GENERAL ARTICLES

CODDLE YOUR TIRES

New tires are out for the duration, Mr. Motorist, so it's up to you to keep the old ones rolling . . . Here’s how

ROSS WILLMOT March 1 1945
GENERAL ARTICLES

CODDLE YOUR TIRES

New tires are out for the duration, Mr. Motorist, so it's up to you to keep the old ones rolling . . . Here’s how

ROSS WILLMOT March 1 1945

CODDLE YOUR TIRES

New tires are out for the duration, Mr. Motorist, so it's up to you to keep the old ones rolling . . . Here’s how

ROSS WILLMOT

YOU’D better take care of the tires you have, Mister Average Motorist, because new tires for your car are out officially out until Hitler is definitely beaten. And thank your lucky stars synthetics have developed as they have, or you probably would not even have satisfactory material to recap your old tires.

Pronouncements and prophecies in the press, as late as last autumn, led you to hope, as an ordinary civilian not engaged in essential war work and not qualified under the tire rationing order, that you would get synthetic tires early in 1945. But because of unexpected war developments all tire reserves were quickly sent overseas.

Actually, Canadian plants are now producing more tires than the Canadian forces require —but not nearly enough to meet the heavy, urgent demands of the United Nations. Canadian tire workers pledged themselves to produce 50,000 additional heavy-duty tires during the first three months of this year, workers in the United States more than 20 times that amount.

So great is the demand from the Western Front that it is far beyond the productive capacity of the tire

industry. Every 24 hours one out of every 100 vehicles in the United States Army—and probably in the Canadian Army as well—is incapacitated because its tires have worn out. Bouncing over the unrepaired transport arteries of France and Belgium takes a lot of wear and tear. Even captured European tire factories have been put into operation by the Allies with raw material shipped from our synthetic plants in North America. It is hoped to get 125,000 tires, mostly retreads, by this venture. Tires are being stripped from nonessential military vehicles throughout North America and also in other less urgent theatres of war to be sent to Europe.

To meet the pressing need it is not without possibility that essential civilian users of tires -doctors, nursas, fire fighters, warworkers, and milk truckers— might be further restricted. And as for the ordinary motorist—his chances have simply disappeared.

Serious as the tire situation is, it is expected that our mushrooming synthetic rubber production, plus the Allies fast-dwindling hoard of natural rubber, will meet the demands of war. The United States and Canada are co-operatively producing more than

800.000 long tons of synthetic rubber yearly.

This is a considerable increase from our 1939 production, when only 2,000 tons were produced. In addition, here in Canada we have huilt up a reserve of scrap rubber expected to last us until the end of 1946. Reclaimed rubber is being produced from scrap in the two countries at a rate which just about equals the demand.

At least 90% of our needs are being supplied by our synthetic rubber plants. There are more than 50 such plants in the United States, employing more than

20.000 workers. One huge collection of 10 factories at Sarnia has 1,500 on the payroll. Our Polymer plant there has an annual productive capacity 34,000 long tons of Buna-S rubber and 4,000 tons of butyl rubber —equivalent to that coming from 120,000 acres of rubber trees. It would require more than 144,000 tappers to obtain this amount of natural rubber.

More than 75% of Canada’s rubber is used for tires,

but only tires for military use and for the cars and trucks which are considered essential to the war effort - about one third of our 1,250,000 passenger cars and approximately 250,000 of about 300,000 trucks. About 10% of our rubber is designated to all nonessential civilian uses.

Most of our synthetic rubber tires are now made of Buna-S, or Government Rubber-Styrene, the most widely used synthetic. This is the lowest priced because of the small amount of power required in its manufacture, but the main consideration Ls that it can be manufactured quicker than other synthetics.

According to Bradley Dewey, former U. S. Rubber Controller, these Buna-S tires are “better than all but the top-grade tires made with natural rubber before the war,” whose chief advantage was that they had about 10%; more mileage. Compared with other synthetic rubbers used for tires, Buna-S possesses superior wearing qualities, stronger resistance to abrasion, and blends well wjth crude rubber.

But for tires for large buses and trucks, military vehicles, heavy bombers, and large transport planes, Buna-S heats up more rapidly than natural rubber and is more liable to cut and crack. A higher proportion of natural rubber is needed for these tires. Admitting their deficiencies, the U. S. Army has still expressed confidence in these heavy tires.

