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Surly’s Karate Monkey has always been a crowd favorite, but it’s about to get a lot more versatile. Unlike the race oriented Foundry Firetower, the Karate Monkey is gaining a new wheel size trick. But part of that is the introduction of a brand new frame and fork that adds benefits even if you plan on running it as a 29er instead of plus thanks to more modern geometry. In fact, the Karate Monkey will be sold in both builds, each making use of the Gnot Boost spacing…

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Similar to the dropouts that were introduced on the Wednesday, the Gnot Boost dropouts are exactly what they sound like. They’re not Boost. But they’re also not 142mm. Instead, the dropouts measure 145mm which can easily stretch to fit Boost hubs, or crank down to fit 142mm hubs. The horizontal dropouts also include a vertical slot to make wheel changes easier after the TA is removed.

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Another clever touch, the included thru axle will work with both 142 and 148mm hubs thanks to the cap on the end. One a 142mm hub the extra axle slides inside the cap to allow it to tighten down. Going even further, Surly offers 10/12 adapter washers that will allow you to use 135mm QR hubs with the frame as well.

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Thanks to the chainstay plate and Gnot Boost dropouts, the 4130 Natch chromoly frame will clear 27.5 x 3.0″ or 29 x 2.5″ tires. While the frame keeps a classic threaded 73mm bottom bracket, geometry becomes more modern with a longer top tube and shorter stem, 69º head tube angle (down to 67.5 depending on fork), and a shorter 30.9mm seat post for use with internal droppers. Sold with a rigid Boost 110 spaced fork suspension corrected to 100mm sagged, the frame will work with up to a 140mm travel suspension fork which is where the slacker head tube comes in.

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Surly has also added an XS size to the line up thanks to the longer front center which allows for a tiny bike without toe overlap.

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Over on the purple side, this 29″ build only needs one gear. That means the build options will be an orange 1×11, 27+, Boost Karate Monkey, or the purple, 1×1, Gnot-boost, 29er (both are also front derailleur compatible). Complete builds will only be available in one color each, but both colors will be available as framesets.

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Both builds include tubeless ready Alex rims and tubeless tires, with the plus build taking advantage of the newer 27.5 x 3.0″ Dirt Wizards. Expect these to hit the trails this October.


  1. Well, Surly, you had me with the MDS dropouts, which were/are awesome, and now you’ve completely lost me. 145mm?! Why bother making it even remotely compatible with modern stuff if it’s not a captive axle? Why bother with a lazy attempt at modern spacing, if it’s difficult to even remove your wheel?

    It’s obvious people whined about SS capability, so why not just make an SS only bike? Have fun adjusting the rear brake on that thing either way.

  2. Quirky little indie bike company makes new “standard” = Hooray for the little guy, how cool, let’s drink IPAs with punny hop-themed name, grow 1800s-era mustaches and go for a pub crawl on our fixies!

    Big company that starts with S or T or G makes new “standard” = The Apocalypse is nigh

    Love the double (here it comes…) standard!

    • I’m no fan of Surly; basically fairly expensive frames made from crappy tubing, crappy welds, crappy paint. They are indie in the sense that Blue Moon is a craft brew – it’s not, but they market like it is. They are owned by QBP, the largest distributor of bike parts probably in the world.

      But for sake of honesty, they are not introducing any new standard. They are making a half-assed way to shove either size wheel in there without either really fitting. It’s been done before. They (and a number of others) sold bikes with 132.5mm spacing for those that couldn’t decide between 130 and 135; same idea: it works – not well, but it works.

    • Surly may be small but they drive a lot of what is on the market today. Large tire gravel bikes, 29+, 29ers in general, fat bikes. While I dont think that 145mm dropouts are a revolutionary (or even a good idea), they certainly have proven that they can basically do whatever they want and the rest of the industry will eventually follow. I’d bet that if daddy QBP wasn’t bankrolling them that none of it would have happened. Turns out you have to make money at some point.

