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I'm up in Naknek, AK working commercial seafood in a seasonal office and my vehicle to drive is a '93 Ford Arerostar van. This baby has a manual transmission, 4-speed with "overdrive". It got me thinking, why "overdrive" and simply not a 5 speed? It certainly feels and acts like a 5th gear.
Looking back I remember when "overdrive" was more common but haven't heard the term in 20 plus years.
Anyone know why?
Is there a modern vehicle with "overdrive"
Sure it is just another gear..............or is it????
Just like a granny-gear on a bicycle will give you a torque-advantage/speed-disadvantage, and the highest gear on the same bike will give you a speed-advantage/torque-disadvantage...........the same applies to car transmissions.
With a car, of course fuel-mileage is a factor. Once the momentum of a vehicle gets you up and running, the amount of engine power you need to maintain this speed, in many cases, is quite small. So the gear with the best speed-advantage, a very high gear, is the best thing. A UUUUGE driving-gear and a tiny driven-gear, that is one of the keys to great gas mileage.
Sure it is just another gear..............or is it????
Just like a granny-gear on a bicycle will give you a torque-advantage/speed-disadvantage, and the highest gear on the same bike will give you a speed-advantage/torque-disadvantage...........the same applies to car transmissions.
With a car, of course fuel-mileage is a factor. Once the momentum of a vehicle gets you up and running, the amount of engine power you need to maintain this speed, in many cases, is quite small. So the gear with the best speed-advantage, a very high gear, is the best thing. A UUUUGE driving-gear and a tiny driven-gear, that is one of the keys to great gas mileage.
Granny gear is first gear on a manual transmission in a pickup, only time you use first gear is if you’re towing or carrying a heavy load in the bed, otherwise you start out in second gear.
Once the momentum of a vehicle gets you up and running, the amount of engine power you need to maintain this speed, in many cases, is quite small. So the gear with the best speed-advantage, a very high gear, is the best thing. A UUUUGE driving-gear and a tiny driven-gear, that is one of the keys to great gas mileage.
There is trade off, as the speed increases the friction increases. Thus the power and fuel consumption needs to increase as the speed increases. A very powerful engine may be able to maintain 150MPH at low RPM's but it's still a huge engine using a lot of fuel
There is trade off, as the speed increases the friction increases. Thus the power and fuel consumption needs to increase as the speed increases. A very powerful engine may be able to maintain 150MPH at low RPM's but it's still a huge engine using a lot of fuel
Certainly. But at reasonable highway speeds, most vehicles on the road could use a slightly taller top gear and get a bit better gas milage. Taller gearing improves fuel economy up to the point that you can't maintain speed in that gear; in the vast majority of cases there is no point at which a lower gear delivers better fuel economy.
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