![Pirelli Diablo Rosso](https://upload.wikimedia.org/wikipedia/commons/5/58/Pirelli_Diablo_Rosso.jpg)
A motorcycle tyre (motorcycle tire in
American English
American English, sometimes called United States English or U.S. English, is the set of variety (linguistics), varieties of the English language native to the United States. English is the Languages of the United States, most widely spoken lan ...
) is the outer part of
motorcycle wheel
Motorcycle wheels are made to cope with radial and axial forces. They also provide a way of mounting other critical components such as the brakes, final drive and suspension. Wheels, and anything directly connected to them, are considered to be un ...
, attached to the
rim, providing
traction, resisting wear, absorbing surface irregularities, and allowing the motorcycle to turn via
countersteering
Countersteering is used by single-track vehicle operators, such as cyclists and motorcyclists, to initiate a turn toward a given direction by momentarily steering counter to the desired direction ("steer left to turn right"). To negotiate a turn s ...
. The two tyres'
contact patch
Contact patch is the portion of a vehicle's tire that is in actual contact with the road surface. It is commonly used in the discussion of pneumatic (i.e. pressurized) tires, where the term is used strictly to describe the portion of the tire’s ...
es are the motorcycle's connection to the ground, and so are fundamental to the motorcycle's
suspension
Suspension or suspended may refer to:
Science and engineering
* Suspension (topology), in mathematics
* Suspension (dynamical systems), in mathematics
* Suspension of a ring, in mathematics
* Suspension (chemistry), small solid particles suspend ...
behaviour, and critically affect
safety
Safety is the state of being "safe", the condition of being protected from harm or other danger. Safety can also refer to risk management, the control of recognized hazards in order to achieve an acceptable level of risk.
Meanings
There are ...
,
braking
A brake is a mechanical device that inhibits motion by absorbing energy from a moving system. It is used for slowing or stopping a moving vehicle, wheel, axle, or to prevent its motion, most often accomplished by means of friction.
Background ...
,
fuel economy,
noise
Noise is unwanted sound considered unpleasant, loud or disruptive to hearing. From a physics standpoint, there is no distinction between noise and desired sound, as both are vibrations through a medium, such as air or water. The difference arise ...
, and rider comfort.
History
The history of motorcycle tyres is a clear progression of steady improvement in grip, allowing better acceleration, braking, and turning, along with improved comfort, safety, durability, and reliability. This progression has generally meant a steady increase in tyre width, so much so that
Kevin Cameron noted the assumption among riders that "bigger must be better in every way", leading to, "the temptation to overwhelm motorcycles with the biggest tyres the owner can find."
[ While many advances in tyre materials and construction have yielded unalloyed benefits, at a given level of technological sophistication, every design choice, such as tyre width, diameter, cross-section curvature, and the geometry of the motorcycle the tyres are intended for is a trade-off and a compromise.][
]Pneumatic
Pneumatics (from Greek ‘wind, breath’) is a branch of engineering that makes use of gas or pressurized air.
Pneumatic systems used in Industrial sector, industry are commonly powered by compressed air or compressed inert gases. A central ...
tyres were invented by John Boyd Dunlop
John Boyd Dunlop (5 February 1840 – 23 October 1921) was a Scottish-born inventor and veterinary surgeon who spent most of his career in Ireland. Familiar with making rubber devices, he invented the first practical pneumatic tyres for his c ...
in 1888, and were in widespread use on bicycle
A bicycle, also called a pedal cycle, bike or cycle, is a human-powered or motor-powered assisted, pedal-driven, single-track vehicle, having two wheels attached to a frame, one behind the other. A is called a cyclist, or bicyclist.
