Our Tyre Advisory Bureau
Page 31
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• Answers Your Problems
A Further Selection of Replies by Our Tyre Expert to Questions Arising Out of Operators' Difficulties
"BUFFER" STOCKS TO MEET NIGHT-SERVICE NEEDS •
0,—We have a large fleet of vehicles
operating a day and night service. What are we to do if a tyre be urgently ,wanted in the middle of the night, when the Authorized Tyre Depot with which we are registered is closed?
A.—Firms which run night services can
sometimes obtain a "buffer" stock of tyres over and above the number required for actual running wheels. These stocks are allowed only at the discretion of the Regional Tyre Officer, who should be approached, giving full details of the circumstances, PRESENT-DAY CONDITIONS OF SALE ARE NOT NEW
O.—Our Authorized Tyre Depot has
called our attention to some new Conditions of Sale, in which it disclaims all responsibility for any damage or loss arising Out of any goods which it sells to ui. It also states that no guarantee is offered with any tyre: In other words, we are asked to indemnify the A.T.D. against all losses associated with any tyre that it may sell us. Are we obliged to do this.
A .—These are not, as you seem to
think, new Conditions of Sale. With the exception of one clause, they have been in operation for many years and have been published in the manufacturers' price lists. Nowadays, they are receiving more publicity because of the possibility of the debasing of tyre quality. The tyre manufacturers may no longer be allowed to make tyres of their pre-war standard of quality, and are, therefore, not prepared to give any guarantee in respect of them. They have asked all Authorized Tyre Depots to indemnify them in this respect, so the A.T.D. has no alternative than to ask for a similar indemnity of the operator. I am afraid You must accept the conditions as a normal war-time risk.
OVERLOADING NOT OFFSET BY ADJUSTING PRESSURES 6 0.—Our lorry, equipped with six 32
by 6 Heavy Duty tyres, is carrying an average load of 6 tons. What adjustments of pressure should we make to counteract this overloading?
A .—If your lorry be carrying 6 tons on six 32 by 6 Heavy Duty tyres, it is grossly overloaded, because the weight of the vehicle must be taken into account when calculating the total load on the tyres. Overloading cannot be offset by overinflation. You must either reduce your loads so that the weight of vehicle and load does not exceed 6 tons 15 cwt. (at which the correct tyre pressure is 90 lb.) or else you must convert to 34 by 7 tyres running at 95 lb. pressure. Do not delay. Tyre Control takes a very poor view of this kind of thing. FINAL DECISION TO SUPPLY RESTS WITH A.T.D. 0..—We obtained a permit, stamped by the Ministry of War Transport, for two tyres to be fitted to our vehicle. On calling at our Authorized Tyre Depot, it refused to supply, on the ground that the tyres were not worn out. Has the A.T.D. the power to override the Ministry permit in this matter? A .—This is a common error on the part of vehicle operators. The " per. mit," as you call it, was not a_permit at all. It was merely an application form, which is stamped by the M.O.W.T. to prove to the A.T.D. that the vehicle is fuelled in its district. The stamping of the form merely conveys this information and does not constitute a Permit to buy. The M.O.W.T. has no power to authorize the purchase of tyres, Such permission can be obtained only from Tyre Control or the A.T.D. Having produced the stamped application to prove to your tyre depot that your vehicle is fuelled in the district, it is then the Depot's responsibility to decide whether replacements are justified or not.
A TYRE CONTROL RULE THAT NEEDS REVISION 0.—Our vehicle sustained a burst tyre when about 150 miles from its base. In accordance with tlib usual breakdown practice, the driver went to the .nearest Authorized Tyre Depot to obtain a replacement. It refused to supply, pointing out that he had a spare tyre and could not, therefore, be regarded as a breakdown case. He pointed out that he had a night journey to do and did not wish to risk it without a spare, but this argument was of no avail. During the journey he sustained a puncture in another tyre, and, because he now had no spare, the driver was obliged to continue. Needless to say, the tyre was ruined. Was the A.T.D. in order. If so, surely this rule should be relaxed.
A .—Yes, so far as Tyre Control rules stand .at the moment, the A.T.D. was not allowed to supply. We quite agree that this point needs revision. The idea seems to be that the driver must risk running without a spare until he gets back to the Authorized Tyre Dealer with whom he is registered. We fail to see what good purpose is served by this arrangement, as it makes little difference to our national tyre stocks whether the tyre be supplied by the one A.T.D. or the other. In your case the second tyre would have been saved if the driver had been granted a spare.
WHY DO NEAR-SIDE TYRES
WEAR FASTER? . .
Q.—We operate a large fleet and keep ,careful tyre records: from these, we have noticed that the near-side tyres do not give quite such good mileage as those on the off side. The difference is not great on individual tyres, but when totalled up or the whole fleet it represents a fair loss. Can you suggest the reasons and a cure?
A .—There are tworeasons but, I am afraid, no cure. The near-side tyres are run nearer to the gutter than the off-side tyres, consequently they are running amongst the abrasive deposits (small flints, etc.) which roll into the gutter from the crown of the road. This would account for slightly faster wear on the near-side tyres. Another reason is that on steeply cambered roads there is a tendency for the load to " pitch " towards the lower slope. Thus the neanside tyres carry more load than those on the off side.
HOW TO ARRIVE AT WHEEL OFFSET 0.—How is wheel offset measured? A .—Offset is the distance from the
nave plate to an imaginary line drawn from the middle of the rim on one side of the, wheel to the middle of the rim on the other side.. For all practical purposes, it can be calculated by first removing the tyre and replacing the detachable flange. The distance across the extreme tip of the flanges is then measured. Next lay the wheel, disc uppermost, on a perfectly flat surface, such as a concrete floor, and measure the distance from the nave plate to the ground. Deduct half the distance across the flanges from the distance from the nave plate to the ground. This is the offset.
SPARE TYRE AND TUBE FOR A NEW VEHICLE 0.—We are expecting two new vehicles to be delivered shortly and we are told that these will be supplied without a spare tyre and tube. We understand that the procedure for obtaining spare tyres for new vehicles is rather different from that applying to replacement tyres. Can you let us have details?
.—The vehicle manufacturer will issue a certificate stating that the vehicle is supplied without a spare cover and tube. This should be sent to your Regional Tyre Officer, giving the name of your Authorized Tyre Depot. The R.T.O. will instruct the A.T.D. to supply and the certificate (duly endorsed) must be handed in when the tyre is supplied. It is also necessary, of course, that the usual application form be filled in and stamped by the appropriate authority. Incidentally, it is a Tyre Control rule that spares may be rebuilts or partworn tyres—but not new tyres.