OT: Driving electric cars in winter

[Dave Plowman (News)]

Why have two feet and only use one?

Most gearbox places are simply fitters of reconditioned units. So can't be expected to truly understand them.

[Dave Plowman (News)]

My BMW has a so called manual mode (Steptronic). Move the gearlever over to the left and it becomes like a motor bike change. Flick forward or back to change gear. But it will still change up or down if you try and go outside the preset limits for that gear, speed wise. Which means you can't start it in 3rd gear on ice, which you could with my previous version.

The odd thing is if you have an electronics fault, the limp home mode gives only 3rd gear, neutral and reverse.

[Dave Plowman (News)]

The 'mini' has a four speed AP box, due to the very small engine for an auto. It also has something more akin to a fluid flywheel than the common torque converter - again because of the limited power. It wasn't the most refined of autos.

B-W also made a four speed when 3 was the norm. Fitted to some Hillmans.

And the first UK auto - Rolls Royce - was four speed, just after WW2. Although half way through the production run of the Shadow (about '70) they changed to a three speed.

[John Rumm]

Yup, similar to mine. Move it to the right and it goes into full auto "sport" mode (changes up later and down sooner mostly), if you then flick it forward or back (something you can only do with the stick in the right hand position), or use the buttons on the steering wheel, then it goes to (nearly) full manual. It won't change up for you (it will just let you hit the rev limiter), but it will change down if you drop below the minimum speed for the gear (if you manually try to down shift above its limit it just beeps at you).

Mine lets you select 2nd to pull away in if you want for ice/snow driving.

[Mr Macaw]

Horns are supposed to be used on single track roads. You either drive slowly enough to stop if someone comes round the bend, or you make a noise on each blind one. If you get a noise back, you know someone has to give way. In France for a small tunnel they have signs which say "Soundez obligatoire" (might be spelt wrong) which means you must sound your horn.

Then you should visit specsavers.

Wrong. Look up "crying wolf". If everyone is lit up, you won't notice the out of the ordinary things any more (motorbikes, emergency vehicles, etc). You also spot unlit things less (pedestrians for example).

Odd, they're 21 watts like brake lights aren't they? Brake lights don't dazzle me. They're nothing like as bright as dips or DRLs.

I'm very courteous, I don't put them on at all :-)

Which means he can tell when I apply the brakes.

Again, visit specsavers. This causes no problem for me. They are less than half the power of a dipped beam.

People who take their foot off the brake and apply the handbrake annoy me, because they take longer to set off.

Now that annoys me, as to go from drive to park, you go through reverse. That puts the reverse lights on so I wonder what the f*ck they're doing.

What you have to do to pass the test is not necessarily what's the best thing to do in practice. Take wheel shuffling for example.

[Dave Plowman (News)]

Ah. Mine changes up even in the manual mode. The nanny maker strikes again. I don't so much object to that, but I would like the ability to start off in any gear.

Yes- this one does too. But 2nd is still rather low for slippery surfaces. As I said 3rd was better on my previous one, which didn't have the Steptronic. But did lock completely in any gear you could select manually.

[Davey]

That as stated does not require you to go into Park or Neutral, though. Every time an automatic gearbox is moved into Drive, it wears the bands a little, as evidenced by the resulting jerk. If you wish to be kind to the mechanics, stay in Drive, and let the torque converter do the work. This changes if the stop is long, but for traffic lights and similar short stops is the right procedure. Applying the handbrake while staying in Drive is the perfect solution. What is the advantage of moving out of Drive? If your handbrake won't keep the car stationary, you need to visit a garage pronto.

[polygonum]

And if your vehicle doesn't have a handbrake?

For example, like many Mercedes, which have foot-operated parking brakes.

[Dave Plowman (News)]

The clutches in an auto are designed to handle full power gear changes. When you engage a gear from rest, the load on them is tiny compared to that. I would be amazed if it made any practical difference to their life.

Also, at idle, a torque convertor can transmit very little torque. So it will 'slip' when a gear is engaged. If you get a big jerk when you engage drive, either the box is faulty or the idle speed too high.

I tend to use park when stopped for a while - were others might use the hand brake. It's an easier operation than applying the handbrake.

[Davey]

Probably not, but there is no reason to not do the best thing.

Every automatic I have ever driven, and that includes living in the US for thirty years, has made a definite 'thunk' when Drive is engaged. Not always a big jolt, but definitely there.

