Building a Surly Karate Monkey: A Bike With Many Personalities

I’ve had my eye on a trail bike for a while now with ambitions of facing more technical terrain than I’m accustomed to riding on. Dreams of doing parts of the Colorado Trail also influenced my decision to acquire a trail bike. A hardtail seemed to be the best balance between versatility and trail riding comfort so I got to work and built a Surly Karate Monkey from the ground up.

Deciding on a frame wasn’t easy. Although carbon bikes were out of the question, there are many great steel hardtails frames in the market. I mainly decided on the Karate Monkey because of its history. Just like the Salsa Fargo, the Surly Karate Monkey has some history in pushing biking into new territories. While the Fargo is a mythical bikepacking frame, the Karate Monkey helped push the 29er movement into what it is today.

From the Ground Up

I have built a few bikes now, so I decided to make things more interesting by also lacing the wheels. Wheel building was a mysterious art form to me until I read Roger Musson’s e-book. All of a sudden, building my own wheels seemed like an achievable task. I have to say that anyone can build their own wheels after reading Roger’s step-by-step guide. Lacing my own wheels did require purchasing some tools, but now I can use these tools to build other wheels in the future. I might have found myself a new hobby.

I like to think that I made sensible choices when choosing the components for the Karate Monkey wheels. Hope Pro 4 hubs are affordable, look cool, and will last a great deal of time; exactly what I needed for this trail bike. WTB Scraper rims are not flashy by any standards, but they are nice wide (i40) rims that fit my build budget. To round things up, I spent a little bit of extra cash on Sapim Race double butted spokes

The Build

I had fallen in love with the yellow/orange Karate Monkey, but unfortunately, that color wasn’t available anymore. By the time I called my LBS to put in an order for the frameset, the only two available colors were “hi-viz black” and “stand back purple”. At first, the idea of having a purple bike didn’t really resonate with me but now I can’t believe I had doubts about this frame color.

Karate Monkey Build Parts

As with all my builds, I purchased parts from a few different retailers, including some international ones.

FRAMESET2017 Karate Monkey - XLMotorless Motion (LBS)
FORKFox Float 34
HEADSETChris King Inset 7Wiggle
STEMTruvativ Stylo T20 - 60mm; 5 degree riseParts Bin
HANDLEBARH-Bar Jones Loop - 710mm wideJones Bikes
SEATPOSTTruvativ Stylo T30Ebay
SADDLEBrooks C17Chain Reaction
HUBSHope Pro 4Bike24
RIMSWTB Scraper i40World Wide Cyclery
SpokesSapim RaceYojimbo's Garage (Ebay)
FRONT/REAT TIRESMaxxis ChronicleEbay
GRIPSRace Face Half NelsonAmazon

Nothing like spending some quality time in the shop drinking a beer and working on a new build. Having a Belgian style beer during my bike builds has become sort of a tradition.

A Westmalle Tripel as the beer of choice to work on the Surly Karate Monkey

I choose SRAM GX Eagle parts because I have had luck in the past with the GX line of components. The Fox 34 fork will smooth out the ride without breaking the bank.

Here’s a timelapse of yours truly fitting all the parts onto the bike.

Finally Done

I need all the help I can get when it comes to climbing steeps hills and the SRAM GX Eagle drivetrain should make it easier going uphill. Moreover, the 32T chainring coupled with the 10T cog can get me up to 35km/h (21.7 mph) at 80 RPM; plenty for the type of riding I’ll be doing with this bike.

The newest Karate Monkey frame is designed around 27.5″ Plus tires, so it’s no surprise there’s plenty of clearance to fit Maxxis Chronicle 27.5″ X 3.0 tires.

You can never go wrong with the good ol’ Shimano XT brakes – trustworthy and affordable.

Many Personalities

Like I mentioned, I’ve been looking into taking on some more challenging bikepacking routes, like the Colorado Trail, where a bike with suspension is more suitable than my fully rigid Salsa Fargo. But I live in Wisconsin, where access to decent mountain bike trails is a bit limited. Not only that, but winter, snow, and unbearably low temperatures are the norm for a good part of the year. I really didn’t need another bike that can only be ridden for 5-6 months out of the year, like my road bike.


That’s where the idea of a 27.5″ plus bike came into play. The suspension and the extra volume tires would provide a comfortable platform to take on more technical trails during the summer. Meanwhile, the rigid fork along with the wider tires would provide a stable ride during the snow months.

How does this work anyway?

Switching forks back and forth is not as practical as I had hoped. Removing the stem/handlebar and realigning the brake calipers is not something I would like doing on a ride-by-ride basis. I’m only planning on switching forks twice a year – once in the spring and again in the fall. The original Surly fork is suspension corrected to match a 120mm travel fork. Since I fitted a 140mm travel fork, handling with the suspension fork is slightly different than when outfitted with the rigid fork. This difference in handling is not necessarily a bad thing, just something to be aware of.

On the bright side of things, there is no need to switch the bottom cup of the headset when switching between a 1-1/2 tapered fork and a straight 1-1/8 fork. I fitted the rigid 1-1/8 fork with a reducing crown race – Chris King calls these Devolution crown races.

The Fox Float 34 fork came fitted with a remote lockout damper but I haven’t added a fork remote on the Karate Monkey yet. Largely because I’m not willing to pay $70 for a Fox brand remote. I’m researching other options like modifying a friction shifter to make it work as a lockout remote. If anyone has made it this far in the post and has a good idea about a lockout remote, leave suggestions in the comment below.

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5 Responses

  1. Nicholas Ryan says:

    Hello Andre, it’s a great looking bike you’ve built. I’m looking to do a similar build, using a KM with a Fox 34 120mm (which can be converted to 140mm) fork and wondered whether you could answer some questions. I noted you’ve got an XL frame – how tall are you and how have you found the fit and ride of the XL? I am 6’1″ but deliberating on whether to go with a size large or XL. Is your Fox fork a 27.5 or a 27.5+? As I’ve got a Fox 34 27.5 120mm, I am curious to know if you got the 3.0 Maxxis tire into a 27.5 fork as opposed to the plus-specific sized fork. Finally, how have you found climbing trails with a 140mm fork? Any feedback would be most appreciated – thanks. Regards, Nicholas

    • André says:

      Hi Nicholas, I’m 6’2″ and I find the bike fits me just fine. I was also trying to decide between the L and the XL when I bought the frame. I went with the XL because I like the stability of larger bikes in general. The fork is a 29er (boost) fork, so clearance with a 27.5+ tire is not really an issue. Climbing seems fine with the 140mm fork, the biggest difference I have noticed between the rigid fork and the 140mm suspension fork is in how the bike handles tight corners.

  2. Jeff says:

    BTW nice video and blog ! It’s been some time since the build. Anything you would change. Regrets? I am thinking of building a 2019 KM with left over parts from my Marin Pine mountain 2. A lady ran into my bike rack and bent my frame and rear wheel. Do you think my fox 34 27.5+ fork 120mm travel would be toobshort? Is it worth converting to 140mm?

    • André says:

      Hey! 27.5+ and 29″ forks are the same length, so no issues there. I haven’t thought about changing anything, really. I do wonder if the 120mm would handle better, so if I were you, I wouldn’t convert right away. Sorry to hear about your Pine Mountain!

  1. November 11, 2018

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