In recent years, road bike equipment has continuously evolved. From the introduction of disc brakes a few years ago to the current trend of tubeless tires and tubeless wheelsets, disc brake road bikes have gradually gained acceptance among the general public. Tubeless tires and wheelsets have also become a hot topic. Tubeless tires offer lower rolling resistance and better comfort, which has led many riders, including top professional teams, to adopt them. With the growing development of tubeless tires in road cycling, hookless rims have also been applied to road bike wheels. So, do we really need hookless rims?

Conclusion: Yes, but not right now (this is just my personal opinion).

Now that we’ve stated the conclusion, let’s discuss why hookless rims might be the future trend and why I don’t recommend purchasing them just yet. First, let’s understand what hookless rims are. As shown in the image, from left to right, we have the regular clincher wheels, hooked tubeless wheels, and today’s main focus—hookless tubeless rims. The biggest difference between hookless tubeless rims and regular tubeless rims is the removal of the “hook” at the top that secures the tire. Hookless tubeless rims are lighter, stronger, and offer better performance for the tires. Let’s explore these points in more detail.

Higher Strength After Removing the Hook

The continuous carbon fiber structure (as shown in the image, where the carbon fiber material prevents bending) increases the overall strength of the rim, making the rim walls more durable and robust. This is especially beneficial when using lower tire pressures, as hookless tubeless rims are less likely to be damaged during impacts or bumps.

Wider Internal Tire Width for Better Tire Shape

When using hookless tubeless rims, you get a wider internal tire width, which improves the shape of the tire. This allows you to achieve the same grip, comfort, and performance of a larger tire with a smaller one, offering a weight advantage as well.

Better Performance in Cornering

In corners, the tire maintains its shape better, offering superior grip. The stronger sidewall support of the hookless rim further enhances tire performance when cornering, providing more stability and control.

Improved Aerodynamics of the Wheelset

This mainly refers to the aerodynamic benefit between the tire and the wheelset. While this improvement is marginal, it’s still worth considering. It’s difficult to say how noticeable this effect is during actual riding, as manufacturers cannot provide specific quantifiable data. The aerodynamic improvement comes from the position of the tire shape relative to the rim. Traditional hooked rims cause the tire to take on a bulbous shape, with the tire significantly tapering inward near the rim. On the other hand, hookless rims allow the tire to maintain a rounder shape, with a smoother transition towards the rim, creating a more streamlined effect. It’s surprising to think that even road bike wheels are now designed with tire aerodynamics in mind.

Continuing the Discussion on Hookless Tubeless Rims

After discussing the advantages of hookless tubeless rims, let’s return to the topic itself. Hookless rims are a very mature technology, originally applied in motorcycles and cars, and later used in mountain bikes. In fact, choosing mountain bike wheelsets without hookless design, especially high-end products, now feels somewhat outdated. In recent years, with the development of tubeless tires in road cycling, hookless rims have entered the road bike market. This suggests that hookless rims are an excellent technology worth promoting and using. However, at present, most cyclists are not fully convinced. Apart from compatibility issues, the main concern is whether the tire will fit securely without the hook, and whether it will stay in place.

Tire Fixation Principles and Why the Hook Can Be Removed

To address these concerns, let’s take a look at how tubeless tires are fixed to the rim and why the hook is not necessary. Regular clincher wheelsets mainly rely on the hook on the rim to secure the tire. Over time, this has become a conventional belief among cyclists that the tire and rim fitment depend entirely on the hook. As a result, many cyclists feel that hookless rims are dangerous. However, in reality, the fitment of the tire to the rim, whether the rim is hooked or hookless, is not solely dependent on the hook. Both sides of the tire bead engage with the rim bead seat and rim bead lock, ensuring a tight seal and proper tire retention.

However, achieving this effect requires a tight fit between the tire bead and the rim. This means that the diameter of the tire bead must precisely match the rim’s bead seat to ensure sufficient airtightness and tire retention. Additionally, the width of the tire bead needs to match the grooves of the bead lock, which keeps the tire bead securely in place and prevents it from being pushed inward, potentially leading to displacement or even detachment. In summary, using a compatible tire with the rim eliminates concerns about the tire coming off.

Since the tire needs to fit tightly with the tubeless rim, all specifications must match for proper use, which brings up an issue of compatibility between the tire and the rim. This is one of the main reasons why I believe tubeless rims will be a trend for the future and are worth using, although they are not yet mature. Currently, manufacturers offer a limited number of compatible tires for these wheelsets, resulting in a very restricted selection. Many dealers are also not fully aware of whether a particular tire is compatible with a specific tubeless rim. Additionally, some products lack necessary purchasing channels. Consequently, many users of tubeless rims who encounter dangerous situations often do so because they are not using compatible tires or do not have the correct tire pressure.

It’s important to emphasize that tubeless rims must be used with tubeless tires! Tubeless rims must be used with tubeless tires! Tubeless rims must be used with tubeless tires!

Regarding tire pressure, different manufacturers have varying requirements for their products. However, the maximum pressure limits set by most manufacturers are generally lower than those for conventional clincher or hook-type wheelsets (though some manufacturers, like ZIPP, make this choice based on performance rather than safety). Excessively high pressure can cause the tire to displace or even be positioned incorrectly, leading to dangerous situations. Below, let’s take a look at the relevant regulations from manufacturers using tubeless rims.

Wolf Vorm Walde, the tire product manager at Lightning, stated, “First, ETRTO (the European Tire and Rim Technical Organization) specifies that any high-pressure tire with a pressure exceeding 5.5 bar (80 psi) must have rim hooks. Our high-pressure tires meet this standard. We have also produced a hooked steel rim and a tubeless straight-edge solid steel rim in accordance with ETRTO regulations. Testing of clincher tires at maximum pressure has shown that hooked rims can withstand 20% more lateral pressure than straight-edge rims. The results from testing with tubeless tires are similar. In summary, our tests indicate that traditional hooked rims can handle greater lateral pressure than tubeless rims; thus, we do not recommend using a pressure higher than 5.5 bar (80 psi) on straight-edge rims (tubeless rims).”

For instance, the recently released Zipp 303-S wheelset has a recommended maximum pressure of only 72.2 psi. Zipp claims that lower tire pressure provides better road feel and increased speed.

In conclusion, do road bikes really need tubeless rims? Yes, they will gradually replace other products in the future. So, are they worth purchasing now? Yes, but attention must be paid to tire compatibility. However, I believe that if you’re not in a hurry to upgrade your equipment, it might be wise to wait for more manufacturers to release relevant products (both wheelsets and tires) before making a purchase. Are tubeless rims safe and reliable? Yes, as long as they are installed correctly and compatible products are used. Personally, I have been using tubeless rims on my mountain bike for some time, and I will continue to observe the developments in road biking.