  3. Man that’s awesome!

    You guys realize it isn’t a ‘new’ standard it’s a way of making it compatible with 135/142/148 right? that’s pretty awesome to me! Also, not captive is a way to also make it singlespeed compatible (which is definitely part of their market). I really can’t see a downside to this….

    • Working on a brake inside the rear triangle is a full-size pain in my nethers. I always appreciate exposed brakes. Always. If you don’t work on your own bikes, it probably doesn’t matter.

  4. I like to think of Surly frames as canvasses for parts bikes to become real bikes. Collect a few parts, slap them on a decent handling frameset, make a few upgrades, and eventually move the bits over to a nicer frame with a little more purpose in the design. This bike can take all your current parts, let you save up for some Boost parts and install them when you get the chance, then you can transfer it to your sweet new Niner/Fat Chance/Yeti/artisan bespoke frame. No, they’re not the best frames, but nobody claims that. They’re reliable, adaptable, and sometimes a little silly. No harm there.

    • I think you have summed it up well Timothy with your comment “They’re reliable, adaptable, and sometimes a little silly.”

      Here I was thinking that Surley had put some great thought into making a bike compatible with a few different standards. The most easiest to fit & remove wheels it is not, but it opens it up for a lot of people to fit their existing parts to a new frame.

      The only reason I haven’t, and wouldn’t, buy a Surly is the massive amount of braze-ons. I get why they do it, it’s awesome to be able to have so much compatibility to fit stuff but I’m just not that target customer, and find it rather unsightly.

  5. I love the updates to the good ol KM, but I’m not too crazy about the 145mm spacing. I’ve got an old ‘cross-check (2005) with 132.5mm spacing and I’ve run both 130mm and 135mm hubs with success. But, both chainstays have developed serious cracks from either squeezing them to fit 130 or spreading them to fit 135. Fortunately, I’ve had them repaired cheap, but I have reservations about buying an oddly-spaced bike like that again…

    • 132.5mm spacing is lame. I’d probably pick a hub spacing and stick with it. Going back and forth between 130 and 135 is probably what caused your cracking.

  6. I will keep my old karate Monkey with steep head tube angle. No need to slack it. Makes the bike slow and unresponsive.

    Longer head tube as well. Might as well add weight to a niner and ride that.

    Rear spacing makes no sense. With other available frames to run 3″ tires, this frame didn’t need this downgrade. Step in the wrong direction for sure.

  7. I love my Karate Monkey. Things change I guess. I like the steeper head angle on the old one, I hope QBP gets another shipment of the 2016 frames so I can have a back up. I like the purple color. Not sure about the new spacing, seems like nothing fits right but it can work. I would have to mess around with it before casting my opinion.

  8. The purple looks nice. Still, front derailleur compatible?!? I don’t doubt a FD would fit the seat tube but that plate looks like anything except mighty small rings would hit it. Maybe 33×20 max with one of their OD cranks? The BB drop appears to be 13mm less too, so with a 140mm fork the BB height is going to be astronomical.

    I’ve no doubt they’ll sell, just not to me. I guess they’ll sell a few more Ogres now, assuming that hasnt changed too.

  9. There’s a lot of riders out there that think my surly sucks but most of them have only seen it from the rear. Surly makes totally decent sh*t and has great customer service. My surly has outlasted my Santa Cruz so far and I’ve ridden home from wrecks on my KM that would have left carbon sprinkles all over the forest.

  10. I love Surly in general, but this bums me out. The MDS dropouts on my 2015 Karate Monkey are great. Even bigger, I’m sad to see that they adopted the new trend of slack angles on everything – it just feels slow and cumbersome to me. I bought my current KM specifically because of the head angle and tire clearance. Also bought a Pugsley because it’s the only fat bike that I’m aware of with a reasonable head tube angle – it actually feels fun to ride and like a mountain bike. My old (slack) Mukluk was not nearly as fun to ride. Time to stock up on old Surlys… or resign to the fact that I need custom bikes now to get what I want (threaded bb’s, non-mega-proprietary parts, good geometry, etc).

