What gear to use for economy?

lilac_lady

For best fuel economy what's the best gear to use when driving a 1200cc car at 30mph? (4th or 5th?)

steveo3002

varys from car to car , some have taller gearing than others

id imagine 4th would be correct

kitchpoo

Lots of debate on this - a modern 1.2 car is more than capable of rolling in 5th at 30mph, thus turning at low RPM. But a modern car now shuts down fuel delivery when in a lower gear when you back off the gas - conserving fuel. The IAM's current advice (which changed about a year ago) is not to go for economy of 5th but 3rd or 4th as this gives you greater control at 30 mph, allied to the fact that in 5th at 30mph it is very hard to maintain a constant speed to you end up putting more pressure than required to accelerate (therefore more consumption) through the car say going from 25 up to 30 in 5th without changing down a gear.

To make a long story short - for safety a compromse would be 4th. (assuming a 5 gear car)

vansboy

Beat me too it on the 3rd at 30mph comment.

This is THE gear to choose, you feel much much MUCH more in control of the vehicle & it'll save you £$£$£ 'cos theres virtually no chance of you getting a speed camera attacking your purse strings, simply 'cos you'll always be below the limit!!

& to answer the fuel efficint gear.... at any speed, you need to travel at a pace that you can change up to the highest gear smoothly & maintain the desired speed, without any sign of the engine labouring/shuddereing, so that you'll be driving cofortably.

VB

anewman

At 30 I used to use third, but now tend to use fourth.

RichyRich

I was taught to always drive in the highest gear for the speed at which I am travelling.

In my 1.2 Corsa that's 3rd when travelling at 20, 4th at 30 and 5th at anything above that. It doesn't like being in 5th at 30; judders a bit and more difficult to control.

Thanks
Rich

astonsmummy

I never drive in 5th at 30mph, I change when i get to 40mph, and use 4th for 30mph.
Have no idea if it;s economical, but it feels better.

tomstickland

I'd probably use 3rd, maybe 4th. 5th would generally offer no acceleration to speak of if you pushed on the accelerator.

scbk

There was a long stretch of roadworks with 30 limit and SPECS that I had to go through loads of times, found it much easier in 3rd as you tend to drift over 30mph in 4th

thescouselander

I've never been in a car that drives well at 30 mph in 5th gear - generally 5th is too high for this speed and makes the engine labour - bad for fuel economy and bad for your engine.

I would have though the most efficient gear is the one that requires the least amount pressure on the accelerator pedal.

greenman7

I agree it depends on the car you are driving and it's gearing, my 1998 1.25 petrol Ford Fiesta was very comfortable in 5th gear at 30mph, I used to return about 38mpg. In fact 5th seemed a very versatile gear. Since I have replaced this with a Citroen C3 1.4 diesel it labours and shudders for the most part in 5th gear at 30mph, so I drive differently in 4th gear. Now I return about 65mpg as it is a more efficient engine. For fuel economy I would drive in the highest gear possible.