What are tyres
●Structure of bias tire
Bias tire is intercrossed by multilayer treads. Due to different materials, it can be divided into cotton tire, rayon tire, nylon tire, polyester tire and steel wire.
Here are their features:
1. Cotton tire. Cotton tread is made by cotton textile. Cotton is the earliest material used in tire making. Due to its low intensity, multiple layers, high heating, slow heat transfer, few re-treading time and much water absorption, it has no longer been used. Even so, other materials still take cotton as standard, which has become a practice in tire industry till now.
2. Rayon tire. After cotton, rayon has been widely used, which firstly appeared on Paris Exhibition in 1889. Invented by a famous French physiologist, it has the same luster and feeling like silk but is more highly tensile than cotton. By its features like heat and fatigue resistance, it became main material of tire making. Compared with the cotton tire, rayon tire is better in comprehensive performance, which made tire industry stride forward again. Its disadvantage is hygroscopic so as that its strength will be reduced in wet condition.
3. Nylon tire. Nylon was invented by an American chemist and published by his Dupont Corp. in 1938. Since publication, it has caused widely attention in the world. Some guys called it “Tougher than steel, thinner than spider silk, made by coal, air and water, but elastic and shining like protein fibre”.
As tire tread, nylon is more tensile, impact resistant, elastic, lower density, renewed and difficultly hydrophilic, but its disadvantages are thermal expanded and easily deformed. In winter, if vehicles parked outside for a long time, there will appear “flat spot”, which is caused by this, too.
4. Polyester tire. It has the same strength with nylon, but tensile ability is better than it. So it’s widely used as the backbone of tire among foreigners.
5. Steel tire. It’s invented by France Michelin Tire Corp. in 1946. It features large strength, low rolling resistance, impact and wear resistance, safety and high turned over rate. Its shortcoming is too tough to buffer comfortably.
You’d better to know more tires when selecting one correctly. For example, if you ride on a wet road, you should not choose nylon tire. If you need more turn-over rate, you can use nylon tire. Totally, you’d better choose one suitable tire in accordance with various conditions.
●Structure of radial tire
Radial tire was firstly found in a world famous tire factory-- France Michelin Tire Corp. in 1946, which once was a small agricultural plant co-established by Barbier (the grandfather of Michelin brothers) and Daubree at Clermont Ferrand. At first, it made rubber balls and invented bicycle tire that could be changed within 15 minutes and obtained champion by it on one bicycle match. In 1946, they invented the radial tire.
The birth of radial tire symbolizes tire industry entering into a new era. Here, thank France Michelin Tire Corp. for making such great contribution to world tire history.
The bead of radial tire is arranged by the center spot and hooped by 10°to 20°. (The angle of steel belt inner wire)
Radial tire is made by nylon and rayon mostly, but that for trucks and heavy load vehicles are made by steel. Besides, the compound and material are changed with various functions and forces.
Here are the compounds to different tire positions.
1. Tread compound
Tire tread will contact with road directly, so it should have better wear resistance, lower rolling resistance and lower noise as well as better heat and puncture resistance. In addition, the radial tire’s little buffer can bear more loads, especially on poor roads. Tread compound should have good flexibility, high fatigue resistance and anti-aging performance. Hence the materials of it should be very particular.
2. Sidewall compound
The side bending deformation of radial tire is bigger than that of bias tire. Therefore, bending deformation resistant rubber should be used. In addition, the sidewall easily cracks in effects of ozone and also will bear greater mechanical deformation. Therefore, sidewall compound should have lower tensile strength, superb fatigue resistant and ozone-resistant performance.
3. Belt compound
Radial tire belt layer should bear higher shearing stress than bias tire buffer layer, as well as achieve gentle transition to hard buffer layer and eliminate void phenomenon of tire shoulder. Therefore, belt compound should have higher strength, fatigue resistance, heat resistance and viscosity.
4. Carcass ply compound
Radial tire carcass has larger circumferential deformation and shear deformation along the cord than bias tire, therefore, ply compound should have higher strength, fatigue resistance, heat resistance and viscosity as well as high cohesion.
5. Shoulder pad compound
Shoulder pad compound should separate ply and buffer layer so as to make hard tread transit to soft sidewall gently and absorb the shoulder stress at dynamic condition as well as reduce the risk of shoulder void. Due to shoulder pad compound located at high stress area, it should have high fatigue resistance and viscosity.
