OT: Brakes seizing on electric cars? (2024 Update)

[invalid unparseable]

Varies with the car. There were some very low powered cars which could only get up the worst slope in reverse because it was lower geared.

[Xeno]

Autos of *any era* have a first ratio (lowest fwd reduction gearing). It is usually arrived at by *compounding* the reduction ratios of 2 or more epicyclic gearsets. The torque converter does not provide a "1st ratio", it merely increases (multiplies) torque through use of a *hydraulic feedback mechanism* incorporating the *stator* whilst at the same time providing a slip factor up to the point of torque converter stall. A small percentage of that slip occurs even at highway cruising speeds

*unless* the torque converter is equipped with a lockup clutch.

Please, try not to comment on matters of which you lack comprehension.

[Commander Kinsey]

Don't assume you know how every car works. I speak from 1st hand experience when I tell you with 100% certainty that my 1998 VW Golf 1.9 TDI had precisely 4 ratios. You can tell when you're driving it! The first ratio took it up to 50mph, the second ratio to 75mph, the third ratio to 100mph, and the 4th ratio to 125mph (speeds are approximate but you get the idea). A similar manual car got to speeds of 25/50/75/100/125mph in each gear. Clearly mine had the lowest ratio removed.

[Xeno]

For the record, a lot of autos, under light throttle, will skip the lowest ratio at launch. Under heavy throttle however, *every available ratio* will be used *in sequence*.

I know way more than you, that much is certain.

You cannot compare *ratios* of an auto with a manual gearbox. gear ratios of a manual are selected, in conjunction with a final drive ratio, by reference to *engine performance* and, in particular, the

*power band* of the engine. Autos are the same but with a significant difference - they have a torque converter and allowances has to be made for torque converter *capacity* when selecting gear ratios as well as engine performance. As well, given the torque converter has an approximate 5% slip factor at cruise, the final drive ratio is slightly higher on *most* autos to compensate. This becomes moot if said torque converter has a lockup facility - and most do these days in the name of fuel economy.

[Dave Plowman (News]

Our resident idiot likely thinks if 1st gear isn't on the selector mechanism it doesn't exist. And autos that only have drive neutral reverse and park on the selector only one forward gear.

Many 3 speed autos have a higher geared reverse than 1st. I'd guess a function of how reversing the motion is achieved.

[Dave Plowman (News]

Do remember many autos around these days that don't have a torque convertor. In the US, they seem to think they ain't autos. ;-)

[Xeno]

A lot of people haven't a clue. They just drive the things.

[Xeno]

Yes, exactly that. The power input on a typical compound gearset (eg. BW35) enters at different points. For low, it enters at the primary sun gear, for reverse at the secondary sun gear. That's where you get the higher reduction reverse ratio. I won't try to explain that to a person who has no clue about the internals of an auto trans given he thinks a torque converter gives a *reduction ratio*.

[Commander Kinsey]

Bullshit. I was going by noticing when it changed gear - blatantly obvious from the rev counter and the engine pitch.

However it did it, it was bloody fun.

[Commander Kinsey]

Of course it does. It varies the ratio between the engine speed and the wheel speed, just like the gears do.

[Commander Kinsey]

Presumably ALMOST in contact, otherwise you're just wearing them out.

I guess you're right though, occasional braking, even just twice each time you use the car (stopping at the destination and stopping when you get back), still moves all the brake parts so they can't rust up. Or maybe they've come up with the wonderful idea of not using rustable metals! You'd think we were still in the last century.

[Commander Kinsey]

Different skill set. Cars ain't like houses.

[Commander Kinsey]

Then put me in your killfile you moron.

[Commander Kinsey]

You wash a device which is outdoors? Do you not have rain where you live?

Mine does it by just parking on the drive for a week.

Never had the latter happen.

[Commander Kinsey]

I virtually never use the handbrake, it's unnecessary unless you're parked on a very steep hill and can't find anything like a kerb to steer the wheels into.

[Commander Kinsey]

What's wrong with your feet? I can do that using the footbrake. Hold the car on the brake with the clutch pressed in fully. Lift the clutch until just before the point the engine will stall. This will hold the car for the split second required for the next step. Now move your foot from the brake to the accelerator, apply power, and release the clutch. I always do that and find it much easier than faffing around with the handbrake.

It's one of those things you do on the test then don't do again, like using both hands on the wheel.

All cars should be automatic, then you wouldn't have to do the above. There really is no point in inventing a far superior gearbox, then continuing to make cars using the old one. Same applies to petrol cars, they were superceded by the more efficient and longer lasting diesel engines.

So there are actually drivers even more incompetant than you?

[Commander Kinsey]

Wow, all that clever tech, when they could have just fitted an auto box.

[Commander Kinsey]

I went to school every day on a Greyhound bus. The oldest ones they had, as kids tend to vandalise the interior. They required double-de-clutching, not sure if that was the way they were made or because the gearboxes were f***ed. When Tayside buses bought them over, it was quite funny to see the new set of drivers having no clue how to change gear.

[Commander Kinsey]

Actually, sometimes wheelspinning helps. I once tried to ascend a steep hill with deep snow in a VW Golf auto. Nobody else was managing to get up the hill and had given up. I tried it and went up gently, but there wasn't enough traction in the snow. So I just stood on the throttle. Being an auto the front wheels very quickly got up to a tremendous speed (about 100mph on the speedo) and snow flew everywhere. It dug through to the tarmac and got grip. I continued this all the way up the half mile of road, going about 5mph but with the wheels at 100 and made some nice tracks, which other cars then followed.

[Xeno]

Gears are a *fixed ratio*. A torque converter has no ratio as such. It has, instead, a *variable slip factor* and a variable torque multiplication factor. No gears are used in a torque converter.