SPEEDOMETER ERROR

[The Breeze]

Every once in a while, I have noticed signs on the side of the road, which I think are intended as suggested speeds for optimal travel. I often find the suggestions pessimistically low, though...:clap:

I always thought the 2 numbers on the gauge were supposed to equal each other.
i.e. - Speedometer equals the Thermometer.

Winter sucks.
Summer rocks!!!!!

:roflblack:

 

[irish2themax]

Yes, I have. My Spyder typically reads about 4-5 kilometres per hour faster than the speed indicated on my Garmin Street Pilot 2610.

My concern is that, if the speedo is reading high, does that affect the odometer? Are those with high readings putting on "invisible miles"?

Just tell them you're trying to catch up with the person ahead of you to tell them that they're speeding!

Or the old joke about the guy that told the cop "My ex-wife ran away with a State Trooper and I was afraid it was you trying to give her back!"

 

[zzneonzz]

My concern is that, if the speedo is reading high, does that affect the odometer? Are those with high readings putting on "invisible miles"?

I don't really see this as being a problem even though it will throw the odometer off a bit but since the waranty is for unlimited miles this shouldn't really be an issue.

 

[M2Wild]

I have compared my speedometer speed with the Unmanned Police radar systems they set up on the side of the road. My speedometer reads the same as these systems. Every time. :2thumbs:

I also noticed that I have to get a lot closer to one of those unmanned police radar before it would read .... yay, Spyder is almost invisible to radar.

 

[Director]

I also noticed that I have to get a lot closer to one of those unmanned police radar before it would read .... yay, Spyder is almost invisible to radar.

Especially those stealthy "Blackbird" Spyders :

 

[bone crusher]

Sweet looking Phantom...not for me as I wanna be as visible as possible...but, it's an awesome looking beast!

 

[Director]

Sweet looking Phantom...not for me as I wanna be as visible as possible...but, it's an awesome looking beast!

:agree: Stealth is a good thing for an SR71, but not so great when you are hoping to be seen by brain-dead cage drivers.

 

[rleathen]

You should keep in mind that the GPS (signals from the GPS satatlites) that we "civilians" get to use is nowhere near as accurate as the GPS signals that the military uses (otherwise any terrorist using a GPS unit purchased at Best Buy would have an accurate targeting device). I was told by a couple of different friends with pilots licences (who make used of GPS regularly) that the civilian GPS signals are accurate down to about 5o feet or so whereas the military GPS signals are accurate down to a few feet. With this designed and built in inaccuracy in the civilian GPS network it is safe to assume that the accuracy of the speed as indicated by your GPS unit is going to be less then 100% accurate.

 

[NancysToy]

not necessarily true...i work on gps's as part of my job...they are never real accurate, unless u spend 5 thou or so......i wouldnt rely on the gps totally

Very true, for the most part. A standard GPS may be accurate only within tens of feet, usually 25-75 feet maximum error. On the other hand, a moving GPS measures relative position, so the mph usually reads much more accurately than a fixed position. Just to really monkey up the works, remember that GPS speed will read slower than ground speed when going up or down a grade. Those satellites are high in the sky and don't take the actual road distance into account, only the apparent position from space. It's a geometry thing.

I hear they make the speedo read a few mph higher on motorcycles on purpose so the rider will go slower. All of the bikes I owned reads higher then the actual gps speed.

Actually, most speedos read high due to the fact that they are calibrated for the largest standard tire, at its unloaded diameter. The rolling diameter is always smaller, due to the way the weight flattens the bottom of the tire. For vehicles with a variety of optional tires, manufacturers usually choose the largest available size tire for their speedo calibration. A half inch flattening of a tire will result in about a 4 mph difference in actual speed vs. calculated (speedo) speed at 100 mph (depending on gear ratio, tire size, and other factors). Some vehicles are notorious for optimistic speedometers. Older BMWs averaged about 12 mph high.
-Scotty

 

[M2Wild]

You should keep in mind that the GPS (signals from the GPS satatlites) that we "civilians" get to use is nowhere near as accurate as the GPS signals that the military uses (otherwise any terrorist using a GPS unit purchased at Best Buy would have an accurate targeting device). I was told by a couple of different friends with pilots licences (who make used of GPS regularly) that the civilian GPS signals are accurate down to about 5o feet or so whereas the military GPS signals are accurate down to a few feet. With this designed and built in inaccuracy in the civilian GPS network it is safe to assume that the accuracy of the speed as indicated by your GPS unit is going to be less then 100% accurate.

