Hookless vs Hooked: An Explainer
The hooked vs hookless debate has been important in wheel engineering for the last few years, particularly with the increased adoption of road tubeless. At HUNT, we’ve had an interesting relationship with this debate as we were one of the first companies to offer a road wheelset using our hookless (then called H_LOCK Wedge) technology back in 2016, with our 55 Carbon Wide Aero in (2016-2017) and 30/50 Carbon Aero Disc (2016-2018). We felt it was a natural step for the company to make, already being a huge advocate for road tubeless since our inception.
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.
Ultimately in 2018, we opted to update those wheels to hooked rims because, especially at that time, customers wanted to run a wide range of tires, often not tubeless. Hookless compatible tires were limited. Feedback from customers at the time prioritised tire selection over the rim weight advantages of hookless. At our core, we are all riders and although we know wider tires and tubeless can provide many benefits, we will always represent the needs of the wider cycling community. For riders not ready to make the switch to low-pressure tubeless, we felt it was important to offer them the versatility of hooked rims.
There have been significant changes within the industry since we first came out with our own hookless models in 2016, with the largest manufacturers in the industry now making hookless wheels. With the newly announced ETRTO guidelines, the variances between tire and wheel manufacturers (“tubeless standards”) have reduced, resulting in more informed acceptance by some riders running hookless on the road.
Tire pressures on hookless wheels should not exceed 72.5psi, and many riders are starting to see that lower pressures help them to ride faster. Further, our work in the wind tunnel and using CFD software has indicated to us that a hookless bead may achieve a slightly more aerodynamic shape because of the way the tire interacts with the rim. As mentioned above, it is also less costly to manufacture hookless rims to tight tolerances, which is beneficial for the rider if that reduction in cost is passed onto them. With this in mind, we are actively looking at offering more hookless options/variants of our wheels, particularly for gravel riding or forms of riding where lower tyre pressures are considered the norm.
As with anything, there are benefits and compromises in either direction. It is a fine balance of where the benefits will outweigh any penalties, across different riding disciplines with ever-shifting perceptions on performance. With the lower pressures of gravel, and even lower pressure of MTB, the compromises gradually become less of an issue. The benefits (weight and cost) in MTB generally outweigh any small negatives such as having to use only tubeless tires (as almost every MTBer does anyway) meaning the vast majority of carbon MTB wheels are hookless.
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).
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?
HUNT 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.