The Stovebolt Site Forums The Parking Lot Big Bolts Power for the big bolts prior to the 261s etc.

I am just curious how the big trucks like the 6400 size and buses up through the 1940s early 50s got around hauling heavy loads being limited in engine horsepower. I know my 6400 with a good running 235 is underpowered when under a load. Did the older trannys/rearends have lower gearing?? My 53 6400 has a 1955 4 speed in it. I know that 235 will pull way down when climbing hills with a load on it. Did they have lower gearing?

The 4-speed in the '55 and '53 is exactly the same. These trucks heavily loaded did not go very fast. Things like the deep granny 1st gear and 2-speed rear axles make it possible for them to move the load.

Lots of gears, and really slow speeds! I worked on a big Ford grain truck once, a 1951 F-8 or bigger with about a 24-foot box and dual rear axles, IIRC, with a Lincoln flathead V-8 engine, a 5-speed main transmission, a 3-speed Brownie, and a manual-shift 2-speed rear end. I've seen pics of trucks like that, and the early semis, pulling the Grapevine hill with the drivers standing out on the running board steering through the window to get away from the heat inside the cab. The truck was running 3 or 4 MPH with the hand throttle set wide open, in whatever gear it needed to pull the hill. My grandfather hauled cases of bottled beer from Milwaukee to Nashville after Prohibition was repealed on a couple of 34 Chevy stake-body trucks with what was probably the old 207 engines. They were slow, but they got the job done! One truck would pull hills much better than the other one for some reason. On a particular hill in Kentucky, the sheriff would stop any truck that had to go to first gear to pull the grade, and weigh it. The sluggish truck would get a legal load, and crawl up the hill. While it was pulled over being weighed, the other one with the big overload would sail on by in 2nd. gear! They got caught and fined eventually, but they made a lot of trips up that hill with an overload before that happened!
Jerry

I find that there are some today that don't do too well on the big hills. I guess in the early days life wasn't conducted as the mad dash it is today! I have always wondered why the early heavier trucks had larger rads etc. considering the small engines. I guess if they were running at near full throttle for long periods of time, they would need extra cooling.

That's a great story Jerry!

I worked on and drove farm trucks for a while around 1980 and even with V-8s it was hard to get 18,000 to 20,000 pounds up to the speed limit. The boss once told me to not worry about the speed limit, when loaded you'll never get one of these trucks to go that fast.

Most of that fleet were F-600 or F-700 Fords with 330s and 4- or 5-speeds and 2-speed rears. There were a couple of Internationals, one was a '53 with a six that was rarely used and the other was a tandem axle with a 394 and a 5+4 setup. That tandem was the fastest truck in the bunch.

Except for the old International they were all V-8 powered and still relatively slow compared to the cars and pickups I was driving at the time. The '53 International was the slowest and carried the smallest payload.

This was an agricultural operation and they paid almost nothing by the hour. Back then they ran a dozen gas powered trucks. Today that same operation has three or four Diesel powered trucks that are lengthened semi tractors with grain beds added. As it became practical to haul larger loads with a single truck the cost of labor was also going up.

Back in the day equipment was expensive and labor was cheap. Today equipment is expensive, but not so much when compared to the cost of labor. Last time I talked to them trucks were actually costing them about the same 25 years later as they did when I was working there. Today's labor cost creates demand for trucks that can do the job with fewer people on the payroll.

Or at least that's my analysis of the situation... I left the trucking operation at the end of 1981 so its not like I'm close to it any more. The boss remains a good friend whom I see only once every five years or so.

That's also true of the big diesels of today. The cooling system has to be able to dissipate approximately 1/3 of the heat the fuel develops as it burns, and a non-turbocharged engine loses almost a third of its energy out the exhaust. The heat simply can't be trapped in the engine long enough for the pistons to absorb the energy and apply it to moving the vehicle. If somebody would just devise a way to trap and use all that energy the cooling system and exhaust throws away, we could go three times as far on a gallon of gas (or diesel, or propane, alcohol, etc.) A turbo grabs some of that exhaust energy and recycles it back into intake manifold pressure, but it's not very efficient, even with an aftercooler in the mix.
Jerry

Another problem with these older trucks was getting them stopped. They did not have the brakes that we have today. For that reason it probably was good they didn't go that fast. They worked every where they went.
Jim

Thanks for the response guys and the great story Yes I agree due to breaking issues it is best to not be going all that fast.

5 speed mains, 3-4 speed auxiliaries, and then throw in 2 speed MANUAL shift rears and thats why those old truckers were a special and proud bunch. You had to be a much better driver/operator in those days than is necessary today reclined in your Bostrom air seat, CB & CD and a condo on the back. Talk about a tough life...!

That B-73 Mack 3-axle that I learned to drive on had a 262 Cummins engine and a TriPlex transmission, 5X3 in the same box, with two shifters for 15 forward speeds and 3 reverse ratios. We called driving it "Rowing it with the shift lever"!
Jerry