Like 50 feet is gonna make a difference to a rag head with a bomb strapped around his waist. These idiots aren't smart enough to make a guided rocket. And if it is a rocket, will it make a difference? A city block is a city block. Miliatray used to purposly add error in the calibration on their GPS sats .... but they have since realized that its a waste of time. The newer GPS with WAAS option is accurate to within 3 feet.

 

[aubierules]

You should keep in mind that the GPS (signals from the GPS satatlites) that we "civilians" get to use is nowhere near as accurate as the GPS signals that the military uses (otherwise any terrorist using a GPS unit purchased at Best Buy would have an accurate targeting device). I was told by a couple of different friends with pilots licences (who make used of GPS regularly) that the civilian GPS signals are accurate down to about 5o feet or so whereas the military GPS signals are accurate down to a few feet. With this designed and built in inaccuracy in the civilian GPS network it is safe to assume that the accuracy of the speed as indicated by your GPS unit is going to be less then 100% accurate.

actually, that was the case, but is not anymore.....im quoting wikipedia..."On May 2, 2000 "Selective Availability" was discontinued as a result of the 1996 executive order, allowing users to receive a non-degraded signal globally." in other words civilian gps units were capable of being as accurate as military ones. any person off the street can buy a very accurate gps unit.....I work for the city in which i live in and the gps unit we have is survey grade, meaning it is sub centimeter accurate....it is also over ten thousand bucks...but the general public can purchase these from any dealer, iw u dont need to be a government official. the units most of us have are not nearly as accurate

 

[aubierules]

Like 50 feet is gonna make a difference to a rag head with a bomb strapped around his waist. These idiots aren't smart enough to make a guided rocket. And if it is a rocket, will it make a difference? A city block is a city block. Miliatray used to purposly add error in the calibration on their GPS sats .... but they have since realized that its a waste of time. The newer GPS with WAAS option is accurate to within 3 feet.

true, but only if the 1 waas satt is available to ur gps....alot of times it is not high enuf in the sky to actually use it. therefore accuracy seriously degrades

 

[bone crusher]

Like 50 feet is gonna make a difference to a rag head with a bomb strapped around his waist. These idiots aren't smart enough to make a guided rocket. And if it is a rocket, will it make a difference? A city block is a city block. Miliatray used to purposly add error in the calibration on their GPS sats .... but they have since realized that its a waste of time. The newer GPS with WAAS option is accurate to within 3 feet.

Saying 'raghead' is not PC...what we now have to say is 'angry man/women/person with strapped on bomb who is angry with the U.S.'s arrogance and wishes to display such by reducing the American civilian population. The anger is justified as the U.S. is the evil of the world'.

 

[dltang]

Like 50 feet is gonna make a difference to a rag head with a bomb strapped around his waist. These idiots aren't smart enough to make a guided rocket. And if it is a rocket, will it make a difference? A city block is a city block. Miliatray used to purposly add error in the calibration on their GPS sats .... but they have since realized that its a waste of time. The newer GPS with WAAS option is accurate to within 3 feet.

I know what you meant here, but please be careful with your remarks. We have SpyderLovers from many ethnic backgrounds here and a broad derogatory statement can still be hurtful to some.

 

[dltang]

Saying 'raghead' is not PC...what we now have to say is 'angry man/women/person with strapped on bomb who is angry with the U.S.'s arrogance and wishes to display such by reducing the American civilian population. The anger is justified as the U.S. is the evil of the world'.

It's not about being PC, it about broad based statements. It would be like saying all SpyderLovers are empty brained webheads because a small percentage of them did something really hurtful. That is all I am saying on this. I did not mean to get off topic and hijack this thread.

 

[SpydeeBite2]

My gps is 3 mph slower that digital speedo which explains why my :f_spider: reaches its destination before my gps arrives!:hun: