gearing V mpg

mondeo

If I use 5th gear in 50/60 kmh zones am I actually saving fuel or wasting it?
Someone told me I may think I'm saving but It does not make a differance...
I use 5th gear on the occasional long 50kmh straights in hope I'm saving a drop or two of fuel. What do you think is good economical driving practice?

colm_mcm

on the S80? doesn't it have a trip computer showing momentary fuel consumption?

unkel

At 50km/h you're wasting your time - the savings will be minimal. Not the safest practice either because if you need to accelerate (even a bit) the car will do nothing until you shift down.

Seweryn

mondeo wrote: »

If I use 5th gear in 50/60 kmh zones am I actually saving fuel or wasting it?

Depending on the car, but generally at that speed 4th gear is the most suitable for both fuel economy and engine longevity. Also the above speed would be (for most of cars) the most economical speed.

daveharnett

mondeo wrote: »

If I use 5th gear in 50/60 kmh zones am I actually saving fuel or wasting it?
Someone told me I may think I'm saving but It does not make a differance...
I use 5th gear on the occasional long 50kmh straights in hope I'm saving a drop or two of fuel. What do you think is good economical driving practice?

For maintaining that kind of speed on a straight flat road, fifth might be marginally more efficient, but any kind of load at all (acceleration/incline/bend/headwind) will cost a lot more than it would in 3rd/4th

Prenderb

5th is definitely too high a gear for that kind of speed, imho. You'd want to have some level of acceleration available to you just in case - reaching an incline, for example. 3rd or 4th ftw.

Mr Benevolent

If you're driving in the suburbs or an urban environment 5th gear at such low speeds is a bad idea as you'll effectively have zero acceleration until you shift down to 4th or 3rd. Not recommended imo.

JHMEG

Assuming the engine isn't labouring it's fine to use any high gear. Ratios are different in all cars so saying something like '5th is best' really means nothing.

The less pressure you have on the accelerator pedal the less fuel you're using.

AugustusMaximus

Doesn't a car use more petrol if its labouring in too high a gear ?

I've always wondered why all cars don't have a 6th gear suited to 75 to 80mph for motorway driving. It would hardly complicate gearboxed that much ?

colm_mcm

a lot of cars would struggle with a 6th gear.

JimmyCrackCorn!

READ here!

http://autospeed.com/cms/A_111510/article.html

BigEejit

Ooo ... very interesting page there Jimmy....

But to be honest, my observations of cab drivers (who drive in more or less the style described in Jimmys link) makes me think that they have been doing this for ages.

Esel

AugustusMaximus wrote: »

Doesn't a car use more petrol if its labouring in too high a gear ?

'Labouring' an engine usually means asking it to pull from low revs in too high a gear (also known as 'lugging') and is very bad for the engine.

Know what you meant, btw.