A motorcycle tyre (spelt tire in American English) is the outer part of motorcycle wheel, attached to the rim, providing traction, resisting wear, absorbing surface irregularities, and allowing the motorcycle to turn via countersteering. The two tyres' contact patches are the motorcycle's connection to the ground, and so are fundamental to the motorcycle's suspension behaviour, and critically affect safety, braking, fuel economy, noise, and rider comfort. [1] [2]
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." [3] 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. [3]
Pneumatic tyres were invented by John Boyd Dunlop in 1888, and were in widespread use on bicycles and some early motorcycle prototypes by 1895. [4] They were used on the first production motorcycle, the 1894–1897 Hildebrand & Wolfmüller, and have been on nearly all production and special motorcycles ever since. [5] [6] During this period tyre sizes were usually 22 to 28 inches (560 to 710 mm) diameter and 1+1⁄2 to 2 in (38 to 51 mm) wide. [6]
The early wheels were spoked, made of all metal, or wood and metal, and used inner tubes to hold air. [6] Flats were a constant problem; largely the fault of poor roads and not necessarily tyres. [6] For easier repair, butt-ended or open ended inner tubes were used on some models, and some brands made rear wheels easier to detach. [6] Spoked wheels with tubes remained standard until the 1970s, when solid, usually alloy, wheels began to appear and eventually dominate street motorcycles, making lighter tubeless tyres practical.
As the early motorcycle industry progressed, larger tyre sizes accompanied larger engine displacements, so that by 1909–1914, 2+1⁄4 in (57 mm) section, 26 in (660 mm) diameter tyres were used on 250 to 350 cc (15 to 21 cu in) motorcycles, and 2+3⁄8 to 2+1⁄2 in (60 to 64 mm) section tyres appeared on motorcycles with displacements over 350 cc. [6] Indian tyres reached 3.0 in × 28 in (76 mm × 711 mm), giving even greater rider comfort but with a taller seat height. [6]
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. [6] Banded-edge tyre were obsolete and replaced entirely by the wired-on type by 1930. [6] In the period 1956–1964, typical tyre grip increased by 40%, resulting in better cornering, shorter stopping distance and overall improved safety. [6] This was the result of a greater range of tyre sizes appearing on the market, from small 3.5 in × 8 in (89 mm × 203 mm) scooter tyres through 4.5 in × 19 in (110 mm × 480 mm) 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 sidecars. [6] Both natural and synthetic rubber were used, and tyres included fibres of cotton, nylon, and rayon for various structural benefits. [6]
During the 1970s, the increasing widths of tyres led to major changes in road racing 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 of the rider plus bike, in order to turn at a given radius and speed at less of a lean angle. [8] Racer John Surtees had been hanging off his MV Agusta 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." [9] 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. [8] 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. [8] Ablative 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. [8]
The first radial tyres for cars appeared in 1943, [10] but motorcyclists waited forty more years for this technology to come to motorcycles. These were the 1983 Pirelli MP7 radials, introduced on the European version of the 1984 Honda VF1000R, a limited edition exotic motorcycle that showcased a number of new technologies including carbon fibre reinforced bodywork and air-adjustable anti-dive front forks. [11] [12] The new radial tyres had to provide race-replica handling for the very heavy 238 kg (524 lb) dry weight chassis, up to a top speed of 240 km/h (150 mph), making it the fastest production motorcycle of its day. [12] The MP7 radials came to the US market in 1985. [13] 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. [11] 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. [11]
Changing tyre technology continued to influence riding style in 2013 in MotoGP, when rider Marc Márquez adjusted the knee-down cornering style begun by Mike Hailwood to a more extreme knee-and-elbow down turning, with much of his upper body off center. [14] Márquez was working to use to best advantage the characteristics of the spec Bridgestone 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. [14] 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. [14]
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Motorcycle tyres are available for many different applications, including: Sport, Sport Touring, Touring, Cruiser, Scooter, On/Off Road, Dual-Sport, Enduro, Motocross and Racing. There are tyres designed for dirtbikes, touring, sport and cruiser bikes. | Sport/performance tyres provide excellent grip but may last 1,000 miles (1,609 km) 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. [15] 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.
Dual-sport tyres have grooves that flow through from one side of the tyre to the other forming islands of tread, they are classified as 40/60 or 60/40 as in designed for time spent 40% on road, 60% offroad and vice versa, 40/60 has much smaller tread islands than 60/40 for increased traction offroad
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 temperatures. 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.
There are several properties of motorcycle tyres that influence the performance, handling, and stability of a motorcycle.
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.
