Not all mountain bike rims are hookless, but most new MTB rims, especially carbon and even many aluminum ones, are now designed as hookless. The main reasons are:

1. Technology & Safety

>Low tire pressure riding needs

Mountain bikes typically run at lower tire pressures (e.g., 18–28 psi). Under such conditions, the traditional “hooked” structure is less meaningful, since the pressure isn’t high enough to blow the bead off.

>Better bead-to-rim fit

Hookless rims feature a wider, flatter shelf that allows tubeless beads to seat more securely and evenly, reducing burping or blow-offs.

>More impact resistant

With no thin “hook” section, the rim sidewalls are thicker and stronger, distributing impact forces more evenly and resisting rock strikes better.

 2. Manufacturing & Cost

Simpler production

>Hooked rims require more complex molds and machining—especially with carbon fiber. Hookless rims are easier to manufacture with more consistent strength.

>Stronger structure

Without a delicate hook, the overall rim is stiffer and more durable.

3. Tire Development

>Tubeless adoption

Modern MTB setups are almost all tubeless-ready. Tire beads are now reinforced and specifically designed to pair with hookless sidewalls.

>Industry standards

ETRTO (European Tyre and Rim Technical Organization) has established standards for hookless MTB rims, ensuring reliable compatibility and safety.

 4. Road Bike Comparison

Road bikes run high pressures (70–100+ psi), so hooked rims traditionally remained safer, preventing blow-offs.

But with wider tires and tubeless adoption, hookless is gaining traction in road rims too, usually with a pressure limit ≤72 psi.

So.

For MTB (low pressure + tubeless) → Hookless is safer, stronger, and more economical, so it has become the mainstream.

For road bikes (high pressure) → hooked rims still exist, but hookless is growing in popularity.



Feature Hookless Hooked
Structure Vertical straight sidewalls, tire bead rests on a flat shelf Sidewall has an inward “hook” that holds the tire bead
Recommended Pressure Low pressure (commonly 15–30 psi) High pressure (more stable above 50 psi)
Main Use Mountain bikes (XC, Trail, Enduro, DH), some low-pressure Road/Gravel Traditional road bikes, some older MTB rims
Impact Resistance Stronger, thicker sidewalls, less prone to cracking Weaker at the hook area, more vulnerable to rock impacts
Manufacturing Simpler mold, stronger structure, lower cost More complex mold, hook section is thinner and weaker
Weight Can be made lighter Usually heavier or needs reinforcement
Tire Compatibility Designed for Tubeless Ready tires with reinforced beads Wider compatibility, also works with traditional clincher tires
Safety Safer at low pressure, prevents burping or bead blow-off Safer at high pressure, prevents bead from lifting off