Surly Mr. Whirly Pugsley Crankset

The MWOD (Mr. Whirly Offset Double) system is a modified spider and ring combination for Mr. Whirly cranks, designed specifically for use on bikes running very large tyres and rims, such as the Surly Pugsley. Standard triple ring cranks can allow the chain to rub the rear tyre when shifted into the lowest gears. On a bike made for crawloing through the thick and sloppy or over insane terrain, these low gears are essential and cannot afford to be compromised.

To solve this problem, the MWOD system ditches the big ring. The outer (largest) chainring on a mountain triple is rarely used with extra wide tyres. With the outer chainring removed, the granny and middle chainrings are shifted outboard to the old locations of the middle and outer chainrings. The shift effectively gains you around 7mm of tyre clearance at the chain without increasing your Q-factor and without losing your crawling gears.

With the rise in popularity of so-called 'fat bikes', there now exist a lot of tyre, rim and frame options, creating a no-man's-land of mostly, but not completely, compatible combinations. While MWOD complete cranks are set up specifically for Pugsley frames (which are designed with lateral 28mm offset to rpovide clearance for 100mm rims and 4.7" tyres), the MWOD system also works with other frame and wheel combos. Say you want to run 82mm rims on your Pugsley. The frame's offset is designed around 65mm rims and 3.8" tyres. Wider rims will place the tyre closer to the chain in its lowest gear. If you've got Mr. Whirly on your Pug, you can install the MWOD ring set and just like that you've got a bigger footprint and no chain-on-tyre-rub.

Get it? Got it? Go for a ride.

• 22t/32t rings (aluminium and stainless steel).
• Moonlander spindle for 100mm BB shells.
• 170mm or 175mm versions.
• Black.