Rolling: The Wheels

Without the wheels a bike is pretty much useless and certainly isn’t going anywhere fast (unless you want to use it as a towel rack or a seat, that is). Often the most obvious component when you think of a bike, the wheels are a key defining feature of any cycle.

The number of wheels can vary from machine to machine, not surprisingly bicycles have a pair. While three wheelers remain largely uncommon, tricycles are still produced for specialist applications. Unicycles make use of a single wheel and again, remain largely uncommon.

In this guide, we will consider the wheels on a bicycle. Put simply, the wheel is the circular part of the bike that rotates as the bike moves across a surface. One is located at the rear of the bike, which is rotated through the transfer of energy via a belt, or (more commonly) a chain that is then linked to the drive system. The rear wheel is fixed in place in the frame so although the wheel freely rotates it does not pivot or change angle. In contrast, while the front wheel also freely rotates, it can also change direction in terms of the angle via the turning of the handlebars. The front and the rear wheels are completely independent of one another, so one can rotate while the other is stationary, and vice versa.

The dimensions of the wheel and associated parts are often the best indicator of what terrain the bike is designed to conquer and straight away you can get a pretty good idea about what the bike is intended for just by looking at the size and width of the wheels. Although this is not to say you cannot ride around town on a bike with 20 inch wheels, or ride down a mountain with 700c wheels, more and more specialist manufactures are increasingly exploring the use of different wheel sizes for different uses.

In the guide below, each component that makes up the wheel will be identified, deconstructed and explained.

1. Hubs

The hubs are located in the middle of the wheels. The defining characteristic of a hub is to be the fixing point between the outer wheel that is in contact with the ground, and the bicycle, while allowing the wheels to rotate freely.

In the simplest terms, a hub is essentially a solid axle (which attaches to the bike) connected through rotational bearings to a metal outer shell (which attaches to the spokes).

Front wheel cup and cone hub - MadeGood.bikes

Adjusting the cone on a cup and cone front wheel hub.

The main difference between the front and the rear hub is that the rear hub is also tasked with transferring the rider’s energy into rotating the wheel, thus producing forward thrust (traditionally through a belt or chain). There are a number of methods that are designed to do this (see The drive system below).

Below the key components of the hub will be identified and explained:

The axle (or spindle)

This is the central component of the hub and runs all the way through the middle. The axle provides the method of attachment onto the bike (to the frame for the rear, or fork for the front).

Two types of wheel hub axels - MadeGood.bikes

On the left is a front wheel with a quick release skewer. On the right is a front wheel with solid axel set up.

Axle designs vary greatly depending on the type of hub, but the most common are either a solid axle set up, where bolts are threaded onto each end of the axle, fixing the wheel into the bike. Older style or more basic bikes adopt this method, due to it being economical to produce, as well as being a relatively low maintenance method. Heavy-duty bikes also use this method, for the its strength and reliability, such as BMX bikes, post bikes & other commercial cycles.

The other most common axle type is the skewer, where the main axle is actually hollow, and a 5mm skewer runs through the centre, which then is tightened to clamp the hub and bike together. This type accommodates the quick release method of attachment that was invented by Tullio Campagnollo in 1927. This is the most common method for road and racing bikes, as it allows the wheels to be removed with very little effort and without tools – which is great for quick maintenance, or packing up a bike into the boot of a car, but not so great if you are popping into the pub for ‘a quick pint’ without locking up your wheels.

Other, more specialist axles are also in use, such a through axle, which is a larger (9, 12, 15 & 20mm) axle that runs through the centre of the hub shell. This type of axle is noticeably larger and therefore much stronger, and was originally designed to cope with the demands of off road cycling, such as with dirt jumping, downhill mountain biking and freeride.

The bearings

The bearings are located inside the hub shell (we will get there in a minute), and provide the outer hub with the freedom to rotate around the centre axle.
Traditionally a loose ball bearing system was the most common, whereby bearings (often in a bearing cage or spider) sit inside a race and cone set up, and are allowed to freely rotate within the housing, thus providing the wheel with a free spinning movement. Loose ball bearing set ups have to be maintained and adjusted, often regularly. This mainly entails cleaning the race and bearings, reapplying grease and then fine tuning the cone adjustment so the bearings have enough room to freely spin, but not so much room that they can wobble, as this produces play in the wheel itself.

Front wheel bearings - MadeGood.bikes

The ball bearings of a front hub sitting in grease in the inner race, exposed because the outer cone has been removed.

