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Power Unit for Triples -A C.O.E. 4 × 4 Tractor
ISSN: 0148-7191, e-ISSN: 2688-3627
Published February 01, 1969 by SAE International in United States
Annotation ability available
Event: National West Coast Meeting
Two configurations of highway truck-trailer combinations being evaluated for hauling gcw loads over 100,000 lb are triples (27 ft trailers) and long doubles (40 or 45 ft trailers). If and when these units become legal, the triples will probably be more widely used because of their better maneuverability which would make it feasible to operate both on and off the thruways.
It is generally agreed that two driving axles would be required for the higher gcw loads in order to provide the needed gradeability and give acceptable axle component life and tire mileage. In the case of triples, the 4 × 4 tractor is the ideal power unit. Tests have shown that on snow-covered grades, the 4 × 4 has superior traction characteristics over the tandem 6 × 4 tractor having the same fifth wheel loading.
The axles for a 4 × 4 power train should provide for a 2 to 1 proportioning of the torque between the rear and front axles for equal tire tractive effort. In order to obtain optimum axle life and tire mileage, the front axle should be designed to operate as a full-time drive unit.
CitationPanny, W. and Riddle, A., "Power Unit for Triples -A C.O.E. 4 × 4 Tractor," SAE Technical Paper 690550, 1969, https://doi.org/10.4271/690550.
- Kaye Michael C. “An Investigation of Intercity High way Truck Drive Traction. ” SAE Transactions 77 1968 680548
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- Chew Norman B. “The Power Dolly Approach to High way Transportation. ” Paper 650724 presented at SAE Combined Power plant and Transportation Meeting Cleveland November 1965
- “Traction Characteristics of Trucks and Truck Combinations. ” W.H.I. Research Committee Report No. 1, January 1969 (Covers Hondo tests and 1967 Mount Hood tests).
- “Braking, Stability and Structural Integrity of Longer Combinations. ” (Covers 1967 Utica tests conducted jointly by the A.M.A. and T.T.M.A.)
- “Report on Winter Traction Tests,” January 1969 (A preliminary report covering 1969 Mount Hood tests conducted by the W.H.I.)
- Kaye Michael C. “Intercity Truck Tire Operating Cost.” Research and Development Report #09-68 Freightliner Corp.