Factors which effect tyre life;
Proper inflation-a must
The tyres designed to carry loads upto the maximum Specified load at the inflated pressure for a desired tyre deflection and road contact area, Neglect of inflation pressure is one of the major causes for premature failure of tyre. It is unsafe to run a tyre with any pressure different from specified. It is important to check pressures of all the tyres at a regular
Under-inflation is the greatest enemy 01 a tyre. Reducing front wheel inflation pressure to obtain a softer ride is very unsafe and should never be done. Low air pressure can result in rapid tread wear at the shoulders, and over flexing and excessive heat generation, causing premature failure of tyre. This abnormal flexing action will breakdown the card structure, with a result that the tyre is weakened in this area and unable to withstand ordinary road shocks. The individual cards will become loose and
in addition, ply separation may result. Under inflation is also the cause of rapid and uneven tread-wear resulting in high cost.
There is a mistaken concept on the part of many users that a tyre can be overloaded safety by over-inflating. This is a very dangerous Increasing air pressure to offset overloading simply distorts and
practice cord plies of the tyre beyond their capacity, eventually weakening strains the Over-inflation promotes danger of concussion cuts. the entire structure.
Over-inflation causes vast tread wear in the center of the tread, due to decrease in road contact area and resulting in increase of load per square centimeter.
It must be remembered that over-inflation reduces traction and skid resistance, because of the smaller tread area in contact with the road surface. Over-inflation also gives harder riding due to the fact that the tyre cushioning is greatly reduced: apart from discomfort this will result in higher maintenance cost. Always remember that tyres are costly, whilst air is free.
A large proportion of the premature failures experienced is due to over-loading. Every tyre is designed to carry a specific load at a specific inflation pressure. If the load per tyre is in excess of the maximum
specified limit, then the mileage will vary proportionately.
Tyre bleeding is the practice of letting air out of tyres when inflation pressures build up due the heat of the operation. This procedure is wrong. It has been proved that such a practice causes even greater increase
in tyre temperature resulting in premature failures; also people forget to reinflate these tyres after the vehicle has been standing overnight and consequently tyre failure occurs due to gross under-inflation.
If the tyres are not “bled” an equilibrium is reached between heat generated by the tyre flexing and heat dissipation, so that temperature of the tyre remains constant. The bleeding of tyres reduces the air pressure, but not the temperature of a tyre.
Effect of Speed
High speed is always dangerous and destructive to the tyre. All tyres are designed for Speeds up to certain range. the high-speed result in fast tread wear and excessive heat buildup. When speed increases, tread life
reduces rapidly. Hence loss in tyre life and mileage.
Effect of Heat on Tyre
Heat generation in a tyre is directly proportional the frequency of flexing, friction of road surface and atmospheric temperature. Flexing is the result of tyre deflection. Heat generation due to friction depends upon the speed; less speed creates less heat and high speed generates abnormal heat.
Sometimes the tyre may not feel too hot touch even though the internal temperature works nearly at 212° F (boiling point of water). This high temperature will reduce the tensile strength of the cord fabric in the
tyre casing. At the same time the abnormal rise in temperature promotes pressure build up in the tube. The combination of these two conditions will end in a “Blow-out”, because the week cords will no more be able to withstand high tension due to pressure build up and road shocks and vibration. The cords once weakened remain weak forever. The effect of heat on tyre compounds is similar to that of heat on cord body. Thus, under the effect of heat, the tread rubber becomes soft, and therefore wears more rapidly resulting in low mileage.
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