Another case of the shakes WITH reference to the letter
Page 29
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from D. G. Bonner (CM, November 29) and the experiences of H. W. Wilson and T. Lyles (CM, January 3) concerning front-end shakes with certain Bedford and Dodge Vehicles.
I experienced the same problem with two Commer VAAS 762 models.
These were "fitted with optional 9.00 x 20 radial tyres, the wheels used were heavier than the normal Commer type.
When checked, the radial lateral run out far exceeded acceptable 3mm maximum. cessive vibration w transmitted to the front beam, the flexible characteris of which exaggerated the cor tion.
Furthermore, the poor 'at: stability of the radial ty caused a "jelly-like wobble".
The manufacturers were helpful, so I decided to stil the front springs by adding a to replace the radial tyres % 14pr diagonal (cross) ply tyre These modifications cc pletely cured the problem the trouble did not reapr during the six years the vehi remained in service.
Before the changes w made, the vehicles were un: above 30mph when unladen.
Regarding H. Wilson's lett( which he says he cured vibration on a Bedford TK 1 by altering the castor angle, worth mentioning two points
The castor angle increi when the vehicle is laden as deflection of the rear sprinc greater than those at the f and wedges, if fitted, mus. installed with the thin edg the front.
Secondly, due to the kin: inclination, the front of vehicle lifts slightly on turn weight to the front of the vel improves stability and damr wheel vibration — but tend affect castor action.
R. HARDING
Technician engineer Burnham, Bucks