Coasting

[Segilla]

How illegal / foolish is it to coast?
Maybe not so bad now that car brakes are so effective and gearboxes synchromeshed?
I get 64mpg from my 1.9 diesel, and drive up to 70 mph on M ways and accelerate moderately etc.

[Toureman]

It is not illegal and I do not think it is foolish if done under the right circumstances though less inept drivers will soon be answering to critizise me.

My driving style is similar to yours, very few drivers know how to drive economicaly.

As you say brakes are so good on modern cars, though you should never freewheel on steep downhills but stay in a lower gear to help slow the car.

I get an average of 41 mpg in my petrol 1.8 car.

[homer75]

You will gain even more 'free miles' by switching off the engine altogether on long downhill gradients. The down side of this is that the power steering ( if applicable ) and the brake servo ( if applicable ) will cease to function. However, when employing this 'fuel saver' technique, be careful not to engage the steering lock ( if applicable ) by clicking back too far on the ignition switch - this would cause some handling problems as your control over the vehicle would be compromised. Just out of interest - are you a fan of tobogganing ?

[Segilla]

Switching of the engne could be too dangerous.

Toboganning?
Not at my age (72), young man!

[Segilla]

Toureman, I know when to slip out of gear in the same unconscious way as I know when to change gear. It's 'automatic'; so I do it down any hill too.

[homer75]

omg Segilla ! unconscious ? you are getting scarey !! lol

[juggler]

In my early motoring day, Rover cars were renowned for having a free-wheel option. Does anyone have experience of them which will maybe help Segilla?

[woodchopper]

For safetys sake dont switch off the engine ( coasting ) when freewheeling an extra 1mpg or two ain't worth the risk.

[derekpara]

JUGGLER. In my youth (1955) I owned a 1937 Rover 14 hp. A monster of a car with a six cylinder engine, huge leaf springs and a chassis like a tank. 20 mpg maximum.

It had the famous Rover free wheel which was designed to aid economy ! When you took your foot of the gas the gearbox disengaged from the engine so you were 'free wheeling'. The gears re-engaged only when you accelerated again. Hard on the brakes, which weren't very good anyway. There was a control wheel on the dashboard so that you cou disengage the system at will. Lovely as a passion wagon though !

[pagey]

I often coast for a smoother deceleration, but you need to consider extra brake wear as there is no engine braking. Also, if you are coasting to a stop, the fuel used may be more than if you engage gear. Engine consumes fuel to keep ticking-over, but sometimes less when the engine turns over under car's motion.

It really depends if you are coasting down a hill with the intent to maintain speed after hill, or are coming to a stop.

Also, if you have your left foot on the clutch you will not be able to apply as much force on the brake with your right foot under emergency braking, or would have to drop the clutch first, introducing delay and weight-shift.