Too high or too low gear?

Question

When driving around town I often find that the while one gear seems too low & rev's like mad, the next gear seems too high and chugs too much.

So here's my question... Which is better for the engine and which is more fuel efficient?

Thanks for the comments so far. I'm probably not explaining myself very well so will try again with an example...

When travelling at constant 25 mph, second gear requires a lot of rev's to maintain speed. However, in 3rd gear I need almost as many rev's to stop the car from stalling, and must maintain speed using the clutch. Does this make things clear?

And thanks for the advice to get an Automatic and learn clutch control but my driving skills aren't the issue. I only have 11 years experience but am quite proficient :-D

Answer 1

I know exactly what you mean. I would suggest choosing the lower gear. There is also a safety issue here. In the lower gear you will start to slow down as soon as you take your foot off the accelerator. In a higher gear you get less "engine braking" and don't really slow down until you apply the brake. Thus you can stop more quickly in a lower gear.

As you've been driving for 11 years you will probably realise that the exact speed for a particular gear depends on the model.

Lower gear would definitely be better for the engine (as marinespill states), but it doesn't really matter: car engines last for ages. Also, it's not clear cut as to which uses less fuel. Car engines are more efficient at higher revs but frictional (viscous) losses are greater. When driving on a clear road it is best to get through the low gears as quickly as possible and then use the highest gear at which the car does not chug.

Answer 2

You need to adjust your speed, you have to keep with the flow of traffic, not travel at exactly the same speed as the car in front. I don't think I've ever had a problem where i couldn't decide which gear was best ! Mind you, I've only been driving for 25 years so i guess there is time yet.

Your car will have between 4 and 7 gears, surely there is one in there thats ok ?

Perhaps you need an automatic ?

If your "revving like mad" in one gear, I guess you mean it going at >4000 RPM, changing up will take the engine own to about 2000 RPM, perfectly fine for all car manouvers.

For fuel efficiency you want your engine to be between 1000 and 2000 RPM but without being laboured, so going up hill its better to be at 3000 RPM than labour at 1500

Answer 3

Third gear should be prefectly adequate for 25mph. If the car is chugging and you keep needing to use the clutch to keep it going you need to get your car looked at.
I would use 4th gear in a 30 limit in both my wifes 1.8 focus and my BMW 530.

As for which is best, it is better to keep the car in a lower gear to prevent the chugging that you get when the car is going too slow for a particular gear. This chugging is not good for the engine and is also not very fuel efficient so you will probably use more petrol keeping the car in a higher gear it is not comfortable in. But as I said if your car is not smooth at 25mph in 3rd then it has a problem.
How many rpm does 25mph in third equate too?

Answer 4

The lower the rpms the less gas it is burning, so you are better off in a higher gear. HOWEVER, not too high because that puts a strain on your engine, any savings on gas would be more than eaten up by blowing your engine out. By not having an automatic transmission to run you are saving energy right there. It is against the law to take your car out of gear and coast downhill or coast to a stopsign or stoplight, it subtracts from your ability to control the car.

Answer 5

That doesnt sound right but I think I get what you mean.

You should stay at a gear which is at a lower rev if you are in traffic.. like say 1500 revs - 2000 revs.

There is an optimal level at which to be in certain gears. That is when the revs are say between 1500-2000 revs. Any higher & your gas will be used faster. Any lower & you might stall.

Answer 6

Too high a gear is most definitely not good for the engine. You don't feel it, but the stresses inside the engine are much greater because you're trying to get more power per rpm out of the motor. You also end up using your brakes more in low gear and wearing them out quicker.

Answer 7

I'd generally say that it's better to go for the lower gear when in doubt, but second gear is way too low at those speeds.

Stick it in third.

Unless you have an ancient 4-speed car, in which case you might need second sometimes.

Answer 8

In a 30 zone you should look to be in 3rd gear in traffic and 4th on quiet roads. Read thr road well ahead and you should only need to stop at lights junctions or roundabouts.

If you feel the engine chugging in 4th or 3rd, change down. Always use your gears to match your speed and not visa versa.
Happy motoring....vroom vroom..

Answer 9

Best not to labour the engine - does it no good at all

More fuel efficient to keep it spinning ( but not too high revs)

As you describe, you may need to change gear a lot to achieve it - depends on the car. Mine prefers 3rd in town - 4th is too high to comfortably maintain 30mph

Answer 10

Has to be the lower gear. You do not have enough control in the higher gear, and you'r wearing the clutch out.