    • Orangee? Yes! Purples YES! Modern geo, headtube size, intyernal dropper routing? yes, yes, yes! Those track ends? Awww hell naww.

  11. I like Surly but those rear facing dropouts are a total pain. I thought those dropouts were on there way out with MDS. What happened? Surly could have gotten all of that compatibility with various MDS chips. Was MDS unreliable and Surly is silently dropping it?

  12. Wait… Is the ss gonna be 29″ or 27.5+? BikeRumor and QBP say 29″, but and Dirt Rag say 27.5+!? Im hoping the ss is 27.5+!!! Anyone got the inside scoop?

  13. SS is 29. Geared is B+. I’m not sure I appreciate the bigger seat post diameter. But the other changes I am willing to try. Surly has been the leader in every major advancement in mountain bikes since their inception. The day there is a press fit bb on a karate monkey is the day I won’t buy one.

  14. I’m hoping for a 27.5+ SS also!!!!

    I bet they got away for the MDS chips because of cost. The pricing on these seems much more competitive then the MDS versions that were out…and I think that is where Surly is losing market share, they look a lot less expensive then their list price, especially pictures on-line, and bike shops around me do not stock Surlys, and to understand a Surly you have to ride one.

    I love my 1×10 Krampus and will always have it, but I’m thinking a Purple 27.5+ SS KM will complement it nicely.

  15. Those dropouts suck. I had a older Monkey. Great bike in all ways except the track dropouts. It was so fiddly to get a wheel in and out that I sold it for that reason alone. Why they didn’t put MDS on the new Monkey is a total mystery. Was hoping MDS was going to migrate across their bikes but guess not.

    • The track style dropouts on the new Karate Monkey have a cutout on the inside, just like the Surly Wednesday. This allows you to put a wheel in and take it out, just as you would with vertical dropouts. It is very easy, and a great improvement over the older track dropouts. Go to the website fax sheet and there is a good diagram under the Wednesday that shows the new design of these track dropouts.

      Also, I see some people are slamming Surly, but really at $1175 and $1400 they are great bikes. I find the welds to be very good and the paint is actually powder coat.

      Yes, Surly are not the lightest bike but they are durable, fun bikes. And, some of us find them to be just cool looking bikes.

      As for people who still want traditional geometries, it looks like they are still selling the Pugsley as frameset, and because these frames are so durable l, you should be able to pick up a used traditional frame Surly for ever.

  16. Can someone explain to me what is going on with that crankset & chainring? It looks like a direct mount ring on a bolt on crank… or am I missing something?

  17. I am totally jazzed on the new Geared, B+ KM! I had been hoping that this is the year for me to go B+, but I really don’t want an aluminum hard tail. I’m bit of an old BMX retro-grouch guy who still likes horizontal dropouts. This bike with a 120mm Pike and I’ll be good to go. Simple and durable. I’m looking forward to Oct!

    • Stays will only need to move 1.5mm per side, surely the “flex stays” in habit an other rear suspension design flex more than this, with exponentially more cycles. Great idea, and new geo will draw cross shoppers of other slacker hard tail frames- SS purple+ Yari for swapping is under $1800-

    • Based on the weight of the Surly Wednesday being in the 36 pounds range, my guest on the geared 27.5+ will be about 1.5 pounds lighter in each wheel tire combination and about 1lbs lighter in the drive train. So, my guess is 31 to 32 pounds. My guess on the single speed is 28 to 29 pounds.

  18. Love the original design KM geometry. Glad I just bought a 2016 frame for my new SS build for angry SS racing. Feel like going “slack” is simply pandering to the sheeple. Stay surly, 4130, and aggressive!

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