Bic ...
s and some early motorcycle prototypes by 1895.[ They were used on the first ]production
Production may refer to:
Economics and business
* Production (economics)
* Production, the act of manufacturing goods
* Production, in the outline of industrial organization, the act of making products (goods and services)
* Production as a stati ...
motorcycle, the 1894–1897 Hildebrand & Wolfmüller
The Hildebrand & Wolfmüller was the world's first production motorcycle. Heinrich and Wilhelm Hildebrand were steam-engine engineers before they teamed up with Alois Wolfmüller to produce their internal combustion ''Motorrad'' in Munich in 1894 ...
, and have been on nearly all production and special motorcycles ever since.[ During this period tyre sizes were usually diameter and wide.][
]
The early wheels were spoked, made of all metal, or wood and metal, and used inner tube
An inner tube is an inflatable ring that forms the interior of some pneumatic tires. The tube is inflated with a valve stem, and fits inside of the casing of the tire. The inflated inner tube provides structural support and suspension, while the ...
s to hold air.[ ]Flats
Flat or flats may refer to:
Architecture
* Flat (housing), an apartment in the United Kingdom, Ireland, Australia and other Commonwealth countries
Arts and entertainment
* Flat (music), a symbol () which denotes a lower pitch
* Flat (soldier), ...
were a constant problem; largely the fault of poor roads and not necessarily tyres.[ For easier repair, butt-ended or open ended inner tubes were used on some models, and some brands made rear wheels easier to detach.][ Spoked wheels with tubes remained standard until the 1970s, when solid, usually ]alloy
An alloy is a mixture of chemical elements of which at least one is a metal. Unlike chemical compounds with metallic bases, an alloy will retain all the properties of a metal in the resulting material, such as electrical conductivity, ductility, ...
, wheels began to appear and eventually dominate street motorcycles, making lighter tubeless tyre
Tubeless tires ( also spelled as tubeless tyres in Commonwealth English) are pneumatic tires that do not require a separate inner tube.
Unlike pneumatic tires which use a separate inner tube, tubeless tires have continuous ribs molded integral ...
s practical.
As the early motorcycle industry progressed, larger tyre sizes accompanied larger engine displacement
Engine displacement is the measure of the cylinder volume swept by all of the pistons of a piston engine, excluding the combustion chambers. It is commonly used as an expression of an engine's size, and by extension as a loose indicator of the ...
s, so that by 1909–1914, section, diameter tyres were used on motorcycles, and section tyres appeared on motorcycles with displacements over 350 cc.[ ]Indian
Indian or Indians may refer to:
Peoples South Asia
* Indian people, people of Indian nationality, or people who have an Indian ancestor
** Non-resident Indian, a citizen of India who has temporarily emigrated to another country
* South Asia ...
tyres reached , giving even greater rider comfort but with a taller seat height.[
From 1915 to 1929, tyre quality continued to increase, and beaded edge tyres began to be replaced by wired-on beads, which used steel loops embedded in the tyre's edge to prevent it from expanding under pressure, so the bead no longer needed a grooved rim to hold it in place.][ Banded-edge tyre were obsolete and replaced entirely by the wired-on type by 1930.][ In the period 1956–1964, typical tyre grip increased by 40%, resulting in better cornering, shorter stopping distance and overall improved safety.][ This was the result of a greater range of tyre sizes appearing on the market, from small scooter tyres through heavyweight motorcycle tyres. A variety of rubber compounds and tread patterns further expanded the options, specialized for wet roads, smooth dry roads, racing, off-road use, and ]sidecar
A sidecar is a one-wheeled device attached to the side of a motorcycle, scooter, or bicycle, making the whole a three-wheeled vehicle. A motorcycle with a sidecar is sometimes called a ''combination'', an ''outfit'', a ''rig'' or a ''hack''.
