Tube or tubeless, hooked or hookless - those are the questions. At some point, every cyclist faces them: namely, when a new wheelset is due and you have to decide which system to choose. To keep them from turning into paralyzing deliberations, as in the case of the tragic Danish prince, we’ve put together the most important information for you here. What are the advantages and disadvantages of the common rim types? Which tires are they compatible with? What do you need to bear in mind to ride safely? You’ll find out in this little compendium.

The hooked rim

Let’s start with the classic. Anyone who gets on a bike from time to time has probably ridden a hooked rim (Crotchet in English). Its defining feature is a small hook on the rim edge, into which the tire bead hooks (see illustration). To make this work better, wire-bead tires are typically used. Their bead is reinforced with a steel wire that prevents the material from stretching or deforming. The English term for wire-bead tires is clincher, which is why this type of rim is sometimes also called a clincher rim. 

You can use folding tires just as well, though. In these, plastic fibers do the job of the wire, often making the tires significantly lighter. Since, as the name suggests, they can be folded, they also have a more practical pack size.

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

Hookless

But what’s the point, really? Cars and motorcycles manage without them. And didn’t a colleague of yours recently - an experienced mountain biker, no less - just shrug when the subject came up and say: Pfff, hookless - we’ve been riding them for years?

That’s right, and it could have been that way. The hook is not a load-bearing part of the rim. However, with very narrow tires ridden at high pressure, it increases the blow-off pressure - that is, the pressure at which you have to expect the tire to blow off the rim. That’s why it was a safety feature on bicycle rims for a long time. Since wide mountain bike tires are generally ridden at very low pressures, the smooth rim edge has already proven itself here as well.

Why hookless?

The advantages of hookless rims initially lie in manufacturing, particularly when it comes to carbon rims. Carbon is not a metal but a fabric of carbon fibers impregnated with synthetic resin and cured by heat. Forming delicate components such as the hooks of a rim from this material is very labor-intensive. Manufacturers state that they can produce hookless profiles more economically, more robustly, and with less waste, which ultimately also means they are more environmentally friendly.^[1]

What users appreciate about hookless rims: They do not pinch the tire as tightly as rims with hooks. This can provide a more stable riding feel, especially in corners. Whether you can save weight with hookless rims, on the other hand, is disputed. The same applies to aerodynamic benefits, which could theoretically result from the smoother transition between rim and tire. Manufacturers such as Zipp promote their hookless rims, among other things, for their improved aerodynamics^[2] DT Swiss, on the other hand, which continues to rely on proven hooks, particularly for narrow rims, says it has not measured any significant advantages in the wind tunnel so far.^[3]

Hookless and Road Bikes

In road cycling, the use of hookless rims is still quite new. It only became relevant there when frames for disc brakes, with room for 28 mm or even 30 mm tires, became widespread. This also lowered the tire pressures used into ranges compatible with hookless profiles.

When technologies are newly introduced or modified, incidents unfortunately sometimes occur. This was also the case, for example, with tubular tires, where problems arose with the heat resistance of the adhesives used during long descents. However thoroughly manufacturers or standardization organizations such as ETRTO and ISO test, it takes time for standards to become stable.

And that brings us to Thomas De Gendt. During a stage of the UAE Tour in February 2024, he suddenly crashed for no apparent reason. Fortunately, it was not serious, and he was even able to continue the race. But afterward, images of his shredded front wheel circulated throughout the cycling press, making it a symbol of the risks of hookless rims, particularly on road bikes.

What had happened? According to his team and the equipment suppliers, the materials used had been 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 on 25 mm rims with 28 mm tires.^[4] Some time earlier, ETRTO had adjusted its standards once again and now recommended tire widths of at least 29 mm for this rim width.

De Gendt was therefore at the limit of the system tolerance permitted by the standard. When riding over an obstacle, the following can then happen: The tire is pinched, causing 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 know

None of this is intended to discourage you from trying hookless rims if you are curious about them. It is only meant to inform you about the possible risks. You could say that hookless rims are currently the divas of the rim universe. You should handle them with some caution, otherwise things may go with a bang. But if you know what to look out for, there is no reason why you cannot work well together.

In any case, be sure to take the following into account:

• Hookless rims must always be combined with tubeless tires. These have a sturdier bead that allows them to rest against the rim shoulder. However, if you do not want to deal with the mess of sealant (see below), you can also use this system with inner tubes.
• The ratio of the tire width to the rim's internal width is safety-relevant. That is why manufacturers always provide precise specifications for this. You can find them on the packaging, on the rims/tires themselves, or on the manufacturers' websites. Be sure to take the time to look them up. Then you will be on the safe side.
• The specified tire pressure must be observed. For road bike tires, for example, 5 bar must generally not be exceeded. But here too, pay close attention to the manufacturer's instructions. If the tire permits a higher pressure than the rim, you must follow the rim's limit.
  

