Taking on the GDMBR with Flatbar Yaupons
As one of the pinnacle routes in the realm of bikepacking, the Great Divide Mountain Bike Route (GDMBR) sets itself apart with varied terrain across gravel, jeep tracks, and technical singletrack. It offers a test of endurance, strength, and mental fortitude over the course of 2,700 miles from Banff, Alberta, Canada, to Antelope Wells, New Mexico, USA with nearly 150,000’ of climbing. When planning to ride that long and that far, a lot of decisions need to be made, ranging from the type of bike used, down to the tiniest detail such as which type of spork to bring.
Along with these decisions comes a lot of careful planning and comparing options based on performance, weight, durability, and cost. Sometimes concessions in one aspect of your rig need to be made to allow for comfort and reliability in another. With a wealth of knowledge and experience, one of our favorite excercises at Chumba is to help riders plan out their bike grand adventures such as the GDMBR. With our years of experience, we’ve helped many, many riders plan for this journey, and get excited drilling down into the nitty-gritty details to help plan the perfect Chumba build to take on the GDMBR with confidence, speed, and peace of mind.
Earlier this year, Arjuna and Sophie reached out about planning some steel flatbar Chumba Yaupon builds for an attempt this August. Two riders taking on the route for the first time, and riding together poses some interesting build choices and comparisons. While similar, their two builds ended up having some key differences that are fun to pick apart based on the rider.
The duo plan to ride from the US/Canada border, down to Antelope Wells starting in early August, keeping their itinerary loose and are planning to take their time on the route to stop and soak up all the experiences. You can follow along with their trip on instagram:
Arjuna - @hands.habit on Instagram | Sophie - @cream__sleeze on Instagram
Frame - Chumba Yaupon Steel MD
FORK - ENVE Carbon Rigid Boost
WHEELS - Industry Nine Trail S Hydra w/ Dynamo Front by Stoke Custom Wheels
TIRES - Vittoria Mezcal 29x2.35”
CRANKSET - Cane Creek Titanium eeWings
BOTTOM BRACKET - Cane Creek 110
DRIVETRAIN - SRAM GX Mechanical 10-52T
HANDLEBAR - Thomson Titanium Riser 31.8mm 800mm
STEM - Paul Boxcar Silver Polished
GRIPS - ESI Chunky
HEADSET - Chris King Inset
BRAKES - Shimano XTR 4 Piston
SADDLE - Ergon SMC Core
SEATPOST - Thomson Silver Elite 31.6
PEDALS - Shimano XTR Trail
Lighting - kLite Adventure Kit
Frame - Chumba Yaupon Steel SM
FORK - ENVE Carbon Rigid Boost
WHEELS - Industry Nine Trail S Hydra w/ Dynamo Front by Stoke Custom Wheels
TIRES - Vittoria Mezcal 29x2.35”
CRANKSET - White Industries M30 Alloy
BOTTOM BRACKET - White Industries Gold
DRIVETRAIN - SRAM GX Mechanical 10-52T
HANDLEBAR - Thomson Alloy Trail Riser Bar 800 x 35mm
STEM - Industry Nine A35 Gold
GRIPS - Ergon GS2-S
HEADSET - Industry Nine iRiX Gold
BRAKES - Shimano XTR 4 Piston
SADDLE - Terry Butterfly Cromoly
SEATPOST - Thudbuster ST 31.6
PEDALS - Shimano XTR Trail
Lighting - kLite Adventure Kit
What’s the Same
Comparing the build kits, the common factors lie in their choice of frame, fork, drivetrain, brakes, and wheels. The Yaupon is an excellent frame choice for the GDMBR, as it blends efficient pedaling, a comfortable all-day rider position, and trail capabilities.
The ENVE Mountain fork is a great choice for the GDMBR with ample mud/tire clearance, light weight, cargo mounts, and a built in fender. Paired with tires on the bigger side (2.35”) for the GDMBR, they likely won’t miss having a suspension fork.
The SRAM GX drivetrain offers a budget friendly mechanical groupset that’s reliable and offers a huge gearing range from 10-52t, providing pedaling both speed and climbing capability. Their XTR 4 piston brakes are known for their reliability, and the extra pistons provide some extra stopping power for going downhill with a loaded bike.
Industry Nine’s Trail Wheelset provides a high-engagement rear Hydra hub with a sturdy aluminum rim. Paired with Vittoria Mezcal tires that are extremely versatile for long stretches of gravel, and being able to dig into some dirt when needed. The dynamo front hub is a major advantage with this build. Paired with the kLite light/charger provides serious ease of mind for keeping phones and GPS charged, and paths illuminated.
Riding together, it made sense for many of the parts to be similar, and Arjuna and Sophie nailed these from a compatibility standpoint. Some common spare parts to bring along are brake pads, chain quick links, and extra spokes - all of which they can share out on the trail.
Arjuna’s Key Components
Arjuna’s black and silver stealth build made it easy to get matchy with his component choices. One major highlight are his titanium eeWings cranks made by Cane Creek. These are some of the lightest and stiffest MTB cranks out there. Being made of titanium, they’re heralded by bikepackers for being able to stand up to pedal strikes, and offer simple refinishing to look like new with some simple scotch-brite after the ride.
This build also has a focus on comfort up front with a titanium handlebar paired with comfy ESI foam grips. The Thomson Titanium bars offer a lot of natural vibration dampening and compliance, easing out arm fatigue over long days.
The Ergon SMC saddle is one of the comfiest performance saddles out there. With a layerd foam core, it adds some extra comfort for the tailbone and lower back, essential for riding long stretches of chunky terrain.
Sophie’s Key Components
Where Arjuna opted for some extra comfort up front, Sophie opted for a “soft tail” approach with a Cane Creek Thudbuster ST seatpost. This post has a built in elastomer which provides up to 50mm of travel. While a dropper post might be handy on some stretches of the divide, a seatpost like the Thudbuster provides both small and large bump compliance, making long miles more enjoyable and technical sections more manageable. Matched with a women-specific Terry Butterfly saddle, there should be few complaints in seated comfort on this ride.
For grips, Sophie opted for the GS2 model from Ergon. Hand numbness is a common complaint on the GDMBR, and these offer a rest for your palm, and multiple hand positions with the bar ends.
Sophie opted for White Industries M30 cranks - a bikepacking staple. Ultra reliable and strong, these cranks are worry free on the trail. Sophie also was able to get matchy between the cranks, bottom bracket, stem and headset for an awesome gilded finish.
Which would you choose?
Both of these Yaupon builds are extremely solid and will provide ample comfort and performance over the thousands of miles on the GDMBR. Which build would you take on the route? Build your own using our custom bike builder and start planning for your own adventure.