Used: BMC Kaius 51cm Purple

BMC Kaius – Size 51cm | Custom SRAM Force AXS / XX1 Build

This BMC Kaius (51cm) is a thoughtfully curated custom gravel race build, designed for riders who want top-tier performance, durability, and precision. Mechanic owned and meticulously maintained, this bike blends cutting-edge road and mountain components into a fast, versatile package that’s ready to line up—or disappear down back roads.

The drivetrain features SRAM Force AXS 1x with a 44T Quarq power meter chainring, paired to a SRAM XX1 mountain rear derailleur and XX1 10–52 cassette. This setup delivers massive range, crisp wireless shifting, and reliable chain retention for everything from fast gravel to steep, punchy climbs. An XX1 Gold chain finishes the build with both durability and a little extra flair.

Rolling stock comes courtesy of Whiskey No.9 GRVL carbon wheels, laced to dependable DT Swiss 350 hubs, offering an ideal balance of low weight, stiffness, and serviceability. Challenge Getaway XP 700x40 tires provide confident traction and comfort across mixed terrain without sacrificing speed.

Up front, the cockpit is dialed with a Bontrager RSL aero carbon handlebar, measuring 39.5cm at the hoods and 42cm at the drops, giving you a narrow, efficient position with added control when descending or riding technical terrain.

This bike has been fully inspected and professionally tuned by our mechanics and earns a 4.5 out of 5 mechanical condition rating. Like all used bikes sold at The Bike Porch, it includes our 90-Day Ride-Ready Guarantee, so you can buy with total confidence.

Highlights:

• BMC Kaius frameset – Size 51cm
• SRAM Force AXS 1x with Quarq power meter (44T)
• SRAM XX1 rear derailleur, 10–52 cassette, XX1 Gold chain
• Whiskey No.9 GRVL carbon wheels w/ DT Swiss 350 hubs
• Challenge Getaway XP 700x40 tires
• Bontrager RSL aero carbon handlebar (39.5cm/42cm)
• Mechanic owned & professionally maintained
• 90-Day Ride-Ready Guarantee

A purpose-built gravel machine that’s fast, capable, and impeccably maintained—this Kaius is ready for its next chapter.