology creates a lighter, stiffer and stronger crankset - Carbon-tuned lay-up crank design provides extreme stiffness and light weight - Included direct mount X-SYNC 2 chainring provides significantly quieter performance, with better mud clearing and durability - Chainring is designed specifically for Eagle chains and drivetrains - DUB compatible bottom bracket sold separately - Boost Compatible - BB Included: No - Chainring BCD: Sram Direct Mount - Crank Intended Use: Mountain - Number of Chainrings: Single - Drivetrain Speeds: 12, 11, 10 - Spindle Interface Type: SRAM DUB - Chainline/Hub Compatibility: 141/148 Boost Hubs

You have a lot of choices when choosing a crankset, and your choice says a lot about your personal style. SRAM designed the X01 Eagle crankset for riders who feel most stylish when they stand on top of the podium. This is a completely reengineered design, employing their proprietary CARBON TUNED lay-up technology. Built tough, to handle aggressive lines through rock gardens and big hits wherever you find them. The new X01 Eagle is SRAM's best, toughest, and most aggressive Trail and Enduro crankset thanks to DUB technology, which features a better-engineered bottom bracket and a new spindle design. Together, these allow for a more uniform approach to bottom bracket fitment, better sealing against contamination—and define a new measure of durability. If you’re into that kind of thing. - DUB technology delivers the strongest, stiffest, lightest crankset available - SRAM CARBON TUNED crank technology provides extreme stiffness and light weight - Chainring technology is designed specifically for Eagle chains and drivetrains - The X-SYNC 2 chainring provides significantly quieter performance, with better mud clearing and extraordinary durability - Chainline: 56.5mm

Same Same. But Different. For the artist, the challenge of the solution is the inspiration to create. The crank arm—perfected in performance by SRAM engineers—is a utilitarian canvas begging to be transformed. Troy Lee, design artist, took to that canvas and now, those of us who have seen, can never unsee. It's the crank, made more. Same same. But forever different. Specifications: - Speeds: 10/11, 11/12 - BB Compatibility: DUB BSA MTB83, DUB PF MTB104.5/107, DUB:BSA73, PF89.5, PF92, PF30 MTB73, BB30 MTB73, BSA MTB68SP - Chainring Size: 32, 36 - Crank Arm Length: 165mm, 170mm - Chainline: 49.0mm, 56.5mm - BB Spindle Interface: DUB - Chainring Material: Aluminum - Guard: No Guard - Bolt Circle Diameter (BCD): Direct Mount (DM) - Crank Arm Material: Carbon

Shimano's Dura-Ace Track Cranks transform every last watt into oval-scorching speed in the velodrome. These cranks set the bar for low weight and unmatched efficiency, with hollow forged aluminum crank arms and an Octalink bottom bracket (sold separately) for power transfer and acceleration that will blow you, and those trying to hold your wheel, away.