AA article - Gearing down when slowing down

How is it wasteful with fuel? Your foot is off the accelerator and you just using your clutch and brake. Most modern fuel injected cars use 0 fuel when the engine is decreasing rpm when your foot is off the accelerator. Fulling engaging the clutch to where the engine is at idle while braking uses fuel to keep the engine at idle. I clutch brake not to save the brakes but I feel it's a more efficient way of breaking especially if I don't have to come to a complete stop or I am going into a corner.

Edit: I see this point has been put across quite thoroughly :P
 
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I gear down because my dad was old school and taught me that way. I do it now because I like to be prepared in case I need to get out of a sticky situation. Only an idiot would use just brakes to come to a stop in JHB CBD at night and not shifting into the correct gear for a pull off before coming to a dead stop.

And I really wish people would learn to lift off on the highway rather than hitting the brakes. The weight of the car slows it down naturally, and unless its an emergency there is no reason to hit the brakes while on the highway. I picked that little tip up from Jeremy Clarkson and its useful.
 
killerbyte said:
I gear down because my dad was old school and taught me that way. I do it now because I like to be prepared in case I need to get out of a sticky situation. Only an idiot would use just brakes to come to a stop in JHB CBD at night and not shifting into the correct gear for a pull off before coming to a dead stop.

And I really wish people would learn to lift off on the highway rather than hitting the brakes. The weight of the car slows it down naturally, and unless its an emergency there is no reason to hit the brakes while on the highway. I picked that little tip up from Jeremy Clarkson and its useful.
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Nope. The weight of the car keeps it moving*. That's momentum.
The drag on the car slows it down.



*unless you're driving downhill
 
We delivered a beautiful Legacy to a customer last year and 3 weeks later it came in on a flat bed with the nose destroyed, so I went to the owner and asked him what happened....................

He immediately said that there was a fault with the car, so obviously I wanted to know what had happened......soooooo this is his story:

Definitely something wrong with the car because it doesn't stop when you need it to....knowing that we have an excellent braking system, I asked him to explain exactly what he did...apparently a car slammed on brakes in front of him, and he "immediately" hit the paddles and changed down to a lower gear and the bloody car didn't stop until it hit the guy in front! :wtf:

He "thought" ( actually not much thinking process was involved ) that because the car had flappy paddles, he didn't need to use the brakes at all if he wanted to slow the car down from speed!!!!!!

R 100 000 later in panel beating bills, he now "understands" that the brake is actually there for a reason! :rolleyes:

There is no substitute for stupid!
 
Gearing down doesn't waste fuel on modern cars, since the engine does not use any fuel under compression.

I drive a Defender - braking without gearing down is not an option.

In the new A3 it's different - that thing has been setup to minimise fuel consumption, the other day I managed to coast a full 150m from 60kmh to the lights on a level road :wtf:
 
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Sinbad said:
Gearing down wastes fuel? What a load of tripe. Modern engines use zero fuel on overrun. Clutch wear? Seriously? wtf.

Furthermore, being in the appropriate gear for your road speed already is a safety benefit should you suddenly need to accelerate for whatever reason.
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I think the MOST clutch wear occurs due to crawling in traffic on over-congested roads.
 
I've always changed down when breaking. Never changed down sequentially though, that seems like a needless hassle. As long as the gear is low enough to maintain control over the vehicle then fine. I dont' like the idea of something happening, me needing to respond rapidly, and the car being stuck 2 gears too high.

I learnt to drive in large-ish (2 tonnes or so) old 4WD vehicles though so I think that is probably where I picked it up.
 
Naks said:
Gearing down doesn't waste fuel on modern cars, since the engine does not use any fuel under compression.

I drive a Defender - braking without gearing down is not an option.

In the new A3 it's different - that thing has been setup to minimise fuel consumption, the other day I managed to coast a full 150m from 60kmh to the lights on a level road :wtf:
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Glad to hear you are going happily with your new A3 man :D, what's your mileage?
 
You simply can't beat the braking power of using the engine and the brakes together. Cars handle noticeably better when doing this too. Even more so a motorcycle. I wouldn't really care if it did use more fuel or increase wear on the clutch.
 
Debeer165 said:
Glad to hear you are going happily with your new A3 man :D, what's your mileage?
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ta.

it's got 800-ish on the clock now, avg fuel consumption is 5.2l/100km, 90% is town driving.

a very different drive to the old one, and way more annoying with all the new electronic nannies.

rides the bumps better, way more comfortable and way less NVH :)
 
Something else to think about besides the technical stuff.

When not gearing down there is a much larger delay should you have to accelerate for some reason. So if you need to move the correct gear needs to be selected first instead of just flooring it. Its the same as leaving your car in neutral while waiting at a red robot. Begging to join the SAPS statistics :D
 
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