bc40

SRAM XX SL Eagle AXS Transmission Bike

Current lead time 14 weeks.

Regular price $11,070

Inspired by the legendary Back 40 trail system, designed by our engineers, built entirely in our Bentonville factory – the BC40 is a modern racing machine that updates the XC playbook with the capabilities of an all-day trail sled. The bike’s 120mm suspension provides a second-to-none pedaling platform, and its progressive geometry delivers precise handling and tracking with stability at speed.

The BC40 wants to push watts through switchbacks and punch it over rolling singletrack. In the new SRAM Eagle XX SL, it’s found the ideal partner. SRAM’s Eagle transmission hinges on its axle-mounted derailleur, which sheds the noodly appendage of a derailleur hanger and anchors directly to the frame and cassette. The result is stiffer, more responsive shifting that lets you move the chain under extreme loads. It’s revolutionary, and it’s new, and it feels like no other derailleur we’ve shifted in anger.

XX SL is the lightest, most race-tuned version of Eagle. It looks the part, too, with lines so clean you almost hate to get it dirty. Almost. Direct-mount and lightweight don’t mean likely-to-break, though – the derailleur’s breakaway construction lets it disengage to, well, break away from impacts rather than breaking away from the frame.

XX SL’s narrower Q factor helps reduce that risk, situating the derailleur and crankset more inboard to avoid trail obstacles. It also self-adjusts, removing the greatest temptation of home mechanics: limit screws. We’ve succumbed to that siren song ourselves, thinking a slight tweak would do it, only to completely detune our shifting and end up in the shop, having an actual mechanic remedy our hubris. That’s less time waiting sheepishly at the bike shop and more time on the trail.

Engineered for the needs of the modern trail shredder. Built entirely in the Allied Technology Center. The BC40 is Made Here.

  • Stretches the capabilities of what a cross-country bike can do while making no compromises with weight and pedaling efficiency. 
  • Built with SRAM’s ultralight XC-racing transmission, the new Eagle XX SL
  • In-house development with proprietary testing methodology and machines, with performance benchmarked against our competitors’ bikes.
  • Every piece of carbon is meticulously cut, stacked, formed, and molded to hit the highest possible quality standard in our Allied Technology Center / Bentonville factory. 
  • Aluminum suspension linkage and floating brake mount machined in-house to ensure the highest precision for fitment and alignment. 
  • Built to exceed the expectations of multi-time Olympians and national champions, for ultimate performance at the highest level of competition.
  • Inspired by decades of riding and racing, and purpose-built for the hundreds of miles of trails in our backyard.

Key Features


FRAMESET WEIGHT
1950 grams (Lrg)
GEOMETRY
A slacker front headtube angle for predictable handling at speed across buff and technical terrain. A longer front-to-center measurement shifts the weight of the rider further behind the front wheel for more control to maneuver at high speeds.
SUSPENSION
Designed for 120mm front and rear travel, can be adjusted down to 100mm for optimal terrain performance. Faux bar system (four bar flex stay) kinematic designed for pedaling efficiency.
COMPATIBILITY
Cable management at the headtube allows for easy compatibility across components, including dropper posts and remote lockouts.
BOTTLE MOUNTS
Capable of carrying 2, 1 on the downtube and 1 on the seat tube
TIRE CLEARANCE
29x2.4

Build Kit

BOTTOM BRACKET
SRAM Dub 73 BSA
BRAKES
SRAM Level Ultimate Stealth 4 Piston 180 Front / 160 Rear
CASSETTE
SRAM 1299 XX SL Eagle 10-52
CHAIN
SRAM XX T-TYPE Flat Top
CRANKSET
SRAM XX SL Eagle Transmission
FORK
Rock Shox SID Ultimate RL
FRONT DERAILLEUR
N/A
HANDLEBAR
FSA KFX Carbon
HANDLEBAR TAPE
ESI Chunky
REAR DERAILLEUR
SRAM XX SL Eagle Transmission
SADDLE
Selle Italia Novus Boost Superflow
SEATPOST
Rock Shox Reverb AXS
SHIFT LEVERS
SRAM AXS Pod Ultimate
STEM
Industry Nine A318
TIRES
MAXXIS Rekon 29x2.40 WT EXO/TR Tan Wall
WHEELSET
Industry Nine UL 280 CARBON

Sizing Guide

SM MD LG XL
Crankset 170 170 175 175
Stem 40 50 50 50

Frame Geometry

SM MD LG XL
A. Stack 598 609 622 633
B. Reach 420 445 475 501
C. Front Center 710 739 775 806
D. Seat Tube Angle 76 76 76 76
E. Wheel Size 29" 29" 29" 29"
F. Headtube Angle 66.5 66.5 66.5 66.5
G. Fork Rake 44 44 44 44
H. Head Tube Length 95 105 120 135
I. Bottom Bracket Drop 40 40 40 40
J. Wheelbase 1145 1174 1210 1241
K. Chainstay Length 435 435 435 435
L. Horizontal Top Tube 569 596 630 659
M. Seat Tube Length 395 420 450 500
Have a Question?

Lightweight Frame

When traversing countless steep pitches, weight matters. The target 1950g frame weight is achieved by careful placement of the most advanced composite materials available and countless hours iterating and testing to ensure ride performance, durability and strength are all in perfect balance.

Two Bottle Mounts

Hydration is critical on any long ride or race. The BC40 design allows for a full size bottle on the downtube and small bottle on the seat tube.

Aggressive Geometry

The needs and capabilities of a modern cross country bike have completely evolved. BC40 pushes the envelope of race worthy bikes with a 66.5 degree headtube angle and 76 degree seat tube angle to allow you to optimize your weight well behind the front wheel for descending and further forward when climbing in the saddle.

Made Here

Like all ALLIED bikes, the BC40 is carefully crafted one frame at a time in our headquarters in Bentonville, AR to ensure each bike is built to the highest standard of quality possible.

120mm Travel

BC40 bolsters a full 120mm of travel front and rear with kinematics carefully positioned for pedaling efficiency and easy tunability.

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