The rim is the piece, usually metal, on which a tire sits and that is part of the wheel (the latter consisting of rim and disc). A tire can be found in vehicles such as cars, motorcycles, trucks, planes. On a bicycle wheel the rim is a large circle shaped rim at the outer ends of the wheel spokes that maintains the tire and air chamber.
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- 1 rim
- 1 History
- 2 How to read a tire?
- 2 Tire Measurements
- 1 Characteristics of the rims
- 3 Types of tires
- 1 For its construction
- 2 According to the camera
- 3 Old tires
- 4 Economic tires
- 4 Source
- 5 External link
It is the element of the wheel on which the tire is supported and mounted. The rim is in turn attached to the axle of the vehicle by means of the wheel disk or a series of spokes. The close interdependence between the elastic element, in direct contact with the road and its correspondingly rigid housing (already evidenced in the numerous models designed to fix semi-pneumatic and solid rubber rings to the wheels of ancient carriages and velocipedes ), explains how the evolution of the rim generally occurs together with the evolution of the tire.
It should be noted that, by extension, especially in sports language, the rim voice is used as a synonym for tire, especially in some Latin American countries. The first rim proper for automobiles, which allowed mounting and dismounting of the tire, was the rim with beads, which appeared at the beginning of the century. It took the name of the homonymous tires, whose hook-shaped beads (to be attached to the rim edges) were retained in their housing by inflation pressure.
In 1887, Scottish veterinarian and inventor John Boyd Dunlop developed the first tricycle inner tube tire that his nine-year-old son used to go to school on the bumpy streets of Belfast. To solve the trike’s rattling problem, Dunlop inflated rubber tubes with an air pump to inflate balloons. Then he wrapped the rubber tubes with a tarp to protect them and glued them to the rims of the trike’s wheels. Until then, most wheels had solid rubber tires, but the tires allowed for a noticeably smoother ride. He developed the idea and patented the tube tire on December 7, 1888. However, two years after he was granted the patent, Dunlop was officially informed that the patent was invalidated by the Scottish inventor.Robert William Thomson , who had patented the idea in France in 1847 and in the United States in 1891 .1 Dunlop won a legal battle against Robert William Thomson and revalidated his patent.
The development of Dunlop’s tube tire came at a crucial time during the expansion of ground transportation, with the construction of new bikes and cars.
In countries like Mexico , Guatemala , El Salvador , Honduras and ColombiaThe tire is called a rim, and the metal wheel is called rim. The wheel is a round support, usually with openings in the disc to achieve lightness while allowing air flow for brake aeration. The passenger car rim itself is attached to the disc. The function of the rim is to hold the tire and the function of the disc is to be attached to the vehicle. In such a way that the fit of the disc in the rim can be external (offset) or internal (Inset) the way it is fitted determines the vehicle’s track width. This socket is marked on the wheel by the letters ET and a numbering (ET 18). This numbering indicates the millimeters from the middle of the rim to the disc casing with the hub in the vehicle. According to Spanish regulation RD 736/88, RD 3191/02 and RD 750/10 the modification of this data in the change of a wheel or rim supposes a modification of importance type 45 (Replacement of wheels with different characteristics, modification of PUMPING) and type 11 (Modification of the track gauge ). It must pass a new ITV inspection and be verified by the Industry department, among other procedures. There is an important Reform Manual where a summary of all this is published by the Ministry of Industry, Tourism and Trade and was published on 06/16/2004.
How to read a tire?
- The marking of a wheel goes something like this: LEMERS MADE IN USA 06 99 DOT 7 1/2 J 17 H2 5 ET 36 078532
- Where the first word is the manufacturer
- Then comes the country of manufacture
- Manufacturing week or month
- Year of production
- 7 1/2 = 750 width between the rim hooks where the tire will be fitted. See CE92 / 23
- J type of hook to hold the SEAT (seat or bead) of the tire
- 17 disc diameter
- H 2has two hooks on the rim to hold the SEAT, this determines the mode and number of “clips” so that the bead does not get into the bottom of the throat of the wheel when it is rolling.
- ET 36 is the distance from the middle of the rim (3 1/4) to the socket with the hub. (In this case the disc is external). In the BMW it comes as IS 36 (Inset) because the disc is internal.
