WHEEL WOBBLE

Evening Post, Volume CXVII, Issue 111, 12 May 1934, Page 17

WHEEL WOBBLE

"FLAPPING" AND "TRAMP"

, Wheel wobble troubles, which were once so prevalent, have been largely overcome and now make themselves apparent only when factors such as wear, unduly low tire pressures, or other faults are present. At low speeds tho phenomenon may consist of a' wobble, pure and simple, the steering being deflected alternately to the left and right at a rate of just a £envibrations per second.

A High-speed wobble is of quite a different character, being far moro rapid and more violent; it is usually accompanied by tramp. Thus, in addition to "napping," left and right, tho wheels move up and down alternately and the front axle vibrates Jiko a sec-sau\ Many cars' which are normally safe will develop this wobble if over-driven downhill at a speed materially higher than their normal maximum.

As wobbles is fundamentally, due to the gyroscopic effect produced when a front wheel is tilted at an angle, it is often stated that the new' systems of independent wheel springing should enable tliis trouble to be entirely overcome. The point which is missed is that although each wheel ■ may be so connected as to move up and down in a straight lino, tilting can only be obviated if the chassis to which it is attached is sufficiently stiff to remain horizontal. Otherwise, tramp and wobble can- occur with independent wheel springing, a twisting movement of tho front end of the frame taking the plaeo of the usual criss-cross axle vibration. For those reasons concerns which have adopted springing of this typo have so braced tho chassis as to maUe it nearly twice as stiff as that ut' a couvoulioiially sprung tar.