As with four-wheeled vehicles, tyres for motorcycle have a tyre code, which describes a tyre's width, height/width aspect ratio, wheel diameter, load index and speed rating. [16] The most common are:
| LI | kg | LI | kg | LI | kg | LI | kg | LI | kg |
|---|---|---|---|---|---|---|---|---|---|
| 19 | 77,5 | 36 | 125,0 | 53 | 206 | 70 | 335,0 | 87 | 545,0 |
| 20 | 80,0 | 37 | 128,0 | 54 | 212,0 | 71 | 345,0 | 88 | 560,0 |
| 21 | 82,5 | 38 | 132,0 | 55 | 218,0 | 72 | 355,0 | 89 | 580,0 |
| 22 | 85,0 | 39 | 136,0 | 56 | 224,0 | 73 | 365,0 | 90 | 600,0 |
| 23 | 87,5 | 40 | 140,0 | 57 | 230,0 | 74 | 375,0 | 91 | 615,0 |
| 24 | 90,0 | 41 | 145,0 | 58 | 236,0 | 75 | 387,0 | 92 | 630,0 |
| 25 | 92,0 | 42 | 150,0 | 59 | 243,0 | 76 | 400,0 | 93 | 650,0 |
| 26 | 95,0 | 43 | 155,0 | 60 | 250,0 | 77 | 412,0 | 94 | 670,0 |
| 27 | 97,5 | 44 | 160,0 | 61 | 257,0 | 78 | 425,0 | 95 | 690,0 |
| 28 | 100,0 | 45 | 165,0 | 62 | 265,0 | 79 | 437,0 | 96 | 710,0 |
| 29 | 103,0 | 46 | 170,0 | 63 | 272,0 | 80 | 450,0 | 97 | 730,0 |
| 30 | 106,0 | 47 | 175,0 | 64 | 280,0 | 81 | 462,0 | 98 | 750,0 |
| 31 | 109,0 | 48 | 180,0 | 65 | 290,0 | 82 | 475,0 | 99 | 775,0 |
| 32 | 112,0 | 49 | 185,0 | 66 | 300,0 | 83 | 487,0 | 100 | 800,0 |
| 33 | 115,0 | 50 | 190,0 | 67 | 307,0 | 84 | 500,0 | - | - |
| 34 | 118,0 | 51 | 195,0 | 68 | 315,0 | 85 | 510 | - | - |
| 35 | 121,0 | 52 | 200,0 | 69 | 325 | 86 | 530,0 | - | - |
| Rating | Speed (km/h) | Speed (mph) |
|---|---|---|
| Moped | 50 | 30 |
| J | 100 | 62 |
| K | 110 | 69 |
| L | 120 | 75 |
| M | 130 | 81 |
| P (or-) | 150 | 95 |
| Q | 160 | 100 |
| R | 170 | 105 |
| S | 180 | 113 |
| T | 190 | 118 |
| U | 200 | 125 |
| H | 210 | 130 |
| V | 240 | 150 |
| W | 270 | 168 |
| Z | over 240 | over 150 |
A tire or tyre is a ring-shaped component that surrounds a wheel's rim to transfer a vehicle's load from the axle through the wheel to the ground and to provide traction on the surface over which the wheel travels. Most tires, such as those for automobiles and bicycles, are pneumatically inflated structures, which also provide a flexible cushion that absorbs shock as the tire rolls over rough features on the surface. Tires provide a footprint, called a contact patch, that is designed to match the weight of the vehicle with the bearing strength of the surface that it rolls over by providing a bearing pressure that will not deform the surface excessively.
A mountain bike (MTB) or mountain bicycle is a bicycle designed for off-road cycling. Mountain bikes share some similarities with other bicycles, but incorporate features designed to enhance durability and performance in rough terrain, which makes them heavier, more complex and less efficient on smooth surfaces. These typically include a suspension fork, large knobby tires, more durable wheels, more powerful brakes, straight, extra wide handlebars to improve balance and comfort over rough terrain, and wide-ratio gearing optimised for topography, application and a frame with a suspension mechanism for the rear wheel. Rear suspension is ubiquitous in heavier-duty bikes and now common even in lighter bikes. Dropper posts can be installed to allow the rider to quickly adjust the seat height.
Supermoto is a form of motorcycle racing held on race tracks that alternate between three kinds of track surfaces: the hard packed dirt of flat track, the irregular jumps and obstacles of motocross, and the paved tarmac of road racing. Supermoto was originally conceived by Gavin Trippe in 1979 as a segment of the TV show Wide World of Sports. It was something like an all-star game, in which the best riders from the three separate genres of motorcycle racing could temporarily leave their normal race class to come together and compete for the title of best all around racer. Today supermoto is a distinct genre of its own and riders in the other classes do not routinely cross over into supermoto.