...
s.[ Both natural and ]synthetic rubber
A synthetic rubber is an artificial elastomer. They are polymers synthesized from petroleum byproducts. About 32-million metric tons of rubbers are produced annually in the United States, and of that amount two thirds are synthetic. Synthetic rubbe ...
were used, and tyres included fibres of cotton, nylon, and rayon for various structural benefits.[
]
During the 1970s, the increasing widths of tyres led to major changes in road racing
Road racing is a form of motorsport racing held on a paved road surface. The races can be held either on a closed circuit or on a street circuit utilizing temporarily closed public roads. Originally, road races were held almost entirely on publ ...
cornering technique, leading to riders ''hanging off'' or ''knee dragging'', in which the rider moves their body far off centre for the purpose of changing the combined centre of gravity
In physics, the center of mass of a distribution of mass in space (sometimes referred to as the balance point) is the unique point where the weighted relative position of the distributed mass sums to zero. This is the point to which a force may ...
of the rider plus bike, in order to turn at a given radius and speed at less of a lean angle.[ Racer ]John Surtees
John Surtees, (11 February 1934 – 10 March 2017) was a British Grand Prix motorcycle road racer and Formula One driver. On his way to become a seven-time Grand Prix motorcycle World Champion, he won his first title in 1956, and followed with ...
had been hanging off his MV Agusta
MV Agusta (, full name: MV AGUSTA Motor S.p.A., original name: Meccanica Verghera Agusta or MV) is a motorcycle manufacturer founded by Count Domenico Agusta on 19 January 1945 as one of the branches of the Agusta aircraft company near Milan in ...
as far back as the 1950s, in spite of resistance to the practice at that time from other riders, saying, "The idea is to keep the machine as upright as possible for maximum traction." Tyres of the 1960s and early 1970s had a rounder profile, but as they grew in width from the mid-1970s, the cross section became more oval, and the greater width of the tyre meant the contact patch was further off centre, increasing either steering effort or turn radius, at a given lean angle and speed, than it would have been with a rounder profile.[ To compensate, riders leaned out, moving their body's centre of gravity away from the motorcycle, eventually leaning out so far that their knee would skid along the pavement.][ ]Ablative
In grammar, the ablative case (pronounced ; sometimes abbreviated ) is a grammatical case for nouns, pronouns, and adjectives in the grammars of various languages; it is sometimes used to express motion away from something, among other uses. T ...
''knee pucks'' or ''knee sliders'' were then added to the riders' racing leathers to allow their knees to scrape smoothly along the tarmac through turns.[
The first ]radial tyre
A radial tire (more properly, a radial-ply tire) is a particular design of vehicular tire. In this design, the cord plies are arranged at 90 degrees to the direction of travel, or radially (from the center of the tire). Radial tire construction ...
s for cars appeared in 1943,[ but motorcyclists waited forty more years for this technology to come to motorcycles. These were the 1983 ]Pirelli
Pirelli & C. S.p.A. is a multinational tyre manufacturer based in Milan, Italy. The company, which has been listed on the Milan Stock Exchange since 1922, is the 6th-largest tyre manufacturer and is focused on the consumer production of tyre ...
MP7 radials, introduced on the European version of the 1984 Honda VF1000R
The VF1000 is a range of motorcycles produced by Honda from 1984 to 1988. The VF1000 is named after its V-4 double overhead cam 16-valve engine. There were three main models in the VF1000 range, the VF1000F (also known as Interceptor), the VF1 ...
, a limited edition exotic motorcycle that showcased a number of new technologies including carbon fibre
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers (Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon compo ...
reinforced bodywork and air-adjustable anti-dive front forks
In cutlery or kitchenware, a fork (from la, furca 'pitchfork') is a utensil, now usually made of metal, whose long handle terminates in a head that branches into several narrow and often slightly curved tines with which one can spear foods ei ...
.[ The new radial tyres had to provide race-replica handling for the very heavy ]dry weight
Vehicle weight is a measurement of wheeled motor vehicles; either an actual measured weight of the vehicle under defined conditions or a gross weight rating for its weight carrying capacity.
