Road bicycle wheels, wheelsets

Changing the wheel set, switching to the right, is perhaps one of the most popular "upgrades" among cyclists. It's no accident, because a well-chosen wheel can make a lot of changes to the bike's behavior, it can make it more comfortable by absorbing road imperfections, and it can make cycling more efficient by increasing lateral stiffness. The wheels literally keep you moving, the first part of the bike that meets the asphalt and transfers your energy to the ground, reducing road vibration, surface imperfections and terrain changes. According to many, it is the most important part of the bike, it is important to choose the right wheel for your style and preparation!

Before you choose only based on the external appearance and weight data, it is worth reading the following, maybe it will help you see a little more clearly!

Construction of the wheel

A bicycle wheel has four main components, each of which affects weight, performance and durability. The quality of these parts can affect ride comfort, efficiency, braking performance, rolling resistance - so it's worth knowing a little about each of them, how they affect the quality of the wheel.

• rim: The wheel rim is located on the outside of the wheel and has two main functions; holding the tire and providing a braking surface (for wheels with rim brakes, not for wheels with disc brakes). The width of the rim affects the width of the usable tire, which can have a significant impact on the driver's comfort, and the material of the braking surface affects the braking performance.
• hub or just hub: the hub is located in the center of the wheel and ensures rotation with the axle and bearings installed in it - for both the front and rear wheels. The axle fixes and connects the wheel to the bicycle. In the rear wheel hub (hub) is the rotor (freewheel) which is the turn (or cassette with the sprockets) this ensures the transmission of this power from the drive to the wheel when the cyclist is riding, and if the cyclist is not cycling, the freewheel ensures the independent rotation of the wheel from stationary drive. The bicycle chain wraps around the sprockets of the cassette and, together with the crank and derailleurs, forms the bicycle's drivetrain, which provides power transmission and forward motion.
• Spokes: the part that connects the hub and the rim. The number of spokes can vary between the front and rear wheels, with the rear often having more spokes to improve strength and stiffness. More spokes usually mean a stronger wheel, but this obviously means extra weight. The spokes are made of different materials (steel, aluminum, carbon) and can have different shapes (round cross-section or aerodynamically flattened). Spokes are most often made of steel wire, but their shape and diameter can vary greatly.
• Spoke nuts (nipples): The spokes are connected to the wheel or rim with a special nut, called a "nipple". Lug nuts are important for adjusting spoke tension, which "centers" the wheel and makes it run straight when it rotates.

What is a good wheel?

Choosing the right wheel depends a lot on the use. In general, it can be said that a good set of wheels has durable, reliable hubs (which can be installed and repaired by replacing spare parts), provides adequate braking and braking effect, is stiff and thus contributes to effective power transmission, but at the same time - last but not least - it is also light.
Here we can already feel that the individual aspects can contradict each other, which is why this will be a really good and light bike, very expensive!

Lightweight wheels reduce rotating weight thanks to a low rim profile and a small number of spokes. In addition to reducing the total weight, this has the advantage of comfort, as it can provide some damping against forces arising in the vertical direction (vibrations from the road, impacts). Wheels with higher profile rims are fast - it's actually easier to keep up with them - but the ride quality often feels "rougher". Quality, light wheelsets are usually under 1400 grams, the truly "top category", extremely light examples even approach 1000 grams!

Aerodynamic wheels aim to be as fast as possible by reducing air resistance. Aerodynamic wheels are usually taller than 40 mm in profile, and nowadays they are getting wider as well. However, this has its drawbacks, as they are much more sensitive to crosswinds, which can make them difficult to handle, and the extra material adds weight.

Bikes that are not so focused on performance usually have features that make them more suitable for everyday use or general training. The braking surface is made of aluminum, which provides better performance in all weather conditions compared to carbon (although newer composite brake pads already provide surprisingly good stopping power with carbon rims), a larger number of spokes is used for strength and durability, and the rim is wider to accommodate wider tires. can also use it. Accordingly, their weight also increases, usually between 1500 and 1800 grams.

Wheels made for package tours or heavier bikes (over 120 kg) are equipped with a larger number of spokes, 32 or even 36 spokes. Due to the extra stiffness and durability, the weight of the wheels in this form usually exceeds 1900 grams.

Rim material

Most of the lower level wheels come with different quality aluminum rims, while the more serious wheels - even for racing - typically have carbon (carbon fiber) rims, which reduces weight and increases stiffness at the same time.