Modern bearings are most often a sealed cartridge bearing system, whereby the bearings are enclosed in a sealed cylinder. These bearings are much longer lasting, and maintenance free, however they are not practically serviceable, so when they wear out the whole cylinder (of bearings) has to be replaced as a single unit. The advantages of using sealed bearings are many, and all good quality hubs today use this system.

Ceramic bearings are becoming more common as the cost of materials and production decreases, but essentially they are a specialist type of sealed bearing that make use of super smooth ceramic bearings to further reduce the rotational friction, thus keeping the wheel spinning for longer with less effort.

The hub shell

The hub shell is basically the outer skin of the hub, the part that is visible to the eye. Housing the internals of the hub, it is easy to identify the differences in the hub shell designs. The size and shape of the hub shell differ between manufacturers, and much larger hubs tend to be designed for larger axles and bearings, whereas smaller hub shells point towards a much lighter hub, designed for the road.

Front wheel with disc rotor mounted - MadeGood.bikes

This picture was taken from the non-drive side of a front wheel with a hub mounted with a rotor for a disc brake.

Often, a hub shell may have a rotor mount on the non-drive side (left hand side when on the saddle), this is for the use of a disc brake and is more common for off road applications or cyclo-cross style road bikes.

The flange

The flange is specifically the part of the hub shell to which the spokes attach. The number of spoke holes in the flange depends mainly on the style of riding. High flanges are most often associated with vintage road bike hubs, or track style hub designs (most commonly used for single-speeds and fixies). In more modern times, many hubs have actually adopted a flangeless design, where the spokes actually run through the main hub shell. This is a cleaner and sleeker way of packaging the hub and spokes, the aim also being to reduce rotating mass and give a cleaner appearance.

Bicycle wheel hub flange - MadeGood.bikes

Detail of a front wheel hub flange, clearly showing how the spokes are attached.

The drive system (rear hubs only)

The drive system is essentially the means by which the rear hub can rotate via the movement of the chain or belt. In basic form, this set up usually comprises a ratchet system, and a sprocket. The two most common types of ratchet system are a freehub body, or freewheel.

Freehub - MadeGood.bikes

A freewheel unit being screwed onto a rear wheel hub.

A freewheel is a single or group of sprockets wherein the ratchet system is enclosed; this is a solid unit that then screws onto a thread on the rear wheel. Freewheels are manufactured in many different sizes, speeds and configurations, but these cannot be altered, a sealed unit, if you like.

Freehub sprockets - MadeGood.bikes

Individual sprockets being slid onto the spline of a rear wheel freehub.

A freehub system requires a cassette (bank of sprockets) to be slid onto the splines of the hub (where the ratchet system is already in place). A freehub style drive system can have any configuration fitted to the hub, so it is easy to alter gear ratios and spacing, depending on the application.

Generally speaking, these days a freehub and cassette system tends to indicate a better quality wheel. whereas a freewheel style system is most often found on more basic style bikes, or older bikes (before freehub and cassettes were developed). Freewheels are often used on flip-flop style hubs, which are most commonly found on fixie or single-speed bikes.

However a cassette style hub can still be used for a single-speed set up. This is possible by using spacers instead of other sprockets. So, once the size and style of the sprocket is chosen, you simply sandwich it in between a set of spacers to pack out the empty space on the freehub body.

Hub spacing

Hub spacing is an important factor to consider when buying wheels for a bike, or building custom wheels.

Hub spacing essentially refers to the distance between the two outer cones (or locknuts) of the wheel. The hub spacing indicates the size of the frame or the fork that is compatible.

Over the years, the standard hub spacing has changed with technological developments.

Examples of common hub spacings:

96mm – Front – Older style hubs (typically European)
100mm – Front - All modern applications (apart from DH)
110mm – Rear - Old style coaster and track hubs
120mm – Rear – Newer track style hubs (Flip-flop)
126mm – Rear – Older style road (such as 6 and 7 speed)
130mm – Rear - Modern road applications
135mm- Rear - Modern MTB applications

2. Rims

The rim is the outer part of the wheel and is connected to the hub via the spokes; the rim is responsible for connecting the tyre to the wheel.

Bicycle rims vary in design and material depending on the intended use.

