As mountain bike usage becomes increasingly blurred—XC riders take to the trails, Trail riders tackle steep climbs, and All-Mountain riders pursue lightweight performance—rims can no longer be defined by a single performance dimension. The KOIBIKE XC-MA25X33HL-29ER-UL embodies this fusion of riding styles: it's more than a simple addition of "wider" or "lighter," but rather the physical embodiment of a Multi-Modal Terrain Adaptation System.

The 33mm outer tire width, at 20–30 psi, allows tires 2.0–2.45 inches to navigate loose gravel and slippery fallen leaves without compromise. Furthermore, the wide-body construction reduces tire wall wrinkling during low tire pressure impacts, minimizing the risk of "snake bites."

The key innovation lies in the 3mm offset hole design: By shifting the spoke holes 3mm toward the drive side, the spoke tension difference between the non-drive and drive sides is effectively reduced. This ensures more even stress distribution and reduces localized fatigue accumulation during high-intensity lateral impacts (such as landing from jumps or ledges). This design is particularly well-suited for the frequent asymmetric loads found in all-mountain and trail riding.

Product Features and Advantages

33mm Ultra-Wide Outer Diameter: 

Ensures full contact with the ground for 2.0–2.45-inch tires, enhancing traction and cornering stability.

3mm Offset: 

Balances spoke tension on both sides, enhancing the wheel's resistance to asymmetric impacts and reducing spoke breakage and rotational wear.

25mm Low Profile and Lightweight Construction: 

Maintains agility and reduces rotational wear, perfect for climbing and diverse riding conditions.

330g Controlled Mass: 

Achieves optimal quality management, eliminating the traditional drawbacks of "wide and heavy."

20–30psi Wide Tire Pressure Window: 

Compatible with modern low tire pressures, improving comfort and grip.

Multi-Modal Compatibility: 

Supports XC, Trail, and All-Mountain riding styles, enhancing system versatility.

UD Matte Protective Coating: 

Simple and elegant, designed to withstand intense use and challenging weather conditions.

Strict Quality Control:

KOBIKE do 100% tire pressure(150 PSI), flatness(＜0.2mm) and roundness(＜0.2mm) inspections before shipping, also offering 2 years warranty for our carbon rims.

Product Structure

Offset Diameter:

 A 3mm offset design minimizes tension differences between the drive and non-drive sides, enhancing overall wheel structural symmetry and long-term stability.

External Width: 

Validated by dynamic contact patch simulations, the 33mm width provides optimal support for tires 2.0–2.45 inches, reducing tire slip.

Vacuum Seal System: 

An integrated bead interface ensures a highly reliable seal, supporting self-sealing and low tire pressure operation.

Spoke Compatibility: 

Supports 16H–36H spokes, with a cross-3 braid pattern recommended. Carbon fiber-reinforced eyelets improve tension retention.

Material & Process: 

High-modulus Toray carbon cloth, vacuum-bagging, and high-temperature curing ensure a dense structure and uniform resin distribution.

Surface Treatment: 

UD matte paint preserves the original carbon fiber texture. The elegant exterior is coated with a weather-resistant protective film for extended service life.

Application Areas

Application areas for the XC-MA25X33HL-29ER-UL carbon bicycle rim:

• Cross-Country Lightweight Widebody Platform:

  Enhances grip and handling confidence on trails while maintaining climbing efficiency.

• Trail Race Response System:

  33mm external width provides a stable foothold, while 3mm offset enhances structural robustness when landing from jumps.

• All-Mountain All-Terrain Adaptability Unit:

  Demonstrates the combined advantages of a widebody and offset design on steep slopes, rocky terrain, and high-speed descents.

• OEM/ODM Multi-Scenario Infrastructure:

  KOIBIKE offers full customization from offset, hole count, and paint finish, enabling brands to quickly develop versatile, high-performance wheels.

Technical Parameters

Customized Weaves & Finishes:

Customized Holes:

Weight Check:

Clean burrs ＆ residues

Rim Diameters Check:

Cleaning

Packing

XC-MA25X33HL-29ER-UL Product Show