Curb or kerb weight
Curb weight (U.S. English) or kerb ...
chassis, up to a top speed of , making it the fastest production motorcycle
The fastest production motorcycle for a given year is the unmodified motorcycle with the highest tested top speed that was manufactured in series and available for purchase by the general public. Modified or specially produced motorcycles are a dif ...
of its day.[ The MP7 radials came to the US market in 1985.][ Radial construction uses textile or steel belts arranged at 90 degrees to the direction of travel, along with a layer of belts running around the tyre's circumference, with motorcycle radials deviating from the true radial design by adding belts running at angles to the radial belts, in the manner of bias-ply tyres, allowing the grip, durability, feel, and other characteristics to be adjusted to suit the tyre's design.][ The benefit of radial tyres is that the tyres run cooler yet maintain great flexibility, allowing engineers to coax significant increases in both grip and tread life, without compromise, under a broader range of conditions than bias-ply tyres.][
]
Changing tyre technology continued to influence riding style in 2013 in MotoGP
Grand Prix motorcycle racing is the premier class of motorcycle road racing events held on road circuits sanctioned by the Fédération Internationale de Motocyclisme (FIM). Independent motorcycle racing events have been held since the start ...
, when rider Marc Márquez
Marc Márquez Alentà (born 17 February 1993) is a Spanish professional Grand Prix motorcycle racing, Grand Prix motorcycle road racing, road racer, who has raced for Honda Racing Corporation, Honda's Repsol Honda, factory team since his MotoGP ...
adjusted the knee-down cornering style begun by Mike Hailwood
Stanley Michael Bailey Hailwood, (2 April 1940 – 23 March 1981) was a British professional motorcycle racer and racing driver. He is regarded by many as one of the greatest racers of all time. He competed in the Grand Prix motorcycle ...
to a more extreme knee-and-elbow down turning, with much of his upper body off center. Márquez was working to use to best advantage the characteristics of the spec Bridgestone
is a Japanese multinational tire manufacturer founded in 1931 by Shojiro Ishibashi (1889–1976) in the city of Kurume, Fukuoka, Japan. The name Bridgestone comes from a calque translation and transposition of , meaning 'stone bridge' in Japan ...
tyres all teams had been assigned since 2011, moving off center to keep the bike as upright as possible in the corner apex, and off the relatively flexible edge of tread area.[ To keep pace, other riders had to learn this physically demanding maneuver, requiring practice to change body position smoothly without upsetting the bike, a properly set up suspension keyed for this style of riding, and targeted muscle development to hold body position.][
]
Types
Motorcycle tyres are available for many different applications, including: Sport
Sport pertains to any form of Competition, competitive physical activity or game that aims to use, maintain, or improve physical ability and Skill, skills while providing enjoyment to participants and, in some cases, entertainment to specta ...
, Sport Touring, Touring, Cruiser, Scooter, On/Off Road, Dual-Sport
A dual-sport motorcycle is a type of street-legal motorcycle that is designed for both on and off-road use. The terms ''all-road,'' ''on/off road,'' and ''dual-purpose'' are also used for this class of motorcycles. Dual-sports are equipped with ...
, Enduro
Enduro is a form of motorcycle sport run on extended cross-country, off-road courses. Enduro consists of many different obstacles and challenges. The main type of enduro event, and the format to which the World Enduro Championship is run, is a ...
, Motocross
Motocross is a form of off-road motorcycle racing held on enclosed off-road circuits. The sport evolved from motorcycle trials competitions held in the United Kingdom.
History
Motocross first evolved in Britain from motorcycle trials competi ...
and Racing
In sport, racing is a competition of speed, in which competitors try to complete a given task in the shortest amount of time. Typically this involves traversing some distance, but it can be any other task involving speed to reach a specific goa ...
. There are tyres designed for dirtbikes, touring, sport and cruiser bikes.
,
Sport/performance tyres provide excellent grip but may last or less. Cruiser and "sport touring" tyres try to find the best compromise between grip and durability. There is also a type of tyre developed specifically for racing. These tyres offer the highest of levels of grip for cornering. Because of the high temperatures at which these tyres typically operate, use on the street is unsafe as the tyres will typically not reach optimum temperature before a rider arrives at the destination, thus providing almost no grip ''en route''. In racing situations, racing tyres would normally be brought up to temperature in advance by the use of tyre warmers.
