Surly's classic Karate Monkey gets a plus-sized update

Steel and punk, now with more options

Surly's Karate Monkey was one of the first easily obtainable 29er bikes around. Because of that, it gained a bit of cult following. This update to the bike is the first significant change since the mid 2000s, and it now rolls on 27.5+ tires and features updated geometry. Don't despair though, all the classic trademarks remain.

The venerable Karate Monkey now comes ready to disrupt with 27.5+ wheels and tires
The venerable Karate Monkey now comes ready to disrupt with 27.5+ wheels and tires

Surly Karate Monkey highlights

  • 27.5+ wheels and tires
  • Trumpeted 4130 tube set for added strength and stiffness
  • Internal dropper post routing
  • 30.9 seatpost internal diameter
  • Gnot Boost rear hub spacing measures 145mm to fit a 148mm Boost hub, or a 142mm hub
  • Thru-axle with sliding cap system works with both 142 and 148mm hubs
  • 10/12mm adapter spacers to allow the use of a 135mm QR rear hub
  • Rigid fork has 110mm Boost spacing, corrected for a 140mm suspension fork
  • X-small, small, medium, large, and x-large sizes
  • Max tire size: 27.5 x 3in or 29 x 2.5in
  • Frame sets available in black, purple and orange
  • Complete available as SS in Stand Back Purple and in 27.5+ in Rhymes with Orange

4130 chromoly is present as always
4130 chromoly is present as always

The same gets better

The new Karate Monkey shares a lot with its previous model: it's still constructed from 4130 steel, still has sliding horizontal dropouts, still has a pile of braze ons, still comes with a rigid fork, and is still likely to survive almost anything. It can be had with 29in wheels, or as seen here with plus size 27.5in.

Where it gets better though is in improvements that make it more versatile. 27.5+ wheels and tires now fit, the geometry has been modernized with a longer top tube and slacker head angle, and the rear dropouts have been revised with quite a few new tricks, including one Surly calls Gnot Boost.

Big knobbies, a proper sidewall and soft rubber should create huge plus-size traction
Big knobbies, a proper sidewall and soft rubber should create huge plus-size traction

Already featured on Surly's Wednesday fat bike, the Karate Monkey’s Gnot-Boost rear dropouts are 145mm. Whoa, easy now, it's not a new "standard". 145mm falls right between the common 142mm and 148mm Boost hub widths. Thanks to the magic of steel, the Karate Monkey's rear end can be slightly expanded to fit a Boost 148mm hub, or squeezed a tad to fit a 142mm hub. It's the same idea they used with their 132.5mm rear-end on the Cross Check to fit 130mm road hubs and 135mm mountain bike hubs. 

Surly's new thru-axle is also pretty neat. It features a sliding cap system to work with both 142 and 148mm hubs. Plus, 10/12mm adapter spacers allow the use of a 135mm QR rear hub. 

See the little notch that mimics a vertical dropout? No more messing with the rear brake caliper; rear wheel installation and removal is easier than ever
See the little notch that mimics a vertical dropout? No more messing with the rear brake caliper; rear wheel installation and removal is easier than ever

The last trick out back involves the dropouts (or track ends) themselves. Surly now includes a little notch for vertical dropouts so removal and installation of the rear wheel gets much more simple, no more having to adjust the rear brake caliper. Other updates include a 30.9mm seatpost, as well as internal routing for a dropper post. 

Serious rubber

I also feel I should mention the massive, moto-looking Dirt Wizard tires. In addition to having a rad name, Surly claims a super low 42 durometer compound but with good wear characteristics. My unscientific thumbnail impression test confirmed these knobbies are soft and should hook up. 

Can you say moto? Surly's Dirt Wizard tires look incredible
Can you say moto? Surly's Dirt Wizard tires look incredible

The lugs do look well supported, so ripped off side knobs shouldn't be an issue. Surly has also added some sidewall protection, which is very welcome as most plus tires have thin sidewalls in order to trim weight. That said, the 27.5+ versions will likely come in well over 1,000g. 

Pricing and availability

US$1,399 for geared bike, US$1,175 for singlespeed, with October or November 2016 availability. UK and Australian pricing unavailable

Russell Eich

Tech Writer, US
Russell fell head over heels in love with bikes in the '90s, and has been involved in the bike industry ever since. Between wrenching in bike shops, guiding professionally, and writing about bikes, Russell has honed an appreciation for what works, gained knowledge of what doesn't, and can barely contain his enthusiasm for what comes next. His two-wheeled passion continues in the Rocky Mountains high above Boulder, Colorado.
  • Discipline: Mountain, road, cyclocross
  • Preferred Terrain: High altitudes, forgotten singletracks, bike parks, roads without cars
  • Current Bikes: Custom Meriwether steel hardtail, Specialized S-Works Enduro 29, Kona Jake the Snake, Trek 69er, and a bunch more
  • Dream Bike: Yeti SB5c, Intense Tracer 275C, Black Cat custom road
  • Beer of Choice: Gin + Tonic
  • Location: Rollinsville, CO, USA

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