Cratus Mk2 Crank
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Performance Benefit
Tested savings of 0.001–0.002 m² CdA per 10 mm Q-factor reduction, depending on rider.
What It Is
Modular aero crankset with adjustable crank lengths and interchangeable spindle options.
Best For
Time trial and triathlon riders seeking maximum aerodynamic and biomechanical optimisation.
Compatibility
Compatible with DUB bottom brackets and a wide range of frame and pedal systems. Find our fit calculator HERE.
Why Cratus?
Developed for World Hour Record performances and engineered to optimise aerodynamics, biomechanics and drivetrain efficiency
Product Information
The Cratus Mk2 crankset has been engineered for maximum efficiency, optimising aerodynamics, biomechanical performance and stiffness. An adjustable crankarm length system allows precise positional tuning via interchangeable inserts, with adjustment ranges of 145–160 mm (short arm) and 160–175 mm (long arm). This modular design also simplifies bike fitting and aero testing.
A class-leading 125 mm Q factor improves both biomechanical efficiency and aerodynamic performance, while the 144 BCD interface minimises chainring flex.
The Cratus Mk2 is compatible with all major pedal systems and a wide range of bottom bracket standards.
For full details on spindle lengths, Q factor, chainstrike and compatibility, please refer to our fit calculator.
Technical Specifications
FITMENT CONSIDERATIONS
There are two main aspects which need to be considered. Crankarm to chainstay clearance and chainstrike. The latter is between the chain and crankarm when in the smallest sprocket of your cassette.
Please refer to our fit calculator. The dimensions provided will help provide crankarm position relative to the frame centreline; from this, you can work out chainstay clearance.
Secondly, the fit calculator also provides a chainstrike clearance estimate. This is based on your input parameters.
OTHER CONSIDERATIONS
- A 58t chainring is the smallest compatible chainring size.
- For road use, 2x compatibility is not possible.
WEIGHT
- 160-175 DS crank inc dome = 425g
- 160-175 NDS crankarm = 201g
- 145-160 DS crank inc dome = 400g
- 145-160 NDS crankarm = 192g
- DUB Spindle (Ultra-Narrow) = 70g
- DUB Spindle (Narrow) =73g
- DUB Spindle (Standard) = 77g
- Pedal Inserts (inc plates) = 35g/pair
SYSTEM WEIGHT (160-175mm + Narrow Spindle) = 734g
WHAT'S NEW IN CRATUS MK2
Cratus Mk2 builds upon the original platform with several key improvements:
- Reduced overall system weight.
- New +3 mm crankarm option for increased compatibility and clearance.
- Transition to the DUB spindle standard.
Common non-drive side crankarms and spindles across the Cratus range for simplified configuration and future upgrades.
What's Included
A full crankset comprises of the following.
1x pair of crankarms (DS and NDS)
1x DS cover
1x DUB spindle (ultra narrow, narrow or standard)
2x retention bolts (DS + NDS)
1x DS retention bolt removal bolt
1x pair of pedal inserts and plates
Optional Items:
Pedal puller
30mm-to-DUB adapters
All required mounting hardware, included.
More information can be found on each components page; spindles, pedal inserts, pedal puller and 30mm-to-DUB adapters.
Install Guides & Resources
Why we created Cratus Mk2
Cratus Mk2 was created to give riders greater control over aerodynamics, biomechanics and fit. By combining adjustable crank lengths, interchangeable spindle options and an ultra-narrow Q-factor, Cratus Mk2 allows riders to optimise their position without compromising compatibility or future flexibility.
Trusted by World Record Holders and Olympic Champions
Cratus technology has been used during successful UCI Hour Record rides by both Dan Bigham and Filippo Ganna, as well as by the Australian Men's Team Pursuit squad during their 2024 Olympic gold medal-winning campaign.
The platform has also been trusted across numerous World, Olympic and National Championship-winning performances.
Crankarm Lengths
The Short Armed model is optimised for riders seeking shorter crank lengths and supports adjustment from 145 mm to 160 mm. Interchangeable pedal inserts allow crank length to be fine-tuned within the available range.
The Long Armed model is optimised for riders seeking longer crank lengths and supports adjustment from 160 mm to 175 mm. Interchangeable pedal inserts allow crank length to be fine-tuned within the available range.
Straight vs +3 mm Offset Crankarms
The Cratus Mk2 system is available with either straight or +3 mm offset crankarms. The +3 mm option increases pedal stance width by 3 mm per side (6 mm total), providing additional chainstay and heel clearance while allowing riders to optimise Q-factor for their individual fit requirements.
Spindle Lengths
Cratus Mk2 is available with three spindle lengths to accommodate different frame standards, bottom bracket widths and Q-factor requirements. Selecting the correct spindle ensures optimal fit, chainline and crankarm clearance for your bike.
Aerodynamic gains through Q-factor optimisation
A 10 mm reduction in Q-factor has been shown to deliver rider-dependent aerodynamic savings of approximately 0.001–0.002 m² CdA. While the exact benefit varies depending on rider morphology, position and wider bike setup, narrowing stance width can reduce the frontal area and improve airflow interaction between the rider’s legs and the bike.
Using a standard air density of 1.225 kg/m³, this equates to approximately:
- 1.2–2.4 W saved at 45 kph
- 2.2–4.4 W saved at 55 kph
For riders targeting maximum performance, these are meaningful gains from a single fit-related adjustment — particularly when combined with crank length, position and drivetrain optimisation.