Technical vocabulary


Aquaplaning or hydroplaning
Aquaplaning is an occurrence that can happen during driving on a wet road with the vehicle when its weight can´t press all the water under the tire. Since there is a thin layer of water between the tire and the surface it can happen that the tires slide and the driver loses the control over the vehicle.

Tire balancing
Balancing the tires is a procedure when the mass of the wheels on different sides of the axle is being regulated by adding lead weights on the wheel rim. During the spinning the centrifugal force acts on the wheel. If the mass of the wheels is not balanced there is an imbalance that even at a speed higher than 70 km/h results in shaking of the steering wheel or of the entire vehicle.

Balancing not only prevents the shaking, but also the too fast wear and tear of your pneumatics, suspensions, steering system and bearings. Imbalanced tires cause uneven and faster tire wear, vibrations and higher loads on the hanger support on the front end. 

The side wall of the tire
The side wall of the tire is the side part of the tire. It is thinner than the tread, more sensitive to damage and in part responsible for the driving comfort. There you can find the tire marks (tire dimensions, DOT etc.). 
Tread pattern
The tread pattern consists of channels that are cut into the tread. The channels are used for drainage and make sure there is good adhesion to the wet surface. What tread pattern to choose depends on the type of the surface:

  • for hard and dry surfaces, it´s best to choose a pattern with a smaller surface of the channels (a bigger adhesion surface of the tread with the road)
  • for hard and wet surfaces, it´s best to choose a pattern with a bigger surface of the channels that drain the water and thereby make the risk of aquaplaning smaller

When choosing the tread pattern pay attention to the recommendations of the manufacturer as to for which surfaces and other driving conditions particular patterns are appropriate.

Tire dimensions
On the side of each car tire there is all the necessary information that describes the dimensions of the tire. For example, on a tire for passenger vehicles we´ll find a mark saying 215/65 R15. The number „215“ tells us the width of the tread, in millimeters, meaning the width is 215 mm. The number „65“ tells us the ratio of the height of the tire compared to its width in percentages, in this case 65% from 215 mm which makes out 140 mm.

The letter „R“ tells us the tire has a radial construction which means that the belts are positioned radially in relation to the casings and the longitudinal axis. The last number „15“ marks the inner diameter, i.e. the outer diameter of the rim the tire is being mounted on. In these cases the diameter is 15 inches. 1 inch = 2,54 cm 

GAR (Goodyear Authorized Retreader)
GAR (Goodyear Authorized Retreader) is the Goodyear´s authorization to retread tires for truck tires that was implemented in the Gumiimpex manufacturing system in the beginning of 2000. CONSTANT PERFORMANCE SYSTEM is the main characteristic of the GAR technology of retreading truck tires and it is being used by Goodyear on all its own plants and the whole network of its partners. The system defines the work being carried out under Goodyear specifications and under full technical support. All the materials being used during retreading are approved by Goodyear and the tread patterns on the retreaded tires are identical to patterns of new Goodyear truck tires. Gumiimpex-GRP is the only NEXT TREAD partner in Croatia.
Tire tread
The tire tread is the connecting part of the tire that is constantly in contact with the surface. It´s made of hard and very resistant rubber.
Standard performance tire
Standard performance tires are mostly intended for city traffic and are often called three-season-tires. They are optimized for warm weather, both dry and wet surfaces. They don´t have good characteristics on snow and ice so that they have to be replaced in winter. This tire class is generally cheaper than the high performance tires. They are mostly being manufactured in speed indexes S, T, (H) and sizes ranging from 13”-15”.
High performance tires (HP)
High performance tires or summer tires are intended for city traffic and driving on the highway during dry season. Tire treads with shallow channels makes the performance poorer on the wet surface, but better on the dry surface. They are manufactured in speed indexes H, V, (W) and sizes 15”-17”.
Ultra High Performance tires (UHP)
Ultra High Performance tires (UHP) are intended for drivers who like fast sports driving, where the high performances and the best possible adherence means far more than a long life of the tire. They are made from softer compound that enables better adherence and safe and fast driving in the curves on the road. On the other hand, the disadvantage is that they wear and tear fast and last a shorter period of time. The tread is designed so as to accomplish excellent adherence on dry surfaces because of a smaller drainage on wet road. They are being produced in speed indexes W, Z and ZR and sizes 16”-20”.
Speed index
The speed index (SI) determines the highest driving speed allowed and it is the letter mark on the tire that says the maximum allowed speed.