Tubeless and Tubeless-Ready

Innovation in tubeless systems also came from mountain biking. The first tubeless tire was developed as early as 1999. In the latter part of the 2010s, the technology also made its way into road cycling.

If there is no inner tube to contain the air, the tire and rim must logically 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 their own right. For this, you need a UST rim. UST stands for Universal System Tubeless. It is a type of rim designed to be airtight even without rim tape. At first glance, the best way to identify it is that it has no holes for the spoke nipples.

This option is particularly worthwhile if you are absolutely determined to ride tubeless only, because that is what the UST rim is designed for. That does not mean that, in principle, you cannot also install rim tape and use an inner tube. However, to be on the safe side, check what the manufacturer says about this.

Tubeless-Ready rims

If you still haven’t reached a clear decision about whether you want to switch to tubeless permanently, a Tubeless Ready rim may be the better choice for you. You can ride it with an inner tube, but also convert it to tubeless at any time.

And that brings us to the second version of the tubeless setup: With a little tuning, the tire and rim are turned into an airtight unit. It’s not difficult at all. All you need is a suitable, tubeless-compatible tire, special rim tape (feel free to take a look at our article about rim tape) and a tubeless valve whose base seals the valve hole.

In addition, all tubeless systems are filled with what is known as “sealant.” It seals the tire and also plugs or polymerizes small punctures on the go using particles or latex components.

Most modern rims are now Tubeless Ready. They often have a small ridge at the transition between the rim shoulder and rim bed, known as a hump, so that the tire bead stays where it should even when pressure is lost: on the rim shoulder. They are available with hooks on the rim edge or, as mentioned above, smooth (Tubeless Straight Side).

Advantages and disadvantages of tubeless

For mountain bikers, tubeless is essentially standard, at least when the sport is pursued seriously. Tubeless has also been used in the professional road-cycling peloton since the early 2020s. The ride feel is comfortable and direct. The tube and tire can’t move against each other, which reduces rolling resistance. That’s why tubeless systems are considered very fast.

There are advantages off-road, too. Here, you’re often confronted with stones, thorns, or other sharp objects that can damage your tire. Because the sealant immediately seals any minor damage, you get good puncture protection. There’s also no problem with pinch flats (“snakebites”), meaning punctures to the inner tube caused by the rim. That’s why tubeless systems can be ridden at very low air pressures, giving you better grip off-road.

But there’s one more thing you should know: To be happy with a tubeless setup, you need to enjoy tinkering a little. The initial installation can test your patience. What’s more, even a tubeless tire isn’t puncture-proof. So you should never set out completely without an inner tube; it’s best to carry one in your jersey pocket or tool bag, just in case. Alternatively, you can use plugs to repair the tire. Manufacturers offer various repair kits for this purpose.

Whatever you decide: You should be prepared for a mess. Because when the mishap occurs, not only does the air escape, but usually the sealant as well. And, by the way: Nature is not exactly pleased when the latex sauce seeps into the forest floor. Some manufacturers therefore offer biodegradable products. If environmental protection is important to you, you will probably be best served by using them.

Tubular rims

To conclude, another classic should not go unmentioned. For decades, they dominated road cycling, accompanied Tour de France winners, and performed on springtime cobblestones: tubulars, or tubular tires in English.

With this technology, the tire and tube are sewn together and glued into the rim bed as a single unit. Tubular rims therefore differ from other rim types primarily in that they have neither a rim flange with nor without hooks, but dispense with one altogether. They only need a simple concave shape. And this makes them unbeatable in terms of weight.

In addition, 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 with very little air on uneven terrain. As with tubeless systems, you do not have to worry about pinch flats: There are no rim flanges that can cause them. That is why tubular tires were long considered indispensable, especially in cobblestone classics and on the Italian Strade Bianche.

Only very recently has things become somewhat quieter around them. Because, and we do not want to hide this from you: In terms of rolling resistance, tubeless systems are now superior. Changing the tires can also be somewhat tricky, as the sealant must be removed each time. But feel free to browse our shop for them anyway. You might find a bargain that suits your needs.

Footnotes

[1] Kühnen, Robert; Bauer, Kristian: Hookless rims on road bikes, in: Tour-Magazin (27.02.2024, accessed on 2.10.2025) . ↩ Back

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

[3] Steinhoff, Dorian: Hookless rims - How dangerous are they really?, in: Gran Fondo (12.09.2024, accessed on 2.10.2025). ↩ Back

[4] Ibid. ↩ Back