How do nascar drivers know their speed if they have no speedometers?

Question

is it rpm's?

how can they tell?

Answer 1

tachometer reading tells them by the rpms

Answer 2

The engine has a a tachometer that counts the engines R.P.M. (revolutions per minute). In any particular gear once the speed is established it will determine how fast the car is moving, at that certain R.P.M., as long as the transmission is'nt slipping. An example would be at 1800 R.P.M. the car is moving at 55 m.p.h.  NASCAR monitors pit row speed with sensors embedded in the asphalt.

Answer 3

at that speed there not worryed about looking down to see if theyre going 190+

Answer 4

Just to add a tidbit of info to some already good answers: Before the race, when the pace car is leading the field around the track, it leads them at pit road speed so they can calibrate what RPM's they need to make for that speed.  

Answer 5

They use their tachometers to determine speed, "Empress"

Answer 6

They get a reading from their tachs....that's why you hear the crew chiefs sceaming 3500rpm 3500 rpm when they're pitting. So yes it is rpms.

Answer 7

rpm's

Answer 8

R.P.M.'s

Answer 9

Tachometers and yes it is rpms. Tachometer measures an engine's rpms.

Answer 10

they work out the speed by RPM and lap time.

Answer 11

O the pace lap they go down pit road behind the pace car ,that is at the max.pit road speed,they all check their tach.[rpm] so they know what that is. as far as the speed on the track that is a seat of the pants thing. they know basically  what rpm is what speed but that changes depending on which rear gear and transmission is being used.when driving as much as they do they are pretty close withh the tach and the seat of their pants!