Sport Touring tyres are generally not used for high cornering loads, but for long straights, good for riding across the country.
Sport Street tyres are for aggressive street riders that spend most of their time carving corners on public roadways. These tyres do not have a long life, but in turn have better traction in high speed cornering. Street and sport street tyres have good traction even when cold, but when warmed too much, can actually lose traction as their internal temperature increases.
Track or Slick tyres are for track days or races. They may have more of a triangular profile, which in turn gives a larger contact patch while leaned over. These tyres are not recommended for the street by manufactures, and are known to have a shorter life on the street. Due to the triangulation of the tyre, there will be less contact patch in the centre, causing the tyre to develop a flat spot quicker when used to ride on straightaways for long periods of time and have no tread so they lose almost all grip in the wet. Racing slicks are always made of a softer rubber compound and do not provide as much traction as street tyres until warmed to a higher internal temperature than street tyres normally operate at. Most street riding will not put a sufficient amount of friction on the tyre to maintain the slick's optimal tyre temperature, especially in colder climates and in spring and fall.
Cruiser tyres are relatively new. Until recently other tires would be used for cruisers, resulting in a tyre that wasn't quite right for cruising. Sport tyres for example, were often used to enhance the appearance of the bike, even if the bike doesn't have the power to use the tyres to their full extent. Cruiser tyres are often thinner and fatter than sports tyres, meant for a good grip and smooth ride. They are often decorated with custom rims, whitewalls, or tire stickers.
Off road tyres have knobby, deep treads for maximum grip on loose dirt, mud, sand, or gravel; such tyres tend to be less stable on paved surfaces.
Touring tyres are usually made of harder rubber for greater durability. They may last longer, but they tend to provide less outright grip than sports tyres at optimal operating temperature
An operating temperature is the allowable temperature range of the local ambient environment at which an electrical or mechanical device operates. The device will operate effectively within a specified temperature range which varies based on the de ...
s. The tradeoff is that touring tyres typically offer more grip at lower temperatures, meaning they can be more suitable for riding in cold or winter conditions whereas a sport tyre may never reach the optimal operating temperature.
Properties
There are several properties of motorcycle tyres that influence the performance, handling, and stability of a motorcycle.
*Rolling resistance
Rolling resistance, sometimes called rolling friction or rolling drag, is the force resisting the motion when a body (such as a ball, tire, or wheel) rolls on a surface. It is mainly caused by non-elastic effects; that is, not all the energy nee ...
is the resistance that occurs when a tyre rolls on a flat surface. The rolling resistance coefficients of motorcycle tyres are about 0.02. It tends to increase with forward speed and decrease as inflation pressures increase.
*Cornering force
Cornering force or side force is the lateral (i.e., parallel to wheel axis) force produced by a vehicle tire during cornering.
Cornering force is generated by tire slip and is proportional to slip angle at low slip angles. The rate at which ...
is the lateral (i.e. parallel to the road surface) force produced by a vehicle tyre during cornering. Cornering force coefficients of motorcycle tyres tends to decrease with increased vertical load, increased inflation pressure, and increased temperature.
*Camber thrust
Camber thrust and camber force are terms used to describe the force generated perpendicular to the direction of travel of a rolling tire due to its camber angle and finite contact patch. Camber thrust is generated when a point on the outer surface ...
is the force generated perpendicular to the direction of travel of a rolling tyre due to its camber angle
Camber angle is one of the angles made by the wheels of a vehicle; specifically, it is the angle between the vertical axis of a wheel and the vertical axis of the vehicle when viewed from the front or rear. It is used in the design of steering an ...
and finite contact patch.
