MEASURING VEHICLE MILEAGE.
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Accurate Knowledge of the Mileage Run is a Vital Tyre Economy. Factor in Attaining
MANY users pay but small attention to the mileage covered by their vehicles, and when asked for information on this point are usually extremely vague in their replies. This is an unsatisfactory state of affairs, as running costs must necessarily, to serve any useful purpose, be based upon the miles run. Similarly, it is essential that adequate comparisons can be made between the mileage a one tyre and another. It is of little use complaining if a certain tyre wears out rapidly when exact figures regarding its workcannot be produced.
One of the best type of instrument for registering mileage is the hub-odometer. This is usually supplied coin' plate with the particular form of hub cap which is neeessary to replace one of those existing.
Amongst the makers of this type of instrument are Henry Miller and Co., Mileometer Works, Walmer Road, London, W.11, the manufacturers of the Dreadnaught odometer o who have now brought out a new model known as the Super Dreadn !tight. This instrument consists of a recording mechanism contained in an inner dustproof case with an unbreakable transparent cover, so that if by any chance the external magnifying lens on the cap be broken, dirt and water do not enter the mechanism. The train of gears registers up to 100,000 miles and then repeats.
An interesting refinement is the provision of a Hoffmann journal ball bearing, which prevents wear on the spindle. The base is solid with only one minute hole through which it is possible for grease to pass, and this is filled by the spindle of the operating pawl. The most drastic tests up to 4,000 lb. pressure have been carried out in an endeavour to force grease through from the interior of the hub to the dial of the instrument, but without this being effected. Thus one of the greatest difficulties in the construction of such instruments has been overcome.
The new form of drive absorbs any end play between the wheel and the stub axle. Cams are employed for the operation of the pawl, its movement being controlled in each direction.
Space forbids further reference to this interesting model, which we hope to describe in 'fuller detail in a subsequent issue. It is important to note, however, that the guarantee has been increased to two years, whilst it is guaranteed for the life of the vehicle against destruction through collision.
Another instrument which has proved very popular in America and is marketed in this country by Defarkt and Co. *(London), Ltd., 98-100, Clerkenwell Road, London, RCA, is the Veeder.
Its chief features are a patented stuffing-box for preventing leakage of grease into the operating mechanism, absolute sealing of the register by means of a lead ring forced on under great pressure, a glass or bezel 3-16-in, thick similarly secured and water and oil tight, large figures, and a guarantee of 10,000 miles against oil and water leakage. It is driven by a pin screwed into the nut at the end of the stub axle, and can be supplied for practically all types of vehicle.
Davenport Accessories, Ltd., 105, ClerkenwelI Road, London, E.C.1, make various types of recorders, including odometers and others intended to be driven from gearbox, cardan shaft, brake-drum shaft, worm tail shaft, or, in fact, any moving part with a definite gear ratio to the road wheel.
The heavy models have worm retluc.. tion gear and ball bearings. The odometers can be obtained for fitting to existing hub caps, or are supplied already equipped with caps. They record mileage in both directions, and are supplied with a striking pin for fitting to the axle of the castle nut. Special models are provided for the Ford and Morris.
Mileage recorders of the hub-cap and worm tail shaft types are marketed by the Speedometer Supply Co., Ltd., 12, Oreat Q.peen Steet, Kingsway, London, W.C,, for the light Ford van and ton truck, whilst special models are supplied for-the Morris truck and other heavier vehicles.