XC Race

BC40

BC40 SRAM X0 Eagle Transmission Complete Bike

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BC40 SRAM X0 Eagle Transmission Complete Bike

    BC40 SRAM X0 Eagle Transmission Complete Bike

    $6,750 Regular price $9,000

    Hi-tech, perfectly balanced with relentless durability, is what makes the BC40 with SRAM X0 Eagle Transmission one of our fave cross-country MTBs. Climb, descend, and rip singletrack every day with this elite, workhorse build kit.

    Color
    British Racing Green
    Size
    Have a question? Request a Callback

    Lifetime Warranty

    Every ALLIED frameset is backed by our lifetime warranty.

    Flexible Payments

    Finance with Affirm or use your HSA/FSA benefits. Yes, our bikes are eligible.

    60-Day Returns

    Buy with confidence — return within 60 days for a refund or exchange.

    RACE DAY LIGHT

    BC40 was built to race at the highest level, where every gram matters. Its lightweight carbon frame responds quickly to accelerations, climbs efficiently, and delivers the precision needed when every second counts. Proven on World Cup courses, but never limited to the start line.

    BUILT, BOXED, READY

    A complete BC40, built to ride. Thoughtfully spec'd with the components we trust, assembled by our team, and delivered directly to your door. Less time deciding on components, more time getting out on the trail.

    LET’S TALK BIKES

    From finding the right fit to choosing the bike that suits your riding style, our team is here to help. Tell us how you like to spend your time on two wheels, and we'll help you find the right ALLIED for the rides you're chasing.

    CONNECT WITH US
    • Kate Courtney crossing finish line with champagne 2025

    The specs below reflect the default Build Kit and do not account for customizations made in the Bike Builder. See your Build Summary above for custom choices.

    Fork RockShox SID Ultimate 3P 120
    Rear derailleur SRAM X0 Eagle Transmission
    Shift levers OneUp V3 Dropper, 31.6 (S - 120, M/L - 150, XL - 180)
    Cassette SRAM 1295 X0 Eagle 10-52
    Chain SRAM X0 T-Type
    Crankset SRAM X0 Eagle Transmission 32T (S - 165, M/L - 170, XL - 175)
    Bottom bracket SRAM Dub 73 BSA
    Brakes SRAM Motive Silver 180 Front / 160 Rear
    Handlebar ALLIED Duet HB08 Carbon Flat Bar
    Handlebar tape ESI Chunky
    Stem ALLIED ST05 Duet, -6° (S - 50, M/L - 60, XL - 70)
    Saddle SRAM X0 Eagle Transmission
    Seatpost OneUp V3 Dropper, 31.6 (S - 120, M/L - 150, XL - 180)
    Wheelset Zipp 1Zero HiTop S, 6-Bolt, XD Driver
    Tires Vittoria Mezcal XC Race 29x2.40, Black
    Geometry

    For optimal performance and control on fast and technical tracks, BC40 uses a slack head tube angle and a long front-to-center measurement. The result is geometry that positions the rider further behind the front wheel for world-class ride quality and predictable handling, no matter how hard you push it.

    Technical drawing of a MTB bicycle frame with labeled parts on a white background
    All units are in Millimeters or Degrees
    SM MD LG XL
    a Stack 598 609 622 633
    b Reach 420 445 475 501
    c Effective top tube 569 596 630 659
    d Seat tube length 395 420 450 500
    e Head tube length 95 105 120 135
    f Head tube angle 66.5° 66.5° 66.5° 66.5°
    g Seat tube angle 76° 76° 76° 76°
    h Bottom bracket drop 40 40 40 40
    i Chainstay length 435 435 435 435
    k Wheelbase 1145 1174 1210 1241
    m Fork rake 44 44 44 44
    n Front center 710 739 778 806
    o Wheel size 29 29 29 29
    Size Guide

    This chart offers a general size recommendation based on height. Since fit is personal, our team can help dial in the right size using your measurements and current bike geometry. Contact us at support@alliedcycleworks.com for a custom fit recommendation.

    Small Reach: 420mm
    157cm 5'2" - 167cm 5'7"
    Medium Reach: 445mm
    162cm 5'6" - 177cm 5'10"
    Large Reach: 475mm
    172cm 5'9" - 188cm 6'0"
    X-Large Reach: 501mm
    180cm 5'11" - 195cm 6'5"
    Frequently Asked Questions

    You’ll find detailed FAQs, sizing guidance, and support resources in our Help Center.

    Quite simply, we love mountain biking.  It’s in our DNA, and we are lucky enough to live/work in the mountain bike mecca of NWA.  Just like the ECHO and ABLE, we built a bike that we wanted to ride, inspired by our local terrain and the demands our athletes require to perform at the highest level.

    We try our best to accommodate custom options. Please reach out to us and we will let you know if it is possible and give you a quote.

    Yes, all of our bikes and models ship set up tubeless with Orange Seal sealant.

    No, since everyone's proportions are different, we prefer to have a human involved. Please email our fitting team at support@alliedcycleworks.com and we will custom fit you via your measurements and current bike geometry.

    See exploded view HERE

    The BC40 is set up with and designed around 120mm travel front and rear. It can also be set up with 110mm or 100mm options by utilizing different fork and shock options. You will see our athletes using the BC40 in 100mm travel mode for races like Leadville this summer.

    The BC40 frame was designed, prototyped, and fully tested in-house at our factory in Bentonville, AR.  The carbon layup and molding on the front and rear triangles take place at an external factory based in Asia. Each raw carbon part produced at the external factory undergoes a rigorous in-house quality inspection and paint preparation to ensure the highest standards. The suspension link, brake mount, and DUET stem are manufactured fully in-house at our Bentonville location. Finally, the frame is custom-painted and assembled to each customer’s unique order at our Bentonville facility, and goes through a final inspection and test ride before leaving the factory.

    29x2.4” on all sizes.

    We will offer options with SRAM, Shimano, Fox and RockShox so each rider can build their own dream bike.

    Target frame weight including Sid Luxe Ultimate shock is 1950g/4.3lbs for size L; final weight will vary depending on size and paint option selected.

    Like all ALLIED bikes, the BC40 is built to customer order. Each rider can choose from one of our many base and logo color options. Additionally, we hope to offer a couple of our athletes’ custom paint jobs as limited editions.

    See attached for the BC40 Geo and Frame Specs.

    All frame sizes have a 705mm (27.8") standover measured from the center of the bottom bracket to the top of the top tube.

    Please reference our BC40 Saddle Height Guide for minimum and maximum saddle heights per dropper length.

    Absolutely! Click here.

    73mm English Threaded BSA

    We spec it around the Chris King Dropset 3:

    • 41mm 45x45 upper bearing
    • 52mm 36x45 lower bearing

    Two! One of any size on the downtube, and one 21oz or less on the seat tube. Double-check that your lid doesn't rub the shock mount and the base doesn't touch the downtube—you don't want it to rub your beautiful paint!

    Support
    BC40 Exploded Schematic 1 BC40 Torque and Grease Protocol

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