speed limits

scheming_gypsy

scooby75 wrote: »

My speedometer gives the actual speed so if I say I'm doing 70 I am actually doing 70 give or take whatever error the speedo has.

so if you say you're doing 70, you're not doing 70 and your speedo doesn't doesn't give the actual speed.
If it gave the actual speed it wouldn't have an error.

scooby75

Any device will have some error limits in it or some uncertainty about it. With speedometers, a reading of 70 should be anywhere between 69.5 and 70.4 (mine is a digital readout btw - I forget that most are dials). What I was referring to, and did not make clear, is that my speedo doesn't show a couple of MPH extra above actual speed - a safety net if you like - like a lot of people say theirs does.

mikey72

Mine reads 71mph when the sat nav says 70mph.
Most modern electronic speedos are near enough bang on.
The old days of a magnet and a needle on a spring are long gone.

Nearly_Old

scooby75 wrote: »

Any device will have some error limits in it or some uncertainty about it. With speedometers, a reading of 70 should be anywhere between 69.5 and 70.4 (mine is a digital readout btw - I forget that most are dials). What I was referring to, and did not make clear, is that my speedo doesn't show a couple of MPH extra above actual speed - a safety net if you like - like a lot of people say theirs does.

If only!

The calibration of speedometers is governed by the Desgin and Construction Use Regulations (DCUR) that every vehicle has to comply with in order to be used on the highway. A speedometer shall not underread the speed; i.e. a reading of 69.5 at a true speed of 70 would mean that it would be illegal for that vehicle (and all others of that type) to be driven on the highway.

The speedometer reading shall not exceed the actual speed + 10% + 6.25; i.e. at a true 70 the maximum permiited reading is therefore
70 + 7 (10%) + (6.25) = 83.25

Your speedometer will overread because no manufacture will ever run the risk of having all the their vehicles failing to comply with the DCUR and so all have some positive "error" built into them. On my 3 cars 70 on the SatNav gives speedometer readings between 61 and 66.

robbies_gal

i wa son the m1 today and camer across a few idiots one tailgating me even though he could see i was passing cars and couldnt come in i was doing around 75 already

i dont understand the logic if i could let him pass i would wots the point of going up my !!!! to make me speed up im not going to

SHIPSHAPE

gabbyevs wrote: »

i wa son the m1 today and camer across a few idiots one tailgating me even though he could see i was passing cars and couldnt come in i was doing around 75 already

i dont understand the logic if i could let him pass i would wots the point of going up my !!!! to make me speed up im not going to

I love annoying these kind of titters, sales rep types in a hurry to sell their dust cloths.

Like I'm really going to get intimidated by some !!!!!! flashing his lights.

If you get to see them out of their car, maybe at the services, they're usually about 5" 1' and as meek as a kitten.

Funny what a big car does to some.

Strider590

SHIPSHAPE wrote: »

I love annoying these kind of titters, sales rep types in a hurry to sell their dust cloths.

Yeah, really clever, wind him up and let him go cause a 25 car pile up...... Nice...... What's about the innocent people? I guess they deserve his anger for you being taken out on them!

Hammyman

mikey72 wrote: »

You've already claimed your 40 tonner can stop faster than any car on a motorway, and you'll never drive more than half a chevron away from the vehicle in front in a different thread, so I think we know who plays stupid.

Really? Post a link to the message.

Hammyman

scooby75 wrote: »

My speedometer gives the actual speed so if I say I'm doing 70 I am actually doing 70 give or take whatever error the speedo has.

On my mates Vectra, when his speedo said 70, his Satnav said 62...

Hammyman

mikey72 wrote: »

Mine reads 71mph when the sat nav says 70mph.
Most modern electronic speedos are near enough bang on.
The old days of a magnet and a needle on a spring are long gone.

There speaks someone who hasn't a clue how modern speedos are calibrated. But then again you've yet to make one factually correct post on this board since you started.