Bike Wheel Terminology
It can be a little confusing when trying to decipher the various different terms found within wheel reviews and statistics. While some are manufacturer’s terms which relate only to that particular wheel or brand, it is possible to find certain terms in all wheel descriptions. Below are some terms which can be found in most reviews and understanding them can ensure that you select the right wheel for your needs.
Profile
A large number of cyclists don’t fully understand what a profile of a wheel is or how important it can be for a cyclist’s performance. Those who compete or just enjoy watching cycling races, such as the Olympics or the Tour De France will understand how important the wheel profile is and will have witnessed high profile wheels in use. High profile wheels are easy to recognise, they can be seen where the spokes are partially or completely covered. Standard bike wheels often have ‘low profile’ wheels. Low profile wheels have a rim, which forms the braking surface that is approximately 10cm deep. In contrast, higher profile wheels feature a lightweight metal alloy and most recently a carbon sheet at the end of the spokes which are close to the rim. This lessens the spoke length whilst also increasing the rim depth.
There are a large number of higher profile wheels available to cyclists, these include the 38mm rim Campagnolo Pista track wheel, while the Zipp 808 features an 80mm rim.
Aero Spokes
Aero spokes have a unique design, which features a non-circular profile length. This smoother and solid design reduces the air turbulence within the wheel, which in turn reduces the wind drag speed ensuring that a riders overall resistance is reduced to a minimum. A number of wheels include aero spokes, for example the Fulcrum Racing Zero has been designed to be as aerodynamic as possible.
Butted Spokes
Butted spokes are wider at the ends, as it meets the rim and hub. This is to give strength where the force is high and allow less material and weight in the middle.
Radial Spoking
This is the oldest type of spoking a wheel. It is perfect for a front wheel as it gives perfect tension and balance to a wheel. However as the rear wheel has a cassette, it needs a different type of spoking to allow for the in-balance in the wheel. Some are now trying new design with have no added benefit, but look prettier.
Undrilled Rims
Undrilled rims are often featured on the more expensive high performing wheels. The standard rims feature a hole where each spoke nipple joins, undrilled rims often has the spokes welded to the rim. Undrilled rims are often a lot more sturdy and rigid because of this improved process.
Machined Rims
This is the standard practice for the way that rims are made. An extrusion of Aluminium is bent into a circle and then joined seamlessly to create a smooth and perfectly round rim. It is then drilled to allow for spokes and nipples to be fitted.
Tubular and Clincher Wheels
There are two distinct wheel designs available to cyclists.
Tubular Wheels: These wheels have the tyre sealed to the rim of the wheel which contains the air. These wheels are carefully manufactured as it is critical that there are no air leakages resulting in a decrease in pressure. Additionally, some tubular wheels can also be fitted with an inner tube if required.
Clincher Wheels: This name is an alternative name given to a wheel that requires an inner tube within the tyre.
Carbon Fibre Cycle Wheels
There are a growing number of carbon wheels available on the market today; some of these wheels include certain parts of a wheel being created using carbon, for example a carbon hub or carbon rim. Some wheels are also manufactured completely using carbon with no other materials used, these are known as a complete carbon fibre wheels. There are a number of reasons why carbon is increasingly being used on cycle wheels, the first is its exceptional strength and secondly, the light weight of carbon. This combination ensures that the carbon wheels often find a balance between weight and strength, unfound on other wheel designs.
Ceramic Hubs
A lot of the higher priced cycle wheels include ceramic bearings and hubs. These features are guaranteed to decrease the amount of friction ensuring that the wheels spin smoothly. They also help to make the wheel durable and lower the amount of maintenance required.
Variation of spoke numbers on the left/right or drive side
There is a noticeable increase in the number of spokes on the rear wheel positioned on the drive side. The reason for this is that it adds extra stiffness and responsiveness to the wheel which can be helpful when accelerating. Coupled with this, there is often a lower amount of spokes featured on the front wheel compared to the rear; the reason for this is because there is less force transmitted through the front wheel compared to rear.
Freehub
A freehub is very similar to a freewheel arrangement, the only difference is that the freehub features separate gear sprockets which slide onto a carrier within the hub. The advantage to this is that the sprockets can be easily removed and replaced if a different gear ratio is required. In contrast, removing a sprocket from a one piece freewheel can be quite difficult as they become extremely tight after months of riding and a special tool is required in order to remove this type of sprocket setup.
Cartridge Bearings
These are bearings that have been manufactured in one piece as opposed to cone and cup, where you can take it totally apart to bearings and re-grease. Also known as sealed units.
Truing or a True Wheel
A True wheel is one that is perfectly round and absolutely straight in the lane of rotation. If it is slightly out either way it can be a bumpy ride or the wheel can rub on the brakes and wobble. The practice of truing is to make the wheel perfect in both dimensions so the riders gets a balanced wheel.