emmm my speedos broke

afatbollix

so my speedo is broke ( think its a fuse or something..)
i HAVE to head to the north tomorrow, along the M1 withc allways have the gards on it. so is there anyway you could work out what speed your doing?

tryed just staying with one guy there yesterday but think he was speeding as when he say a cop pulling someone over he hit the brakes... should i just stay behind the slowest guy on the road?

cheers
anto...

The tax man

When you're in forth gear the rev counter needle always matches the speedo needle in position. So you could get a rough idea what kind of speed you're at before hitting fifth. It wouldn't be too wise to do the whole motorway in forth though.:D Hopefully your car has a rev counter.
BTW why is it that the needles match each other only in forth gear and is there some sort of engine gearbox ratio term for it?

maidhc

The tax man wrote:

BTW why is it that the needles match each other only in forth gear and is there some sort of engine gearbox ratio term for it?

Never had a car where they did!

You should be able to find out the gearbox ratios from your owners manual. e.g. 25mph/1000rpm.

eamon234

if any of your mates have a sat nav they'll lend you most of them give your speed although it's not 100% accurate my TomTom is usually three or four kph off

zilog_jones

Yeah the manual for my car gives a rough speed range that each gear can do.

Robbo

Same thing happened to me before and it was an embarassing encounter with the law.

I can never go back to that swimming pool again.

Alun

eamon234 wrote:

if any of your mates have a sat nav they'll lend you most of them give your speed although it's not 100% accurate my TomTom is usually three or four kph off

What are you comparing it to to come to that conclusion? A GPS is going to be more accurate than your car's speedo.

eamon234

Alun wrote:

What are you comparing it to to come to that conclusion? A GPS is going to be more accurate than your car's speedo.

My car's speedo ! (digital) - GPS isn't always accurate - depends on how fast the processor on your unit is and can also be affected by signal degradation.

cyrusdvirus

anto-t wrote:

so my speedo is broke ( think its a fuse or something..)
i HAVE to head to the north tomorrow, along the M1 withc allways have the gards on it. so is there anyway you could work out what speed your doing?

tryed just staying with one guy there yesterday but think he was speeding as when he say a cop pulling someone over he hit the brakes... should i just stay behind the slowest guy on the road?

cheers
anto...

What you driving Anto? If a ford then there's a thread here somewhere for fordies that shows how to turn a digital readout odometer into a speedo.

afatbollix

it is a ford but the computer is bust aswell... everything elce works... it try the trick tho.... it happened before, then one day i hit a hole and it fixed it its taking it a lot longer tho this time.... think i need a new car...

Alun

eamon234 wrote:

My car's speedo ! (digital) - GPS isn't always accurate - depends on how fast the processor on your unit is and can also be affected by signal degradation.

Just because your car's speedo has a digital readout doesn't make it any more accurate than a conventional analogue one, I'm afraid. It may make it easier to read to the nearest 1 km/h, but that's the extent of it. Most speedos in modern cars have come a long, long way since the mechanical induction motor driven ones of days gone by, and even on "analogue" speedos the pointers these days are driven by precise stepper motors controlled by the computer in the instrument cluster. There's also considerable evidence that the instrument firmware deliberately adds a fudge factor onto the readings to ensure that the display never under-reads, usually amounting to 5% or more. If you have a car that allows you to go into a diagnostic mode, like most new Fords for example, you'll see that the reading that this displays agrees very well with the GPS reading, to within fractions of a km/h, whereas the main display will over-read by a considerable margin. There's also any inaccuracies due to over or under-inflated or worn tyres to be taken into account too.

GPS's speed readings are actually relatively unaffected by positional errors due to bad satellite geometry or atmospheric conditions since any such errors tend to not vary much over short distances and cancel each other out. My little handheld GPS I use for walking, for example, has a quote accuracy of 0.02m/s which works out at 0.18km/h .. pretty accurate I'd say.

In short, your GPS speed reading is going to be more accurate than your car's speedo .. digital readout or otherwise.

vengeance52

Robbo wrote:

Same thing happened to me before and it was an embarassing encounter with the law.

I can never go back to that swimming pool again.

That one made beer come out my nose


Well my speedo, i have to replace one of two small bulbs behind it as it was blown, and cos of the car (mondeo) the whole instrument cluster had to be removed to fix it. Ford dealer said 60 quiid, cos its over 30mins labour and parts.

So as ya guess i didnt get it fixed yet, so be warned the ford dealers will really charge to fix it. try an independant mechanic

gatecrash wrote:

What you driving Anto? If a ford then there's a thread here somewhere for fordies that shows how to turn a digital readout odometer into a speedo.

Linky

unkel

The tax man wrote:

When you're in forth gear the rev counter needle always matches the speedo needle in position

Eh? Did you just make that up or does that happen to be the case in your car?

cyrusdvirus

unkel wrote:

Eh? Did you just make that up or does that happen to be the case in your car?

tis the same with mine. 4th gear speed and revs are approximate same positions on the guages

mondeo, before you ask!!

vengeance52

mondeo 2.0tdi. in 5th gear at 2000 revs im doin 61mph

oleras

Alun wrote:

In short, your GPS speed reading is going to be more accurate than your car's speedo .. digital readout or otherwise.

On a perfectly level surface yes, inclines and declines no.

oleras

The tax man wrote:

When you're in forth gear the rev counter needle always matches the speedo needle in position.

New one on me, will give it a try in the morning.

And op....... you really should know the difference between 60mph and 70mph without a speedo.

Robbo

oleras wrote:

And op....... you really should know the difference between 60mph and 70mph without a speedo.

I used a calculator and came up with 10mph. Is this correct?

afatbollix

oleras wrote:

New one on me, will give it a try in the morning.

And op....... you really should know the difference between 60mph and 70mph without a speedo.

how?

oleras

Robbo wrote:

I used a calculator and came up with 10mph. Is this correct?

hillarious !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

oleras

anto-t wrote:

how?

i dont know how !!!! lol

seriously, maybe its experience, but i know driving through a village if im over 30mph, even by 2 or 3mph, and the difference between 60 and 70 is enough, maybe i should be in "heroes"............. i can also guestamate the time fairly accurate..........

The tax man

gatecrash wrote:

tis the same with mine. 4th gear speed and revs are approximate same positions on the guages

mondeo, before you ask!!

Nice to know someone else sees the same as me.

I too drive a Ford but also a Seat.

@unkel, Too many people around here talk crap and offer poor advice. I'm not into making up stories. It's just something I noticed with the last few cars I've had(previous cars only had a speedo) that both needles match each other when in forth gear.Just thought it was common to all cars and may have helped the OP. Not having a go at ya BTW.;)
Has no one else ever noticed this

Victor

anto-t wrote:

emmm my speedos broke

erm...

Alun

oleras wrote:

On a perfectly level surface yes, inclines and declines no.

True, but not as much as you'd think .. on a 20% (1 in 5) incline it's going to make a GPS indicated 100 km/h be about 102 km/h in reality. A typical speedo will probably be over-reading anywhere between 5 and 10 km/h at this speed.