bc40

BC40 Frameset

$4,000

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. In fact, by optimizing its carbon laminate schedule to carve out any excess weight, we’ve made the frameset stiffer all around, too, without sacrificing any of BC40’s renowned strength. That means all the power you’re putting down gets into the ground as you fly up the climbs.

Lightweight BC40 on path

Lighter and Stiffer

The BC40 is now 100g lighter than before. In fact, by optimizing its carbon laminate schedule to carve out any excess weight, we’ve made the frameset stiffer all around, too, without sacrificing any of BC40’s renowned strength. That means all the power you’re putting down gets into 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

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A
Anonymous
BC40 Exceptional

The team at Allied was great and kept me informed during the order/build process. The product far exceeded my expectations. That Harlequin purple/green is gorgeous, and component build with XX SL, and Flight Attendant makes the bike fly uphill. It is amazing how efficient this bike is, and at the same time comfortable. I would highly recommend the BC40, as well as any purchase from the amazing team at Allied.

T
T.M.
A Ride to Remember

As I pedaled through the winding trails of Bentonville, the Allied BC40 became my trusty steed. Its sleek design, precision engineering, and responsive handling made every twist and turn an absolute joy. The trail seemed to come alive beneath me, and I couldn’t help but grin as I tackled each obstacle.

But it wasn’t just the ride on this demo bike that left me in awe—it was the story behind the bike. Shane, from Allied Cycle Works, provided a fantastic tour of their manufacturing facility as these are made right here in the USA. As someone who values US manufacturing, this struck a chord with me. Allied’s commitment to quality, innovation, and supporting American jobs is commendable.

The Allied BC40 isn’t just a bike; it’s a testament to American craftsmanship. Whether you’re a seasoned rider or a newbie hitting the trails, this bike will elevate your experience. Kudos to Allied for bringing manufacturing home and creating bikes that inspire adventure!

B
Brian Herlihy
BC40 6000 mile review

I bought my BC40 as a frameset just about a year ago and have put 6000 miles on it. I built it up with Trickstuff C44 brakes, Royal Control SL Wheelset, SRAM XXL Transmission, Gemini Integrated Bar and Fox suspension and fork. I love the bike. The geometry fits me perfectly, balances my weight in a perfect triangle over seat and handlebar. Without pedals - the setup is right about 10kg. The BC40 is very efficient, yet comfortable. I did the 24hour MOAT last year and was shocked how comfortable the bike held up (3D Specialized saddle helps too). I would highly recommend the BC40.

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Anonymous
good bike

This is a fantastic bike I would recommend it is a little pricey but it has electric everything and its so pretty rides super good

K
Ken Sluyter
Everything you need.

This bike is super comfortable. Longer rides just seem easier. I did change the seat and went with the Reserve wheels. Changed the tires to the Mezcal’s. Also I’m not a dropper guy so opted for a carbon seat post. With these changes the bike dropped to 24 pounds even with bottle cage and Shimano XTR pedals. Fit and finish is like a high end sports car. I probably have a couple hundred miles on it now and I’m still excited to get on it. If you need a new bike “this is it”
I’m 5.11 and size Large seems perfect.

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