bc40

BC40 Frameset

Current lead time 4 - 6 weeks.

$3,500

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 BC40 Frameset is the perfect foundation for you to build your dream bike with all of the component options of your own choosing. Might we suggest starting with custom paint? It comes with a Wolf Tooth Performance IS 41/52 Headset and a RockShox SIDLuxe Ultimate 3P Rear Shock as standard equipment. There are upgrade options for both as well as options to add forks too.

  • Recent improvements include 100g weight savings, stiffer front 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. Flex stay w/ kinematics designed for pedaling efficiency.
COMPATIBILITY
Cable management at the headtube allows for easy compatibility across components, including dropper posts and remote lockouts. Threaded BB.
BOTTLE MOUNTS
Capable of carrying 2, 1 on the downtube and 1 on the seat tube
TIRE CLEARANCE
29x2.4

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
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Lighter and Stiffer

The BC40 is now 100g lighter than before. We optimized the carbon laminate schedule to carve out any excess weight that we could, and we did it without sacrificing the strength or stiffness of the frameset. In fact, the rear triangle is now stiffer than before. This means that all of your power gets to the ground as you fly up the climbs.

Lightweight BC40 on path

Lighter and Stiffer

The BC40 is now 100g lighter than before. We optimized the carbon laminate schedule to carve out any excess weight that we could, and we did it without sacrificing the strength or stiffness of the frameset. In fact, the rear triangle is now stiffer than before. This means that all of your power gets to the ground as you fly up the climbs.

Bottom Bracket and Main Pivot Upgrades

Along with the laminate optimization, we’ve made some behind-the-scenes upgrades to the BC40 bottom bracket and main pivot. Both changes involve co-molded aluminum parts that ease maintenance and increase durability. The new bottom bracket allows easier access for cable routing - a boon to home and shop mechanics alike.

Detail shot of BB

Bottom Bracket and Main Pivot Upgrades

Along with the laminate optimization, we’ve made some behind-the-scenes upgrades to the BC40 bottom bracket and main pivot. Both changes involve co-molded aluminum parts that ease maintenance and increase durability. The new bottom bracket allows easier access for cable routing - a boon to home and shop mechanics alike.

Chainguide

The BC40 gets its long awaited chainguide. It’s a small thing, but it makes a big difference. While clutch-type derailleurs and narrow/wide chainrings do an admirable job with chain retention, sometimes one needs that little bit more confidence. This chainguide bolts right to the existing receiver on the pivot axle. Max 34t chainring.

Chainguide

Chainguide

The BC40 gets its long awaited chainguide. It’s a small thing, but it makes a big difference. While clutch-type derailleurs and narrow/wide chainrings do an admirable job with chain retention, sometimes one needs that little bit more confidence. This chainguide bolts right to the existing receiver on the pivot axle. Max 34t chainring.

Ultralight DUET Bar/Stem

DUET is a handlebar and stem system that rivals or betters the weight of most one-piece cockpit systems, yet you still get the adjustability of a traditional two-piece system. Both bar and stem are among the very lightest in the market. The 780mm DUET Handlebar paired with the 50mm DUET Stem totals a scant 199 grams.

Ultralight DUET Bar/Stem

Ultralight DUET Bar/Stem

DUET is a handlebar and stem system that rivals or betters the weight of most one-piece cockpit systems, yet you still get the adjustability of a traditional two-piece system. Both bar and stem are among the very lightest in the market. The 780mm DUET Handlebar paired with the 50mm DUET Stem totals a scant 199 grams.

Customer Reviews

Based on 3 reviews
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Brian Herlihy
BC 40 perfect geometry

I built up my frameset a month ago. I have ridden the BC40 for over 500 miles and absolutely love it. I am 6 feet and the large with a 40mm stem fits me perfectly. While the bike is more aggressive than my previous mtb (Scott Spark 900) it is still more comfortable (at least for me). What I am most impressed with is its balance. I feel perfectly centered and, as a result, find myself hitting corners and downhills faster than ever. All that and it climbs like a champ.

N
Nicky Charles
Rides like a dream

Only one ride in, but when ya know, ya know. The BC40 climbed great as expected, but it also surprised me by how well it descends. The Allied team was a pleasure to work with every step of the way and Allied Cycles is at the top of my list for my N+1.

M
MICHAEL SCHIAVO
magic carpet ride

This bike is the bomb truely an act of perfection. Climbs like a billy goat and decends like its glued to the rails. My new favorite bike by my new favorite bike company.