MPLS Skyline

Nature Boy Disc


It’s finally here, the disc brake version of our iconic singlespeed cross machine. 

Like its cantilever brethren, the Nature Boy Disc carries all of the AC hallmarks that you've come to expect: beautiful lugged fork crown, custom dropouts, custom BB shell, signature head badge and E.D. coating. It has our proven race-inspired geometry, but since we're big fans of riding cross bikes every day, we've built in plenty of room to fit large tires and even fenders. 

We are particularly proud of our new singlespeed disc dropout. It solves our main frustration with dropouts of this style: where do you position the brake caliper for optimum performance? The answer was to develop a proprietary system where the tension screw is used to pull the caliper mount into the correct position. Just loosen everything up, use the tensioner to achieve desired chain slack and tighten it all back up. No more guesswork, just reliable braking performance.

For racing, cruising trails, gravel or daily commuting, disc brakes and a singlespeed setup provide unmatched control and reliability. 

Nature Boy Disc

612 Select Tubing

Our proprietary blend of 4130 double-butted CroMoly tubes. Every piece of tubing on every frame size has been carefully chosen to provide the best ride possible.

E.D. Coating

In Electrophoretic Deposition, or E.D., coating the frame or fork is placed in a paint bath where an electric charge is applied. This fuses a thin layer of black satin coating to the tubes inside and out. This coating acts as both a rust preventative inside and a primer out.

Custom Details

We’re way into the handbuilt touches when it comes to our frames. Which is why you’ll find things like internal cable routing, custom dropouts, lugged crown forks, reinforcements on the bottle bosses, hidden fender mounts, etc on our framesets.

Signature Dropouts

The disc version of our horizontal dropout not only looks stunning, but improves upon the issue of properly locating your caliper in relation to the wheel.

Frame + 612 Select ChroMoly steel. Double butted down, top, and seat tubes. Externally tapered, ovalized, and dimpled chain stays, tapered seat stays
Fork + 4130 ChroMoly tapered fork blades, lugged crown and matching dropout. Straight steertube
Rear spacing + 135mm
Brake Compatibility + Disc only, 160mm max rotor
Seatpost diameter + 27.2
Steertube/Headset + 1-1/8" threadless, EC34 upper & lower, Crown race 30.0
Bottom Bracket Shell + 68mm English
Chainring clearance + 49 Tooth max
Tire clearance + 700x38
Extras + Fender Mounts, ED coated
Headset + Cane Creek 10 series
Stem + Salsa Guide, 1-1/8th threadless, 31.8 clamp
Handlebar + Salsa Cowbell 3, 31.8
Tape + Black
Brake lever + Tektro RL340
Brake + Hayes CX-Expert, 160mm rotors
Crankset + FSA Vero 42T
Bottom Bracket + 68x110mm steel cups, sealed bearings
Seatpost + Kalloy 27.2
Saddle + All-City Gonzo
Freewheel + 17T 3/32
Chain + KMC Z610
Hubs + Surly Ultra New Disc 32 hole
Rims + Alex Black Dragon 32 hole
Tires + Clement MXP 700x33 Steel bead
Nature Boy Disc Geometry Line Drawing
Select up to 3 sizes to view:

Size 46cm 49cm 52cm 55cm 58cm 61cm
Head Tube Angle (A) 70.5 71 71.5 72 72.5 72.5
Seat Tube Angle (B) 74 73.5 73 73 72.5 72.5
Top Tube Length (C) 520 535 550 565 585 605
Seat Tube Length (D) 460 490 520 550 580 610
Chainstay Length (E) 430 435 435 435 435 435
Bottom Bracket Drop (F) 70 70 70 70 70 70
Fork Offset (G) 45 45 45 45 45 45
Total Fork Length (H) 395 395 395 395 395 395
Head Tube Length (I) 95 110 130 150 175 200
Standover (J) 756 778 802 827 853 880
Wheelbase (K) 1001 1013 1019 1030 1039 1059
Stack (L) 526.2 542.2 563 583.9 609.6 633.4
Reach (M) 369.1 374.4 377.9 386.5 392.8 405.3
Handlebar Width 40 40 42 42 44 44
Stem Length 80 90 100 110 110 120
Crank Arm Length 170 170 175 175 175 175
BK1340 Complete 46cm
BK1341 Complete 49cm
FM1340 Frameset 46cm
FM1344 Frameset 58cm
FM1345 Frameset 61cm
BK1374 Complete 46cm Black/Gry $1150
BK1375 Complete 49cm Black/Gry $1150
BK1376 Complete 52cm Black/Gry $1150
BK1377 Complete 55cm Black/Gry $1150
BK1378 Complete 58cm Black/Gry $1150
BK1379 Complete 61cm Black/Gry $1150
FM1374 Frameset 46cm Black/Gry
FM1375 Frameset 49cm Black/Gry
FM1376 Frameset 52cm Black/Gry
FM1377 Frameset 55cm Black/Gry
FM1378 Frameset 58cm Black/Gry
FM1379 Frameset 61cm Black/Gry