The basic dimensions of any rim are governed three main variables:

Rim size

The size of the rim (diameter) is the biggest variable and dictates the size of the wheel itself, as well as the tyre and inner tube. There are many rim sizes available, and the list is mind bogglingly huge. Bellow the most common rim sizes are listed:

Brompton - MadeGood.bikes

A Brompton folding bike with relatively small wheels.

16” – Brompton bikes and children’s bikes
20” – BMX bikes, children’s bikes and older style shopper bikes
24” – Cruiser BMX bikes, some MTBs (DH and dirt jump)
26” – The most common size in the past, now mainly MTBs
650b or 27.5” – A modern size adopted for specialist MTBs
700c or 29er – Most modern town bikes or hybrids and road bikes – as well as a new wider MTB application (mainly XC)

Rim width

The width of the rim also varies, but generally the rim size is the real dictator of use whereas the rim width is more about fine-tuning the set up.

As you would expect, a wider rim accommodates a wider tyre, which tends to point in the direction of off road use, whereas narrower rims are better suited to skinny road or race tyres.

The width of the rim also highlights the strength of the set up; wider rims have a much larger surface area to absorb impact, while super skinny rims tend to buckle more easily. The width of the rim dictates the tyre that can be used, so if you have specific requirements for a wheel and have a tyre in mind, be sure to first check that the rim is a compatible width.

Rim depth

The depth refers to the height of the rim wall. Until recent years, almost all bicycles (apart from some specialist applications) simply had a basic box shape rim design, whereas now deeper rims are becoming more popular. Arguably the reason for this is because the rims are more aerodynamic, and although this is true, in the urban environment the gains are relatively minimal and the reason these aero rims are popular is largely down to aesthetics.
While aero rims can be more efficient in reducing drag, they are much more susceptible to side-winds.

The number of walls a rim has is another distinguishing feature of its design.

When referring to a rim, the wall means the skin of material that makes up the structure and shape of the rim. In the past, almost all rims were what is called single wall, which is when there is one layer of material responsible for separating the tyre from the spokes. Most common these days is a double walled rim, where there is more than one layer used (usually at the central point) to increase the rigidity of the rim. Often an extra wall in the rim design can actually increase the strength of a rim while decreasing the weight, by making use of internal box-sections providing greater structural integrity.

Triple wall rims are also available, mainly for BMX bikes, where strength is the number one priority, and a rim is subject to harsh sideways forces.

The material of the rim is highly important in determining the type of use. The three most common types of rim material are aluminium, carbon and steel. Older bikes tend to use steel rims, which by today’s standards are not up to par, this is due to them being heavy, usually single wall, and terrible under braking conditions (particularly in the wet). Aluminium rims are the most popular, and are suitable for almost all types and levels of riding; they perform well with braking and have a high weight/strength ratio.
Carbon rims are designed for smooth cycling conditions (such as track, racing and time trial). Carbon rims are very light, and can make a big difference to the acceleration of a bike. However, they are also more brittle than metal, so although the benefits are high on the track, the potential cost of slamming into a pothole at speed is a strong deterrent for the use of carbon rims on a daily hack.

3. Spokes

The spokes are the thin rods that connect the hub in the centre of the wheel to the rim on the outside.

Spoke end - MadeGood.bikees

Typical spoke end design with a 90 degree bend.

The most common spoke design is a fine, long piece of metal with a 90-degree bend at one end. This attaches to the hub – the mushroom-shaped stop at this end of the spoke holds it in place. The other end of the spoke is usually threaded, and a nipple (see section 4) is screwed on from the outside of the rim, giving the spoke tension so it is locked in position at each end.

The spoke tension can then be adjusted by turning the spoke nipple, as it slowly threads onto the spoke, the tension increases. Ideally, you want a wheel that is evenly tensioned between all the spokes, which should produce a true wheel. However, often other factors and build tolerances come into play, so although the wheel may be perfectly straight, spoke tension may differ very slightly, in reality this is nothing major to worry about as long as the wheel is straight.

Spoke key in use - MadeGood.bikes

Truing a wheel by turning a spoke nipple with a spoke key to adjust the tension of the spoke.

The number of spokes that any given wheel has depends on the specification of the hub and rim (dictated by the riding application); typically between 16 and 40 (both extreme ends of the scale), but most commonly 20, 24, 28, 32 and 36.

Typically the rear wheel will have more spokes than the front, this is for a number of reasons:
There is more load on the rear wheel due to rider weight distribution on the bike;

The rear wheel is also subject to torsional stress (the hub transferring rotational energy to the rim);

The rear wheel is often not built entirely symmetrically (commonly known as dished).