Speed index(SI) Max speed(km/h)
A1 5
A2 10
A3 15
A4 20
A5 25
A6 30
A7 35
A8 40
B 50
C 60
D 65
E 70
F 80
G 90
J 100
K 110
L 120
M 130
N 140
P 150
Q 160
R 170
S 180
T 190
U 200
H 210
V 240
W 270
Y 300
ZR                                    <240
Wear indicator
The wear indicator is positioned on the tread in the form of bulges in the pattern that are used to control the wear of the tires. The bulges can be in the shape of horizontal lines, letters TWi (tread wear indicator) or as a logo of the manufacturer. You can see the indicator when the tread is wore out up to the level of 1,6 mm which is a sign that the tires need to be replaced. Nowadays every tire has a tread wear index and as soon as the tire hits the mark on only one point, the tire should be replaced by a new one, for one´s own traffic safety.
The load index determines the maximum load of the pneumatics allowed while having the appropriate air pressure at the highest allowed driving speed. For example, if the load index is 70, the tire can carry 335kg with the maximum air pressure.

0 45 40 140 80 450 120 1.400 160 4.500 200 14.000 240 45.000
1 46.2 41 145 81 462 121 1.450 161 4.625 201 14.500 241 46.250
2 47.5 42 150 82 475 122 1.500 162 4.750 202 15.000 242 47.500
3 48.7 43 155 83 487 123 1.550 163 4.875 203 16.000 243 48.750
4 50 44 160 84 500 124 1.600 164 5.000 204 16.000 244 50.000
5 51.5 45 165 85 515 125 1.650 165 5.150 205 16.500 245 51.500
6 53 46 170 86 530 126 1.700 166 5.300 206 17.000 246 53.000
7 54.5 47 175 87 545 127 1.750 167 5.450 207 17.500 247 54.500
8 56 48 180 88 560 128 1.800 168 5.600 208 18.000 248 56.000
9 58 49 185 89 580 129 1.850 169 5.800 209 18.500 249 58.000
10 60 50 190 90 600 130 1.900 170 6.000 210 19.000 250 60.000
11 61.5 51 195 91 615 131 1.950 171 6.150 211 19.500 251 61.500
12 63 52 200 92 630 132 2.000 172 6.300 212 20.000 252 63.000
13 65 53 206 93 650 133 2.060 173 6.500 213 20.600 253 65.000
14 67 54 212 94 670 134 2.120 174 6.700 214 21.200 254 67.000
15 69 55 218 95 690 135 2.180 175 6.900 215 21.800 255 69.000
16 71 56 224 96 710 136 2.240 176 7.100 216 22.400 256 71.000
17 73 57 230 97 730 137 2.300 177 7.300 217 23.000 257 73.000
18 75 58 236 98 750 138 2.360 178 7.500 218 23.600 258 75.000
19 77.5 59 243 99 775 139 2.430 179 7.750 219 24.300 259 77.500
20 80 60 250 100 800 140 2.500 180 8.000 220 25.000 260 80.000
21 82.5 61 257 101 825 141 2.575 181 8.250 221 25.750 261 82.500
22 85 62 265 102 850 142 5.650 182 8.500 222 26.500 262 85.000
23 87.5 63 272 103 875 143 2.725 183 8.750 223 27.250 263 87.500
24 90 64 280 104 900 144 2.800 184 9.000 224 28.000 264 90.000
25 92.5 65 290 105 925 145 2.900 185 9.250 225 29.000 265 92.500
26 95 66 300 106 950 146 3.000 186 9.500 226 30.000 266 95.000
27 97.5 67 307 107 975 147 3.075 187 9.750 227 30.750 267 97.500
28 100 68 315 108 1.000 148 3.150 188 10.000 228 31.500 268 100.000
29 103 69 325 109 1.030 149 3.250 189 10.300 229 32.500 269 103.000
30 106 70 335 110 1.060 150 3.350 190 10.600 230 33.500 270 106.000
The casings is the term used for a worn out tire that is fit to be retreaded.

