Should I buy Hyundai?

Yes, I did for a reason. The person that stated he wished he had overdrive made his statement without saying anything more. My point is, having overdrive is not necessarily a benefit. It may be, in the right engine and gear combination, but it may hurt performance in other combinations. There are many factors to take into consideration. Putting in a very high gear ration in and of itself is the necessarily a good thing.

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.

Maybe they ought to re-invent freewheeling.

L.

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 engineered package.

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 true.

I believe overdrive is a ratio LESS than 1:1, not greater than.

Matt

Yes, I was thinking in terms of low (first gear) and high, in which case it is higher

Yes, people refer to the gears as high or low, but the actual ratio is lower for higher gears.

Matt

Unless you are standing on the other side of it.

I made the original comment about wishing for an overdrive. Since 5th gear apprently technically is an overdrive, what I should have said is that I wish the Elantra had a 6th gear. To me, it just feels like it needs one spinning 3000 RPM before it even gets to 70.

A.

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

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 it does.

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 than packaging.

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:

I agree, please do this! :-)

Matt

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!! :-)

But of course! :-)

Matt

But the original subject was "is overdrive needed?" It is not always a benefit. Not every car has it, no matter the number of gears in the transmission.

Sure it is a benefit. It allows a lower (higher numerically) final drive ratio which allows a lower 1st gear overall drive ratio to making starting out easier.

Matt

It fits as I've been saying all along. We're not really saying much different. I understand well the history of overdrive, but the overdrive in a car today serves the same purpose as it ever did - to reduct engine rpm and save fuel. Even in the good old days it served the purpose of saving fuel. You are correct that today's engines are more efficient, but they are indeed designed with an overdrive in mind.

The final drive ratio is a determining factor but not the single determining factor. Regardless of what the final ratio is, an overdrive is still going to have the same effect of dropping engine rpm's at cruise. That's all overdrive was intended to do.

Sure, but not every car can take advantage of it. Some do, so don't. Other factors are important also.