The difference in spoke numbers between the front and the rear wheels is usually not large: for example, a common combination for the road is 20 at the front and 24 at the rear, or 32 at the front and 36 at the rear, for a town-going hybrid.

As a general rule the greater the number of spokes, the more durable and stronger the wheel (all other factors being the same). However, this is not to say that a 38 spoke wheel is much stronger than a 36 spoke wheel, but a 32 spoke wheel is certainly more resistant to buckling than a wheel with 16 spokes.
Generally speaking, wheels with fewer spokes tend to be much more susceptible to becoming buckled or egged (due to sideways forces). Therefore, if you are a heavy rider going for a minimally spoked wheel, expect to have to true the wheel more often than normal, as well as increased chances of snapping a spoke. Not only that, but a wheel with much fewer spokes is also harder to fine-tune, in terms of straightening and maintaining even spoke tension throughout.

However a minimally spoked wheel will carry less rotational mass, so much like the carbon rims, it does have its advantages for the right application; where weight is a big factor, such as track riding, road racing, time trials or triathlons.

As a general rule, the more force and/or weight being put on a wheel, the more spokes are needed to share the force, and ultimately to avoid snapping under load.

The length of the spoke depends on a number of factors:

Firstly the profile of the rim, and the flange size on the hub - essentially these two factors dictate the distance the spoke has to bridge. A deeper rim, or a bigger hub flange results in the need for a shorter spoke;

The build pattern of the wheel also has an effect on the spoke length. The angle of the spoke is determined by the template of the build (see section 8);

The dish on the rear wheel will change the distance the spoke has to cover (again, see section 8).

Once all of the above factors have been taken into consideration, the spoke length can be calculated. Typically, road going bikes are close to 290 mm, but vary hugely depending on the above factors. Commonly spokes are available in sizes between 180 mm and 320 mm. However, if spokes are proving hard to find, or you need a size that is not available, they can be custom produced with the help of a spoke cutter and threader.

The most common material used for spokes is stainless steel. The reasons for this are that it is: easily available; relatively cheap strong, and; resistant to rust or corrosion. Less commonly used materials include: carbon fibre, titanium and cheaper steel that is chromed.

Stainless steel spokes come in a number of varieties:

Straight Gauge or Plain Gauge

These spokes are the same thickness/diameter for the whole length. They are used most often because they are cheaper to produce than butted spokes. However, there are also advantages in impact strength. As the actual body of the spoke is thicker, the spokes tend to be stiffer as well as far less likely to break if they are hit or knocked (imagine a BMX wheel hitting a grind ledge side on, or a chain slipping off into the spokes). Straight gauge spokes are heavier than butted spokes, so most often butted spokes are better suited, unless there is an expressed preference for heavy duty use.

Butted (this can be Single, Double or Triple)

Butted spokes vary in thickness along their length. Having a spoke that is thinner in the middle section results in the spoke being lighter, which can make a relatively large difference (bearing in mind there can be 70 odd spokes which are subject to rotational movement). However, weight is not the only difference: whereas straight gauge spokes tend to be very stiff, resulting in a very rigid wheel, using butted spokes actually results in a more flexible and malleable wheel. [[This is only a small difference, but as the butted spokes are less rigid, it can actually result in the wheel being more effective in coping with stress, as the it can flex and show elastic properties, instead of buckling or spokes snapping.]]
Another advantage of using butted spokes is that they are much easier to bend, so when lacing a replacement spoke into a wheel or building a wheel from scratch, a butted spoke is much easier to thread into holes and move between other spokes.
One specific advantage of the spokes themselves being more likely to snap is that this can act as a fuse in the setup. A spoke snapping is far cheaper, easier and quicker to fix than an eyelet of a rim pulling through, or the flange of a hub snapping off.

Aero

Standard cylindrical spokes are most often used, for simplicity and ease of fitting and replacement, however bladed (or Aero) spokes are popular among certain groups of riders, particularly with racing bikes, as using these spokes reduces the straight line drag of a bike. These spokes can be expensive though, and much harder to track down in the required size.
Also, similarly to the aero rim situation, by making the component more aerodynamic in a head on airflow, it can result in becoming much more subject to sideways airflow (such as a side wind).

For road racing, triathlons and time trials, the advantages can be justified but for everyday use there are generally many other variables, which should be prioritised.

