Gear Ratios: Misinformation at its worst.

Think I’ll be coming up a little short in my uncles 76 KW this weekend......

clearly doing it wrong though because there’s no way the truck must of been able to make money in the last 45 years according to these guys....

 

Thats what the Diamond T will do with both knobs in od at the dash. A blistering 56 mph.

Same rear gear with the 5x3 and 10.00-22’s

 

Its called torsional activity!

 

Not super helpful, however related to ratio. If you're ever around Nova Scotia stay away from Truro truck shops. We brought out 08 international 4300 in for a transmission replacement. They told us switching to a 10 speed from a 6+1 would be cheaper and we'd prefer it. Got the truck back (3 weeks later mind you) and the truck wasn't able to go over 99 at 28k rpm, they put the wrong gear ratio trans in without even checking to make sure it would work. Took them another 2 weeks to put a rebuilt 6+1 back in that works. All together over a month of work loss and $7000 wasted because the truck shop couldn't even get gear ratio correct.

 

it’s got a 290 in it, so Not like you can get much more then that anyway would love to see a someone run one of those down the road with a 2.xix gear at 1200 rpm.....

 

Let's see the torque curve, I'd be willing to bet it's way above 1200 rpm,

 

As for overdrive that simply means the drive shaft is turning faster than the crank.
Double overdrive means 2 gears above direct vs. single overdrive has 1 gear above direct, the numbers don't matter in that respect.

In direct the torque generated at the crank goes straight through to the drive shaft and therefore more efficient, Over drive creates more heat [wasted energy]

quote -Torque is simply a force acting on something from a distance (i.e. a piston pushing down on a crankshaft, using that leverage to rotate it), while horsepower is torque multiplied by RPM, or a measurement of how quickly an engine can accomplish a certain amount of work. ...Jan. 17, 2018 -quote

TORQUE is king,, HP don't mean squat without it.

 

With the early development of cars and the almost universal rear-wheel drive layout, the final drive (i.e. rear axle) ratio for fast cars was chosen to give the ratio for maximum speed. The gearbox was designed so that, for efficiency, the fastest ratio would be a "direct-drive" or "straight-through" 1:1 ratio, avoiding frictional losses in the gears. Achieving an overdriven ratio for cruising thus required a gearbox ratio even higher than this, i.e. the gearbox output shaft rotating faster than the engine. The propeller shaft linking gearbox and rear axle is thus overdriven, and a transmission capable of doing this became termed an "overdrive"

Maybe what you are referring to is ''how it was done mechanically'' but not why it's called overdrive.

 

Overdrive (mechanics) - Wikipedia