Inspired by the legendary Back 40 trail system right here in Bentonville, the BC40 is a modern racing machine that updates the XC playbook. It combines the sharpness of a race-day bike with the control and confidence of an all-day trail sled. The namesake trail demands a thoughtful bike like this due to its often unpredictably rocky surface, dynamic corners, and endless, punchy climbs. The 120mm suspension is just leggy enough to tame rocky ledges and intermittent flow features, yet it also provides a second-to-none pedaling platform that translates power and efficiency. The suspension performance is anchored by a progressive steering geometry that ensures precise handling and tracking with stability at speed.
The SRAM GX Eagle AXS Transmission Bike provides an awesome blend of performance and cost savings compared to our other SRAM BC40 offerings. SRAM likes to call GX their “People’s Champion.” It combines the same wireless AXS shifting technology as their more expensive groups with a ruggedness that makes it the most durable groupset in the SRAM MTB lineup. Like all Transmission groups, the GX parts work in perfect harmony to ensure precise shifts, even under heavy load.
- Recent improvements include 100g weight savings, stiffer font triangle, stronger and more durable, co-molded bottom bracket insert, and a co-molded alloy insert for the main pivot bearing bores that improves bearing life and ease of maintenance
- In-house development and testing that included building our own testing methodology and machines as well as testing our competitors' bikes to benchmark performance and tearing them apart to weigh each component item
- Designed to stretch the capability of what a cross-country bike can do while making no compromises with weight and pedaling efficiency
- Aluminum suspension linkage, left-side dropout interface/brake mount, and cable management inserts machined in house to ensure the highest precision for alignment and component fitment
- 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 G2 RS 180 Front / 160 Rear
- CASSETTE
- SRAM XG 1275 Eagle 10-52
- CHAIN
- SRAM GX Eagle
- CRANKSET
- SRAM GX Eagle Dub
- FRONT DERAILLEUR
- N/A
- HANDLEBAR
- FSA SL-K MTB Carbon
- HANDLEBAR TAPE
- ESI Chunky
- REAR DERAILLEUR
- SRAM GX Eagle AXS
- SADDLE
- Selle Italia Novus Boost Superflow
- SEATPOST
- Fox Transfer Performance 31.6
- SHIFT LEVERS
- SRAM GX AXS Controller
- STEM
- FSA Gradient
- TIRES
- MAXXIS Rekon 29x2.40 WT EXO/TR Tan Wall
- WHEELSET
- Industry Nine 1/1 Trails S
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 |