For older American cars, and Mercedes, with the foot-operated parking brake, I can see that. More recently, American cars have tended to have proper handbrakes, situated where they should be, and their smaller cars always tended to. My Renault has a proper one, I find it actually easier, and certainly less jerky, to use the handbrake than to put it into Park and back into Drive. It also has the semi-manual Up or Down gearchange option, but as described elsewhere, it decides to change down to '1' when the speed drops below a certain level, such as coming to a stop.

I hired a new Vauxhall about a year ago, a manual as it happened, but it had a horrid electric parking brake that was very difficult to use sensibly. I would have hated to have tried to do a proper hill start using it.

[The Natural Philosopher]

And what is the best thing? E.g. wear the engine out revving it going down a hill? Or wear the brakes out using them?

Its often advised to slip an auto box into neutral to save fuel and overheating on the torque convertor.

very slight on a modern box.

heel and toe and the footbrake?

[Davey]

Possibly, but that should not be necessary.

[Dave Plowman (News)]

Pointless unless it makes a difference. Personally, I don't think it a good idea to leave it in drive in the situations where you need the handbrake. Most modern autos are perfectly capable of driving off with the handbrake on, if say your foot slipped or whatever. Rather like staying in gear all the time in a manual, when stopped.

You can usually tell when they engage, yes. But if it did what I'd call jerk, it's either a poor design or faulty.

Most parking brakes these days are pretty weedy things. They are no longer an emergency brake since all cars have dual circuit foot brakes.

Park, on the other hand, locks the transmission and holds regardless of how steep the hill, etc.

But on an auto, you simply don't need that parking brake at all for driving. Use your left foot on the brakes when coming out of park. A decent auto will neither run back or stall even on a pretty steep hill.

[Dave Plowman (News)]

When going down a hill? You're mad.

Quite the opposite is the accepted view. Even says so in many car handbooks. Never 'coast' under any circumstances.

But earlier, you stated

*************************

From: The Natural Philosopher Subject: Re: OT: Driving electric cars in winter Date: Thu, 11 Feb 2016 08:10 Newsgroups: uk.d-i-y

No, they dont, because te torque converter disengages them from the wheels when in overrun

************************

So I take it you've accepted you were talking bollocks then as now?

[NY]

I don't think any car that I've ever driven, going back to my mum's 1976 Renault 6 and ever since, has had a handbrake that is strong enough to stop the car in an emergency, even when pulled on as hard as possible. It might slow the car down slightly quicker than without using the brakes, but I doubt whether it would bring a *moving* runaway car to rest on a moderate hill. I've always seen a handbrake as a means of holding a stationary car, not of stopping a moving car. If I had to stop a car in an emergency, I'd be more inclined to try to engage a lower gear and let engine braking slow the car down - but let the clutch up gently if going (for example) from fifth to first to avoid locking the driving wheels.

[dennis]

They are really good. To do a hill start you just put it in gear and drive away. No need to touch the switch.

[charles]

A friend did this once - only it was "engine breaking". Very expensive.

[Dave Plowman (News)]

On a front drive car if the handbrake works on the rear wheels, it's likely to lock them without anything like the same stopping power as the fronts. Same on most cars even RWD. But some did have better handbrakes than others. My Rover P6 used to give the same maximum handbrake reading on the tester at MOT time as the footbrake.

All that can be said for certain is it's probably better than nothing.

[NY]

Maybe. But as a last resort, an expensive bill is better than a lost life.

Thankfully in 35 years of driving I've never suffered from brake failure. I'm sure it is terrifying to press the brake pedal and discover that the brakes will not control the car's speed. The nearest I've had to a runaway car was when a throttle cable jammed wide open as I was going up a hill; I changed up into top and the car shot forwards so I had to very carefully turn the ignition off while making sure I didn't turn the key into the steering-lock position (that car locked the steering if you turned the key too far, even with the key still in the lock, which modern ones don't usually do until the key is removed).

[Davey]

If the handbrake is on, then I don't need to keep my foot on the brake pedal. The car stays stopped. And my current Renault lets me know in no uncertain terms if I try to drive off with the handbrake still on, it sounds gongs at me.

snip

And can be difficult to get out of Park if used without the handbrake on a hill.

I don't use it for driving, I use it when stopped for short periods of time, such as at traffic lights when the stop is longer than I want to keep my foot on the pedal, or waiting for the car in front of me at the fuel pump to move off. I already put my foot on the brake to move from Park, in fact most cars require that, and have a defeat mechanism in case it won't release the selector by failure of the interlock.

I guess we'll just have to agree to disagree, and drive our cars in whatever way we each think is the best.