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The Karate Monkey was one of the first production 29ers. It put the 29˝ platform in front of a lot of people at a price within reach of many a bike nerd. Since then, 29” has become a full-blown category, with entire bike companies dedicated to the platform. In contrast to the old standard 26” wheels, 29˝ wheels have unique benefits: delivering increased traction, smoothing out terrain, carrying inertia, and generally fitting tall riders better.

The Karate Monkey helped set the standard for 29er geometry. While its tucked-in rear wheel keeps it nimble and maneuverable, its lack of shifting componentry keeps the bike simple — and the rider filled with a cathartic rage.

With a frame and fork made of custom-designed Surly CroMoly “’Natch” steel, the Karate Monkey delivers a resilient, lively, durable ride. The Karate Monkey frame has recently been updated to include features like internal dropper post routing, a new tubeset that uses the same trumpet tubes found on our Instigator 2.0, and a slight tweak in geometry that is more progressive and trail oriented. The Karate Monkey uses a horizontal dropout with a derailleur hanger spaced to what we call Gnot-Boost spacing. 10 x 135mm QR, 12 x 142, or 12 x 148 Boost™ will all work in the Karate Monkey frame. The frame uses a 44mm headtube for broad fork compatibility and is ED coated for an added layer of internal protection.

The Karate Monkey SS is the sensei for all of your single speed sensations.

Specifications

Karate Monkey 27.5+ Geometry MY21 Karate Monkey Front Suspension - Geo
units:

Select a few bike sizes to compare.

SIZE Small (16) Medium (18) Large (20) xLarge (22)
Reach 15.5 394.9 16.3 415.1 16.9 428.6 17.3 440.1
Stack 23.3 591.1 23.7 602.5 24.2 614.0 24.7 628.2
Head Tube Angle 71.0° 71.5° 72.0° 72.0°
Head Tube Length 3.9 100.0 3.9 100.0 4.3 110.0 4.9 125.0
Seat Tube Length 16.0 406.4 18.0 457.2 20.0 508.0 22.0 558.8
BB Drop 2.7 68.0 2.7 68.0 2.7 68.0 2.7 68.0
Wheelbase 41.2 1046.1 41.9 1064.9 42.4 1076.8 43.0 1093.0
Chainstay Length 17.0 431.0 17.0 431.0 17.0 431.0 17.0 431.0
Top Tube Length, Actual 22.0 557.7 22.6 575.0 23.2 589.9 23.9 607.1
Top Tube Length, Effective 22.7 575.6 23.6 599.3 24.3 616.3 24.9 632.2
Seat Tube Angle 73.0° 73.0° 73.0° 73.0°
Standover Height 30.0 762.9 31.2 792.7 32.4 822.5 33.6 853.5
Fork Length 18.4 468.0 18.4 468.0 18.4 468.0 18.4 468.0
Fork Rake 1.7 43.0 1.7 43.0 1.7 43.0 1.7 43.0

All dimensions are preliminary and subject to change * Standover is measured from the top of the TT, at the center, with a tire measuring approximately Ø737mm

Select a few bike sizes to compare.

SIZE Small (16) Medium (18) Large (20) xLarge (22)
Reach 15.5 394.9 16.3 415.1 16.9 428.6 17.3 440.1
Stack 23.3 591.1 23.7 602.5 24.2 614.0 24.7 628.2
Head Tube Angle 71.0° 71.5° 72.0° 72.0°
Head Tube Length 3.9 100.0 3.9 100.0 4.3 110.0 4.9 125.0
Seat Tube Length 16.0 406.4 18.0 457.2 20.0 508.0 22.0 558.8
BB Drop 2.7 68.0 2.7 68.0 2.7 68.0 2.7 68.0
Wheelbase 41.2 1046.1 41.9 1064.9 42.4 1076.8 43.0 1093.0
Chainstay Length 17.0 431.0 17.0 431.0 17.0 431.0 17.0 431.0
Top Tube Length, Actual 22.0 557.7 22.6 575.0 23.2 589.9 23.9 607.1
Top Tube Length, Effective 22.7 575.6 23.6 599.3 24.3 616.3 24.9 632.2
Seat Tube Angle 73.0° 73.0° 73.0° 73.0°
Standover Height 30.0 762.9 31.2 792.7 32.4 822.5 33.6 853.5
Fork Length 18.4 468.0 18.4 468.0 18.4 468.0 18.4 468.0
Fork Rake 1.7 43.0 1.7 43.0 1.7 43.0 1.7 43.0

All dimensions are preliminary and subject to change * Standover is measured from the top of the TT, at the center, with a tire measuring approximately Ø737mm

Select a few bike sizes to compare.

