After a lot of crawling around and investigation I have had it with trying to get my VDO speedometer working right. I am going to go to a Speedhut Legacy 0-100 mph gps speedometer. A simple install and a good looking speedometer that fits in the existing hole.The only drawback that I struggled with is that it relies on satellite to get the speed information. I started thinking about the number of times that I had lost sat signal using the GPS and it is very very rare.maybe in a tunnel or very tree covered roadway but I can't remember any time other than the Eisenhower tunnel. I can manage that OK. I keep to the main roads that accommodate my MH.Please tell me I am not crazy.I have installed the GPS Speedometer and all is working very well. It came with a hotwire feature that when connecting to an always hot wire you get an instantaneous sat acquire. It is right on the money with my other gps and is very fast to respond. For me this was a great fix.

I many times only look at my GPS display while driving. It gives me a map of the area, current speed, and what the GPS "Thinks" is the speed limit on that particular road. It can be off on the speed limit signs posted along that route, or might not give any speed on the smaller roads. So try a dash mounted GPS, it should work fine. At $100, they are a great price too.Fred.

Probably will work just fine....just a thought however.We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.

downtheroad wrote:Probably will work just fine....just a thought however.We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!

I use mine as the accurate one anyway. Never lost signal for long and you may have a reset button on it if you do. It will reset in about 30 seconds.

My Journey had Canadian specs, so speedometer was in KPH. I found it a lot handier to just keep the MPH window on the gps open rather than squinting for that little MPH scale inside the dial.I never noted it anything other than bang-on accurate, and seldom lost signal.

GPS speedometer replacement (update) | Good Sam Community

Golden_HVAC
Explorer
Aug 12, 2014
I many times only look at my GPS display while driving. It gives me a map of the area, current speed, and what the GPS "Thinks" is the speed limit on that particular road. It can be off on the speed limit signs posted along that route, or might not give any speed on the smaller roads.

So try a dash mounted GPS, it should work fine. At $100, they are a great price too.

Fred.
downtheroad
Explorer
Aug 12, 2014
Probably will work just fine....just a thought however.

We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.
mrkoje
Explorer
Aug 12, 2014
downtheroad wrote:
Probably will work just fine....just a thought however.

We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.

There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!
Passin_Thru
Explorer
Aug 12, 2014
I use mine as the accurate one anyway. Never lost signal for long and you may have a reset button on it if you do. It will reset in about 30 seconds.
obgraham
Explorer
Aug 12, 2014
My Journey had Canadian specs, so speedometer was in KPH. I found it a lot handier to just keep the MPH window on the gps open rather than squinting for that little MPH scale inside the dial.

I never noted it anything other than bang-on accurate, and seldom lost signal.
ScottG
Nomad
Aug 12, 2014
mrkoje wrote:
downtheroad wrote:
Probably will work just fine....just a thought however.

We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.

There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!

It the speedo that's off, not the GPS.
AH64ID
Explorer
Aug 12, 2014
Great idea and should work very well. If you are concerned about speed without a GPS signal, very rare, a simple note of rpms at a given speed will help.

ScottG wrote:
mrkoje wrote:
downtheroad wrote:
Probably will work just fine....just a thought however.

We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.

There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!

It the speedo that's off, not the GPS.

Exactly, I have never seen an accurate OEM speedo. I even had Toyota tell me once that they only have to be ±10%.

Trust the GPS over the truck.
Dog_Trainer
Explorer
Aug 12, 2014
ScottG wrote:
mrkoje wrote:
downtheroad wrote:
Probably will work just fine....just a thought however.

We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.

There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!

It the speedo that's off, not the GPS.

Great Thought Scott. I will record a few speeds at RPM and if ever I lose it I will have a ball park Idea. I run with a new 760 LMT GPS as well so I don't see the concern and it is a heck pf a lot easier than taking the bed out to get to the sensor on the transmission.
msmith1199
Explorer II
Aug 12, 2014
mrkoje wrote:
downtheroad wrote:
Probably will work just fine....just a thought however.

We have a speedometer on our standalone GPS (Garmin). It follows us nicely, but always registers about 2 mph slower than what we are really going. There is a slight delay as it communicates back and forth with the satellites.

There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!

There is still a delay.
dsteinman
Explorer
Aug 12, 2014
mrkoje wrote:
There shouldn't be any delay since the GPS device only receives information from the GPS satellites and it does so at the speed of light!

No, a GPS uses a radio signals from GPS satellites which does not travel at the speed of light. Sorry, I do not know the frequency. A timestamp is in the signal. With 3 GPS satellites you can caculate your position and since the GPS knows where the sattelites are supposed to be, it can calculate the delays. The differences of the timestamps gives your position.

The difference between a speedometer and GPS is that the GPS calculates speed by calculating the time it took to travel between 2 points. So it is an average since the last reading. This depends on how often the GPS calculates your position. A speedometer calculates speed by counting rotations of something on the vehicle, like transmission shaft or axle.

Also, epecially on older GPS's you can get speed inaccuracies if the altitude is incorrect when traveling up and down hills because the distance calculation will no be correct.

David

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