Tubed or tubeless, hooked or hookless, those are the questions. At some point, every cyclist faces them: when a new wheelset is due, and you have to decide which system you want to commit to. To prevent them from becoming paralyzing deliberations, as was once the case with the tragic Danish prince, we have compiled the most important information for you here. What are the advantages and disadvantages of the common rim types? Which tires are compatible with them? What do you need to consider to stay safe on the road? You'll find out in this little compendium.

The Hooked Rim

Let's start with the classic. Anyone who rides a bike occasionally has probably ridden a hooked rim (also known as a crotchet rim). The distinguishing feature that gives it its name is a small hook on the rim flange, into which the tire bead hooks (see illustration). To facilitate this, wired tires are typically used. Their bead is reinforced by a steel wire that prevents the material from stretching or deforming. The English term for wired tires is Clincher, which is why this type of rim is sometimes also called a Clincher rim.

However, you can also use folding tires just as well. Here, plastic fibers take over the job of the wire, which often makes these tires significantly lighter. Since they can be folded, as the name suggests, they also have a more practical pack size.

Classic hooked rims are combined with tube-type tires, i.e., tires designed for use with an inner tube. However, even tubeless or tubeless-ready rims often have hooks.

Hookless

But why? Cars and motorcycles manage without them. And didn't a colleague, an experienced mountain biker, just shrug when asked about the topic: "Pffft, hookless – we've been riding them for years?"

True, and it could have been. The hook is not a load-bearing part of the rim. However, with very narrow tires that are ridden at high air pressure, it increases the blow-off pressure – that is, the pressure at which you have to expect the tire to come off. That's why it was a safety feature for bicycle rims for a long time. But since wide mountain bike tires are usually ridden at very low air pressure, the smooth rim flange has already proven itself here.

Why Hookless?

The advantages of hookless rims primarily lie in manufacturing, especially when it comes to carbon rims. Carbon is not a metal, but a fabric of carbon fibers impregnated with synthetic resins that harden when heated. Forming delicate components like the hooks of a rim from it is very complex. Manufacturers state that they can produce hookless profiles more cheaply, more stably, and with less waste, which ultimately also means: more environmentally friendly.^[1]

What users appreciate about hookless rims: They don't constrict the tire as much as hooked rims. This can result in a more stable riding feel, especially in corners. Whether you can save weight with hookless rims, however, is controversial. The situation is similar with aerodynamic advantages, which theoretically could result from the smoother transition between rim and tire. Manufacturers like Zipp, among others, promote improved aerodynamics for their hookless rims^[2]. DT Swiss, on the other hand, which continues to rely on proven hooks for narrow rims, states that they have not yet measured any significant advantages in the wind tunnel.^[3]

Hookless and Road Bikes

In the road bike sector, the use of hookless rims is still relatively new. It only became interesting there when frames for disc brakes and with space for 28 or even 30mm tire widths became common. This also lowered the tire pressure in this area to levels compatible with hookless profiles.

When technologies are newly introduced or changed, incidents sometimes occur. This was also the case, for example, with tubular tires, where problems with the heat resistance of the adhesives used arose during long descents. No matter how well manufacturers or standardization organizations like ETRTO and ISO test – it takes time until standards are stable.

And that brings us to Thomas De Gendt. On a stage of the UAE Tour in February 2024, he crashed suddenly and for no apparent reason. Fortunately, it wasn't serious; he was even able to continue the race. But afterwards, pictures of his shredded front wheel went through the cycling press, making it a symbol of the risks of hookless rims, especially on road bikes.

What happened? According to his team and equipment suppliers, the material used was perfectly matched, and an obstacle on the road, such as a stone, was the cause of the material failure. However, De Gendt was apparently riding 25mm rims with 28mm tires.^[4] Some time before, ETRTO had once again adjusted its standards and now recommended at least 29mm tire widths for this rim width.

So, De Gendt was at the limit of the system tolerance allowed by the standard. When hitting an obstacle, the following can happen: The tire is pinched, which causes the air pressure to rise locally. And because the system is already at its limit, it loses its grip on the rim.

Hookless: What You Need to Consider

None of this should deter you from trying hookless rims if you're curious. It's just to inform you about the potential risks. You could say that hookless rims are currently the divas of the rim universe. You should treat them with a little caution, otherwise, things might go pop. But if you know what to look out for, nothing stands in the way of a good collaboration.

So, definitely consider the following:

• Hookless rims must always be combined with tubeless tires. These have a more stable bead that allows them to brace themselves against the rim shoulder. If you don't fancy the mess with sealant (see below), you can also ride this system with inner tubes.
• The ratio of tire width to the internal width of the rim is safety-critical. Therefore, manufacturers always provide precise information about this. You can find it either on the packaging, on the rims/tires themselves, or on the manufacturer's websites. Take the time to research it. Then you'll be on the safe side.
• The specified air pressure must be strictly adhered to. For road bike tires, for example, 5 bar should generally not be exceeded. But again, pay close attention to the manufacturer's instructions. If the tire allows for higher air pressure than the rim, you must adhere to the rim's specifications.
  

