Here is some off the top of my head info, which isn’t really US-1 related, but centers around the real trucks the US-1 depicts:
Some trucks back 50-60 years ago used a 5-4 transmission. It was more or less a 5-speed attached to a 4-speed. With both in neutral, you would put the 4-speed in 1st, then the 5-speed in 1st. Take off, shift the 4-speed to 2nd, then the 5-speed to 2nd, and basically switch out shifting each while double-clutching (push the clutch in, take the trans out of gear, release the clutch and rev the engine, clutch in to put the trans in gear, then release the clutch again).
As well as both transmissions had a splitter, so you have a low first gear, and a high first gear. So now you’re 1st in the 4-speed, 1st in the 5-speed, splitter on both in low. You take off pegging the engine almost immediately, and split the 4-speed 1st from low to high, double clutching while dropping the splitter back to low, then grab the 5-speed and do the same, then drop the splitter in low again while taking the 4-speed to 2nd. Before you got through an intersection at 10 MPH, you may have shifted the trans and splitter 8 or 9 times.
And to further complicate matters, semi’s drive from the middle axle, and sometimes, that axle also has a splitter. So then you can switch that between high and low as well. They also have an interlock that will engage and drive both rear axles.
The most I heard about was a truck that had 72, yes.. seventy-two, gears in it..
The 3925 and 3926 are belly dumps. There was a time, which some of you may remember, that these had no safety’s on the clam shell. It wasn’t out of the ordinary for a trailer to dump a load out in the middle of the road. Or the highway..
Modern semis have brakes that are “always on”. They use an engine driven air compressor and tanks to store and use air pressure to release/operate them, so that in the event of an air leak, the brakes will default to apply.
This wasn’t the case 50+ years ago. Trucks were “always off”, so if it lost air pressure, they effectively lost their brakes.
Back in the 80’s, a lot of trucks ran 2-stroke diesels. Like the Detroit Diesel series 71.. Notably a Detroit 8V71.. Just thinking of one of these screaming by you at 55 MPH on the highway… Imagine 8 weed eaters wide open throttle, except the engine on the weed eater is 71 cubic inches, per the 71 in 8V71 (V-8 at 71 CID per cylinder, or 568 CID).
If you ever watched the movie Mad Max, trucks in the 70’s and 80’s used air starters. When Max gets the truck for the escape scene, you can hear it while he starts the truck. There are few things in life as satisfying as hearing an air starter screaming.
If you’re into cars and feel goosebumps looking at a huge 6-71 or 8-71 popping out of a hood, these were developed by GM for use on old Diesel engines like the 8V71.. Notice the similarity..
The US-1 truck rims are modeled after 5 stud 2-piece “rims”. This enabled a “faster” tire change. The hub/drum of the axle was actually the “rim” of the wheel. The tire mounts to a disk and those are slid into the hub. A locking wedge and bolt are then threaded on the stud.
There was also a 20.5” size split rim known as the “Widow Maker”. A one piece rim that the tire goes on and a locking retaining ring secures the tire. These rings were known to explode off while inflating the tire, hense the moniker. I’ve seen tire safety cages with after effects of these rings coming off. And I personally had a set on a service truck I owned. Never so happy to ditch those for some Budd 22.5’s..
This changed into a one piece rim/tire with “Budd” style 2-piece lug nuts. These were in LHT in the driver side, and were prone to cross thread and strip out. An upside was the fact you can change an outer tire on the rear axles without lifting the truck with a jack.
In current form, trucks use 10-hole stud piloted rims with conventional studs and lugs.
Some trucks back 50-60 years ago used a 5-4 transmission. It was more or less a 5-speed attached to a 4-speed. With both in neutral, you would put the 4-speed in 1st, then the 5-speed in 1st. Take off, shift the 4-speed to 2nd, then the 5-speed to 2nd, and basically switch out shifting each while double-clutching (push the clutch in, take the trans out of gear, release the clutch and rev the engine, clutch in to put the trans in gear, then release the clutch again).
As well as both transmissions had a splitter, so you have a low first gear, and a high first gear. So now you’re 1st in the 4-speed, 1st in the 5-speed, splitter on both in low. You take off pegging the engine almost immediately, and split the 4-speed 1st from low to high, double clutching while dropping the splitter back to low, then grab the 5-speed and do the same, then drop the splitter in low again while taking the 4-speed to 2nd. Before you got through an intersection at 10 MPH, you may have shifted the trans and splitter 8 or 9 times.
And to further complicate matters, semi’s drive from the middle axle, and sometimes, that axle also has a splitter. So then you can switch that between high and low as well. They also have an interlock that will engage and drive both rear axles.
The most I heard about was a truck that had 72, yes.. seventy-two, gears in it..
The 3925 and 3926 are belly dumps. There was a time, which some of you may remember, that these had no safety’s on the clam shell. It wasn’t out of the ordinary for a trailer to dump a load out in the middle of the road. Or the highway..
Modern semis have brakes that are “always on”. They use an engine driven air compressor and tanks to store and use air pressure to release/operate them, so that in the event of an air leak, the brakes will default to apply.
This wasn’t the case 50+ years ago. Trucks were “always off”, so if it lost air pressure, they effectively lost their brakes.
Back in the 80’s, a lot of trucks ran 2-stroke diesels. Like the Detroit Diesel series 71.. Notably a Detroit 8V71.. Just thinking of one of these screaming by you at 55 MPH on the highway… Imagine 8 weed eaters wide open throttle, except the engine on the weed eater is 71 cubic inches, per the 71 in 8V71 (V-8 at 71 CID per cylinder, or 568 CID).
If you ever watched the movie Mad Max, trucks in the 70’s and 80’s used air starters. When Max gets the truck for the escape scene, you can hear it while he starts the truck. There are few things in life as satisfying as hearing an air starter screaming.
If you’re into cars and feel goosebumps looking at a huge 6-71 or 8-71 popping out of a hood, these were developed by GM for use on old Diesel engines like the 8V71.. Notice the similarity..
The US-1 truck rims are modeled after 5 stud 2-piece “rims”. This enabled a “faster” tire change. The hub/drum of the axle was actually the “rim” of the wheel. The tire mounts to a disk and those are slid into the hub. A locking wedge and bolt are then threaded on the stud.
There was also a 20.5” size split rim known as the “Widow Maker”. A one piece rim that the tire goes on and a locking retaining ring secures the tire. These rings were known to explode off while inflating the tire, hense the moniker. I’ve seen tire safety cages with after effects of these rings coming off. And I personally had a set on a service truck I owned. Never so happy to ditch those for some Budd 22.5’s..
This changed into a one piece rim/tire with “Budd” style 2-piece lug nuts. These were in LHT in the driver side, and were prone to cross thread and strip out. An upside was the fact you can change an outer tire on the rear axles without lifting the truck with a jack.
In current form, trucks use 10-hole stud piloted rims with conventional studs and lugs.
