Road Angel speed reading!

[Paul.B]

Does anyone know just how accurate they are? I know they can take a while to adjust to speeding up/slowing down. But when at a constant speed?


TIA

Paul.

[Tyre Smoke]

According to the 'bumpf' they update every second.

[Paul.B]

Tyre Smoke said:

According to the 'bumpf' they update every second.

But to what level of accuracy?

[NJW 77]

A lot more accurate than than the bloody speedo on my cerb is all I know.

[ThatPhilBrettGuy]

They're spot on at constant speed, as in less than 0.5% at..errmm...high speed.

[phillwalden]

I was wondering the same about my GPS the other day.. I have a Mio 168 with tom tom software.. With my cars speedo at 30mph the GPS shows I am only doing 25mph? At 70mph the GPS shows about 65? Does not add up really? Or my cars speedo is really that bad..

[ThatPhilBrettGuy]

phillwalden said:

I was wondering the same about my GPS the other day.. I have a Mio 168 with tom tom software.. With my cars speedo at 30mph the GPS shows I am only doing 25mph? At 70mph the GPS shows about 65? Does not add up really? Or my cars speedo is really that bad..

Yup. And to make matters worse, on some cars it's not even linear. Can be spot on at 60, read low at 40 but low at 100. Digital dashes are much better.

[Mr E]

As stated, GPS is going to be craploads more accurate than the average speedo.

My speedo reads 125mph when up against the 112mph limiter. GPS states 112 exactly.

[shnozz]

Mr E said:

As stated, GPS is going to be craploads more accurate than the average speedo. My speedo reads 125mph when up against the 112mph limiter. GPS states 112 exactly.

yep, always said this and then was told by someone on PH that I was spouting shite because of the time delay in GPS and that the speedo was far more accurate. My arse.

[pdV6]

shnozz said:

Mr E said: As stated, GPS is going to be craploads more accurate than the average speedo. My speedo reads 125mph when up against the 112mph limiter. GPS states 112 exactly. yep, always said this and then was told by someone on PH that I was spouting shite because of the time delay in GPS and that the speedo was far more accurate. My arse.

Will be quite accurate with good signal when travelling at constant speed in a straight line. Not quite so accurate when accellerating/decellerating or cornering. Still better than your average speedo, I'd guess...

[Mr E]

GPS actually has to calculate for time dilation in the sats as they're in orbit and thus have more velocity than us mortals on earth.

It's about as accurate as you can get.

As stated, can get laggy when changing velocity dramtically.

[nonegreen]

Mine reads up to 10 mph different from the speedo

ie 60 at 70 90 at 100 160 at 170

It is completely consistant all the way up the range

[pdV6]

nonegreen said:

Mine reads up to 10 mph different from the speedo ie 60 at 70 90 at 100 160 at 170 It is completely consistant all the way up the range

So, -10 at 0 then?

[nonegreen]

pdV6 said:

nonegreen said: Mine reads up to 10 mph different from the speedo ie 60 at 70 90 at 100 160 at 170 It is completely consistant all the way up the range So, -10 at 0 then?

but only if the flux capacitor is plugged in

[mel]

My Road Pilot reads bang on 155 when the car hits the limiter, the Speedo reads 168 ish at the same time.

[TripleS]

ThatPhilBrettGuy said:

phillwalden said: I was wondering the same about my GPS the other day.. I have a Mio 168 with tom tom software.. With my cars speedo at 30mph the GPS shows I am only doing 25mph? At 70mph the GPS shows about 65? Does not add up really? Or my cars speedo is really that bad.. Yup. And to make matters worse, on some cars it's not even linear. Can be spot on at 60, read low at 40 but low at 100. Digital dashes are much better.

According to my understanding of the relevant law and rules, a vehicle speedometer should never show a lower speed than your true speed. They can (and usually do) indicate a higher speed than your true speed, sometimes by a considerable margin, particularly towards the top end of the vehicle speed range.

Best wishes all,
Dave.

[ThatPhilBrettGuy]

TripleS said:

According to my understanding of the relevant law and rules, a vehicle speedometer should never show a lower speed than your true speed. They can (and usually do) indicate a higher speed than your true speed, sometimes by a considerable margin, particularly towards the top end of the vehicle speed range. Best wishes all, Dave.

Yup, sorry, I was having a backwards day. Spot on at 60, High at 40 and 100 was what I was trying to say. I've never seen a speedo read under (apart from some car that had massively different wheels to standard, but that's a different subject).

Cheers

Phil

[andytk]

Here's an intersting question then.

If you're speedo is showing 95 and your GPS is showing a true 90 then what would a speed gun (Laser type) show. The true 90?

That'd be my guess.

Andy

[ThatPhilBrettGuy]

andytk said:

Here's an intersting question then. If you're speedo is showing 95 and your GPS is showing a true 90 then what would a speed gun (Laser type) show. The true 90? That'd be my guess. Andy

If it didn't it'd be a bit cr4p wouldn't it? Also we'd all argue the no speeding fine can be enforced as the equipment obviously doesn't show the real speed.

Aren't they checked regularly anyway (says Phil hoping not to open an old can or worms)?