6. Bead filer
In order to improve bead and achieve rigid transition to tire tread, bead filer with higher or different hardness will be filled into the bead so as to ensure gentle transition from steel bead to soft tread. In addition, it can offer good viscosity.
As our understanding about different compounds, we can know that radial tire is very complex and difficult to manufacture. Additionally, it needs strict production technique, advanced equipment, fine material and strict management and test method. So we can say it’s the wisdom of human being.
According to different belt layers and beads, radial tire can be divided into all-steel radial tire, steel wire belt fiber carcass radial tire (semi-steel radial tire) and all-fiber radial tire.
Heavy load trucks use all-steel radial tire or semi-steel radial tire; light trucks use semi-steel radial tire generally and passenger cars often use semi-steel radial tire and all-fiber radial tire.
Many drivers do not have enough knowledge about the tires on his vehicles. If different carcass tires are used on one car, it will affect performance. Hence, before tire changing, you’d better know what kinds of tires are used and choose a same one.
Here is different material’s representation on tire sidewall:
The structure information will be impressed on tire sidewall clearly, namely, xx layers of treads and sidewalls.
For example: PLIES(2POLYESTER+2STEEL+NYLON) on Japan Toyo Tire 195／50R15 T1 means the tire is a semi-steel radial tire and its tread is consisted of 2 layers polyester, 2 layers steel and nylon.
Also, Shanghai Warrior 185／70R13 Tire:
TREAD: 2PLIES POLYESTER
Tread layer polyester
SIDEWALL: 2PLIES POLYESTER
Sidewall layer polyester
It refers that tire tread is made by two layer polyester and two layer steel and sidewall by tow layer polyester.
TREAD：POLYESTER1 + STEEL2 + NYLON2
Another one, Japan Yokohama Tire 185／70R14(88H707:
TREAD: POLYESTER1 + STEEL2 + NYLON2
Tread one polyester two layers steel two layers nylon
It means tire tread is consisted of polyester, two layers steel and two layers nylon.
SIDEWALL：1POLYESTERFinally, such as America Goodyear 185/70R13(86S) Tire
TREAD; 3PLIES 1POLYESTER+2STEEL
The tread is made by polyester and two layers steel; and sidewall by polyester.
More layers of tread can offer high puncture resistance and heavy load capacity but short for its slow heat transfer. Fewer layers of tread will cause poor tensile strength, easy puncture and poor impact ability but features by good heat transfer and shock absorption performance.
After detailed understanding about tire, you can choose a suitable one by your own experience.
●Structure of tube tire
Tube tire has the similar structure with the tubeless tire, but tube of the former is independent and that of the latter is integrated with casting tire, which can be taken as “inner liner”. The casing tire can not tightly wrap with the hoop. Once inner liner is punctured, air will flow away from the combination part and the bead will be cut off even on slow riding, hence, the tire will be disabled totally. If riding at fast speed, heavy traffic accident like rolling-over and sidelong will occur.
●tructure of tubeless tire
Tubeless tire, also called vacuum tire and hollow tire, means no tube in inner. Some drivers hardly know tubeless tire and feel unreliable. In fact, tubeless tire doesn’t mean no tube in liner but it integrates with casting tire by a more scientific and advanced material and production method.
There is a seal film (chlorinated butyl rubber mostly) with high sealing performance closely attached to inside wall of tire. If punctured by a nail, air will flow away. Inside film of tire will shrink with air flow to block the puncture hole. There is no any air leak because the film is wrapped with the hoop tightly. In addition, there is only one intake, so it can not leak, too. Therefore, when punctured by nail and the same, air can not flow away totally so drivers can have enough time to handle and accident will also not be caused ( when driving at high speed, if front wheel is broken suddenly, traffic accident will occur) while casting tire not damaged by air leak.
We can make a test: blowing a balloon and then puncturing, it will blow up; but if we stick an adhesive plaster on the same balloon and repeat the test, the balloon will not blow up but be plugged by the adhesive plaster accompanied with air flow away slowly.
So, from safety angle, vacuum tire is the most ideal for high-speed vehicles. In addition, it features lower heat generation, lighter weight, fuel saving (It’s been proved tubeless tire can save 1% to 2% of fuel than tube tire) and easy to fit.