Aluminum as a rim material provides better braking performance than carbon, which tends to perform poorly on wet roads and long descents as it heats up during braking. For these, it is very important to use the appropriate (usually the factory) brake pads recommended for the rims.

Some manufacturers also offer models with carbon rims but with aluminum brake surfaces, although these are disappearing nowadays because the lighter weight offered by carbon rims is often lost. However, it is worth noting that these designs can be even heavier than solid rims.

Rim or disc brake

It is perhaps one of the most topical questions today, although to be honest, the question has probably already been decided - of course in favor of disc brakes - if we look at the fact that most manufacturers are starting to abandon rim brakes (perhaps only staying in the "low end" category). Of course, there will always be those who argue in favor of rims with religious obsession.

The transition to disc brakes began a long time ago and is now standard on road bikes. Moving away from rim brakes and traditional calipers opened up new options for manufacturers in terms of both frame and wheel design, the use of wider tires, and the obvious benefits of increased stopping power.

Bicycles using disc brakes can be made with a modified rim profile, which is even more aerodynamic and enables the implementation of faster wheels. The downside is that disc bikes have to have a stronger frame to handle the higher braking force, and require more spokes and special hubs, potentially adding more weight.

The advantage of the disc brake system comes out most with the carbon wheels, as the braking effect of the carbon rim was much lower than the rim brake system (often especially weak in wet weather conditions). Furthermore, since it is not the brake that wears out, the lifetime of expensive carbon wheels with disc brakes is also much longer, the safety of their use is not affected by the progress of wear, since it is not the rim that wears out, but the brake pads.

Wheels designed for use with disc brakes should not be confused with aerodynamic "disc" wheels, which are a single piece from hub to rim to reduce wind turbulence in time trial events.

Rim width and profile height

The width and height of the wheel rim greatly determines how the bike rides and behaves.

Today's trend is that modern rims are getting wider and wider, which results in better aerodynamics and better comfort due to the air volume of wider and taller tires providing more springing. In the past, several manufacturers and independent researchers and test groups have tested and confirmed that the use of wider tires (depending on the speed) supposedly improves (lower) rolling resistance and comfort, and they can even run at lower pressures.

The width of the rim can be measured from the inside or the outside, which can result in confusing numbers if you want to compare wheels or try to find out what width tires you will be able to use with a rim. Generally, when a brand refers to a number followed by a “C,” it means an inside size. According to current standards, a narrow rim has an internal measurement of less than 15 mm, while a wide rim has an internal measurement of more than 17 mm. Taking an external measurement, under 19 mm is considered narrow, while over 22 mm is considered wide.

Although they are closely related, the outer rim width mostly affects the aerodynamics of the wheels, while the inner rim width affects comfort, rolling efficiency or the shape of the tire.

The profile height of the rim affects the aerodynamics of the wheel and the handling of the bicycle. In general, the higher the rim, the more aerodynamic it is, but the more difficult it is to handle, since the side wind "catchs" it more than a low rim. The extra material results in more weight - therefore it can be said that it is more difficult to accelerate, but it is easier to maintain speed. It's worth noting that not all deep rims are created equal, and the exact profile varies greatly from brand to brand. The manufacturers try to achieve the perfect rim shape with continuous fiber channel testing, which also behaves well in crosswinds and, of course, is also sufficiently fast. Brands often recommend which type of tire gives the best results according to their measurements.

In general, rims with a height exceeding 40 mm are called self-profile, and some of them are larger than 80 mm, but there are also 105 mm.

The spokes

The total number, shape and material of the wheel spokes may vary. The high number of spokes increases robustness and durability, but comes with extra weight. Spokes can be made from a variety of materials, including steel, aluminum, carbon fiber, and titanium. Steel spokes are by far the most common.

The number of spokes on the front and rear wheels varies, the number of spokes on the rear wheels is usually more, as they are exposed to greater force (driving force and extra weight). The light front wheel typically has 18-24 spokes, while the rear wheel has 20-28 spokes. This is in stark contrast to the early days of wheel manufacturing when front wheels had over 30 spokes and rear wheels over 40. As materials and manufacturing processes improved, the number of spokes decreased, reducing weight with the same performance.

A flat spoke - often referred to as a 'sword spoke' - provides aerodynamic advantages over rounded spokes. Although more expensive, they are stiff and light.

Standard spokes are either 'straight drawn' or 'J-bend'. "Straight pull" spokes have no bend at the head and require special hubs, "J-bend" spokes are the more traditional solution with a 90 degree bend at the end of the hub that looks like the letter "J".

