Tire Equipment For Fire Apparatus*
Heaviest Tire Not Always the Most Serviceable—Only Standard Solid Rubber and Pneumatic Cord Types Suitable, According to the Author—Cushion Wheels Very Essential to All Apparatus
I BELIEVE that when a member of this association is called upon to prepare a paper on any subject that deals directly or indirectly with the work or interests of the membership, that he should adhere strictly to his own personal experience. If he is governed by this principle he will be in a position to back up any assertion he may make, so if this paper contains any information of value it will be information gained by practical experience and not from speculation or theory.
The question of tire equipment is one that, to some extent, must be governed by local conditions and circumstances. The tire equipment that might prove efficient and satisfactory on a converted touring car or commercial truck would be sadly out of place on a standard built fire truck.
We all appreciate the fact that the fundamental principle underlying the use of rubber as a tire material is to eliminate noise and road shocks. Excessive vibration is caused by uneven roadbeds. The shock or recoil is first taken up by the wheel and then transmitted to the frame and motor. The load carried by the truck sometimes receives serious damage from this cause. Every chief who has had experience with motor apparatus knows what vibration will do to ladder rounds, chemical connections, and pump joints. I do not believe there is any way to entirely eliminate this trouble, but it can be reduced to a minimum by proper tire and wheel equipment; that is, by taking into consideration two very essential points, namely, construction and weight of apparatus, and load imposed.
Heaviest Tire Not Best Tire
The old theory that the heaviest tire is the best tire is groundless and unproven. Tire builders have used the weight of their tires as a selling argument for years. An over-weight tire is a bill of expense from start to finish.
The subject of tire equipment and tire construction is still in its infancy; frequent changes in the blending of the materials and design are constantly taking place. What may be considered the ideal tire of today, tomorrow may be obsolete. It is but a step from the cushion tire of yesterday to the pneumatic cord of today; this same rule applies to the solid rubber types. The up-to-date manufacturers of solid rubber tires have adopted the pressed-on type to replace the demountable-rim style of construction. In making this change they have eliminated considerable weight in bolts and retaining bands, and have not decreased the efficiency of their tires. Any change in construction that tends to lessen weight without weakening or reducing the resiliency of the tire is, in my opinion, a change for the better. Every pound added to the weight of the wheel requires an extra pound of engine power to turn it over. The extra engine power in this case means added cost in maintenance and operation, without a corresponding increase in efficiency.
Only Two Types for Fire Service
Speaking from personal experience, I would say that I know of but two types of tires that will measure up to the exacting requirements of the fire department service, namely, the standard solid rubber and the pneumatic cord. There is a so-called airless tire on the market that is highly recommended by some of the builders of fire apparatus; this tire is of honey-comb construction and is supposed to be puncture proof. This tire may be all that it is claimed to be, but, as I have never had any experience with it, I am not in a position to say anything for or against it. I feel perfectly safe in recommending the solid rubber types for use on standard built apparatus. The type to be used, whether pressedon or demountable, is a matter of personal opinion. The advantages and disadvantages of both types should receive due consideration before either is adopted as standard equipment.
* From a paper read before the annual convention of the Dominion Association of Fire Chiefs.
The Demountable and Pressed-On Types
The demountable type has some features in construction that may appeal to the purchaser. With this style of tire no extra tools are required for replacements; the rim and tire are held in place on the wheel by bolts and retaining rings or rim bands. The work of replacement can be done in any engine house by any member of the department who has mechanical ability enough to handle a wrench and hammer. In almost every case where it is necessary to replace this type of tire, new galvanized bolts and nuts are required. Should the wheels be of dual construction, the required lengths may not be quickly obtainable in the city or town where they are required. In considering this type of tire, we must not forget that the bolts and rims add considerable weight to the wheel equipment without an increase in efficiency.
With the pressed-on type conditions are altered. Powerful presses are required to remove the old and replace the new rims. Very few city shops or tire service stations have the necessary machinery for doing this class of work; this being the case, the wheel must be sent to the tire factory when replacements are needed. The wheel equipped with the pressed-on type of tire presents a far neater appearance, is lighter in weight, and, in my opinion, more efficient than the demountable-rim type.
The Pneumatic Tire
In considering pneumatic or air-filled tire equipment, I know of but one type of tire that will fulfill the fire service requirements—that is the pneumatic cord. For some time I have been acting as purchasing agent for the City of Windsor for all tires used on city cars. I might say that while acting in this capacity I have come in contact with all makes and types of pneumatic tires, and I do not know of a fabric tire that I could or would recommend for fire department use. The danger of a blow-out is always present where this type of tire is used, and should this happen to the front tire of a speeding fire truck serious results would be sure to follow. Future developments in tire construction may produce a pneumatic tire built on a fabric foundation that will deliver the required efficiency, but up to the present time I have failed to find one.
With the pneumatic cord the danger of a blow-out is reduced to the minimum. The construction of this type of tire is such that a blow-out is almost out of the question. I personally know of cord tires that have given twelve thousand miles of service without a blow-out, and the tire is still in service.
All Mounted on Cushion Wheels
In this department we use solid rubber tires; some are of the demountable type and some are pressed on; all are mounted on cushion wheels. With this type of equipment the cost of maintenance for tire and wheel equipment has been too small to receive consideration. Some of this equipment has been in service for five years, and has worked under the severest road conditions; up to the present time it has delivered one hundred per cent, efficiency. Outside of the deterioration that might be expected from the use of skid chains, contact with car tracks, and general wear, this equipment is still in condition to deliver considerable service.
I believe that tire equipment and wheel equipment are very closely related and should be treated as one unit. Tire equipment, no matter how efficient, cannot be expected to deliver the maximum service when mounted on defective wheels. I am a firm believer in the use of cushion wheels for fire service. I find that they prolong the life of the tire, increase resiliency, and to a great extent eliminate the shock to the wheel caused by side thrust in turning corners and skidding on wet and slippery pavements.
I believe that solid rubber tires of a make possessing the greatest resiliency and wearing qualities will prove the most satisfactory and efficient equipment for standard built hose wagons, ladder trucks, and pumpers.
For converted touring cars, salvage wagons, or any other exceptionally light apparatus, the pneumatic cord possesses many favorable features. It is light, resilient, and will give excellent satisfaction as to wearing qualities. In order to obtain the maximum mileage from any pneumatic tire, every precaution should be taken to see that the air pressure is maintained. The greatest enemy to the life and efficiency of pneumatic tires is lack of air or under-inflation. Bad rim cuts and breaking down of side walls are directly traceable to this cause.
Any difference in opinion that may arise regarding the merits or demerits of any special brand or make of equipment or apparatus can be threshed out in friendly discussion in open convention. In this way many important points will be brought to light that might otherwise be overlooked, and every member present will receive the benefit of knowledge gained from Fire Chief’s Master Instructor—experience.