1977 Kenworth C500 Off Highway Truck

kw1a.jpg - 18620 Bytes
1977 Kenworth C500 off highway log truck
kw1a.jpg - 18620 Bytes

If you know much about trucks and the timber industry, you are probably amazed about the lack of mention of Kenworth on this site, at least until you got to this page. Kenworth and Peterbilt are names that go with Paccar of Seattle and their premium grade trucks were invented for the West Coast where trucks that are trucks were invented. Kenworth and their companion Peterbilt dominate the log truck market. The historic reason was simple, they offered big diesel engines and cabs that didn't fall apart on bad roads.

The truck here is made for off highway use, though much of the truck is the same as the highway models. This truck is most like what Kenworth calls the Constructor or C-500 model which is made for the construction industry. Notably absent are the fairings for aerodynamics, and all the things that hang on the frame are hung high. Set back axles are also typical of this model.

What makes this truck special really are simply the axles. To be sure it has a double steel frame, but that can be ordered on a highway truck as well, but the tandem drive assembly is a 60,000lb monster that takes 12 x 24 tube type tires and provides an overall width of around 9 feet. The 11 foot bunk hangs out some but not a lot. The front axle is likewise a heavy weight and is set back more than is common on highway trucks.

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1977 Kenworth

This keeps the wheelbase down and makes the rig turn shorter, but is not favored on highway rigs because 'bridge formula' weight rules usually allow a truck to haul more if its wheelbase is longer. Anyone, it seems, that builds a bridge for 'off highway' use had better make it strong enough that subtleties like wheel base don't matter, as the nature of off highway trucking is that you stack on the truck whatever will fit, or whatever the truck will hold up, not the presumably lesser amount that the weigh master would approve of.

The front bumper is made of real steel, and has a 'follow me' hitch center front that is hooked to the frame well enough that you can tow this puppy with a D-8 and the truck will come. Heavy towing of a highway truck is more problematical. Often finding something really solid on the front is not that easy and one still has to worry about the axles coming off the truck if it is mired in the mud, so I have seen highway trucks with a cable run under the truck and anchored to the rear axles. In this fashion when you hook on with the D-8 and pull, the cable comes up tight and sort of lifts the truck out of the mud, and the rear axles which were likely mired have the cable directly attached to them so the stresses of the tow are not attempting to pull the truck apart. With the mounting of the 'follow me' hitch on the front of this truck, and the double steel frame, I wouldn't worry about pulling it part if one is towing with a mere D-8.

Peerless trailer with Page Supension
Peerless Trailer

Remarkably, you won't find anything under the hood that is a surprise. This truck has what appears to be a very standard Cummins 350 followed by an equally generic 15 speed Road Ranger transmission. Gear ratios in the rear ends make of for the difference. These giant tires would be destroyed if driven over 50 MPH, and since the typical operating speeds are less than 25 MPH, power is not a problem. Those monster powerplants are there in an attempt to maintain 'highway speeds' on hills. A very tall rear end ratio will make this truck a real stump puller at a sacrifice of high speeds, but that is no sacrifice.

Peerless trailer

Peerless has been making log trailers since the mind of man run not to the contrary, and this trailer is no exception. The trailer is really very similar to the highway log trailers only its been on steroids. The brake lining is 10 inches wide on cast steel shoes, and the slack adjusters are of a jumbo size providing a longer handle than the standard truck S cam. Likewise the shaft diameter of the cam is larger than the standard truck.

The wheels are Budd wheels but of the jumbo bolt circle size (larger center hole and jumbo lug bolts that require a 1 3/4" socket for the outer nut and a 15/16" square for the inner nut. The wheels take 12 x 24" off highway tube type tires.

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