THE STABILITY OF AGRICULTURAL TRACTOR-TRAILER COMBINATIONS DURING BRAKING ON THE ROAD

The braking performance of an agricultural tractor was measured when towing a four-wheel balanced trailer and a two-wheel unbalanced trailer using tractor brakes only and using trailer brakes operated from the tractor's hydraulic system either independently or coupled to the tractor brakes. Tests were carried out when braking in a straight line and on bends on an average to good road surface and on a slippery surface. Deceleration, deviation of the tractor rear wheels and the forces between the tractor and trailers were measured. Braking performance was found to be generally better in terms of deceleration with the unbalanced trailer, confirming previous results. However, there was less difference between trailers in terms of deviation of the rear wheels of the tractor when braking on bends. This was explained by the measurements of the forces between the tractor and trailers. The advantages of adding trailer brakes were more marked on the slippery surface. It was found that it is essential that the trailer brakes should be operated by the tractor brake control if they were to be effective in an emergency. The possible effect of fitting brakes to the front wheels of tractors was considered. (Author/TRRL)

• Corporate Authors:

  British Society for Res in Agricultural Eng

  Wrest Park
  Silsoe, Bedford,   England 
• Authors:
  • Dwyer, M J
  • Berry, R H
• Publication Date: 0

Media Info

• Features: Figures; References; Tables;
• Pagination: 15 p.

Subject/Index Terms

• TRT Terms: Brakes; Braking; Control; Control devices; Curves (Geometry); Deceleration; Highway curves; Measurement; Motor vehicles; Pavements; Stability (Mechanics); Surface course (Pavements); Tests; Tractor trailer combinations; Trailers; Truck tractors; Vehicle rear end; Wet weather; Wheels
• Uncontrolled Terms: Front; Rear; Wet pavements
• Old TRIS Terms: Rear wheels
• ITRD Terms: 2872: Bend (road); 1361: Brake; 1874: Braking; 3874: Control; 5416: Deceleration; 9025: Front; 6136: Measurement; 9067: Rear; 6255: Test; 1214: Tractor; 1203: Trailer; 1646: Vehicle handling; 3015: Wet road; 1372: Wheel
• Subject Areas: Highways; Motor Carriers; Pavements; Vehicles and Equipment; I91: Vehicle Design and Safety;

Filing Info

• Accession Number: 00391228
• Record Type: Publication
• Source Agency: Transport Research Laboratory
• Report/Paper Numbers: Monograph
• Files: ITRD, TRIS
• Created Date: Jan 30 1985 12:00AM