SIZE XS SM MD LG XL
Reach 14.8 377 15.8 402 16.8 427 17.7 450 18.6 472
Stack 23.5 597 23.5 597 23.5 597 23.9 606 24.2 615
Head Tube Angle 69.0° 69.0° 69.0° 69.0° 69.0°
Head Tube Length 3.9 100 3.9 100 3.9 100 4.3 110 4.7 120
Seat Tube Length 13.0 330 14.5 368 16.5 419 18.5 470 20.5 521
BB Drop 2.2 55 2.2 55 2.2 55 2.2 55 2.2 55
Wheelbase 41.5 1053 42.4 1078 43.4 1103 44.4 1129 45.5 1155
Chainstay Length 16.7 423 16.7 423 16.7 423 16.7 423 16.7 423
Top Tube Length, Actual 21.6 549.7 22.1 560.4 22.6 575 23.5 597.5 24.6 624.5
Top Tube Length, Effective 22.0 560 23.0 585 24.0 610 25.0 635 26.0 660
Seat Tube Angle 73.0° 73.0° 73.0° 73.0° 73.0°
Standover Height 29.3 743 29.9 759 30.8 783 32.0 812 32.6 827
Fork Length 19.0 483 19.0 483 19.0 483 19.0 483 19.0 483
Fork Rake 1.9 47 1.9 47 1.9 47 1.9 47 1.9 47

*Standover is measured from the top of the TT, at the center, with a tire measuring approximately Ø749mm

Select a few bike sizes to compare.

SIZE XS SM MD LG XL
Reach 14.2 361 15.2 387 16.2 412 17.1 434 18.0 457
Stack 23.9 607 23.9 607 23.9 608 24.3 617 24.7 627
Head Tube Angle 67.5° 67.5° 67.5° 67.5° 67.5°
Head Tube Length 3.9 100 3.9 100 3.9 100 4.3 110 4.7 120
Seat Tube Length 13.0 330 14.5 368 16.5 419 18.5 470 20.5 521
BB Drop 1.7 44 1.7 44 1.7 44 1.7 44 1.7 44
Wheelbase 42.2 1071 43.1 1096 44.1 1121 45.2 1147 46.1 1172
Chainstay Length 16.7 423 16.7 423 16.7 423 16.7 423 16.7 423
Top Tube Length, Actual 21.6 549.7 22.1 560.4 22.6 575 23.5 597.5 24.6 624.5
Top Tube Length, Effective 22.2 565 23.2 590 24.2 615 25.2 640 26.2 665
Seat Tube Angle 71.5° 71.5° 71.5° 71.5° 71.5°
Standover Height 29.8 757 30.5 775 31.4 797 32.5 826 33.7 855
Stem Length 2.4 60 2.8 70 2.8 70 2.8 70 3.1 80
Stem Angle 7° 7° 7° 7° 7°
Handlebar Width 29.5 750 29.5 750 31.5 800 31.5 800 31.5 800
Crank Length 6.7 170 6.7 170 6.9 175 6.9 175 6.9 175
Fork Length 20.5 521 20.5 521 20.5 521 20.5 521 20.5 521
Fork Rake 2.0 51 2.0 51 2.0 51 2.0 51 2.0 51
Tubing

High-Viz Black:

Surly 4130 CroMoly Steel ‘Natch tubing

Mint Green:

Surly 4130 CroMoly steel. Main triangle double-butted. TIG-welded. ED Coated

Ops:

Surly 4130 CroMoly steel. Main triangle double-butted. TIG-welded . ED Coated (black model only).

Rear Dropouts

High-Viz Black:

Horizontal slotted with derailleur hanger; Surly “Gnot Boost” 135, 142, or 148mm hub spacing compatibility, threaded fender eyelets

Mint Green:

Frame comes equipped as a single speed. Our Modular Dropout System gives you the option of 142 x 12 thru-axle, single speed or Shimano direct mount derailleur hanger [axle included], 9mm QR geared. More combos than you can shake a stick at.

