Surly Bikes
Karate Monkey is a highly-versatile trail bike that plays the part of 29er and 27.5+ equally well.
Karate Monkey delivers a resilient, lively ride on all sorts of gnarly terrain. Its frame is a highly-versatile canvas for whatever dirty masterpiece your brain cooks up. According to our computing machine (Thor) it can be set up in approximately 487 different configurations.
Originally designed as a 29er (and the frame that helped spark the 29” wheel movement), the latest Karate Monkey is designed to perform just as admirably as a 27.5+ rig as well. This allows you to pick your poison — provided your poison is having a really great time while permanently donning a shit-eating grin, of course.
- Modern trail standards: dropper post compatibility, 44mm headtube, Gnot-Boost rear spacing, thru-axles, suspension corrected fork
- Compatibility with most mountain bike standards makes it the perfect parts bin bike (no rim brakes allowed though)
- Clearance for 29” x 2.5” or 27.5” x 3” tires
Bike Capabilities
- 5/5 with Singletrack
- 4/5 with Bikepacking
- 3/5 with Commuting
- 4/5 with Tire Clearance
NOTE: You can ride your bike wherever the hell you want, but this is what we think this bike is best at.
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Where to Buy
Specifications
Build Kit
Frameset
| Frame |
Surly 4130 Chromoly Steel
Custom double butted externally flaired tubing. Horizontal slotted with derailleur hanger, Surly “Gnot Boost” 142 or 148mm hub spacing compatibility |
|---|---|
| Fork |
Surly 4130 Chromoly Steel
483mm axle-to-crown x 47mm offset, 110mm hub spacing, tapered and butted straight blade, 4130 Chromoly. 51mm I.S. disc mount |
| Seatpost Clamp | Surly stainless, 33.1mm |
Components
| Headset | Cane Creek |
|---|---|
| Brakes | SRAM Level |
| Brake Levers | SRAM Level |
| Rotors | SRAM Centerline 180/160 |
| Grips | Velo single lock-on |
| Shifters | SRAM NX |
| Stem | Promax, 31.8mm |
| Handlebar | Salsa Rustler 31.8mm |
| Saddle | WTB Volt Sport |
| Seatpost | Promax 30.9mm |
Drivetrain
| Crankset | SRAM NX 30t |
|---|---|
| Bottom Bracket | SRAM Power Spline |
| Front Derailleur | None |
| Rear Derailleur | SRAM NX |
| Cog or cogset | Sunrace 11 speed 11-42t |
| Chain | KMC X11EL-1 |
Wheels
| Front Hub | Novatec, 32h, Thru-Axle |
|---|---|
| Rear Hub | Novatec, 32h, Thru-Axle |
| Rims | WTB ST i40 TCS |
| Tires | Surly Dirt Wizard 27 x 3”, 60 tpi Tubeless Ready |
Frameset
| Frame |
Surly 4130 Chromoly Steel.
Custom double butted externally flaired tubing. Horizontal slotted with derailleur hanger, Surly “Gnot Boost” 142 or 148mm hub spacing compatibility |
|---|---|
| Fork | RockShox Sektor RL, 27.5 140mm travel, 51mm offset, 15x110 front axle, Disc. |
| Seatpost Clamp | Surly stainless, 33.1mm |
Components
| Headset | Cane Creek |
|---|---|
| Brakes | SRAM Level hydraulic |
| Brake levers | SRAM Level hydraulic |
| Rotors | SRAM Centerline 180/160 |
| Handlebar | Salsa Rustler 31.8 |
| Grips | Velo single lock-on |
| Shifters | SRAM NX Eagle |
| Stem | Promax, 31.8mm |
| Saddle | WTB Volt Sport |
| Seatpost | TranzX SP15, dropper post 80mm travel on XS/SM 120mm travel on MD/LG/XL |
Drivetrain
| Crankset | SRAM Descendant 32T |
|---|---|
| Bottom Bracket | SRAM Power Spline |
| Front Derailleur | None |
| Rear derailleur | SRAM NX Eagle |
| Cog or cogset | SRAM Eagle 11-50t |
| Chain | SRAM NX Eagle |
Wheels
| Front hub | 110mm, 15mm thru-axle, 32h |
|---|---|
| Rear hub | 148mm, 12mm thru-axle, 32h |
| Rims | WTB ST i40 TCS |
| Tires | Surly Dirt Wizard 27 x 3”, 60 tpi Tubeless Ready |
Complete bike spec subject to change
Geometry
units:
- in
- mm
| 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 |
| 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 | 60 | 70 | 70 | 70 | 80 |
| Stem Angle | 7° | 7° | 7° | 7° | 7° |
| Handlebar Width | 750 | 750 | 800 | 800 | 800 |
| Crank Length | 165 | 170 | 175 | 175 | 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 |
Frame Specifications
| Frame Construction | 4130 Chromoly, Natch tubing, double-butted main triangle, trumpet flared tubes, TIG welded, ED coated |
|---|---|
| Fork Construction | 4130 Chromoly, Natch tubing, double-butted tapered fork blades, TIG welded, ED coated |
| Rear Dropout Configuration | Horizontal slotted with optional vertical dumpout |
| Rear Hub Spacing | "Gnot-Boost" 145mm |
| Front Hub Spacing | 15 x 110mm (Surly axle included) |
| Rear Brake | Disc - 51mm I.S. (203mm max rotor) |
| Front Brake | Disc - 51mm I.S. (203mm max rotor) |
| Head Tube | Ø44mm |
| Steerer Tube | Ø28.6mm (1-1/8") |
| Crown Race | Ø30mm (1-1/8") |
| Stock Headset Upper (S.H.I.S) | ZS44/28.6 |
| Stock Headset Lower (S.H.I.S) | EC44/30 |
| Seat Collar | Ø33.1mm |
| Seatpost | Ø30.9mm |
| Front Derailleur (Clamp) | High direct mount top-pull (Ø34.9mm) |
| Max Chainring (CL) [3] | 1x (Mtn): 28T |
| Bottom Bracket | 73mm threaded (1.37" x 24TPI) |
| Tire Clearance Frame [1]/[2] | 27.5 x 3.0” |
| Tire Clearance Fork [1] | 29 x 3.0” |
| Rigid Fork Spec | 483 x 47mm |
| Max Suspension Fork Length [4] | 551 x 51mm (27.5+ 140mm) |
| Bottle Mounts Frame | 1 Standard + 1 Three-Pack (XS - M) |
| Bottle Mounts Fork | 2 Three-Pack |
| Rack Mounts Frame | Yes (upper and lower threaded) |
| Rack Mounts Fork | Yes (upper, lower, and mid-blade threaded) |
| Fender Mounts Frame | Yes |
| Fender Mounts Fork | N/A |
| Other Features | Internal dropper post routing compatible |
[1] Different tire and rim combinations will result in different clearances.
[2] Depending on drivetrain configuration, tire clearance may be limited by the chain and not the frame.
[3] Listed chainring clearance is worst case scenario. Clearances vary widely depending on components and configurations.
[4] Suspension fork length listed at full extension (not at sag)
FAQ & Reviews
Support
Downloads
- Karate Monkey Frame Sheet
[pdf] - 422KB - 10/12 Adapter Washers
[pdf] - 546KB - Surly Bike Sizing Chart
[pdf] - 308KB - Universal Thru-Axle Instructions
[pdf] - 269KB - Wheel/Rim/Tire instructions
[pdf] - 279KB
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.