- rim width
The standard sizes in inches are: 3.5, 4.0, 4.5, 5.0, 5.5, 6.0, 6.5, 7.0
- rim diameter
The standard sizes in inches are: 10, 12, 13, 14, 15, 16, 17, 18, 19 J and H are necessary symbols for experts
III. tire offset
It is the distance from the mounting surface to the center line of the wheel. The compensation can be of 3 types: zero, positive and negative.
- number of fixing openings and diameter of the circle where they are located. To see the graph select the “Download” option from the top menu
- diameter of the central opening Oscillates between 55 and 75 mm.
- The tabs, the main function of which is to retain the heels of the cover, especially with regard to the axial thrust to which they are subjected due to inflation pressure. Their vertical flanks approach the heel support base, while the free end must be adequately rounded to allow the correct accommodation of the heels and to facilitate the assembly of the cover.
- The support base of the beads, generally conical (5o taper) to allow, in addition to the support in a radial direction, an adequate tightening that guarantees a stable union between the tire and the rim, and better air retention in tubeless tubes. The width of the base must be such that, for all the sizes of covers accepted for mounting, the inner end of the tire beads does not protrude from the base, which could cause pinching of the air chamber.
- The groove or groove, within which the heels of the cover must be able to find accommodation when assembling and disassembling. In order for these last operations to be easier, it is necessary to meet some requirements: the depth of the channel must be greater than the height of the flanges, so that they can be overcome without difficulty by the heels of the cover; the width of the groove must be wide enough; the flanks of the groove must be inclined towards the center of the throat attached to the support bases and to the bottom with a suitable radius of chord, in order to facilitate the sliding of the heels. The bottom of the throat is the part of the rim that is generally attached to the wheel disc or spokes by welding, riveting or threading.
- The valve hole, for the stable outlet and accommodation of the valve, whose free accessibility is essential for inflation and deflation of tires. It must be located in the center of the sidewall of the rim and be directed towards the exterior of the vehicle and generally has a nominal diameter of 11.5 mm (in some cases a 16 mm hole is allowed). Its edges must be rounded so as not to damage the valve.
Types of tires
For its construction
Diagonal: in its construction the different layers of material are placed diagonally, one on top of the other.
Radial: In this construction the layers of material are placed on top of each other in a straight line, without bias. This system allows to provide greater stability and resistance to the roof.
Self-supporting: in this construction the layers of material are placed on top of each other in a straight line, without bias, also on the flanks. This system allows to provide greater resistance to the cover, although it is less comfortable because it is more rigid, it is used in sports vehicles and has the advantage of being able to roll without air pressure at a limited speed, without losing its shape.
According to the camera
Tubetype tires: those that use a tube and a specific rim for it. They cannot be mounted without a camera. They are used in some 4x4s and agricultural vehicles.
Tubeless or tubeless tires: These tires do not use a tube. To avoid air loss, they have a part inside the tire called the bead, which, as it has steel rings inside, prevent it from falling off the rim. The rim must be specific to these tires. It is used in practically all vehicles.
Research shows that as a tire ages, it begins to dry out and becomes very dangerous, even if it is not used. Although they may look similar to new tires, at high speeds the tread can come off, leading to dangerous loss of control and possible rollover.
The date of manufacture of a tire is in the profile, to the right of the codes, although sometimes it is on the inside. If so, you have to slide under the vehicle to check that date. It is a 4 digit SSAA type code. SS is the week of the year it was manufactured from 01 to 52, and AA is the corresponding year.
Many manufacturers, both automobile and tire, have recommended a limit of up to six years for tires. Anyway, an investigative report from the North American channel ABC, specifically the 20/20 program, made by Brian Ross, showed that many wholesalers, such as Goodyear, Wal-Mart or Sears sell tires manufactured more than six years ago. Currently there is no law in the world that regulates the age of tires, although the ETRTO (European Tire and Rim Technical Organization) recommends checking them after five years of tread and not using them after 10 years of manufacture.
There is research showing that the price of a tire has a reason, since not all tires are created equal. The British magazine Autocar has published in one of its editions a comparison between five cheap Asian imported tires (From the GT Radial, Nankang, Wanli, Linglong and Triangle brands.) And a quality European tire (Manufactured by Continental AG, specifically the model ContiPremiumContact 2.). In the different tests carried out, it has been possible to verify a difference in braking performance on wet ground of up to 28%; Differences of up to 5.5 meters in dry braking from 100 km / h; and up to 10% lower performance at high speeds with imported tires.