Overview of wheels & rim types
The wheel and rim types are available in many different combinations, which leads to a confusing amount of different components. Not every wheel is compatible with every rim. Basically, you have to ask yourself whether you want to ride your bike with or without a tube.
The former requires a clincher rim, while the latter requires special tubeless or UST rims. Tubeless rims can also be ridden with a tube. If you decide to use a tube, there are other possible options: In addition to butyl, latex and polyurethane tubes, there are also tubes that are sewn (or vulcanized) directly to the wheel and glued to a suitable tubular rim.
As if it weren’t enough chaos, you also have to choose between clincher and folding wheels as well as various rubber compounds and carcass structures. You can find out which combination of rims and wheels is best for your area of application here.
What types of rims are available?
Clincher rims are the most common and widely used rims. The rim base of this type is drilled through so that the spoke nipples can be inserted easily, which is why it is essential to ride them with a suitable rim tape. Otherwise the partially sharp-edged holes can lead to punctures. In addition, the rim base is usually leaky (in addition, the rim flange does not seal perfectly with the wheel), which is why a clincher rim with a tube must be ridden. The advantage here is that in the event of a puncture, the defect can be repaired extremely easily and quickly. In addition, it is quite inexpensive since a tube is usually to be patched up only. Because of its simplicity and practicality, this system is now mostly used on city, trekking and racing bikes.
In terms of wheels, both wired and folding wheels can be used, whereby the former are usually very difficult to mount due to the solid wheel bead made of wire. Once installed, these coats are extremely tight and secure, which is why they are often used in downhill use. The counterparts as a folding version are usually a little easier to open and have a lower weight. The seat is more than tight enough for the vast majority of applications. The wheel is traditionally held by a hook-shaped rim flange that wedges the wheel bead. However, newer systems made of rims and wheels also work without hooks, which benefits the stability of the rim flange. This type of rim is therefore particularly interesting for downhill-oriented mountain bikers.
Systems without a tube (tubeless) are increasingly represented in the mountain bike sector and are an indispensable part of professional sport. Basically, rims and wheels are constructed very similar to clincher systems, whereby both the rim well and the rim flange are designed slightly differently. The hook shape is designed so that it seals perfectly with special tubeless wheels. In contrast to clincher systems, no air can escape at this point. The spoke holes are also closed with a special adhesive tape, so that an airtight system is created here.
Alternatively, there are so-called UST rims (Universal System Tubeless), which do not have any spoke holes thanks to a special manufacturing process. This eliminates the sometimes tedious masking. The advantages of tubeless systems are almost obvious: By dropping the tube, the puncture resistance increases because air can only escape if the thick wall of the wheels is pierced. Tubeless tires are fitted with a few milliliters of special sealing liquid, which in the event of a sudden loss of air foams at the appropriate point in a flash and can therefore close the hole. To ensure the protective effect, however, the liquid should be changed regularly. The appropriate interval differs from manufacturer to manufacturer and must be looked up in all cases.
Another advantage of tubeless systems is the reduced weight that results from the elimination of the tubes. By saving on a rotating component, this weight is particularly noticeable when starting, since inertia and rolling resistance are reduced. In addition, the higher puncture resistance allows driving a lower air pressure, which provides more traction and damping on trails.
Tubular rims differ above all on the rim flange and rim bed of clincher and tubeless rims. They do not have a classic rim flange, but are semi-circular. This allows the wheel to be glued directly to the rim, which ensures an extremely secure fit. With this system, the tube is sewn directly onto the wheel (or vulcanized), which is why it cannot be replaced.
In the event of a puncture, the tubular system is therefore somewhat less practical. But you get extremely good emergency running properties and a light weight, because a lot of material can be saved. Road bike riders in particular are happy about the weight savings, which is why tubular rims are mostly found on road bikes. However, more and more cyclocrossers are also opting for this system because it can be ridden with extremely low air pressure and thus generates a lot of traction. Mountain bikers, on the other hand, rarely use the system, here the tubeless or tube system clearly dominates.
What types of wheels are available?
Folding & Clincher wheels
As already described, clincher and folding wheels differ in terms of assembly. The name already suggests that clincher wheels are more difficult to install, since a rather inflexible wire is built into the wheel bead. This also means that they cannot be folded up compactly and are heavier. The wire core of the folding wheel is replaced by a bundle of Kevlar fibers. The wheels are foldable and, depending on the model and size, up to 100g lighter. With ever better rim flanges, folding wheels are even increasingly being installed on downhill bikes, since the seat is perfectly adequate for normal bikers. However, if you are particularly aggressive downhill (downhill), you better rely on the safety of clincher wheels and accept the extra weight.
With regard to the rolling properties, there are slight advantages for the folding wheels due to the lower weight, these being almost negligible. The decisive factor here is the profile of the respective wheel and the air pressure driven.
Even if it sounds strange at first, classic tires are not really tight. If you fill sealing milk into a standard tire, it will press through the side wall over time. This can be seen from small “sealing milk sweat beads”. A tubeless system therefore requires special thick-walled tubeless tires that are able to hold sealing milk. In addition, the tire bead is provided with a thicker rubber lip to enable a real seal with the rim flange.
