When did Governed Trucks begin?

I believe most diesels have always had rev limiters to protect the engine from over-revving and grenading, a form of governing....

As technology advanced, manufacturers, computer engineers and companies started using more intricate forms of governing, to make trucks safer, more fuel efficient, etc...

Dont know when exactly though, sorry.

 

In the late 70's is when things started slowing down. The Formula Cummins came out, turning 1900 rpms, and that was the beginning. The older engines needed to run close to max factory rpm settings, so companies would spec the rear axle ratios to limit speed, such as 4.10, 4.33, 4.44, ect. But many drivers either put shims in the pump, or put a stinger in to turn more rpms.

 

haha till the series 60 come out in 87 .cummins has had to speed limit its motors as its bin costing the drivers to much in speeding tickets passing 60 detroits

 

In the 70's the speed limit was changed to 55 mph. Most trucks had 10:00X22 tires, which are the same height as 11R24.5 tires are today. The somewhat standard gear for a truck with a 10 speed direct drive transmission was 4.10, and 4.33 with a 13 speed overdrive. Both had a top governed speed of appx 72mph @ 2100 rpm. Some trucks that pulled heavy all the time, ran mountains, or had a small engine like a 250 or 318, had 4.33 or 4.44 rears. The top speed on these would put you in the low to mid 60s.

There wern't as many trucks at that time, plus many people had their trucks turning 2300-2400 rpm, which made them much faster. Add in that there were quite a few trucks with 10:00X20 tires that slowed them even more, meant that almost every truck ran at a different speed.

There was such a mixture of engines that clusters of trucks were uncommon. My first truck had a 250 Cummins, that when grossing appx 72k, which 73,250 was the max back then, would only do 53 mph on dead level ground. A 290 would blow my doors off. Cummins also had the 335, and a 350, which were even faster up hills and on level ground. Cat had the daddy rabbit 1693, 425 HP engine, that would leave most trucks in the dust. Some of these were geared as high as 3.70 with a 13 speed OD. Some people had a turned around transmission that had a double overdrive, which put some of the big boys well over 100 mph.

The only times you saw a pile of trucks together is when they all decided to run that way. I used to drive a single axle truck pulling a drop frame furniture trailer. Where I live furniture was the #1 industry at that time. Almost every company had their own trucks, so if you didn't like your truck, you went down the street and got a job at a company that you liked their trucks. I have ran back from Michigan with as many as 20 drop frame stick haulers in a row before. It was not unusual to see 12-15 trucks heading out on a Sunday evening together, as many drivers knew each other. We would go to the nearest truck stop, wait for everyone to get together, then head up the road.

 

this kw limited 105 kph 11r22.5 tires diffs 4.30 gear box rtl020918b,top gear ratio 0.73 .550isx torque 1850lbft. be bit strange setup on your roads lol

 

That truck would pull a hill like it wasn't there with that engine and gearing.

 

yep very hilly and winding roads