A racing slick or slick tyre is a type of tyre that has a smooth tread used mostly in auto racing. The first production slick tyre was developed by M&H Tires in the early 1950s for use in drag racing. By eliminating any grooves cut into the tread, such tyres provide the largest possible contact patch to the road, and maximize dry traction for any given tyre dimension; see Performance. Slick tyres are used on race tracks and in road racing, where acceleration, steering and braking require maximum traction from each wheel. Slick tyres are typically used on only the driven (powered) wheels in drag racing, where the only concern is maximum traction to put power to the ground, and are not used in rallying.
A highsider or high-side is a type of motorcycle accident characterized by sudden and violent rotation of the bike around its longitudinal axis. This generally happens when the rear wheel loses traction, skids, and then suddenly regains traction, causing the rider to be thrown head-first from the side of the motorcycle or over the handlebars.
The lowsider or lowside is a type of motorcycle or bicycle crash usually occurring in a turn. It is caused when either the front or rear wheel slides out as a result of either too much braking into the corner, too much acceleration through or out of the corner, or too much speed carried into or through the corner for the available grip. It may also be caused by unexpected slippery or loose material on the road surface.
Cyclo-cross is a form of bicycle racing. Races typically take place in the autumn and winter, and consist of many laps of a short course featuring pavement, wooded trails, grass, steep hills and obstacles requiring the rider to quickly dismount, carry the bike while navigating the obstruction and remount. Races for senior categories are generally between 40 minutes and an hour long, with the distance varying depending on the ground conditions. The sport is strongest in the traditional road cycling countries such as Belgium, France and the Netherlands.
The tread of a tire or track refers to the rubber on its circumference that makes contact with the road or the ground. As tires are used, the tread is worn off, limiting its effectiveness in providing traction. A worn tire can often be retreaded.
Ice racing is a form of racing that uses cars, motorcycles, snowmobiles, all-terrain vehicles, or other motorized vehicles. Ice racing takes place on frozen lakes or rivers, or on groomed frozen lots. As cold weather is a requirement for natural ice, it is usually found at higher latitudes in Canada, the northern United States, and in northern Europe, although limited indoor events are held in warmer climates, typically on ice hockey rinks. Tracks in North America vary from 1/4 mile to several mile-long circuits.
A beadlock or bead lock is a mechanical device that secures the bead of a tire to the wheel of a vehicle. Tires and wheels are designed so that when the tire is inflated, the tire pressure pushes the bead of the tire against the inside of the wheel rim so that the tire stays on the wheel and the two rotate together. In situations where tire pressure is insufficient to hold the bead of the tire in place, a beadlock is needed.
The six main types of motorcycles are generally recognized as standard, cruiser, touring, sports, off-road, and dual-purpose. Sport touring is sometimes recognized as a seventh category or integrated with the touring category.
Siping is a process of cutting thin slits across a rubber surface to improve traction in wet or icy conditions.
Trail braking is a driving and motorcycle riding technique where the brakes are used beyond the entrance to a turn (turn-in), and then gradually released. Depending on a number of factors, the driver fully releases brake pressure at any point between turn-in and the apex of the turn.
Automotive tires are described by an alphanumeric tire code or tyre code, which is generally molded into the sidewall of the tire. This code specifies the dimensions of the tire, and some of its key limitations, such as load-bearing ability, and maximum speed. Sometimes the inner sidewall contains information not included on the outer sidewall, and vice versa.
The motorcycle sport of racing includes motorcycle road racing and off-road racing, both either on circuits or open courses, and track racing. Other categories include hill climbs, drag racing and land speed record trials.
Track racing is a form of motorcycle racing where teams or individuals race opponents around an unpaved oval track. There are differing variants, with each variant racing on a different surface type.
Ice speedway is a developed form of motorcycle speedway racing, featuring racing on frozen surfaces. The sport uses bikes enhanced for the terrain. Participants can compete at international level.
A bicycle tire is a tire that fits on the wheel of a bicycle or similar vehicle. These tires may also be used on tricycles, wheelchairs, and handcycles, frequently for racing. Bicycle tires provide an important source of suspension, generate the lateral forces necessary for balancing and turning, and generate the longitudinal forces necessary for propulsion and braking. Although the use of a pneumatic tire greatly reduces rolling resistance compared to the use of a rigid wheel or solid tire, the tires are still typically the second largest source, after wind resistance, of power consumption on a level road. The modern detachable pneumatic bicycle tire contributed to the popularity and eventual dominance of the safety bicycle.
Off-road tires are a category of vehicle tires that use deep tread to provide more traction on unpaved surfaces such as loose dirt, mud, sand, or gravel. Compared to ice or snow tires, they lack studs but contain deeper and wider grooves meant to help the tread sink into mud or gravel surfaces.
The following outline is provided as an overview of and topical guide to tires:
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