Road bike wheels: carbon or aluminium rims
This is a question of priorities. A very light road bike wheel, for example, is made of as little material as possible, but this does not make it possible to produce a voluminous, aerodynamically favourable shape - and it is not very stable either. An aerodynamically good wheel, on the other hand, can also be stable - but then it is no longer particularly light. The best way of balancing these opposites is with carbon wheels, but they are expensive to produce and good wheels are expensive. Many, especially inexpensive carbon rims with rim brakes brake worse than aluminium rims and can break down during continuous braking due to the frictional heat. Proven durable carbon wheels cost at least 2000 euros per set. Aluminium plays to its strengths if you don't expect top marks for its properties: good aluminium wheels can be relatively light, relatively stable, relatively inexpensive - and relatively poor in terms of aerodynamics. Nevertheless, you can still have a lot of fun with them.
Bearings for road bike wheels
Today, maintenance-free and adjustment-free deep groove ball bearings are common. Large bearings always have a higher load capacity and are more robust than small ones. Deep groove ball bearings are standardised and interchangeable; they are also available in stainless and/or elaborately sealed versions. Conical bearings with loose balls are only rarely found in modern road bike wheels - for example at Shimano. Disadvantage: If the running surfaces are broken, the whole hub is ruined. Ceramic bearings can run a little more smoothly and theoretically last longer, but are very expensive.
Easy to repair
Most wheels today roll on sealed deep groove ball bearings - standardised parts that can be replaced easily and inexpensively.
Wired tyres, tubular tyres or tubeless?
The classic standard for road bikes is clincher tyres: a tube is inserted into the casing and both are mounted on a hooked rim, in the bed of which a rim tape must be placed. For a long time, professionals mainly rode tubular tyres, but this has now changed, as you can read hereTubular tyres have the inner tube sewn into the casing and the tyre is glued to the rim. Advantages: In the event of a puncture, the tyre does not immediately jump off the rim, and tubular rims are also lighter and more robust than clincher rims. On the other hand, clincher tyres roll more easily, are more puncture-proof, easier to handle and usually cheaper.
Tubeless tyres, on the other hand, look like classic clincher tyres, but can be ridden without a tube. Instead, they require differently shaped rims; these should not have (spoke) holes in the rim bed so that no sealing tape is required (inconvenient), but should have a circumferential recess in the centre to make it easier to fit the tyres. Filling the tyres with sealant makes them more puncture-proof. They also roll a little easier and can be ridden with less pressure, which makes them more resilient.
Spokes
Only the spokes turn the hub and rim into a wheel. There are round and flat forged spokes. The best rounds are forged thinner in the centre section, which makes them light and durable. However, even thin round spokes are aerodynamically poor. Aero wheels therefore have flat forged spokes, and as few of them as possible - twelve in the front wheel is the minimum, below that the wheel becomes unstable. Few, thin spokes, however, reduce the lateral stiffness of the wheels. Depending on the rider's weight and intended use, you therefore have to weigh up stiffness (many,
spokes), aerodynamics and weight.
Freewheel: Rotor types of the impellers
The sprockets are attached to the rotor of the wheels. Three types are common: Shimano and SRAM are compatible with each other; both use a flat splined profile that can accommodate eight to eleven sprockets. Campagnolo has a deeper-cut, non-compatible profile for nine to twelve sprockets. Still relatively new (and mainly found on cross and gravel bikes) are the XD rotors of the 1x11 drivetrains from SRAM, on which the sprocket block is bolted as a whole. The rotors or freehub bodies of many hubs, especially high-quality hubs, can be changed and thus adapted to Campagnolo or SRAM/Shimano. Inexpensive wheels are sometimes only available with a Shimano freehub.
Rim width for wheels
The trend is towards wider rims. An inner width of 19 millimetres and an outer width of 25 millimetres are common today. The rim dimension determines the actual width of a mounted tyre much more than its nominal width. On a wide rim, the air volume is larger, the tyre is better supported and the riding feel is more direct. Without increasing the risk of punctures, you can lower the air pressure, which improves the tyre's suspension.
Rim height of the wheels on the road bike
High rims are aerodynamically better than low ones. However, modern aero rims are not only high - up to 80 millimetres - but also bulbous, which is what makes them really fast. However, strong crosswinds can easily throw them off track, which is why 40 to 50 millimetre high profiles are the best compromise between Aerodynamics and suitability for everyday use. 30 millimetre high rims are hardly affected by crosswinds, but with an aerodynamically shaped cross-section, they are still fast.
Jens Klötzer
Editor
