Oct. 20, 2025
For cross-country riders who demand “light weight without compromising strength” on every climb, descent, and technical section, KOIBIKE is proud to launch the XC-MA25X33HL-27.5-UL carbon fiber mountain bike rim. Tailored for 27.5-inch XC setups, this rim combines a nimble build with rugged durability—perfect for chasing PRs on singletracks or exploring backcountry trails. Dive into full specs and order details on our product page>>https://www.koibike.com/product-carbon-fiber-mountain-bike-rim-all-mountain-carbon-rim-mtb-rim-25x33mm.html
At just
320±15g, the
XC-MA25X33HL-27.5-UL stands out as a lightweight champion for XC riding—35% lighter than equivalent aluminum rims, drastically reducing rotational inertia to ease climbs and boost acceleration. But lightness doesn’t mean sacrificing toughness
The
XC-MA25X33HL-27.5-ULis built with XC riders’ pain points in mind, featuring two game-changing designs:
Ditching traditional bead hooks, the rim’s straight-side structure creates an optimal interface with 2.2–2.6-inch XC tires. Key benefits include:
Tubeless-Ready (No Tape Needed): The integrated rubber sealing layer in the rim well ensures airtightness, eliminating air leakage issues common with taped rims. Riders report maintaining pressure for 6+ months with standard Presta valves.
50% Faster Tire Changes: The flattened rim edge lets you mount or remove tires quickly—critical for on-trail repairs when time is of the essence.
Better Traction: The hookless design allows tire sidewalls to flex naturally, expanding the contact patch by 15% on muddy, gravelly, or hardpack terrain—boosting grip during cornering and steep descents.
Unlike standard symmetric rims, the
XC-MA25X33HL-27.5-UL uses
non-symmetrical spoke hole spacing (paired with high-strength aluminum nipples). This design:
Distributes spoke tension evenly across the rim, reducing stress concentration on the drive side (a common failure point for XC rims).
Lowers the risk of loose spokes or rim cracks, even when riding with max spoke tension (over 300kg).
Extends wheel lifespan by 30% compared to symmetric-rim setups, per KOIBIKE’s 6-month trail testing data.
We put the XC-MA25X33HL-27.5-UL through rigorous lab and real-world testing to prove its XC prowess. Here’s how it stacks up against standard carbon XC rims:
Climb Easier: The 320g light weight cuts fatigue on long ascents, so you save energy for the downhill.
Traction You Can Trust: The 26mm inner width (fits 2.2–2.6-inch tires) and hookless design keep tires planted on loose or wet trails.
Low-Maintenance Tubeless: No need for sealing tape—just mount, inflate, and ride, with airtightness you can rely on.
Backed by KOIBIKE’s 10 years of carbon rim manufacturing experience, each XC-MA25X33HL-27.5-UL undergoes 100% pre-shipment inspections (150 PSI pressure test, flatness/roundness checks) to ensure zero defects.
