GPS Speedometers
Discussion
Anyone any experiences?
Current mechanical speedo has the odometer and tripmeter jammed, cannot find a company to repair it, No one prepared to look at VDO units. I've had it apart got it working but jammed again after a mile.
Replacements aren't readily available so waiting to find a second hand one but thinking of getting a GPS one as a temporary replacement as I need the trip meter.
Are the GPS ones (mostly from China) any good?
Thanks for your thoughts
Current mechanical speedo has the odometer and tripmeter jammed, cannot find a company to repair it, No one prepared to look at VDO units. I've had it apart got it working but jammed again after a mile.
Replacements aren't readily available so waiting to find a second hand one but thinking of getting a GPS one as a temporary replacement as I need the trip meter.
Are the GPS ones (mostly from China) any good?
Thanks for your thoughts
Any views on the accuracy of GPS speedometers? I've tried various comparisons while driving around and never been convinced they're significantly more accurate than the standard mechanical ones.
Then you drive past one of those Council speed warning signs and they tell you you're over the limit when your speedo's dead on 30, which should mean a real speed of 28 or so.
Then you drive past one of those Council speed warning signs and they tell you you're over the limit when your speedo's dead on 30, which should mean a real speed of 28 or so.
I have a GPS speedo in my Land Rover, total custom built, with many features and styles you can choose. I had it from Speedhut in the US…
It also measures fun stuff, like 0-60 and 1/4 mile!
It also measures fun stuff, like 0-60 and 1/4 mile!
Edited by JustGREENI on Saturday 11th September 19:35
Edited by JustGREENI on Saturday 11th September 19:36
voram said:
Any views on the accuracy of GPS speedometers? I've tried various comparisons while driving around and never been convinced they're significantly more accurate than the standard mechanical ones.
Then you drive past one of those Council speed warning signs and they tell you you're over the limit when your speedo's dead on 30, which should mean a real speed of 28 or so.
A digital readout GPS should be very accurate indeedThen you drive past one of those Council speed warning signs and they tell you you're over the limit when your speedo's dead on 30, which should mean a real speed of 28 or so.
There are some caveats e.g. 3s integration time and satellite signal.
It gets less so when you display it on an analogue dial but it does not (of course) have the input error of variable sensor diameter - or tyre wear as we know it
Mrs got caught by a static camera of all things, but thankfully within the allowance so a speed awareness course.
Tried one of these
https://www.amazon.co.uk/Powcan-Speedometer-OverSp...
and sure enough it works well, just sits on the dashboard and does what it says on the tin.
It is accurate but being GPS it loses a small amount of accuracy on inclines for a few seconds.
Display is normally white, turns yellow as speed increases and turns red just over 70mph.
Had considered one of the type that reflects on the screen in front of you, but you need to apply a small strip of film to the screen which i didn't want to do, how easy it would be to see a HUD in bright sunlight was another consideration, no regrest choosing the type listed.
So pleased with its performance bought one for the other vehicle too.
Interestingly Forester speedo shows 71mph at a true 70, most accurate standard car speedo i've seen.
Note during the very hot weather it's worth covering the device if the vehicle is left in the sun, wasn't working one particularly hot afternoon with the screen in direct sunlight, but once cooled down it came back to life and shows no sign of damage or fault.
Tried one of these
https://www.amazon.co.uk/Powcan-Speedometer-OverSp...
and sure enough it works well, just sits on the dashboard and does what it says on the tin.
It is accurate but being GPS it loses a small amount of accuracy on inclines for a few seconds.
Display is normally white, turns yellow as speed increases and turns red just over 70mph.
Had considered one of the type that reflects on the screen in front of you, but you need to apply a small strip of film to the screen which i didn't want to do, how easy it would be to see a HUD in bright sunlight was another consideration, no regrest choosing the type listed.
So pleased with its performance bought one for the other vehicle too.
Interestingly Forester speedo shows 71mph at a true 70, most accurate standard car speedo i've seen.
Note during the very hot weather it's worth covering the device if the vehicle is left in the sun, wasn't working one particularly hot afternoon with the screen in direct sunlight, but once cooled down it came back to life and shows no sign of damage or fault.
jet_noise said:
A digital readout GPS should be very accurate indeed
There are some caveats e.g. 3s integration time and satellite signal.
If you drive at a constant speed with a clear view of the sky, a GPS speedo will give a very accurate measure of your speed, I agree.There are some caveats e.g. 3s integration time and satellite signal.
As you say there are some issues. When changing speed quickly, a GPS speed measurement will take some time to catch up, so for that brief moment it won't reflect your current speed that precisely.
Also if you're inside a tunnel, you won't have a signal at all, so no information. I've also experienced a loss of signal with a view of the sky for a few minutes on very rare occasion.
For these reasons, I personally wouldn't want to fit a GPS speedo as a permanent solution on my dash, because I'd want the immediacy and reliability of a mechanical speedo. However having it as an extra bit of info is handy, or it would do as a temporary solution, hence the phone app.
samoht said:
If you drive at a constant speed with a clear view of the sky, a GPS speedo will give a very accurate measure of your speed, I agree.
As you say there are some issues. When changing speed quickly, a GPS speed measurement will take some time to catch up, so for that brief moment it won't reflect your current speed that precisely.
Also if you're inside a tunnel, you won't have a signal at all, so no information. I've also experienced a loss of signal with a view of the sky for a few minutes on very rare occasion.
For these reasons, I personally wouldn't want to fit a GPS speedo as a permanent solution on my dash, because I'd want the immediacy and reliability of a mechanical speedo. However having it as an extra bit of info is handy, or it would do as a temporary solution, hence the phone app.
You can get OBD speedometers, I'd look at one of them so you're not reliant on GPS signal.As you say there are some issues. When changing speed quickly, a GPS speed measurement will take some time to catch up, so for that brief moment it won't reflect your current speed that precisely.
Also if you're inside a tunnel, you won't have a signal at all, so no information. I've also experienced a loss of signal with a view of the sky for a few minutes on very rare occasion.
For these reasons, I personally wouldn't want to fit a GPS speedo as a permanent solution on my dash, because I'd want the immediacy and reliability of a mechanical speedo. However having it as an extra bit of info is handy, or it would do as a temporary solution, hence the phone app.
Just bear in mind, GPS ones aren't technically legal to use as your only speedometer. It's not explicitly stated in construction and use regs, but you definitely wouldn't get through an IVA test with one. I've always assumed it's because the signal can't be relied on in all circumstances, therefore you may sometimes not have a speedo, which is a no-no.
Though I imagine you'd get away with it, mostly.
Though I imagine you'd get away with it, mostly.
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