Since invented in 1930, tubeless tire has developed for over 60 years. The initial reason of development is safety. But till now, some drivers still worry about its safety, which can prove taht we are still lack of better propaganda and promotion.
Tubeless tire requires hoop no any impact, no rust and passed air tight test, otherwise, tire will not be inflated due to the failure sealing with the hoop.
How to store tyres
1, Tyres should be stored in a dry warehouse where no direct sunbeam shines inside and without much flowing air, the temperature inside in -10-30oC ,relative humidity is 50-80%,The warehouse should keep distance from places, where power generation equipments exist or zone generates, so as to prevent fast oxidization.
2, The place of store tyres inside the warehouse should keep more than one meter away from heat generation equipments and cannot be put together with oil, acid, alkali and inflammable chemical products.
3,Tyres or tyres fitted with inner tubes inside should be placed vertically on shelf. Tyres' contact position with shells should often be changed at least once in 3 months.
4, Tyres fitted with inner tubes inside should be stored with the surfaces of inner tube with talcum powder applied and inflated with low pressure.
5, When inner tubes are being stored separately they should be inflated and hanged on a frame with a semicircle and their hanging positions should often be changed to prevent deformation or fold occurring.
6, When store tyres packed with wrapping material, put them on shelfs don't peel the wrapping material away.
7, Tyres should be stored in lots according to production date or store date first in and first out.
How to use tyres
1, Tyres must be fitted on specified vehicles and rims.
2 ,On an axle should fit tyres of the same size, brand, dimension, ply-rate, inflation pressure and tread pattern.
3, When fitting new tyres on a vehicle we recommend to replace all the old tyres with new ones or to put new tyres on front axle and outside of the back axle.
4, When back axle uses dual tyres the dual spacing should not be less than 20mm and not more than 35mm and the openings on the wheels should be in alignment.
5, When fitting tyres which have specified running direction, the running direction should be the same with the running direction of wheel.
When these kind of tyres often run on hard road, the tyres on the front wheels can be fitted in opposite direction in order to reduce rolling resistance and save fuel.
6, Tyres fitted on a vehicle must keep inflated. If you will not operate a vehicle for more than one week please leave it in garage or a shady place avoiding sunbeam shining directly upon it and jack it up to prevent crack of tyre surface.
7, Tyre should be inflated according to specified pressure. But when vehicles run on the roads which have arch of more than 4%, tyres on front wheel and inside of the back wheel can be inflated 0.2 -0.35kg /cm2 less than specified pressure.
8, When vehicles run for long distance, tyre inflation pressure should often be checked, especially in summer. When you find pressure 1kg /cm2 more than specified pressure, you must stop vehicle at a shady place. After pressure drops to proper value, start again.
9, "More inflation in winter", "less inflation in summer" "deflation midway" can never be used.
10, Tyres 'load, which should be calculated according to maximum load of single tyre, cannot be exceeded. Goods on vehicle should be placed evenly.
11, When vehicles run on bad and complicate roads their running speed should be reduced, Stop, run up and down a slope and corner slowly especially when vehicles cross railway and rut. When a vehicle running on road with arch surface you should drive it in the center of the road to prevent one side wear.
12, According to test reports tyres on front wheel wear 20-30% less than those on back wheel. In order to prolong service life of tyres we recommend to do end to end "X" rotation as regulated when running 8000 -10000km ,and at the same time to check tyres, inner tubes and flaps.
13, When change the tire position, all tires position should be changed at the same time, and the original rolling direction of the tires will be not changed.
14, When a vehicle has stopped in cold weather for a long time and temperature of tyres is less than minus 30-40oC, start it smoothly and in the first 20-30 minutes run it slowly, 5 -7km/h . After tyres warm up return to normal speed.
15, When modify carriage or change distance between two axles or add more parts on a vehicle, each tyre's load capacity on front and back axles must be taken into account so as not to cause partial overload.
16, When chain up tyres, both sides should be chained. Take off chains as soon as vehicle passing through slippy road, Too loose or too tight fitted chain may damage sidewalls and treads.
17, Tyres' appearance should often be checked. As soon as cracks, pierced holes are found they must be repaired immediately so as to prevent damage parts increasing.
18, Tyres should be fitted on standard rims. The edge of rims (or lock ring) should be cleaned periodically to remove rust on it and apply anticorrosive oil.