The advantages of straight spokes are: more precise adjustment, a stiffer, more responsive wheel and weight reduction. The disadvantage of straight-pull spokes is that many companies produce proprietary spokes and hubs, which means that getting a replacement spoke can be time-consuming and expensive. J-bend spokes are often easier to replace and perform close to straight pull spokes in terms of quality and strength.

The spoke can be "stretched", i.e. with a variable diameter along its entire length, in order to achieve weight reduction.

Freewheel and/or rotor

The hub of the rear wheel is the rotor and freewheel mechanics, this ensures that when you turn, the power is transferred to the wheel, and when you stop pedaling, the rear wheel runs freely (just like the front). 

Different shifting systems require different gear sets and a matching rotor - it is essential to check their compatibility when buying the wheel! Typically, according to the manufacturers, these are Shimano, SRAM - these are generally compatible with 9, 10, 11-speed systems, but not anymore with 12-speed systems. While the third - and currently the smallest - Italian manufacturer Campagnolo has a different system, it is not compatible with the other two (in terms of mounting on the rotor).

Bearings

The more expensive a bike is, the higher the quality of the parts used. In the case of bearings inside the wheel hub, this typically results in the generally used steel bearings being replaced by ceramic bearings in more serious high-end wheels. A good ceramic bearing has smoother surfaces and a harder and more durable material, thus ensuring smoother and longer-lasting operation than an equivalent steel bearing. Less friction, better efficiency and performance! However, there are high-quality steel bearings that surpass even these in quality - they are usually less durable.

In addition to the material of the bearings, proper lubrication also affects rolling and the degree of friction. Bearing friction reduces power and slows the wheels. Excessive friction occurs when the bearings are not properly lubricated, when dust, dirt, or other material gets into the bearings, or when the lubricant is flushed out of the bearings by high-pressure washing. Here, better quality wheel hubs provide a better seal against external influences, so they roll more smoothly for longer.

The lower the viscosity of the lubricant, the lower the friction, but as a result durability may be impaired.

The bearings are closed industrial bearings or ball-cone construction. To this day, many manufacturers do not use industrial bearings for their high-end wheels, but instead stick to the classic collapsible ball-cone solution (in their opinion, they give the smoothest rolling), such as Campagnolo, Fulcrum, and Shimano's more serious wheels!

The industrial (closed) bearing consists of balls placed between an outer and an inner ring ball track, which are pressed into the hub sleeve as a complete unit. The sealed bearing is a single unit, if it wears out, it becomes necessary to replace the entire bearing, but it is quite cheap.

Tire types

It is worth knowing the three different types of tires that are used in road wheelsets. Since each of them requires the right special rim, before buying the wheel we should decide what kind of rubber we want to use! Nowadays, "singo" (tubeless) tires are already in the background, many bicycles use so-called rim rims and tires fitted with matching inner tubes. Due to its good puncture resistance, the "tubeless" system (without an inner tube - but not the same as the previous "singo" solution) coming from the mountain bike sector is also becoming more and more popular.

The most common form of tires currently used on road bikes is the solution with rimmed tires and inner tubes. Unless stated otherwise, it is assumed that a newly purchased bicycle has "clincher" i.e. rimmed tires. These tires have a rim that fits into the grooved "trench" on the rim and remains taut on the rim due to the pressure. The pressure is maintained by the inner rubber and valve located on the outside.

"Singo" tires also have internals, but in a completely different way. The inner of the tubular tire is sewn directly into the tire and then the tire is glued directly to the rim. Until now, professional racers have almost exclusively used "singo" tires, thanks to their reduced weight, good grip and controllability. Even in the event of a defect, you can drive with it for some time, and there is a small chance that the tire will come off the rim, which reduces the risk of accidents.

The disadvantage is that it is expensive and difficult to replace and repair a puncture. In competition conditions, the wheel is completely replaced, the defect is not repaired.

Tubeless tires have long been used on mountain bikes, and today they have arrived and spread in the world of road bikes as well. Since 2015, Trek has been installing tubeless-ready wheels on most of its road bikes, and Giant has exclusively offered tubeless tires on its top-of-the-line models since 2017.

As the name suggests, tubeless tires do not require an inner tube, but are connected to a special rim design that creates an airtight seal. This is a technology very similar to that found in modern cars and motorbikes.

Tubeless tires are considered better than clincher tires as they result in less friction, which improves rolling resistance, can be used at lower pressures, improving comfort, and provide better puncture protection. In order to prevent punctures, tubeless tires can be used with a liquid sealant, which, when placed in the tire, immediately seals smaller punctures.