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Home > News > Bicycle Wheel Standards Explained: ASTM Levels and OEM Carbon Rim Mapping

Jun.2026 22

Bicycle Wheel Standards Explained: ASTM Levels and OEM Carbon Rim Mapping

Introduction

The classification system for bicycle wheels is defined by ASTM International under the ASTM F2043 standard. This framework categorizes bicycle use cases into performance levels based on riding terrain, impact severity, and intended application.

Details

The system is presented on a Level 0 to Level 5 scale, helping manufacturers, OEM/ODM partners, and bicycle brands align product design with real-world riding conditions and safety expectations.

ASTM F2043 Wheel Classification Overview

Level 0 – Children’s Bicycle Use

Applied to bicycles intended for children (commonly sidewalk or beginner bicycles), operated under appropriate parental supervision and within the limits of the rider’s cycling ability.

Minimum rider age: 3 years
Maximum rider weight: 36 kg (80 lb)

This category defines controlled, low-speed riding environments with minimal impact exposure.

Level 1 – Road / Asphalt

Designed for bicycles used on smooth, paved surfaces where continuous tire contact with the ground is expected.

Short, incidental loss of tire contact may occur due to minor surface irregularities.

Level 2 – Gravel / Mixed Terrain

Extends Level 1 conditions to include unpaved roads, gravel paths, and moderate gradients.

Temporary loss of tire contact is acceptable
Jump/drop allowance: up to 15 cm (6 in)

This category is widely used for gravel and cyclocross applications.

Level 3 – MTB XC / XCM

Includes all conditions from Levels 1 and 2, with additional use on rough off-road terrain requiring advanced technical riding skills.

Jump/drop allowance: up to 61 cm (24 in)
Suitable for cross-country (XC) and marathon (XCM) disciplines

Wheel damage may still occur due to improper riding technique or unexpected impact forces.

Level 4 – Enduro

Builds on Levels 1–3 and includes aggressive trail riding and technical downhill sections.

Maximum speed: 40 km/h (25 mph) on technical descents
Jump/drop allowance: up to 122 cm (48 in)

This category is intended for enduro and trail applications requiring higher structural strength and impact resistance.

Level 5 – Downhill / Freeride

The most demanding category within the ASTM classification system.
Includes extreme terrain conditions, high-impact landings, and advanced downhill riding scenarios.

No defined limits for jump height
No speed limitation within test scope

Due to extreme loading conditions, wheel damage may still occur even under intended use conditions.

NTP Open-Mold Carbon Rim Classification Overview

Model	Usage	ASTM	ERD	Width	Depth	Weight
EN32-23	Enduro	Level 5	592mm	32/39mm	22/23mm	480g+/-15
XC30-22	MTB XC	Level 3	594mm	30/35mm	22mm	270g+/-15
G30-45	Gravel/Adventure	Level 2	550mm	30/34mm	45mm	410g+/-15
G28-45	Gravel/Adventure	Level 2	550mm	28.5/34mm	45mm	400g+/-15
G30-50	Gravel Racing	Level 2	539mm	30/38mm	50mm	460g+/-15
R25-45	All-Road	Level 2	550mm	25/30mm	45mm	360g+/-15
R25-52	All-Road	Level 2	536mm	25/30mm	52mm	380g+/-15
R23-55	Road	Level 1	530mm	23/28.5mm	55mm	415g+/-15
R23-60	Road Racing	Level 1	520mm	23/28.5mm	60mm	420g+/-15
R23-168	Tri, Flat Road	Level 1	303mm	23/28.5mm	168mm	780g+/-15
R21-40	Road	Level 1	560mm	21/26.4mm	40mm	360g+/-15
R21-50	Road	Level 1	540mm	21/26.4mm	50mm	375g+/-15

View more open-mold product info >>

OEM/ODM Engineering Support

Each rim model is developed with application-specific carbon layup engineering, ensuring alignment with ASTM performance categories and real-world riding demands.

We provide full OEM/ODM support, including:

Custom rim geometry and carbon layup development
Application-based performance tuning (road, gravel, MTB, downhill)
Prototype sampling and validation support
Mass production with strict quality control standards
Packaging, branding, and global shipping solutions

Talk to our engineering team to develop your next high-performance wheels.

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Email: koko@ntpcomposites.com
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