Carbon Fiber Sporting Goods
29er Hookless Carbon MTB Rim – 23mm Profile, 28mm Inner Width, Tubeless Ready, 300–375g
29er Hookless Carbon MTB Rim – 23mm Profile, 28mm Inner Width, Tubeless Ready, 300–375g
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29er Hookless Carbon MTB Rim — 23mm Profile | 28mm Inner Width | Tubeless Ready
The Bola MTB34-C23-29 is a hookless, tubeless-compatible carbon fiber rim engineered for 29-inch cross-country and trail mountain bikes. At 300–375g per rim depending on layup grade, it offers a verified weight advantage over comparable alloy rims (typically 450–550g) while maintaining structural integrity for riders up to 100kg.
Key Specifications
| Specification | Value |
|---|---|
| Rim Diameter | 29er (ISO 622mm BSD) |
| Rim Profile Height | 23mm (low-profile XC) |
| Inner Width | 28mm |
| Outer Width | 34mm |
| ERD (Effective Rim Diameter) | 592mm |
| Rim Shape | U-shape hookless |
| Weight — Standard | 375 ± 15g |
| Weight — Superlight | 330 ± 10g |
| Weight — Ultralight | 300 ± 10g |
| Tire Pressure Range | 45–65 psi (hookless limit) |
| Max Rider Weight | 100kg |
| Spoke Hole Diameter | 4.5mm (customizable) |
| Valve Hole Diameter | 6.5mm (customizable) |
| Assembly Hole Diameter | 7.5mm (customizable) |
| Nipple Direction | Left 5° / Right 7° (customizable) |
Structural Strength Data
- Forward Compressive Strength: >300kg
- Lateral Torsion Resistance: >50kg
- Spoke Hole Tension: >280kg
- Dynamic Equilibrium (imbalance): <3g
- Flatness Tolerance: <0.15mm
- Roundness Tolerance: <0.3mm
Hookless Design — What It Means for Your Build
Hookless rims omit the traditional bead hook, reducing rim wall mass and enabling a more uniform carbon layup. This design is compatible with tubeless-ready tires that meet ETRTO hookless standards. Important: hookless rims require tubeless-specific tires and are limited to a maximum tire pressure of 65 psi. Clincher tires with inner tubes are not recommended on this rim.
Compatible Tire Widths
The 28mm inner width is optimized for 2.1–2.4 inch (53–61mm) XC and trail tires. This width improves tire casing support, reduces pinch flat risk, and promotes a rounder tire profile for better cornering traction on hardpack and loose terrain.
Weight Grade Options
- Standard (375 ± 15g): Best for trail and endurance riders prioritizing durability over minimum weight.
- Superlight (330 ± 10g): Balanced option for competitive XC riders seeking rotational weight savings without maximum layup risk.
- Ultralight (300 ± 10g): Race-optimized layup for sub-100kg XC racers on groomed or low-impact terrain. Reduced impact tolerance compared to standard grade.
Known Tradeoffs
While the hookless construction saves weight and simplifies layup consistency, it caps maximum tire pressure at 65 psi and requires ETRTO-compliant tubeless tires. Riders requiring pressures above 65 psi or using clincher tires should select a hooked-bead carbon rim instead.
Frequently Asked Questions
- Q: How light should a carbon 29er rim be for competitive XC racing?
- A: Most competitive XC rims weigh between 280–360g. This rim's ultralight grade at 300 ± 10g sits within that range, while the superlight grade (330g) offers a more durable race option.
- Q: Is a 28mm inner width good for tubeless mountain bike tires?
- A: Yes. ETRTO and most tire manufacturers recommend 25–30mm inner width for 2.1–2.4 inch MTB tires. At 28mm, this rim is well-positioned for XC and light trail use.
- Q: What is the difference between hookless and hooked carbon rims?
- A: Hooked rims have a retaining bead that supports higher pressure and is compatible with standard clincher tires. Hookless rims require tubeless-ready tires, limit pressure to 65 psi, and achieve slightly lower rim weight through a cleaner carbon layup.
- Q: Are hookless carbon rims safe for aggressive trail riding?
- A: This rim is rated for riders up to 100kg and supports compressive loads exceeding 300kg. It is suitable for XC and light trail use. For aggressive enduro or downhill terrain with high-impact forces, a taller-profile, heavier-layup rim is recommended.
- Q: Can spoke count and hole diameter be customized?
- A: Yes. Spoke hole diameter (standard 4.5mm), valve hole diameter (6.5mm), assembly hole (7.5mm), and nipple offset angles are all available in custom configurations. Contact the manufacturer with your build specification.