Because of the nature of the spoke design, it is much easier to give the spoke an exact tension. Standard spokes tend to wind up once you get to a certain tension, while bladed spokes tend to cope with staying super tensioned for longer, as the spokes stay completely still when the nipples are tightened.

As mentioned before, other spoke materials are available. Titanium spokes are often used for their weight saving properties. However, the difference is only minimal, and Ti spokes tend to be a bit of a novelty in reality. If you want titanium spokes then be prepared to pay the premium on price, as they can be very costly. Titanium spokes have also been noted as slightly more inclined to stretch than stainless steel spokes, resulting in problems achieving initial spoke tension. Also, due to the bonding process, it is advisable to only use brass nipples with titanium spokes, which in real terms are not much lighter than stainless spokes with aluminium nipples.

Carbon fibre spokes are most common in a bladed format, the idea being that these spokes slice through the air with reduced resistance, while also being lighter than steel spokes. Carbon spokes can have a place on racing bikes, but for regular road use they are not advised, as they are extremely brittle and once they bend, they snap or crack and flake, like bending bamboo.

4. Nipples

The nipples are the small screw on cylinders that thread onto the end of a spoke, and tension the spoke in place in relation to the rim. They are adjusted through rotation, by either using a flat screwdriver from the top (only accessible when the wheel is tyreless), or through using a spoke-key to grip and turn the flat edges on the nipple.

Spoke nipple - MadeGood.bikes

Spoke off the wheel with a nipple screwed half on.

Nipples are most often made from nickel-plated brass. This is due to the nipple needing to put up with fine adjustment, so the thread has to be good quality and long lasting. Aluminium nipples can be used to save weight over brass nipples, however these are more susceptible to the threads wearing out, or the flat adjustment edges rounding off, especially when they are tensioned a lot or at higher tensions. Another reason aluminium nipples are used is because they can be treated (anodized), and the colour can be changed – so you can have multi coloured nipples on a wheel. Ultimately the most common reason aluminium nipples are chosen is to keep rotational weight down to a minimum.

In optimal conditions, aluminium spokes can work perfectly, however for ease of adjustment and reliability brass nipples are advised. Nipples can also come in different lengths, depending on the rim and spoke design but the most common are 12, 14 and 16 mm.

Nipples are generally supplied with the spokes. With every box of spokes, the same number of matching nipples will be supplied. These nipples will be the most common nickel-plated brass types. Wherever possible, try and use the matching provided nipples with spokes, as they will be the most compatible.

5. Rim-tapes

Often the forgotten component of a wheel, the rim tape is the barrier between the spoke holes, spokes, nipples and inner tube.

Rim tape - MadeGood.bikes

Removing old rim tape that has failed. If you look closely you can see a tear by the valve hole.

All of the these, as well as the metal on the rim, can have coarse surfaces, which can penetrate the inner tube and cause a puncture. It is therefore important for the inner tube to be seated within a smooth and clean environment between the rim and the tyre, and that’s what the rim tape provides.

Rim tape is available in a number of widths, depending on the width of the rim. Unsurprisingly a wider rim construction requires a wider gauge of rim-tape, and vice versa. The idea is for the rim tape to be seated in the bottom surface of the rim, but be cautious as if the rim tape is too wide or not seated correctly it can affect the seating of the tyre on the rim, and cause the tyre to pop off under pressure.

The material can also vary, the most popular rim tapes are usually a rubber composite, however these do tend to be more susceptible to becoming damaged or cracking over time. Fabric based rim tapes are far superior as they are tougher, so can deal with much higher pressures more easily, and also tend to stick to the rim, so you don’t have to reposition or realign the tape every time you remove the tube. Plastic and nylon rim tapes are also popular and again are far superior to the rubber type, but they tend to be size-specific, so can prove to be more of a chore to stretch onto the rim and position.

6. Tyres

The most visible part of the wheel, the tyre is the rubber layer on the very outside of the wheel, in contact with the riding surface.

The size of the tyre is mostly dependent on the rim to be used, but there are many options of tyre design and size depending on the application or rider preference.

Mountain bike tyre - MadeGood.bikes

A fat tyre with nobbles designed for off-road riding.

Tyres with knobbles on the outside are generally designed for loose surfaces, such as sand, dirt or mud, and mostly come in a wider size to suit wider rims used on mountain bikes or BMXs. At the other end of the spectrum you have slick tyres, which are smooth in appearance and are in general much thinner than treaded tyres. This type of tyre is meant for smooth and dry conditions, such as road races or a track. In between you find many different variations of narrow tyres with knobbles and wider tyres which are completely slick; each tyre is designed for a specific use.

