Bike Tyre Buying Guide - GO Outdoors
A good pair of tyres makes a huge difference to the quality of your cycling experience. They can improve your speed, control, comfort and confidence on the bike. Different tyres are suited to different conditions and designed for different types of riding and it is important to use the right ones. This is our guide to help you do just that. We'll be covering clincher tyres, the most common form of bike tyre.
Clincher tyres are have a U-shaped construction designed to be filled by a separate inner tube, which is the part that actually holds the air inflating the tyre. The tyre itself is designed to protect the inner tube against punctures and to provide grip and traction on the ground. Wheels designed to take clincher tyres have two raised sections on the edge of the rim called the 'bead hook' which hold the tyre in place once inflated.
Each clincher tyre is made up of three main parts:
The beads are more rigid parts at either edge of the tyre that hold it in place against the bead hook of the wheel. Tyres come with either a wire bead or a folding bead. Wire beads are the heavier of the two, but also offer great strength and durability. Folding beads, as the name suggests, allow the tyre to be folded for easier storage and transport as well as being considerably lighter.
The casing is the main structure of the tyre, consisting of a fabric woven between the two beads. The casing must be strong enough to contain the air pressure of the inner tube while remaining supple. Supple tyres are beneficial because they flex more while you are cornering or riding over uneven surfaces, increasing the amount of tyre in contact with the ground and improving grip and traction. Supple tyres also absorb impacts more easily for greater comfort at the risk of more pinch punctures (when the inner tube gets pinched between the tyre and the rim). The thread count of the casing (measured in Threads Per Inch or TPI) is used as an indication of its quality. A higher thread counts generally means a better casing.
The rubber tread on the outside of the tyre provides grip and protection against punctures and impacts. The design of the tread and the nature of the rubber compound effects the grip, durability, weight and suppleness of the tyre. Tread design ranges from totally slick road race tyres to nobbly mountain bike tyres. Compounds and treads are suited to specific terrains, uses and conditions.
Many tyres also include an additional puncture protection layer between the tread and the casing. These layers are made of a tough material, often Kevlar, which stops sharp objects deflating the inner tube at the cost of adding extra weight and making tyres less supple. Since the task of puncture protection is delegated to this inner layer, the design of the outer tread is then freer to focus on grip and traction.
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Although tyre design varies hugely between different disciplines, there are still some things that are worth looking out for in general:
Wider tyres have a greater surface area in contact with the ground. This means improved grip and traction but can also mean extra rolling resistance, which slows the bike down. Wider tyres also have greater air volume inside which acts as a sort of natural suspension against bumps and impacts for a comfier ride. Road tyres are generally measured in millimeters and MTB tyres in inches.
Thicker tyres offer better protection against punctures but are heavier and less supple. As explained above, supple tyres offer superior grip and comfort.
Different tread patterns offer improved performance in dry or wet conditions and on hard or loose surfaces. Mountain bike tyres sometimes also have different treads on the front and rear tyres to since these tyres behave differently and perform different roles on the bike. Tread patterns are often 'directional', meaning that they only work properly went fitted in the right direction. So make sure you put your tyres on the right way around!
The rubber compound used for the outer surface of the tyre can drastically change its characteristics. Compound choice will affect the tyre's weight, suppleness, tackiness and susceptibility to punctures. Different compounds are suited to different conditions and riding styles.
Different tyres are designed to work best at different pressures. As a general rule, lower pressures mean better grip and comfort whereas higher pressures mean improved rolling resistance. Rider weight is also a consideration: heavier riders will require higher pressures in their tyres. There are exceptions however, and choice of tyre pressure comes down to a good deal of personal preference - within the manufacturer's recommended pressure levels for each tyre, of course.
Different designs have different levels of puncture protection, either in the tread itself in with a separate puncture protection strip.
Road tyres are designed to keep rolling resistance as low as possible for top-speed road riding. They are narrow with a minimal or slick tread and are inflated to high pressure - anywhere from 80-120 PSI. The relative lack of bumps, holes and sharp stones on the road means that road tyres can get away with a thinner rubber layer on the outside and minimal puncture protection underneath. Along with the narrow, tread-less design leads to a very light overall weight. Narrow tyres (and correspondingly narrow wheels) also have aerodynamic benefits.
That's the general rule, but of course there are all sorts of road rides and all sorts of tyres to match. Race-orientated tyres are extra thin with the bare minimum tread and puncture protection for optimum weight, rolling resistance and suppleness. There is nothing better to help you get an edge in competition, but most of the time we have other concerns besides top speed. Sturdier tyres built with thicker rubber and a tough puncture protection strip will help prevent reduce the amount of time spent at the side of the road with a mini pump in your hand. Tyres with a grooved tread help maintain grip in wet weather.
One important consideration is tyre width. In the past it was common to see road race tyres as narrow as 18mm across, but they are now most popular in 23mm or 25mm sizes with tyres up to 28mm also available. As explained above, wider tyres offer greater comfort because the greater air volume inside to soak up impacts and vibrations. If your area suffers with poor road surfaces, wider tyres might be good idea. Another benefit is that they run more effectively at lower pressures. This is particularly helpful in wet weather when lower tyre pressures are advised to help maintain grip. Wider tyres at a lower pressure are also handy for extra traction if you ever find yourself on a gravel section as part of your road ride.