Ops:

Surly Modular Dropout System gives you the option of 142 x 12 thru axle (Shimano Direct Mount derailleur hanger [axle included]), 10mm QR geared, or singlespeed

Brake Compatibility

High-Viz Black:

51mm I.S. disc caliper mounts, 180mm max rotor size

Mint Green and Ops:

51mm IS disc mounts front and rear

Braze-ons/extras

High-Viz Black:

Dual bottle-mounts on XS–M, three bottle-mounts on LG–XL, dropper post routing, rack and fender mounts

Mint Green and Ops:

Dual water bottle mounts, Surly Trip Guides for continuous brake and derailleur housing

Seatpost Diameter

High-Viz Black:

30.9mm

Mint Green and Ops:

27.2mm

Seatpost Clamp DIameter

High-Viz Black:

33.1mm (Surly stainless included)

Mint Green and Ops:

30.0mm (Surly stainless included)

Headset/Steerer Tube

High-Viz Black:

44mm

Mint Green:

Cane Creek 40 for 44mm, 1-1/8˝ threadless. Black

Ops:

44mm ID. Recommend EC44 lower cups. Zero Stack on top is OK

Front Derailleur Clamp Diameter

High-Viz Black:

34.9mm, high direct-mount

Mint Green:

28.6mm (high-direct)

Ops:

28.6mm (high-direct) adaptor included

Bottom Bracket Shell

High-Viz Black:

73mm

Mint Green and Ops:

73mm wide, standard English threading (1.37˝ x 24t)

Chainring Clearance

High-VIz Black:

32t Boost 1x, 24/36t Boost 2x, 28t 1x, 24/34t 2x

Mint Green and Ops:

24/36/48t

Tire Clearance

High-VIz Black:

27.5 x 3.0" and 29 x 2.5", individual tire and rim combos affect tire clearance

Mint Green:

29 x 2.5" knobbies. Individual tire and rim combos affect tire clearance

Ops:

29 x 2.55" knobbies. Individual tire and rim combos affect tire clearance

Fork

High-VIz Black:

140mm travel suspension fork compatible (547mm A-to-C max)

Mint Green:

1-1/8" straight steerer, suspension-corrected (80mm), tapered and butted straight blade, 4130 CroMoly. 51mm IS disc mount

Ops:

1-1/8 to 1.5 tapered steerer, Fox Float, 32mm 100mm travel; 15mm thru-axle mount

Thru Axle

HU0138 Surly 15x110 Front Thru Axle
HU0134 Surly 12x142/148 Rear Thru Axle

Colors

High-Viz Black

Mint Green

Spray Tan

Support

Frame Warranty

LIMITED WARRANTY

This Surly product is warranted against defects in materials and workmanship for three years from the date of retail purchase of the product, subject to the limitations detailed below. Save your dated receipt for proof of purchase.

This warranty does NOT cover the following:

  • Damage due to improper assembly or follow-up maintenance or lack of skill, competence or experience of the user or assembler
  • Products that have been modified, neglected, used in competition or for commercial purposes, misused or abused, involved in accidents or anything other than normal use
  • Installation of components, parts or accessories not originally intended for or compatible with bicycle as sold
  • Damage or deterioration to the paint, surface finish, aesthetics or appearance of the product
  • Normal wear and tear
  • Labor required to remove and/or refit and re-adjust the product within the bicycle assembly

This limited warranty is expressly limited to the repair or replacement of a defective product, at the option of Surly, and is the sole remedy of the warranty. This limited warranty applies only to the original purchaser of the Surly product and is not transferrable. This warranty applies only to products purchased through an authorized dealer or distributor. In no event shall Surly be liable for any loss, inconvenience or damage, whether direct, incidental, consequential, or otherwise resulting from breach of any express or implied warranty or condition, of merchantability, fitness for a particular purpose, or otherwise with respect to our products except as set forth herein.

This limited warranty gives the consumer specific legal rights, and those rights and other rights may vary from place to place. This limited warranty does not affect your statutory rights.

TO THE EXTENT NOT PROHIBITED BY LAW, THESE WARRANTIES ARE EXCLUSIVE AND THERE ARE NO OTHER EXPRESS OR IMPLIED WARRANTIES OR CONDITIONS INCLUDING WARRANTIES OR CONDITIONS OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.