Tubeless and Tubeless-Ready

Innovation in tubeless systems also came from mountain biking. The first tubeless tire was developed in 1999. In the later 2010s, the technology also found its way into road cycling.

If there's no inner tube to hold the air, then logically the tire and rim must form an airtight chamber. This can be achieved in two ways.

UST Rims

The first option would be for the tire and rim to form an airtight unit in themselves. For this, you need a UST rim. UST stands for Universal System Tubeless. It is a type of rim constructed to be airtight even without rim tape. You can recognize it best at first glance because it has no spoke nipple holes.

This option is particularly worthwhile if you are determined to ride tubeless exclusively, as the UST rim is designed for this. This does not mean that you cannot, in principle, also mount rim tape and use an inner tube. However, check the manufacturer's specifications to be sure.

Tubeless-Ready Rims

If you haven't yet definitively decided whether you want to switch to tubeless permanently, then a tubeless-ready rim might be more suitable for you. You can ride these with an inner tube, but also convert them to tubeless at any time.

And that brings us to option two of the tubeless setup: the tire and rim are made into an airtight unit with a bit of tuning. This is not difficult at all. All you need is a suitable, i.e., tubeless-compatible tire, special rim tape (feel free to check out our article on rim tape), and a tubeless valve whose base seals the valve hole.

In addition, all tubeless systems are filled with a so-called "sealant." This seals the tire and also clogs or polymerizes small damages on the go with particles or latex components.

Most modern rims are now tubeless-ready. They often have a small hump at the transition from the rim shoulder to the rim bed, so that the tire bead stays where it should be, even in case of pressure loss: on the rim shoulder. They come with hooks on the rim flange or, as mentioned above, smooth (Tubeless Straight Side).

Advantages and Disadvantages of Tubeless

For mountain bikers, tubeless is basically standard, at least if the sport is pursued ambitiously. Even in the professional road cycling pelotons, tubeless has been adopted since the early 2020s. The riding feel is comfortable and direct. Inner tube and tire cannot work against each other, which reduces rolling resistance. Therefore, tubeless systems are considered very fast.

But there are also advantages off-road. Here, you are often confronted with stones, thorns, or other sharp objects that damage your tires. Because the sealant immediately repairs any small damages, you have good puncture protection. Furthermore, there is no problem with pinch flats ("snakebites"), i.e., punctures of the inner tube by the rim. Therefore, tubeless systems can be ridden with very low air pressure, which gives you better grip off-road.

One thing you should know, though: To be happy with a tubeless setup, you need to enjoy a bit of tinkering. The initial installation can be nerve-wracking. Furthermore, a tubeless tire is not un-flattable. So you should never be completely without a tube; at least one should be carried in your jersey or tool bag just in case. Alternatively, you can rely on plugs to repair the tire. Manufacturers offer various repair kits for this.

No matter what you choose: you should be prepared for a mess. Because if the mishap occurs, not only the air escapes, but usually also the sealant. And, by the way: nature is not exactly pleased when the latex goo seeps into the forest floor. Some manufacturers therefore offer biodegradable products. If environmental protection is important to you, you're probably best off with those.

Tubular Rims

Finally, another classic should not go unmentioned. For decades, they dominated road cycling, accompanied Tour de France winners, and performed on spring cobblestones: tubulars.

With this technology, the tire and inner tube are sewn together and glued into the rim bed as a single unit. Tubular rims therefore differ primarily from other rim types in that they have no rim flange with or without hooks, but rather do without them entirely. They come with a simple concave shape. And this makes them unbeatable light.

Furthermore, they have a huge range in terms of the tire pressure at which they can be used. You can inflate them rock hard, just as you can ride them on uneven ground with very little air. Similar to tubeless systems, you don't have to expect pinch flats: there are no rim flanges to cause them. That's why tubular tires were long considered the only option, especially for cobblestone classics or on the Italian Strade Bianche.

Only in the very recent past have they become a little quieter. Because, we don't want to hide this from you: In terms of rolling resistance, tubeless systems are now superior. Also, changing tires can be a bit tricky, as the glue has to be removed each time. But feel free to browse our shop anyway. Perhaps you'll find a bargain that suits your needs.

Footnotes

[1] Kühnen, Robert; Bauer, Kristian: Hookless-Felgen am Rennrad, in: Tour-Magazin (27.02.2024, accessed 2.10.2025). ↩ Back

[2] Zipp: How Hookless Makes You Faster (Manufacturer's website, accessed 2.10.2025). ↩ Back

[3] Steinhoff, Dorian: Hookless Rims – How Dangerous Are They Really?, in: Gran Fondo (12.09.2024, accessed 2.10.2025). ↩ Back

[4] Ibid. ↩ Back