While driving my path Speedometer display 100 Km but GPS Speedometer display 90 there is 10 km difference. is that normal
Do i have to calibrate Speedometer?
GPS Speedometer which one is correct ?
Moderator: volvite
I'm not 100% sure on this but my instincts would tell me to go with the GPS. It uses multiple satallites to triangulate your location, speed, etc. Your speedometer is mechanical and has a some variables that can throw it off by a small percentage. The faster you go, the higher the percentage of your speed to your speedometer that will be off. Does that make sense to you? Just my .02 cents.
Gonzo
Gonzo
-
LittleStevie
- Posts: 193
- Joined: Wed May 23, 2007 4:32 am
- Location: West Palm Beach, FL
Go with what the GPS says. The vehicle's speedometer relies on assumptions of tire diameter in calculating a linear distance from number of tire revolutions. Treadwear and tire pressure could contribute to error.
I've observed the opposite of Mark, on every vehicle I've seen the speedometer reads 2-3 mph faster than the GPS. I would not be surprised if the automakers do this intentionally for conservatism, to avoid getting sued by someone who says their speedometer caused them to get a ticket.
I've observed the opposite of Mark, on every vehicle I've seen the speedometer reads 2-3 mph faster than the GPS. I would not be surprised if the automakers do this intentionally for conservatism, to avoid getting sued by someone who says their speedometer caused them to get a ticket.
My apologies, I meant to say 2-3 slower on the GPS...got distracted and mis-typed...so, same experience. And your reasoning makes sense. Same reason most law enforcement officers won't stop a vehicle for going 5mph or less over the limit...room for error/calibration of the radar equipment & the speedometer. Makes sense...and actually is a little comforting to know the vehicle is reading 2-3 faster than actually moving...LittleStevie wrote:Go with what the GPS says. The vehicle's speedometer relies on assumptions of tire diameter in calculating a linear distance from number of tire revolutions. Treadwear and tire pressure could contribute to error.
I've observed the opposite of Mark, on every vehicle I've seen the speedometer reads 2-3 mph faster than the GPS. I would not be surprised if the automakers do this intentionally for conservatism, to avoid getting sued by someone who says their speedometer caused them to get a ticket.
One of the biggest culprits is that the mfr calibrates the speedo for one size tire. On the Pathfinders with 16" wheels, that means everything is calibrated to 265/75/16 tires (which is the tire size indicated in the OP). But, the second new tires start rolling, the diameter begins to shrink as the tread gets worn, which also contributes to the problem. As others suggested, I'd stick to what the GPS says.
Find Your Forum!