Tyre pressure - MadeGood.bikes

The maximum and minimum pressure of this road tyre are written on the side.

Tyre pressure depends on a number of factors, but as a rule the smoother the riding surface, the higher pressure you want – this is due to higher pressures reducing the contact area with the surface, thus reducing drag and friction and making it easier to roll for longer. Lower pressures are mostly used where grip is the highest priority, such as downhill mountain biking, trials riding or BMX. This is because a lower pressure tyre will generally mould to the surfaces and create a larger contact area.

For an extreme example, picture a low pressure tyre rolling over a section of tree roots smoothly with ease, providing grip and stability, while a high pressure tyre would violently bounce and slip on the roots due to the lack of holding. For the opposite, imagine a high pressure tyre rolling on the road surface freely and with little resistance, due to its small contact area, while a lower pressure tyre creates a much more sluggish roll and increases friction.

As well as riding conditions, tyre pressure is determined by personal preference, many people prefer speed over comfort, and many comfort over speed. Finding somewhere on the spectrum that suits you is the answer; you can experiment by choosing different pressures depending on the conditions, for example, 90PSI on the road, and 55PSI on a bumpy towpath.

Road bike tyre - MadeGood.bikes

A thinner tyre designed for riding on the road.

The material of the tyre also varies widely, and most of the tyres available are constructed from a relatively similar rubber compound. Many tyres are available with other materials integrated, for example, Kevlar or high compound nylon, which are added to help prevent punctures and reduce the risk of anything penetrating the tyre.

The bead of the tyre is the inner lip, which hooks on to the inside of the rim to fix the tyre in place. The sidewall of the tyre is the section between the rim and the tread, this is generally the thinnest part of the tyre, and its main job is to maintain structure and shape of the tyre. The tread of the tyre is the part in contact with the surface; tread designs vary widely from smooth, to lots of huge nobbles, or even metal studs. The tread is the thickest part of the tyre.

Pushing tyre beed over rim wall - MadeGood.bikes

Pushing the wire bead over the wall of the rim.

As manufacturing technology advances, tyres and rims are becoming more and more specialist, and the build tolerances are becoming so small that very high tyre pressures can easily be managed: in the past only specialist tyres would be able to cope with higher pressures.

Every tyre has a recommended pressure stated on the sidewall. Having a pressure outside this range is not recommended as it can result in the tyre popping off the rim, which can be particularly dangerous (especially when you are chasing down that Brompton rider along City Road).

It is vital to regularly inspect the tyre for any defects or splits, as well as keeping an eye out for anything that may have lodged itself into the tyre as again, these can result in blow-outs or punctures. Generally if a tyre pressure is maintained to the recommended level, and the rider is careful (i.e., not skidding all day long – sorry to be a bore), tyres can last a long time. It is important to keep on top of your tyre maintenance.

7. Tubes

The inner tube is a rubber tube that is located inside the tyre, and is responsible for holding air. The size of the tube depends on the size of the tyre. Inner tubes are made from rubber, and have a valve, which is where the air enters and exits the tube. The valve is located on the inside edge of the tube, and slides inside a hole in the metal rim, so once the tyre is fitted over the tube the valve is still accessible.

Inner tube - MadeGood.bikes

Holding an inner tube outside of a bike wheel.

There are three different types of valve that are most commonly found on bikes today:

Schrader/Auto/car type – These valves are most common on town bikes and hybrid bikes. They are the same type as found on cars and motorbikes. These are wider in appearance to Presta types, and tend to point towards a low-pressure or standard setup. This is an automatic valve, as the air can be pumped into the tyre without manually opening the valve.

Schrader or auto valve - MadeGood.bikes

Using a tyre lever to release air from a Schrader, or auto valve.

Presta/sports - This valve is much slimmer in appearance, and most commonly is found on road bikes, due to its ability to cope more easily with higher pressure. With this type of valve, you have to unscrew the nipple on the top to release the lock, only then can you add or release air. These valves also tend to be less prone to perishing.

Presta or sports valve - MadeGood.bikes

Pressing the nipple on a presta, or sports valve to release some air.

