scott wrote:
>> Well, I've seen quite a few cars, and almost all of them had 4 gears.
> 
> Funny, I usually take about 10 rental cars per year and I don't recall 
> any of them ever having 4 gears, even when I picked the absolute 
> cheapest one they offered.  Can you give any examples?
> 
>> And yet, the gears are spaced so that changing gear is only useful at 
>> speeds below 50 MPH. Once you're doing more than 50, you're in top 
>> gear and there's no advantage.
> 
> Some people like to accelerate above 50 MPH you know :-)  I suspect at 
> 50 mph in your car you still have the choice of 3rd, 4th, 5th and 6th 
> gears, how is that not useful?  Even at 80 mph I suspect that 4th gear 
> would still be available to give you the maximum acceleration (should 
> you ever need it). That's the idea of gears.

Doesn't match what I have observed. If this were the case, it would be 
*useful*, and indeed this is was I was expecting to find.

On the contrary, it appears that unless you're in 6th gear, you can't 
exceed about 65 MPH.

If the gears were more spaced out, then at high speed I'd have a choice 
of gears, and I could use that to get more acceleration. But no, the 
gears are all bunched up at the low speeds, where I didn't have an 
acceleration problem in the first place, even with my old Pergeot with 
just 4 gears. This is what's puzzling me.

>> It's just that when the engine revs get high, you feel like you should 
>> be changing up a gear. (But there aren't any.)
> 
> Driving around at low revs might be fine at low speeds, but at higher 
> speeds you *need* the higher rpms to generate the power to overcome the 
> air drag. 6th gear is designed specifically so that the engine is 
> developing its maximum power at the top speed of your car, otherwise you 
> wouldn't be able to reach that speed!

Mmm, OK.

BTW, is drag proportional to speed linearly? Or quadratically? Or...?

>> Interesting. I always through disk brakes are cheaper, so they use 
>> those where they can't afford to fit propper drum brakes.
> 
> Hehe no, otherwise F1 cars would use drum brakes and cheap cars would 
> use disc brakes.  It's the other way around.

It's news to me that it *is* the other way around. I thought F1 cars had 
drum brakes. (You'll be surprised to hear that I haven't actually taken 
too many F1 cars apart.)

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