If you are thinking of increasing your tyre width for extra grip or comfort, you will first have to make sure that there is enough clearance between your wheel and your frame to accommodate the bigger tyre.
Road wheels typically come in one diameter, 700c/28", and road tyres are the same. You'll see tyres listed by diameter and width, e.g. 700c x 23 for a 23mm road tyre. Some manufacturers use 28" instead of 700c so just remember that they mean the same thing!
Mountain bike tyres are designed for off-road performance with a thick tread consisting of raised knobs that dig into loose ground for traction and provide grip on uneven terrain. The outer rubber layer is thicker for durability and impact resistance/absorption.
There is much greater variety amongst mountain bike tyres than road tyres, both in terms of style and sizing. When chosing a tyre, you'll need to consider the wheel size, tyre width and tread design that you need.
MTB tyres, like MTB wheels, come in three diameters: 26", 27.5" (650b) or 29". Your tyre must match your wheel size. Just check the label on the side of your wheel if you're unsure what you need.
MTB tyre width can range from anywhere from 1.8" all the way to 5". As explained above, wider tyres offer better grip, traction and stability at the cost of some speed. Within the range, the different sizes appeal to different types of riding depending on their balance of speed and grip. Cross country riding benefits from the extra speed of a thin tyre whereas all-mountain or downhill riding requires a wider tyre for improved grip on rough terrain. The biggest tyres - known as fat tyres - are designed for on specific fat bikes in loose surfaces such as snow or sand. Their extreme air volume also acts as a sort of natural suspension when they are used on normal trails.
Bikes designed for these different types of riding are also designed to accomodate the relevant tyre sizes. This means that the frame on a cross country bike might not have enough clearance around the rear wheel to fit a particularly wide tyre designed for downhill use. Remember that your tyre often gets covered in mud and this has to be able to fit through the frame as well. The width of your wheels or wheel rims will also affect which tyres you can use on your bike. Fat tyres will only fit on fat bike.
Despite these constraints, there is some room to manouver with tyre widths and you can customise the feel of your bike to suit your riding within a certain range. Fancy taking your bike on some gnarlier trails? Beef up your ride with some wider tyres to help stay in control! If you do want to change tyre width, just check tyre compatibility with your wheels and frame beforehand.
MTB tyre sizes are listed in a similar way to road tyre sizes, by the wheel size and width, but they are measured in inches instead of millimeters. For example, a tyre marked 26x2.4" is a 2.4” wide tyre for 26” wheels.
Once you have chosen the best width of tyre for your riding style, you'll have a range of tread designs to choose from as well. These differ depending on the type of riding and the conditions for which they are designed.
A deeper tread with large knobs provides better traction in loose or muddy conditions by digging into the ground as the tyre rolls along. A larger tread also provides extra impact protection and durability on rough terrain. This does, however, increase rolling resistance on hard, dry ground and cross country riders looking for speed will want a less prominent tread unless the conditions demand it.
The layout of the knobs will also affect performance. Some tyres, for example, have a flatter central section to limit resistance while pedalling in a straight line but still include larger side knobs for grip while cornering. There are also choices between different rubber compounds. Tackier compounds are preferred for extra grip in rocky terrain.
Front and Rear Tyres
The front and rear wheels behave differently on the bike and affect handling in their own ways, and some tyre treads are designed specifically for use on the front or rear wheel to optimise performance.
The main challenge with the rear tyre is to maintain traction in loose or muddy conditions. Rear tyres tend to have knobs arranged horizontally across the tread to help prevent the wheel from spinning out when you pedal and ensure that all your effort comes out as forward motion. The weight distribution on a bike also tends to sink the back of the bike lower into the mud, causing the rear tyre to pick up more mud than the front. As such, rear tyres are often designed with a lower profile to stop all that mud rubbing against the frame.
Front tyre design is focused on speed and cornering traction. Knobs are more in line with the direction of travel to improve rolling resistance and the side knobs are more prominent for better grip through corners. They often have a larger profile since mud clearance isn't as much of an issue.
A front specific tyre can be used on the rear wheel and vice versa if necessary but you'll enjoy better performance if you use the right tyre on the right wheel.
A good city tyre gets you around town quickly, safely and with a minimum of fuss. You don't want to be slipping and sliding with traffic around, so tyres have to be grippy. You don't want to be replacing your tyres all the time, so they have to be durable. And you definitely don't want to be late for work because you had to fix a flat, so puncture protection is key.
As such, city tyres are wider than a standard road tyre for extra grip and comfort. A thicker tread constructed from tougher rubber compounds and additional puncture protection strips take care of durability. The tread on city tyres is designed for use in all weathers and features knobs and grooves to improve grip and traction in the wet. The textured tread also makes city tyres suitable for the gravel paths or brief off-road shortcuts that are often a part of urban cycling, but they are still intended to provide road speed so aren’t as nobbly as MTB tyres.