Woods/Dunlop - This is a much older type of valve, and was the original air valve, before the likes of Presta and Schrader became available. This is essentially an automatic valve with a screw lock, only found on much older bikes. A tube with a Schrader valve is most often used to replaces a Woods tube, as it is a more up to date and reliable system to work with, and they are completely interchangeable.

Woods or Dunlop valve - MadeGood.bikes

Connecting a pump hose to a woods or auto valvle.

For certain applications different tubes with varying thicknesses of rubber are available. Often racing bikes will utilise a lighter weight tube, which has a slightly thinner construction to save rotational weight. At the other end of the spectrum mountain bikers often use ultra thick, heavy-duty tubes to give extra protection against pinch flats and punctures.

The length of the valve can also vary; if the rim has a deeper design then the valve will need to be taller in order to still give clear access. A standard valve is around 40-50 mm, common longer valves are anything above 60 mm.

Valve extensions can also be used to thread onto valves to make them more accessible. These can be straight extensions, which are most common for track style wheels, or, angled extensions, which are most common for tricky jobs where space and clearance is an issue, such as on a wheelbarrow or a pushchair.

8. Wheel building

Custom-built wheels enable specific and personal wheel requirements to be met. Although many wheels can be bought off the shelf, the potential variation of wheels that can be built is huge, so custom-making wheels (or commissioning someone to do so) can result in a perfect combination of parts according to your own preference. One-off builds often cater for the needs of riders who are riding cross discipline, or simply want to build a wheel set in line with the aesthetics of their bike.

Due to the advances in manufacturing technology, wheels can now be fully built autonomously by a machine. Although this may sound great, in reality the quality of the machine built wheels is low. You tend to find these mechanically built wheels on much lower end budget wheels and cheaper bikes.

Due to the range of variables and complexity of a wheel build, the best wheels are built by hand. Although building a wheel can be a daunting prospect at first, once a decent system is consistently adopted by the builder it’s all down to practice - and lots of it! Initially a wheel build may take hours, days almost. But once the skill is honed and the (vast amount of) experience gained it is not uncommon for builders to complete the whole process from start to finish in less than half an hour.

Preparation is crucial when building a wheel. It is essential, once the hub and the rim are chosen, that the spokes are exactly the right length - a couple of [[millimeters]] can make all the difference. As long as the spokes are the correct length, and the hub and rim have the same number of spoke holes, you are good to go!

The build pattern (or lacing technique) varies a lot depending on the type of wheel, and the required usage. The most common lacing styles include 2 cross, 3 cross & radial.

The cross part refers to the number of times a single spoke crosses paths with another spoke. So on a 3 cross wheel build, each spoke will either go under or over another spoke 3 times. Unsurprisingly on a 2 cross build, a spoke intersects other spokes twice. Alternatively, on radially laced wheels the spokes do not cross one another at all as the spokes lie at a straight angle at the shortest distance between the hub and the rim.

Radially laced wheels tend to be found on the front of road going bikes, or on older style BMX wheels. Although radial laced wheels tend to point towards a much lighter, more minimal wheel build, a radially laced wheel does not cope with sideways stress or impact as well. It is not advised to use a radially laced wheel for the rear, as the transfer of twisting stress puts a lot of pressure on the build strength of the wheel.

Much like a chain, any wheel is only as strong as its weakest part. So even if you invest in a top quality rim, and pair it with a strong hub, the build of the wheel will determine its durability, so a top quality build is always recommended to prevent problems in the long run.

Wheel building is the most complex part of assembling a bike, please refer to the full guide for information and help when taking on a wheel build.

Replacing spokes on a wheel can vary in difficulty depending on the specific scenario. If one spoke has snapped, then replacing it shouldn’t be too much of an issue for any rider who is handy with a spanner. Generally, replacing a spoke on the front wheel is much easier than the rear wheel, as all the spokes are the same length and the wheel can be much more easily removed. If a rear spoke replacement is needed, that is when it can start to get complicated.

If the broken spoke happens to be on the drive side (the side with the sprockets) of the rear wheel, this can become even more compacted as the cassette or freewheel will most likely have to be removed to allow the spoke to be threaded through the hole in the hub shell.

Bearing all this in mind, if a spoke is replaced quickly, then the process should be relatively simple and the wheel will not have to be re-tensioned. However if a wheel is ridden with missing or broken spokes then this can result in more spokes breaking and the wheel becoming more buckled, so it is advised to replace any broken spokes as soon as they are spotted to avoid needing a rebuild.