Casings or the body of the tire is the main part of the tire that ensures the firmness and elasticity of the tire. It is made of one or more layers of fabric that can be made out of different types of fibers (cords) or out of steel.

Cords are rubberized fabric fibers that make out the casings. They can be out of textile, viscose, polyamide or steel. By the vulcanization process the cord fibers are rubberized and melted together.
Summer tires
Summer tires are made so as to be more resistant to higher temperatures. That is why the construction is harder and reinforced on the side of the tire, for a better stability in curves, and generally there is a higher concentration of synthetic materials in relation to the natural rubber.

In summer, besides the air and asphalt temperatures being higher, the working temperature is higher as well. Higher working temperature is the result of greater speed (it´s logical since there is nice weather, greater visibility, dry road, etc.) and the bigger contact area with the road. The minimum air temperature under which one should not use summer tires anymore and replace them by adequate winter tires is 7°C.

Tire retreading or rebuilding
Retreading or rebuilding  tires is a technology that makes already used tires usable again by replacing the worn out and damaged top layer, mostly of the tread, by a new layer of rubber. By using retreaded (rebuilt) tires for trucks and busses, the transporters make their costs lower because retreaded tires are more economical than new ones.
Labelling tires


Pneumatic (tire)
The tires are filled with pressurized air and lately also with nitrogen. Nowadays mostly tubeless tires are being used, meaning they don´t have the inner tire.toggle]
Tire pressure
The tire pressure can be reduced due to tiny perforations, natural exit of air through tire components or even due to the decreasing temperatures of the surrounding. The pressure in your pneumatics, including the spare tire, should be checked once a month and before every long journey, preferably when the pneumatics are cold. If you test them when they´re hot, add 0,3 bars to the prescribed pressure value.

It is important to check the pressure once a month because:

  • the low pressure increases the danger of damaging your tires and can lead to an uneven wear of the tire and its shorter life
  • a too high pressure, more than 20% higher than the prescribed value, can decrease the life span of your tires up to 10 000km
  • a too low pressure increases fuel consumption

The tire pressure decreases by a fall in temperature, so you should check your tire pressure even more often in winter.

The tire retreading system RECAMIC was developed by Michelin as an answer to the demand for the possibility to retread other casings by original Michelin materials. This way buyers that use new tires by some other manufacturer, they can retread them and get the Michelin quality. RECAMIC is an integrated part of the Michelin corporation and was introduced to Gumiimpex-GRP through a partnership agreement. Exclusively original materials and profiles by the MICHELIN corporation are being used in the retreading. Gumiimpex-GRP is the only RECAMIC partner in Croatia.
Tire rotation
Rotacija guma je proces periodičkog prebacivanja guma s jedne pozicije na drugu kako bi se umanjilo neujednačeno trošenje. Na primjer, automobili s prednjim pogonom u normalnoj vožnji više troše prednje gume a manje stražnje. Zbog toga periodički mijenjamo stražnje i prednje gume kako bi ujednačili trošenje i osigurali duži radnji vijek kompleta guma.
Tubeless tire
Tubeless tires don´t have an inner tire and almost all of the tires nowadays are this type of tires. 
Car tire valves
Car tire valves are used to let out and fill the tires with air or nitrogen. With tubeless tires the valves are fastened directly to the rim. Valves and their components can be made of rubber so they are in time susceptible to wear. Replacing them when buying new tires is an economical way to protect your tires, the vehicle and yourself. Valve cap is also important. It is the primary protection from air leaks and helps in protection against dust and particles of dirt. You should check the state of the valves and valve caps in order to:

    • keep the tightness and prevent air leaks
    • keep the right pressure value in the tire
    • ensure a longer life of the tires 
Law regulations on traffic safety
According to the regulations on traffic safety, winter tires are to be mounted on all four wheels. Winter tires have a mark on their side M+S which is winter equipment of a passenger vehicle for all four wheels required by law. Normally under winter equipment we consider a summer tire too, if it has profiles at least 4 mm deep and compulsory snow chains on drive wheels, and in mountainous regions on all four wheels. In practice this is not recommendable because of the great hardness of the summer tires that become very dangerous in cold weather and slick surface and act like plastics.  
Winter tires
Winter tires have a mark M+S on the side wall, which is winter equipment of a passenger vehicle on all four wheels required by law. At a temperature of 7°C it’s important to have winter tires on, mostly because they are made of a softer rubber compound that keeps elasticity at very low temperatures. Deeper channels in winter tires drain water and sludge and more ribs on the block type tread compared to the summer tires ensure a good adherence when driving in winter condition.

Manufacturing and manufacturing processes in rubber industry

Extruding is a process of pressing raw rubber compound through a metal matrix in the shape of the end rubber profile. Extruded rubber profiles are being used as sealants in industrial plants in order to dampen vibrations, noise, as protection against dust and a temperature barrier.
Gasket Jet (WATER JET)


Gasket Jet is a highly technological process to manufacture flat gaskets of high accuracy and quality. After determining the shape of the gasket based on a pattern or imported drawings (AUTO CAD), the GASKET JET system cuts out the gaskets by a water jet a bit thicker than human hair. Using a water pressure of approx. 4000 bars and a speed that is almost three times the speed of sound, the water jet cuts even the hardest materials, besides the classical gasket materials. In the non-metal gasket chamber the production is possible on the surface of 4000x2000mm. Produced gaskets, i.e. their shape, the kind of material used, etc. can be saved in the computer memory and produced again.

  • 1839 Goodyear discovered vulcanization, the procedure of processing raw rubber under high temperature and under a great pressure while adding sulphur, giving the tire its features
  • 1888 Dunlop patented the pneumatic tire, the predecessor of the tires of today
  • 1891 Édouard Michelin, who was known for his work in optimizing rubber vulcanization made a tire that could easily be demounted from the wheel and mended

Combined with reinforcers such as steel and nylon strings, rubber becomes highly efficient raw material for great strains. Car tire is the best example of such a complex compound. Rubber is an elastic product that is produced by turning natural or synthetic caoutchouc into a linked structure. It is a material that can be reversed and deformed in a broad range of temperatures. Connecting macromolecules of caoutchouc are called vulcanization.