*Pneumatic trail
Pneumatic trail or trail of the tire is a trail-like effect generated by compliant tires rolling on a hard surface and subject to side loads, as in a turn. More technically, it is the distance that the resultant force of side-slip occurs behind the ...
is a trail
A trail, also known as a path or track, is an unpaved lane or small road usually passing through a natural area. In the United Kingdom and the Republic of Ireland, a path or footpath is the preferred term for a pedestrian or hiking trail. Th ...
-like effect generated by compliant tyres rolling on a hard surface and subject to side loads, as in a turn. It is the distance that the resultant cornering force of side-slip
A slip is an aerodynamic state where an aircraft is moving ''somewhat'' sideways as well as forward relative to the oncoming airflow or relative wind. In other words, for a conventional aircraft, the nose will be pointing in the opposite directio ...
occurs behind the geometric centre of the contact patch.
*Relaxation length
Relaxation length is a property of pneumatic tires that describes the delay between when a slip angle is introduced and when the cornering force reaches its steady-state value.
It is also described as the distance that a tire rolls before the later ...
describes the delay between when a slip angle
In vehicle dynamics, slip angle or sideslip angle is the angle between the direction in which a wheel is pointing and the direction in which it is actually traveling (i.e., the angle between the forward velocity vector v_x and the vector su ...
is introduced and when the cornering force reaches its steady-state value.
Dual-compound tyres
Since about 2005 many manufacturers are producing rear tyres with the centre made of harder, long lasting rubber and the edges made from softer material, often high in silica. Most road bike manufacturers now specify these dual compound tyres as standard equipment due to their proven performance advantage. Single-compound tyres tend to wear down the centre strip well before the sides are worn out. The superior grip of the softer side material allows better grip at more extreme angles in dual compound construction.
Speed and construction
As with four-wheeled vehicles, tyres for motorcycle have a tyre code
Automotive tires are described by an alphanumeric tire code (in North American English) or tyre code (in Commonwealth English), which is generally molded into the sidewall of the tire. This code specifies the dimensions of the tire, and some o ...
, which describes a tyre's width, height/width aspect ratio, wheel diameter, load index and speed rating.[
The most common are:
* 3 digit number: The "nominal section width" of the tyre in millimetres; the widest point from both outer edges.
* /: Slash character for character separation.
* 2 or 3 digit number: The "aspect ratio" of the sidewall height to the total width of the tyre, as a percentage.
* An optional letter indicating construction of the fabric carcass of the tyre:
** B: bias belt (where the sidewalls are the same material as the tread, leading to a rigid ride)
** D: diagonal
** R: ]radial
Radial is a geometric term of location which may refer to:
Mathematics and Direction
* Vector (geometric)
In mathematics, physics, and engineering, a Euclidean vector or simply a vector (sometimes called a geometric vector or spatial vector) ...
*** if omitted, then it is a cross ply tyre
* 2 digit number: Diameter in inches of the wheel that the tyre is designed to fit.
* 2 or 3 digit number: Load index; see table below
* 1 or 2 digit/letter combo: Speed rating; see table below
See also
* Bicycle tyre
A bicycle tire is a tire that fits on the Bicycle wheel, wheel of a bicycle or similar vehicle. These tires may also be used on tricycles, wheelchairs, and handcycles, frequently for Wheelchair racing, racing. Bicycle tires provide an importa ...
* Inner tube
An inner tube is an inflatable ring that forms the interior of some pneumatic tires. The tube is inflated with a valve stem, and fits inside of the casing of the tire. The inflated inner tube provides structural support and suspension, while the ...
* Outline of motorcycles and motorcycling
The following outline is provided as an overview of motorcycles and motorcycling:
Motorcycle — two-wheeled, single-track motor vehicle. Other names include: motorbike, bike, and cycle.
Motorcycling — act of riding a motorcycle, around wh ...
* Outline of tires
The following outline is provided as an overview of and topical guide to tires:
Tire (North American) or tyre (British) – ring-shaped covering that fits around a wheel rim to protect it and enable better vehicle performance by p ...
* Tyre manufacturing
References
External links
Motorcycle tyre measurement
{{Motorcycle components
Tires