Continued on page 40

Continued from page 13

In general the Canadian public is unaware that many of their everyday goods are now being manufactured in this country from our own synthetic rubber. GR-S is being used to make footwear, hot-water bottles, insulated wires and cables, belting, automobile and airplane parts, and tire repair material. Our butyl, which is now being used in the manufacture of inner tubes because of its amazing ability to resist the passage of air and its great resistance to tearing, is also used for selfsealing gasoline tanks, hospital sheeting, flotation equipment and other essential articles.

Someday, perhaps soon, as a result of high-paced war research, synthetic rubber may be preferred to natural,

¡ just as today in the manufacture of : synthetic tires the use of cotton cord has been abandoned for that of its substitute, rayon. It has been found that rayon is stronger than cotton, pound for pound, or gauge for gauge. Tires using rayon develop less heat and are not as subject to premature body failures; and help conserve rubber.

The chief recognized deficiencies of !. synthetic rubber for tires are that it

develops too much heat when flexed, loses extensibility and is prone to tear when it is hot. These deficiencies, however, are being corrected.

James I. Simpson, chairman of the Canadian Rubber Advisory Committee says that if you would list realistically the qualities of synthetic rubber for tires over against those for natural rubber, you might find that in certain regards synthetics approach or even equal natural rubber, but taken as a whole natural rubber is still preferable.

Our only other source of rubber, native plants such as the American guayule, wheat, milkweed, and Russian dandelion, would require 10 years of research to develop to any practical extent. The manufacture of tires from reclaimed scrap rubber in Canada has been stopped, because the tire produced was both costly and unsatisfactory. Our scrap is now being used in the production of less essential rubber articles.

Last year the luckier essential tire users were given some 870,000 synthetic tires manufactured in Canada, more than 300,000 over the previous year. In 1943 some 314,000 were manufactured during the year, mostly from reclaims, while only a few came from synthetics. The rest were pre-war tires. Canadian synthetic rubber tubes were also supplied to the privileged

few. Enough butyl and Buna-S is being produced by our Polymer plant to meet all our Canadian needs, and some is being exported.

Recapping Satisfactory

You might not be able to get new or secondhand tires for your car without a permit, but anybody may have his old tires retreaded satisfactorily, providing the carcass is still sound. You will need about nine dollars for each one you renew. This figure is a ceiling set by the Government for the recapping of a 600-16 tire—the most common passenger-car size.

Besides experience and knowledge of retreading by the operators, you should look for modern equipment in the shop itself. All shops should have a drying room in active use, a spreader, which spread-eagles the tires for inspection of the fabric, and, preferably, a precision power buffer, which roughens the tires across the tread rather than parallel with it, thus permitting’escape of air when the “camel back” retreading layer is stuck firmly on the tire by a power press. A matrix, holding the tire by means of a collapsible rim, and a “curing bag,” under pressure and steam heat for about 70 minutes at a temperature of 300 deg. Fahr., may complete the recapping or retreading operation.

There are various types of molds used in retreading, but the process of “curing” the retreading material, that is, changing it from a plastic to a tensile material, is mainly done by steam heat. In one process the whole tire is placed in a steam chamber, and after a proper period of curing, the carcass with its affixed camel back is removed to be grooved either by machine or by hand. Another patented method goes to the opposite extreme and applies steam heat only to the patch itself.

“Heat applied to the carcass actually harms it,” the manager of the shop using this last principle, declared. “It is the same thing with retreading as with cooking a roast. You are apt to spoil your product by overheating. That also is the reason vulcanizing a tire is never wholly satisfactory.”

No tire is better than its casing and this is particularly true in the retreading trade. Not all tires are sound enough to stand a new retread. One operator in a modern retread shop explained that tires should be “pulled,” or removed for retreading, as soon as or just before the nonskid pattern has worn off.

In other words you should not necessarily run your tires smooth before taking them in. A slight indication of tread left on the face of the tire indicates that the cords of the carcass of the tire itself have not been worn weak or damaged by bruises or nail holes, nor has the layer of spongy rubber gum protecting the cords been worn away. And any good operator will not buff away a customer’s rubber.

Actually the tire should only be roughened to hold the rubber cement. The layer which the customer leaves is still there for future use.