With modern rims it is possible to get a more or less tight system with standard tires, but it is absolutely not advisable. Even if the air is held, the tires usually do not sit securely in the rim flange without the pressure of a tube and can jump off in curves. It is therefore important to ensure that a tubeless ready tire is used. Only these sit firmly on the rim even at low air pressure and can properly exploit the advantages of the tubeless system. The reduced air pressure is one of the main arguments for tubeless tires. Of course, they also roll more easily due to the lower weight compared to tire-tube systems and the lack of friction between tube and tire. Last but not least, tubeless tires are also more puncture-proof, as the likelihood of puncture is significantly lower and valve breaks cannot occur.
In tubular tires, the tube is directly connected to the tire (sewn or vulcanized), which means that some material and thus weight can be saved. In order to cope with the poorer handling in the event of a puncture, some riders pour some sealing liquid into their tubular tires. Small holes are thus sealed directly. It is also popular to use thicker liquid from the automotive sector.
The popularity of tubular tires in the road bike and cyclocross sector stems from the improved rolling properties, which may be more a matter of faith than fact. For this, however, many professionals accept the more complicated repairability. In any case, you can always come to a safe stop in the event of a puncture with tubular tires because, unlike clincher or tubeless, the tire stays on the rim even without air.
In addition to ensuring traction and damping, puncture protection is probably the most important task of a tire. The easiest way to achieve particularly good values here is to use a thick rubber. City bikes in particular rely on this, since weight and rolling resistance are not so important. On the plus side, these tires are of course significantly cheaper, which is crucial for everyday use in wind and weather. Thanks to the plump material, the tires can be ridden for a very long time without hesitation.
In the high-quality area, however, special nylon or aramid protective inserts are used. These are thinner and lighter than rubber, but cause significantly higher costs during production. Modern tires are made up of several layers in order to meet the exact requirements at each point. The tread is made of a different rubber compound than the tire sidewall, while both sit on a third carrier material. In between are the protective layers mentioned, which stop penetrating objects before they can penetrate the inside of the tire.
Other protective mechanisms have also been established in the mountain bike sector to improve puncture protection. A special inner tire is installed in a tubeless tire. The tire therefore has two different air chambers. These are filled with air by a special valve independent of the respective chamber of the tire. The idea behind it is that you can drive a lower air pressure in the main chamber, but instead drive 4-5 bar air pressure in the inner chamber. This completely prevents breakthroughs. In addition, the inner tire presses the outer tire against the rim flange, which means that it can be held more securely. Crucial, especially at low air pressures. Similar systems use foam inserts, which also protect the rim and offer improved emergency running properties.
What material are the tubes made of?
The classic among tubes is made from butyl (butyl rubber). It is a very elastic and extremely airtight synthetic rubber. Due to its great elasticity, a butyl rubber tube can be used for several different wheel sizes. For example, a 26 inch tube fits into a 27.5 inch wheel and vice versa. Ideally, of course, the right wheel is used to prevent creasing and thus increased friction and damage in the tire.
In addition to various wheel sizes, butyl rubber tubes are also available in many different widths and strengths. While there are particularly thick, heavy tubes for downhill use, very thin-walled, light tubes are also available for marathon or cross country use. However, these are relatively prone to breakdowns.
PU, or in this case thermoplastic, is actually known from plastic pipes or the like, but more recently, extremely high-quality tubes have been made from the aging-resistant material. These are extremely light and yet puncture-proof. On the negative side, tubes made of PU are quite expensive and only keep the air in for a short time. So the wheel pressure should be checked and adjusted before each ride. In addition, the tubes are almost inelastic, which is why only the right size with a certain wheel size can be used.
Latex tubes are more elastic and puncture-proof than their brothers made of butyl, but they hold the air significantly worse. Due to the high elasticity, latex wheel systems roll off particularly well, but here too, as with PU tubes, it is often necessary to pump again. In the meantime, only a few manufacturers still manufacture latex tubes because the advantages hardly outweigh the negative sides.
What types of valves are available?
The Presta valve is the most widespread among high-quality bikes thanks to the simple handling. The narrow valve it is also suitable for less wide road wheel rims. The small diameter can also save a few grams compared to Schrader valves. Most tubeless valves are also designed as Presta valves. What is special here is that these are of course not connected to a tube, but are used in the rim by means of a rubber seal that is pulled into the rim hole by a nut placed on the outside. This seals the tubeless valve and prevents the air from escaping.
No matter whether tube or tubeless, a Presta valve always has a removable valve core, which is particularly practical for cleaning dirty valves. This point is particularly interesting for tubeless systems because the sealing liquid can stick the valve.
Dunlop valves are still one of the most common valves because many older wheels are equipped with them. However, the list of advantages is very limited: only the particularly quick air deflation is to be mentioned here. Otherwise, these valves are to be assembled quite fiddly, since the valve core must always be removed before assembly. In addition, due to the system, no air pressure can be measured. This valve rarely finds its way into modern bicycles.
The Schrader valve is extremely robust and enables filling by a compressor at any petrol station. For this reason, many touring cyclists rely on it, since there are of course almost enough petrol stations around the world. In addition to the somewhat higher weight, the larger diameter of the valves is a negative point, since narrow rims may not offer enough space for a sufficiently large bore. The Schrader valve is still very suitable for city and trekking bikes, since you are usually near the petrol station and robust wheels are installed that offer space for a large bore.