Correct me if I am wrong...

[chopper602]

dibbers006 said:

But how many cars actually can achieve a higher Top Speed by going down hill with a chasing wind?

Citroen 2CV6 - mine will do over 85mph downhill with a following wind (only about 70-75 on the flat). The tops of the doors tend to allow light in quite well at that speed too . . .

[soda]

dibbers006 said:

Top Speed of a vehicle is limited by the final drive gear ratio?

But how many cars actually can achieve a higher Top Speed by going down hill with a chasing wind?

Most of the cars I've owned can achieve a higher speed downhill with a tailwind.

Not all cars are limited by the final drive gear ratio, many don't have sufficient power to reach the rev limiter in 4th or 5th gear.

[Alex@POD]

The effect from having the wind behind you isn't that it will push you, but that there is less air resistance, as the air is moving with the car, so a higher speed than in a normal "still" air is acheivable.

But as mentioned, top speed is rarely restriced by gearing only in real life...

[Papa Hotel]

doogz said:

Most cars aren't restricted to a top speed by the gear ratio. That assumes the car can hit the rev limiter in top gear, which is not usually the case.

What doogz said. My Clio would hit the rev limiter in 6th, so it actually was limited to 135, absolutely regardles of whether there was a 60 mph tail wind or not. My Fiesta, that still had some left in the rev range when it ran out of steam... with a good tail wind, it would have gone faster.

[chopper602]

dibbers006 said:

So it has the ratio, but not the power?

Yep - only 29bhp to push it along !!