Tires which have been worn down to the cords, if not too far gone, may be repaired and then recapped satisfactorily, but their chances of having a second recapping job are not as good as those whose carcasses are sound. Theoretically, with a good foundation, there is no limit to the number of times you may pull your tires for retreads. Some truck fleets have already had their tires recapped five times,

although, admittedly, they have been very careful in using them. Most

reliable retreaders should guarantee their work to stand up to reasonable standards, providing there was no weakness in the fabric. In some cases

these synthetic retreads give as much wear as the original.

In Ontario some retreaders have formed an association which aims to set certain standards of workmanship and materials and to prevent the retreading trade from developing into a gyp game.

The membership to the association is not limited. Any recapper can belong and a good proportion of them in Ontario do. They discuss new ideas at meetings and have already made recapping recommendations to Ottawa. However, many recappers, particularly those living in small towns, remote from the Toronto meeting place do not belong.

Other Methods Used

The average layman can usually judge his chances for a retread himself.

A cheap, poor-quality tire is a bad gamble. So are tires with broken or badly kinked “beads” (the rubbercovered wire edge which is enclosed by the rim). Tires with badly cracked or cut side walls are definitely out, although slightly weakened walls may be reinforced by a retread. A retread is distinguished from a recap in that it encloses the tire more. Generally speaking there is little difference in the wear of the two, and no difference in the price, although a retread required more rubber than a recap. Reliable operators also refuse tires which show evidence of having being run flat or of having been consistently overloaded.

Then there is regrooving. By that is meant the process of cutting a thin, makeshift, antiskid tread into a tire which has worn smooth. Today, when rubber is so scarce, these incisions are unadvisable because of the danger of cutting into the basic tire cords.

Retreading, based on pre-war experience, is definitely past the experimental stage. Today recaps for passenger cars are made almost entirely from GR-S synthetic, while truck tires use this GR-S with the addition of some crude rubber. Reclaim rubber retreads were found to be unsatisfactory, and so are not used in Canada, although they are in the United States, with several grades of synthetics.

Flat synthetic camel backs (so called because of the hump on the pre-war patch) have been produced commercially only since last fall, after reclaim rubber had been found unsatisfactory. Average mileage figures are therefore not yet available, although they will be better than the below 5,000-mile average of the reclaim rubber recaps.

Advice as to tire maintenance generally is agreed upon by all tire men. Put first proper inflation of 32 pounds for the 600-16 tire size and make weekly inspections to be sure that the pressure is at the proper amount.

A tire underinflated 20% gives 15% less mileage. Underinflation weakens cords, increases the distribution of heat, causes irregular tread wear. Overinflation is just about as bad. It causes rapid tread wear, abnormal tire cord stretch, and excessive strain on the beads and rims. If a considerable pressure drop is noted you should check the valve core, and if the trouble is still not j corrected you should remove the tube for a thorough examination.

Look After Car

Then make certain that the parts of your car which affect the wear of your tires are in perfect running condition. The wheel alignment and other frontwheel mechanism should be frequently inspected. A tire on a wheel one half inch out of alignment is dragged sideways 87 feet in every mile the car travels—and scrapes off its tread.

Your brakes should be adjusted so

that one wheel is not doing more work than another. If the brake drums are kept true the wheels will not always stop on the same wearing surface. Particularly in the later models tire balance is very important. 'Phis is only attained by having the whole assembly — tire, tube and wheel balanced as one unit.

Stay out of the streetcar tracks. Thin slivers of steel, worn off the tracks by the trolleys, can cut up tires considerably, particularly if the driver has to put his brakes on while in the tracks.

Many tires have had their carcasses ruined’ and rotted from “sticky shoes,” or blowout patches, which have been left in the tire too long. A sticky shoe should only be resorted to in an emergency.

Be very careful in your driving. Reduce your speed, particularly over rough roads and at turns; accelerate and stop slowly. That black streak you leave on the pavement, caused by locking your brakes, may represent 300 to 500 miles of wear.

If your tires are synthetic you should never exceed 35 miles an hour, for intense disintegrating heat is built up at high speeds. Even with natural rubber tires a reduction of speed of 25% may effect a saving of 80% in wear. High speeds generally cause more tire slippage, because, as the car sways, more rubber is scuffed off the tread. The heat generated weakens the tire body and inner tube. You use your brakes more often, too, at high speeds. An ordinary quick stop from 45 miles an hour wears off more than a mile of normal tread wear.