Rubber granulate
Rubber granulate is manufactured using modern technology by repeated mechanical grinding of waste tires while at the same time separation of steel and textile. The granulate is gradually sieved through special sieves and this way you get different sizes of granulate or rubber powder. 
Rubber buffings
Rubber buffings are manufactured by buffing different kinds of tires on special machines made for that purpose. Rubber granulate, rubber powder and rubber buffings are being used in a wide range of products such as: sport surfaces, safety and protective surfaces, stable and farm surfaces, roof insulation linings, sound barriers in construction, various traffic signs, shoe soles, solid tires for carriages and waste bins, car parts, various moulded products, porous bitumen binders, asphalt additive, etc.
Roller rubber coating
Rubber coating rollers is a process of coating metal cores with a raw rubber compound. Hereby first the roller is processed by sand-blazing the core of the roller, then it´s coated by a raw compound, vulcanized in an autoclave and finally grinded to a wanted measure. Rollers can be used as a means of transport (metal, construction, timber industry), as a paint applicators (printing industry), as glue applicators (wood-processing industry) and as running elements for various transporters, conveyor belts, etc. 
Rubber coating of big containers
Rubber coating of big containers is a process of coating different reservoirs for aggressive chemicals (acids, alkaline fluids), whether these are complete pipelines or just their parts, valve housings (membrane valves), basins, vibrators for cleaning metal hammering waste, anion-cation exchangers or different galvanization tubes by a rubber compound. 
Rubber conveyor belts
Conveyor belts for cargo per piece or scattered (bulk) cargo are made for a large number of uses in various conditions, where well defined characteristics for each belt is a precondition for its efficient use from the aspect of power – the elastic durability, number of inserts (canvases), thickness of rubber layers, layer characteristics and characteristics of rubber coating for resistance to temperatures and aggressive media, for pulling cargo at certain angles (elevator belt). Connecting conveyor belts may function the ”hot way”, where the rubber is melted and connected by vulcanization, or the ”cold way”, where the belt layers are separated and sealed together. Installation of conveyor belts is also possible in user factories or shops on the site where our professional road team can fix all defects and prevent longer work stoppages.

Types of rubber conveyor belts:

  • two or more EP elements – Y
  • W and WH – resistant to wear
  • S, K – fireproof and self-extinguishing
  • MOR, MG, GMG – oil resistant
  • T1, T2, T3 – temperature-resistant
  • CHEVRON – with vulcanized profiles of a height from 14 to 32mm, width of 2200mm
  • RIPCHEK; RC, SC, BC – with a cross metal reinforcement – for mobile shredders
  • ELEVATOR BELTS – for a vertical transportation, metal and PVC cups can be fastened on them
Natural or synthetic mass used in rubber production. Natural caoutchouc is dried milky juice of the rubber tree, it´s a high-molecular condensed product from diverse unsaturated carbons (isoprene, butadiene, styrene, etc.), while synthetic caoutchouc is a common name for a wide range of products in the chemical industry that replace natural caoutchouc.
Stable rubber floor covering
Floor coverings for the stables are rubber floor coverings that are more appropriate for hoofs and claws because they can smoothly immerse into the surface. Soft and warm feeling while lying on a rubber surface decreases stress in animals and they increase their condition features: their mobility, healthier feet and hoofs and more milk which results in a fewer number of veterinary interventions. Rubber floor coverings are also being used in training spaces (riding grounds dry fast and are not slippery), floors in stables, protective hangar walls, water vessels, protective fences, grounds for silos and warehouses and alike. 
Polyurethane is a high-quality artificial material (elastomer) which „replaces“ rubber. It has very good physical and technical characteristics: hardness and toughness, discontinued elongation, reflective elasticity, high resistance to wear and excellent chemical characteristics – stability with regards to hydrolysis and aging, resistance to micro-organisms, diluted acids and bases. The hardness of polyurethane ranges from 70-94 Sh, A scale.
Seal Jet


Manufacture of seals using the SEAL JET system represents one of the most sophisticated technologies in the world. Preparation and manufacture, use the “ECONOMOS” cutting edge computerized equipment “NG 40”. Over 150 pre-programmed profiles with 17 types of standard materials for manufacturing of seals comply with sealing requirements in 0 – 700 bar pressure systems. Sealing materials include and cover all media in hydraulic and pneumatic systems, and temperatures from -200ºC to +260ºC. SEAL JET system enables seals to be manufactured and delivered in a very short time.

In 1843, Englishman Thomas Hancoock defined the procedure for developing rubber in specific proportions of Indian rubber (as a base ingredient) and other additives, in defining lengths of time and heating temperatures. He called the process ‘vulcanization’.

Vulcanization is a chemical mechanical process which turns caoutchouc into rubber under the influence of pressure, time and temperature, which makes it resistant to chemical and weather influence and mechanical strain.

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