Cratus Mk2 Crank

Our updated Cratus Mk2 crank offers an increased compatibility range. With a +3mm version specifically for road use. Depending on the spindle and crank model selected, the Q factor will vary from 125mm to 141mm. Stock crankset Q factors vary from 145mm to 150mm. This means you can expect a minimum Q factor reduction of 4mm.

Manufactured from 7075-T6 aluminium, anodised black and subtly laser etched with WattShop branding.

CRANK FEATURES

- Aerodynamically designed to reduce turbulence and separation around the spider, chainring and crankarm.
- 144mm BCD for track and road, improving power transfer by eliminating any chainring flex.
- 125mm Q factor. Narrower than nearly every crankset currently on the market.
- Adjustable crankarm length between 145-160mm and 160-175mm at 2.5mm increments for each crank size.
- Interchangeable spindle lengths.
- Compatible with all frames that accept a DUB bottom bracket.
- Laser etched WattShop logo to the drive side and non-drive side.

The crank comes supplied with a DUB spindle. If you have a 30mm diameter BB, you will need to either change to a DUB BB or use 30mm to DUB adapters. If you have a 24mm diameter BB (Shimano users), you will need a new DUB BB.
For spindle selection, you will need to consider the as-fitted BB shell width. We recommend the super-narrow spindle only for use with BSA bottom brackets measuring no wider than 87mm.

This crank is only compatible with 58T or larger chainrings, and it is currently a 1x (single ring) only design.

Additional pedal insert lengths can be purchased separately.

TEST DATA

A 10mm reduction in Q factor equates to a rider dependent saving of 0.001 to 0.002m^2. Assuming a standard air density of 1.225kg/m^3, this results in a saving of:
- At 45kph = 1.2-2.4w
- At 55kph = 2.2-4.4w

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 dimension guide. The dimensions provided will help provide crankarm position relative to the frame centreline; from this, you can work out chainstay clearance.
Secondly, the dimension guide also provides a chainstrike clearance estimate. This is based on predetermined parameters that are outlined in the guide.

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

HARDWARE

- DS & NDS crankarms
- DS cover
- 1x spindle (super-narrow, narrow or standard)
- 2x retention bolts (DS + NDS)
- DS retention bolt removal bolt
- 1x pair of pedal inserts and plates

SPINDLE LENGTHS
We recommend referring to our dimension guide to understand spindle fitment and spacer requirements. But for complete clarity, the available spindle length is noted below.
- Ultra Narrow = 88.75mm
- Narrow = 93.50mm
- Standard = 99.00mm
If your as-measured BB shell width is wider than the available spindle length, that specific spindle would not be compatible.

CUSTOM

Custom spindles can be produced to accommodate nearly any bottom bracket/frame. Please email info@shopforwatts.co.uk to discuss your requirements.