If you are driving a truck don’t overload it. Go by the weight of your load rather than by the space it takes up. Even when the load is within the total recommended, be sure that it is equally distributed over the truck body. Tests have shown that as little as a 10% overload will develop critical temperature in a tire.

During U. S. Army tests some synthetic tires were overloaded 20% and tested on long hot runs similar to severe trucking operations. These tires failed at an average mileage of 4,954 miles. Tires underloaded 10% on the same runs were still running after 10,000 miles, and the test is still proceeding.

Bradley Dewey, former U. S. Rubber Controller, in one report, says: “A

crude rubber tire, although permanently injured by overloading, will operate under an overload for a much longer time than a comparable synthetic tire. The same overload, which would be carried for thousands of miles by a crude rubber tire, may, on a road with medium speed, cause the blowout of a synthetic tire in less than half the mileage. An overload which might reduce the life of a crude rubber tire only 25%, or even be carried through until the tread was worn smooth, may reduce the life of a synthetic rubber tire 50% or moreand result in a blowout while there is still wear in the tread.”

Alternate All Tires

Because there is different wear on each of the four wheels of a car, it is advisable to alternate your tires every 500 miles. One way is to change the left front with the right rear and the right front with the left rear, without removing the tires from the wheels. For the maximum benefit and for even wear, remove one front tire from the wheel, turn it around and put it on the rear wheel on the same side of the car so that the tire wall which was formerly facing outward now is facing inward. The rear tire likewise should be turned around and put on the front wheel.

Repeat the performance with the tires on the opposite side of the car. And don’t forget to give your spare its proper share of work.

A frequent and regular examination should be made of the surface of your tires for cuts and other injuries. It is advisable to have any damage repaired by an expert tire vuleanizer rather than ¡ to resort to a temporary homemade repair. The rims should be free from j rust and any kind of corrosion and should not be bent, dented or damaged in any way. All oil and grease should be removed immediately from tire surfaces.

All tires deteriorate with time. If it is necessary to store your tires, keep them away from direct sunlight. If the tires have been removed from the wheels, keep them in a darkened room at ordinary room temperatures, preferably in a place which can be closed up to prevent the circulation of air. Otherwise your tires should be well covered up in some way. If you are storing your car, jack up the wheels, deflate the tires to the point where they barely hold their position on the rims. Brown paper wrappings will protect the tires against light and excessive heat.

Our expenditure in synthetic rubber research will pay us dividends in full, even if the production of synthetic rubber does nothing but stabilize rubber prices after the war. Two or three years may be required to bring back the natural rubber plantations into full production, and an adequate j supply of natural rubber will be assured j by our plants. And if the trees have been destroyed it will take at least seven years for new ones to grow. Less mechanized countries, which have been opened up by the war, are becoming motor conscious. War-devastated areas ip Europe will also be demanding tires and rubber. Our nationally owned Polymer rubber plant, in which every Canadian man, woman and child theoretically has a four-dollar share, is capable of turning out postwar products. It could make styrene, a plastic base, and butadiene, an elastomer base, I and with minor alterations it could | produce industrial alcohols, acetic and I other acids, and numerous other ! products. Surplus rubber could he | taken up in new uses after the war insulation, rubber wallpaper, clothing, flooring, mattresses, and upholstery. R. C. Berkinshaw, president of Polymer, says that synthetic rubber manufacture is a sound commercial proposition and that Canada will he assured of a permanent supply after the war at about 21c. a pound. The price of natural rubber in pre-war days was 15 to 25c. a pound for Number One grade, and, with markets under stress, as low as three cents.

That, Mr. Motorist, is the picture for synthetic and natural tires . . . for essential and not so essential uses. What is important to all tire users is that they look after the tires they have . . . pamper them . . . baby them . . . protect them . . . you’ll need them!

Pass Along Your

Maclean7s to the

Boys in Uniform

Letters from troops, sailors and fliers tell how much they enjoy seeing Maclean’s. If when finished with your copy you take it to the Active Service Magazine Depot in your city or to a Navy League branch, it will be sent to the boys in uniform here and overseas and to the men on the merchant ships. If there are no depots near you write to Active Service Magazine Depot. 122 King Street West, Toronto, or to Navy League Magazine Depot, 1193 Bay St., Toronto. Or give your old copies to a salvage organization. Paper is needed in the war effort. Do not burn or destroy it.