Not having driven one at that speed, I can't say. I'd have thought if thee
was an advantage to slowing the engine and getting better mileage, the
engineers would have done so today, but may not have back in the days of
cheap gas 50's and 60's. At lower RPM, it may not have the power to cruise
at 70 at a lower speed.
FWIW, my Sonata turns 2200 at 70
LeSabre turns 2000
Regal turns 2000
I had a rental Dodge Stratus a few years ago and it too was at or near 3000
rpm at 70
It means the same in the dictionary and in practice as it did 20 years
ago. Tell me how it was different 20 years ago?
I never said overdrive was better. I just said it means the same now as
it ever did, and that is simply that the transmission has ratios less
than 1:1. That is all it ever meant, no more and no less. And it means
exactly the same thing today.
I'm talking in practice, not in dictionary terms. Years ago, you paid extra
for an "Overdrive" transmission and it was used on the highway to save gas.
In practical terms, using overdrive today is not necessarily a good or a bad
thing and it may not be best for a particular car. To say, as the poster did
"I whish it had overdrive" is without merit unless you know if the car is
going to perform properly with a higher gear ratio. It is did, the economy
conscious car makers would put it in so they can get a higher number of that
window sticker. If you are putting five gears in a transmission, it matters
little cost wise what the ratio is, but it matters greatly on performance.
Just like having 8 cylinders today. Most 6's will out perform the small
block V-8's of years ago. Or a turbocharged 4. Just having a certain number
of cylinders does not ensure a given performance level.
Correct. Overdrive is anything over a nominal 1:1. Still a very meaningful
term today. As has always been the case, final drive ratio is the key, but
overdrive determines what that ratio translates to in mileage - and
Overdrive is a term meaning the transmission high gear ratio is greater than
1:1. The final drive gear ratio determines mileage and performance,
overdrive or not. Having an overdrive ratio in the transmission does not
bestow magical qualities in and of itself. It is merely a part of an
Number or cylinders is not a measure of mileage or performance either. Nor
do many other popular misconceptions such as imported cars are small and get
better gas mileage. Or that Jaguars are unreliable. Oh, wait, that one is
That's where you're missing the point Edwin. Overdrive effectively changes
the final drive ratio given that it's greater than 1:1. No, I know it does
not really change that ratio - it effectively changes it.
Mike it is you that is missing the point. I know what overdrive is and what
My point is, unlike 50 years ago, it is not necessarily a benefit in a car
today as they are designed more for optimum performance at highway speed, be
it the high gear be 2:1, 1:1 or 1:2.
Go back 50+ years ago and most cars had 3 speed manual transmission with a
high gear of 1:1. As an option, you could get "Overdrive" for highway
driving. On at least some cars, it was mechanically activated by some other
means then the shift lever on the column. As time moved on and engines
improved, some cars were given four speed transmissions. In some, but not
all, cases, the top gear was an overdrive gear and it was not an option.
Others, mostly smaller cars, still had the top gear at 1:1 because they did
not have the power to operate properly with anything higher for the final
drive.. They have to run at 2500 to 3200 rpm to make the power needed to
drive the car.
What is important is the final drive ratio. How you get there is not as
important from the consumer end. It may be a 3.08 rear, or a 4.56. It may
or may not have overdrive and no, you don't get to choose it as an option
like you could in 1953. Back then, no one really cared about fuel cost and
the government did not mandate anything as is the case today. Thus,
drivetrains are built to optimize fuel and have as high a number for highway
mileage as possible.
Now, most importantly, put all of this in proper context with the original
comment and see how it fits in.
It is exactly the same benefit today as 50 years ago. The only
difference is that today the overdrive ratio is integrated into the
transmission/transaxle rather than being a separate box as in the early
days. The fact that it is integrated rather than being tacked on makes
no difference in the function.
The advantage of an overdrive ratio in the transmission is that you can
use a lower (higher numerical ratio) final drive ratio to allow easy
starts and good acceleration in the lower gears, yet still have a lower
RPM in high gear. There is nothing magical about having an overdrive
ratio in the transmission as the same affect could be obtained by
lowering all of the transmission ratios and raising the final drive
ratio. I think the balance has more to do with the logistics of gear
sizes than anything else. Very small gears driving very large gears
places a lot of stress on the small gear and thus avoiding large
numerical ratios is probably a good thing.
However, the point remains that the 4 or 5 speed transmissions today
accomplish exactly the same thing as did the old 3 and 4 speed
transmissions with a separate overdrive gearbox. No difference other
No, what is important is OVERALL drive ratio. The final drive ratio is
easily offset by the transmission ratios and isn't the final determinant
of how fast the engine spins for a given road speed. Unfortunately,
some people use final drive ratio as a synonym for overall drive ratio,
but that doesn't make it correct.
Here is the correct definition:
No shit, you figured out what I've been saying. It may or may not be
integrated. If it works, it is, if it does not work for that particular
drivetrain in that particular vehicle, it is not. It is not offered as an
option any more.
By golly, I think you've got it! I knew you had it in you. I've not taken
a survey of gear ratios, not do I intend to, but they may or may not be an
overdrive ratio. It is what drives that particular vehicle the best.
And Matt would never leave a nit unpicked. (neither would I)
Great, I'm glad you agree that your statement that overdrive today is
different from overdrive of years gone by was incorrect. Overdrive is
the same now as it was 50 years ago functionally. Only the packaging
has changed. I knew you'd come around!! :-)
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