Le 07/10/2011 14:54, Francois Labreque a écrit :
> Le 2011-10-07 08:12, Invisible a écrit :
>> These gear settings seem very strange to me. Rather than adding more
>> gears up top where there's lots of empty space, they've added more down
>> at the bottom where there's already plenty of them...
> 
> 
> Gears are chosen so that your car engine remains as close as possible to
> the peak of its power curve while under load, and so that the
> revolutions are kept as low as possible when cruising to save on fuel.

In fact, some countries have taxes based on the engine and the gear-box.
For the same engine, there could be "short" gear-box or "tall".

Tall are for large sedan-like or touring car.
Short are for sport car. (the one you encountered seems a short)

back to taxes: same engine, short gearbox was in the next higher
categories than same engine, tall gearbox.

So economic, from the car-maker, was to push more tall gearbox (it sells
better).
(That kind of tax was yearly-recurring in France... now dropped).

Nowadays, the important selling point is CO2 and this is measured at
fixed speeds (70 & 90 km/h), and time from 0 to 100.
(as advertising a maximal speed above the official limit is a very big
no-no, nobody is publishing a "can race at 254 km/h" anymore).

So, what is the best to minimize CO2 on the test: having the top gear (5
or 6..) already engaged at 70 km/h... hence short box everywhere now!

For the 0 to 100km/h time... well, a good pilot will happily jump a few
gears in its way to the record, and push on the engine too.

> All things being equals, the more gears, the better.

Well, No gearbox and no clutch at all the better.
(and no belt either!)

> 
> For "normal" transmission boxes, more gears cost more money, so you only
> see 7 or 8 gear transmissions on luxury german or italian cars.  For the
> rest of us mortals, adding gears for speeds that are illegal in most
> countries is not a cost-effective measure.
> 
You can of course have a bus (usually 8+) or even a truck (mmm... some
reaches 16 or more, and yet they are limited to 100 km/h )

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