Care of the Tyres

Manawatu Times, Volume LV, Issue 6866, 24 May 1932, Page 4

Care of the Tyres

Every day thousands of pounds arc thrown away by motorists, and a further huge sum is added to their running costs, through neglect of their tyres. A motor vehicle only functions in proportion to the time, care and inspection given to it, but how many motorists include tyre inspection under this heading? It is dangerous to run an engine short of oil, but how many realise it is equally dangerous to run their tyres short of air? The tyro manufacturer makes a tyre suitable for every vehiclo at present being manufactured, and issue, in printed form, information showing the correct load any tyre should carry, and the right air pressure necessary to produce maximum riding comfort, and minimum fatigue in steering. Beneath the rubber t-rcad on a tyre is a carcase of cotton, built up to carry a dcfmito load. The sidewalls of this carcase arc so constructed as to flex without fracturing the cotton. The tyro pressure recommended for any vehicle is such that a motorist can take advantage of this flexing without causing damage to the tyres, hut should this pressure be maintained at a higher or lower level than that recommended, the motorist lays himself open to serious trouble at a later date, the interval of time being controlled by the degree of over or under inflation. In an under-inflated tyre, the flexing of the sidewalls sets up friction, which causes heat. Rubber is a bad conductor of heat and cotton loses its flexing qualities with increased temperature. The result is that either the cot ton cords will fracture, or the rubber wall will scpa.rate from the cotton, thus weakening the sidewalls of the tyre, possibly causing complete collapse at a very early stage in its life. An over-inflated tyre compels the tread to assume an incorrect contour, which does not allow tihe full tread width of the tyre to come into contact with the road surface, so the tyro load is carried only by a portion of the actual tread. That portion is.over-loaded and in consequence, generates excessive heat.. Immediately underneath the tread is a section of what is known as “cushion”; in other words, a layer of rubber around its circumference; which is softer than the outside tread. This acts as a shock absorber. Should the tyre be over-inflated, the shock will bo absorbed by a small percentage of that cushion, and the benefits which should .be obtained are not only eliminated, but the shock and heat arc transmitted to the carcase of the tyre,.'which, deteriorates rapidly. Pressure, however, whilst a very important factor, is not everything to be considered when caring for tyres. Pew motorists appear to appreciate that it is possible to wear the tread completely off any tyre inuin extraordinarily low mileage, should, the wheels of the vehicle be running out of alignment. You cannot seo in many cases when-looking at a vehicle, whether or not the wheels are running in line, and it is necessary to have them checked by:your service agent should you wash, to obtain from your tyres the maximum life built into them by the manufacturer. • Thccr is also, a further condition which requires consideration, that is cuts in tyres. Should .a .tyre, receive a cut which penetrates the tread Tubbcr, and exposes the carcase, this cut or hole •forms a passage for all foreign matter, including water, .into the carcase. The greatest enemy of . all 'is water. In running on- wot roads the injury becomes filled with waiter, and the cotton in - the carcase soaks up some of- this water like blotting . paper. This eventually. causes the wet cotton to separate from the rubber, and soon a section of the tyte has no resistance to the internal air pressure, beyond the rubber forming the tread or sidewall. Thus often results in a blister, and eventually causas a burst, which ruins both tyre and tube. A little time spent on inspecting the tyres on your ear will be amply repaid by the fact that it will be possible to obtain maximum “life” from them. The following arc the major points, which, when checked, will go a long way towards achieving this end. 1. Remove all tyros periodically. 2. Inspect rims, removing rust and giving a coating of stock black or similar solution. 3. Inspect the inside of the covers for pieces of foreign matter or small fractures of the carcase, due to concussion bruises incurred during running. 4. Inspect the treads for small cuts, embedded flints and the like. 5. Inspect the tube for porosity, rust marks, damaged or leaky valves, loose particles, etc. 6. Refit the tyres, and inflate to correct pressure’. 7. Test wheel alignment and steering connection in order to ascertain whether any excessive play is to be traced between the steering wheel and in the movement of the wheel on the huh. Your dealer will quote you a small inclusive char go for this service, a charge which will no doubt, be saved over and over again by the extra tyre mileage achieved. Finally, tost your pressures once every .week.