
XC Race
Build Your BC40
- Carbon frame
- 120mm front/rear travel
- SRAM GX Eagle Transmission

RACE-DAY LIGHT, PLAY-DATE READY
Inspired by the rocky surfaces, dynamic corners, and punchy climbs of our legendary Back 40 trail, BC40 is a second-to-none, modern XC racing bike with legs to take on much bigger trails. Its lightweight, high-performance carbon frame and progressive geometry deliver fast accelerations and race-day sharpness. Its World Cup talent extends to the 120mm suspension travel that also sets it up as a do-it-all weekend trail sled, delivering uncanny levels of control and confidence beyond its category.
The SRAM GX Eagle Transmission Build
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.
Front derailleur | N/A |
Rear derailleur | SRAM GX Eagle AXS |
Shift levers | SRAM GX AXS Controller |
Cassette | SRAM XG 1275 Eagle 10-52 |
Chain | SRAM GX Eagle |
Crankset | SRAM GX Eagle Dub |
Bottom bracket | SRAM Dub 73 BSA |
Brakes | SRAM G2 RS 180 Front / 160 Rear |
Handlebar | FSA SL-K MTB Carbon |
Handlebar tape | ESI Chunky |
Stem | FSA Gradient |
Saddle | Selle Italia Novus Boost Superflow |
Seatpost | Fox Transfer Performance 31.6 |
Wheelset | Industry Nine 1/1 Trails S |
Tires | MAXXIS Rekon 29x2.40 WT EXO/TR Tan Wall |
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.

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
Please note, we do not have a height-based size chart. 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.
Small
Reach:
420mm
Medium
Reach:
445mm
Large
Reach:
475mm
X-Large
Reach:
501mm
157cm
5'2"
-
167cm
5'7"
162cm
5'6"
-
177cm
5'10"
172cm
5'9"
-
188cm
6'0"
180cm
5'11"
-
195cm
6'5"
Frequently Asked Questions