View Full Version : RE: Which is more accurate?



firefighterjake
07-10-2006, 02:41 PM
I know quite a few sledders will talk about how fast they were able to get their sleds going and they often qualify their speed by saying it was the speed achieved by their GPS unit.

As for myself in the car I have noticed that sometimes (in fact oftentimes) the speed registered on the speedometer is off a bit from the speed shown on the GPSr.

Call me bored or just plain curious, but in your opinion what is more accurate most often (recognizing that if you have an EPE reading of 360 it may not be all that accurate and that snowmobiles may have some track spin giving a false speed reading for example) -- speedometers or GPSrs?

robt
07-10-2006, 03:04 PM
I hope the answer is GPS cause that is what I set my cruise control by.... :) if not I do alot more speeding then I thought :D

becket
07-10-2006, 03:11 PM
As for myself in the car I have noticed that sometimes (in fact oftentimes) the speed registered on the speedometer is off a bit from the speed shown on the GPSr.

Call me bored or just plain curious, but in your opinion what is more accurate most often (recognizing that if you have an EPE reading of 360 it may not be all that accurate and that snowmobiles may have some track spin giving a false speed reading for example) -- speedometers or GPSrs?

i don't know - you and dave told me to watch the road, not my gps! :D

Hiram357
07-10-2006, 03:16 PM
well I drove a service truck that didn't have a working speedometer for almost a year, and I just used my GPS, never got pulled over. :D but if you really wanna know how fast your sled is going, just go flyin by a cop down the road, I'm sure he'll be glad to let you know. :p

J_Cyr
07-10-2006, 03:24 PM
I took your advice Hiram, OH, HE LET ME KNOW ALRIGHT, thanks alot... $239.00





lol

Hiram357
07-10-2006, 03:35 PM
I took your advice Hiram, OH, HE LET ME KNOW ALRIGHT, thanks alot... $239.00





lol

hehe, was that the speeding ticket or the stupid ticket for running your sled in the middle of summer!?!? :p :D

Beach Comber
07-10-2006, 03:46 PM
hehe, was that the speeding ticket or the stupid ticket for running your sled in the middle of summer!?!? :p :D

That was funny!!!

MoxieMan
07-10-2006, 04:18 PM
It's funny you brought this up...I had mine out today on the dash to check how close it was. From what I could, between looking at the GPSr, the spedomete and the road they were very close to being the same.

dí76
07-10-2006, 05:06 PM
THe gps and the speedometer are usually very close. I did notice a difference when I put bigger tires on the truck. SO now I use the gps for the spedometer

brdad
07-10-2006, 07:10 PM
I think either can be accurate, but you have to consider with the GPSr, if you are going up an incline, only your lateral speed is measured. So, if the road is not level, it will be off a certian percentage. also, the GPSr obtains speed from one point to another, so if you are turning slightly it will, again, determine your speed as if you were going in a straight line. Speedometers, on the other hand are unaffected by these issues.

dí76
07-10-2006, 07:12 PM
I think either can be accurate, but you have to consider with the GPSr, if you are going up an incline, only your lateral speed is measured. So, if the road is not level, it will be off a certian percentage. also, the GPSr obtains speed from one point to another, so if you are turning slightly it will, again, determine your speed as if you were going in a straight line. Speedometers, on the other hand are unaffected by these issues.

If you drive like hiram the tires are usually turning faster than the vehicle is moving.:p

brdad
07-10-2006, 07:22 PM
If you drive like hiram the tires are usually turning faster than the vehicle is moving.:p

Am I right in iterpreting that as "With Hiram, the wheels are spinning, but the car is going nowhere?" :p

Hiram357
07-10-2006, 08:34 PM
Am I right in iterpreting that as "With Hiram, the wheels are spinning, but the car is going nowhere?" :p

sometimes i make the engine noises too... brrrrrrr brrrrrrrr vvrrrrorooooom :D

tat
07-10-2006, 09:17 PM
Either could be more accurate. Both have significant sources of error. As mentioned before, you need something much more accurate to determine if it is your gps or your speedometer. But, instead of blasting by a cop, try the old fashioined way: find a measured mile, they are everywhere! Drive at 60 miles per hour using the gps. It should take 60 seconds. Then, repeat the test with the speedometer. The closest to 60 seconds wins.

MoxieMan
07-10-2006, 10:34 PM
Either could be more accurate. Both have significant sources of error. As mentioned before, you need something much more accurate to determine if it is your gps or your speedometer. But, instead of blasting by a cop, try the old fashioined way: find a measured mile, they are everywhere! Dive at 60 miles per hour using the gps. It should take 60 seconds. Then, repeat the test with the speedometer. The closest to 60 seconds wins.

Okay, that just takes WAYYYY tooo much time! :) Blowing by the cop is much quicker and easier...unless of course you have to pull over, show license and registration...get a background check...show him the GPSr for proff of what you were doing...blah blah blah

Hiram357
07-11-2006, 03:19 PM
Okay, that just takes WAYYYY tooo much time! :) Blowing by the cop is much quicker and easier...unless of course you have to pull over, show license and registration...get a background check...show him the GPSr for proff of what you were doing...blah blah blah

i agree, but as long as you don't stop you shouldn't have a problem... unless you drive slow... :D