BMW - 6 Series Convertible. Too many gears?: Motoring Motoring Discussion forum

Motoring Discussion > BMW - 6 Series Convertible. Too many gears?
Thread Author: VxFan	Replies: 22

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New Tue 10 May 11 12:44

BMW - 6 Series Convertible. Too many gears? - VxFan

Just watched last weeks episode of 5th Gear where VBH did a road test of the above car.

8 speed automatic gearbox!!!

Do cars really need that many gears?

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New Tue 10 May 11 12:49

BMW - 6 Series Convertible. Too many gears? - Zero

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New Tue 10 May 11 13:10

BMW - 6 Series Convertible. Too many gears? - Armel Coussine

No they don't. Nor do they need self-important, waddling old prats as owners. One got in my way for three or four miles yesterday on an A road, doing 40 when we were lucky.

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New Tue 10 May 11 13:18

BMW - 6 Series Convertible. Too many gears? - Boxsterboy

Maybe they had a hairdo to preserve?

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New Tue 10 May 11 13:30

BMW - 6 Series Convertible. Too many gears? - diddy1234

what's the point of more gears, you cant go any faster.

The only reason that I would think is that each gear has a narrower speed range for the engine revs so the car has quicker acceleration.

But then I think any owner would soon get miffed at changing gears so often.
If it's an 8 speed autobox, wont it be forever hunting between gears at say 30mph or 40mph ?

I think its more money than sense on BMW's part.

Why not have the least gears tailored correctly to the engines power and torque ?
It's not rocket science.

Maybe i really am getting old, so i will stop winging now.
sorry.

Last edited by: diddy1234 on Tue 10 May 11 at 13:34

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New Tue 10 May 11 13:34

BMW - 6 Series Convertible. Too many gears? - Londoner

Who cars how many gears a car has got if it is an automatic - you don't have alll the hassle of changing gear anyway.

OK, I jest - but there is a need to have enough gears on the one hand so that you have an optimum gear available for your speed/load, and on the other you don't want too many gears so that you are forever "hunting" between them, and wearing out components with the frequent changes.

For some reason five or six gears strikes me as about right. Maybe some engineers have done a study of the subject?

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New Tue 10 May 11 13:30

BMW - 6 Series Convertible. Too many gears? - Alanovich

Interesting, AC. I've often felt BMW to be the second most commonly mimsed marque after Honda.

Loads of retired types dawdling round my parts of the Home Counties in 5, 6 and 7 series motors. Some are even graduating to the SUV models, for shame.

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New Tue 10 May 11 13:53

BMW - 6 Series Convertible. Too many gears? - Iffy

I remember asking a mate if his mountain bike needed 27 gears.

"No," he said. "But I have used every one."

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New Tue 10 May 11 16:15

BMW - 6 Series Convertible. Too many gears? - Dave_

>> I remember asking a mate if his mountain bike needed 27 gears.
>> "No," he said. "But I have used every one."

It used to be inadvisable to use the extreme crossover gears (innermost rear cog / outermost front and vice versa) as it could damage the chain.

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New Tue 10 May 11 17:02

BMW - 6 Series Convertible. Too many gears? - WillDeBeest

Still is, I reckon: puts too much strain on the whole setup. With that and overlaps within the range, I think my 3x7 combination yields about 16 distinct, usable ratios. Humph can advise on how it should be done, but I find I do almost all my shifting with the rear set and shift the front set only when there's a radical change in surface or gradient.

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New Tue 10 May 11 14:28

BMW - 6 Series Convertible. Too many gears? - Skoda

I think these are the new-ish autoboxes from ZF. Impressive kit.

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New Tue 10 May 11 14:33

BMW - 6 Series Convertible. Too many gears? - Mike Hannon

Lots of ratios selected by electronics must be the cheapie construction option today I guess.
I believe the best autobox is a hydraulic one which has fewer ratios but is attached to a properly-designed and efficient torque converter. Presumably a lot more expensive to make though.

Last edited by: Mike Hannon on Tue 10 May 11 at 14:33

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New Tue 10 May 11 15:25

BMW - 6 Series Convertible. Too many gears? - oilburner

It's to do with having just the right ratio at just the right time. You don't get hunting through the gears any more than you do with a 5 or 6 speed auto when you're at a speed right between gears, and the advantages are that you can always be in either a perfect spot for acceleration (with kick down), or at the perfect spot for optimal cruising. Plus, because the jump from one gear to another is very small, the gear changes are super smooth.

What you will see is that a good 7 or 8 speed torque converter auto will be both quicker and more economical than a 5 or 6 speed manual. Having your cake and eating it! Assuming you want an auto, of course.

You could get the same, maybe better effects with an 8 speed manual box, but obviously it would be undriveable for 99% of people, myself included!

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