The hooked vs hookless debate has been important in wheel engineering for the last few years, particularly with the increased adoption of road tubeless.From our development of hookless rims, we saw clear weight savings (about 10-15g lighter per rim) for the same profile and dimensions, when compared to hooked. There's also a cost reduction owing to a simpler manufacturing process, which we passed on to the rider. We provided clear guidance that they were to be used with certain tires and at certain pre-tested pressures.

In the end, we chose to update these wheels to hook-shaped rims, because customers wanted to use various tires, usually not tubeless tires. Non-hook compatible tires are restricted. Customer feedback at the time put the choice of tires above the weight advantage of hook-free rims. At our core, we are all riders, and although we know that wider tires and tubeless tubes can provide many benefits, we will always represent the needs of the wider cycling community. For drivers who are not ready to switch to low-pressure tubeless, we think it is very important to provide them with the versatility of hook-shaped rims.

The Difference Between Hooked & Hookless Rims

The definitions and descriptions of a hooked and hookless rim are fairly self-explanatory. A hooked rim has hooks.  Shown below, the “hooks” on a hooked rim are circled in blue.

A rim that is referred to as “hookless” does not contain hooks. The second picture shows a hookless rim. As you can see, the blue circles do not contain hooks.

The History Of Why Rims Have Hooks

You will not find hooks on a car or motorcycle rim. So, why do bicycle rims have hooks? The answer takes us back to the 1970’s when, in an attempt to save weight, tires made the switch from rigid, non-folding tires to folding bead tires.

Car and motorcycle tires can stand on their own. However, a bicycle tire does not contain the same structure and will collapse on itself. The thinner casings of a bicycle tire allowed the tire to stretch under pressure. While this saved weight, it led to tire blow offs at high pressures. To prevent blow-offs, hooks were added to the rims to hold the tire in place.

The image below shows a section of a clincher tire installed on both a hooked and hookless rim. You can see how the hook of the hooked rim helps hold the tire beads in place. The tire beads are the yellow circles shown in the picture.

Today, hooks are still used to provide stability and retention of the tires, especially at higher pressures.

FAQs

What is hookless?

Hookless rims are manufactured without bead hooks, the inward protruding edges at the top of the rim bed that help to retain clincher tires under pressure. The internal rim walls of a hookless rim are flat and straight (and hence also sometimes known as TSS - Tubeless Straight Side).

Why hookless?

The key benefits of hookless can be distilled down to the following:

• Stronger rim construction
• Lighter weight rims
• Slightly more aerodynamic profile of the global system (rim and tyre combined)
• Lower manufacturing costs, which benefit the rider if they are passed on

How easy is it to fit tyres?

DCH wheels featuring hookless rims are no more difficult to fit tires to than our regular hooked rims. The process is exactly the same.

Can I fit a tube in (generally) and in an emergency

Yes, you can! But you must only do this in a tubeless-ready tire that is safe for use on hookless rims

What happens if I split a sidewall?

Accidents can happen, and if you split a sidewall then it can be tricky to fix. However, this is likely to be the case whether hooked or hookless, and whether tubeless or clincher. A split sidewall will need to be repaired.

What is the maximum tire pressure I can run with hookless rims?

Tire pressures on hookless wheels should not exceed 72.5psi. Please also refer to any additional guidance from the tire manufacturer, and do not exceed the tire’s maximum stated pressure.