How accurate is your speedometer

FricFrac · 08-18-2009, 12:56 AM

Hmm GPS is not necessarily accurate. Depends on how many satellites, etc you are receiving. Likely less than normal unless you have a roof antenna. The greater the distance traveled at a fixed speed will also increase the accuracy.

Chan Chee Hoe · 08-18-2009, 07:35 AM

Quote:

Originally Posted by SDWayne

Do you have stock tires?

Wayne

I think the standard 18'' rear tyres is a bit smaller than the 19'' ones..

LiquidZ · 08-18-2009, 07:58 AM

How would you go about calibrating your speedo? For OCD types like me, I would like to have it recalibrated if I were to get different tires/wheels.

zZSportZz · 08-18-2009, 08:20 AM

Mine seems pretty accurate.....its my cruise control I'm worried about.

It seems that it can fluctuate a lot. I've been like 6 mph over going down a hill.

drdre8424 · 08-18-2009, 02:41 PM

mine simes to be about 2 mph off from my GPS, i dont lose sleep over it.

rudi · 08-18-2009, 08:28 PM

A possible reason for the error is Nissan my have calibrated the speedo to suit the 19" rims and not the 18's. Does anyone know if the rolling diameter is different for both wheels?

davidyan · 08-18-2009, 11:31 PM

the GPS speedometers are usually pretty accurate unless you are accelerating hard or slowing down in which case, there is some lag in the calculation.

I had a portable Garmin and used it in 5 different cars (sometimes I drive my parent's cars) and it always seems like the car speedometer is about 1.5 - 2 mph faster than the car.

08-18-2009, 12:56 AM	#16 (permalink)
FricFrac A True Z Fanatic Join Date: Dec 2008 Location: Victoria, BC Posts: 1,481 Drives: 370Z 300ZX 280ZX 240 Rep Power: 229	Hmm GPS is not necessarily accurate. Depends on how many satellites, etc you are receiving. Likely less than normal unless you have a roof antenna. The greater the distance traveled at a fixed speed will also increase the accuracy. __________________ '09 370Z - '93 300ZX Vert - '83 280ZX - '83 280ZXT -'81 280ZXT stroker - '72 240Z - Stillen CBE, HFC, G3, Grounding Kit, Sways // Swift Spring // H&R 15mm // 5% Tint // Clear Bra //

08-18-2009, 07:58 AM	#18 (permalink)
LiquidZ A True Z Fanatic Join Date: Nov 2008 Location: Columbus, OH Posts: 1,940 Drives: Mag. Black 2009 370Z Rep Power: 705	How would you go about calibrating your speedo? For OCD types like me, I would like to have it recalibrated if I were to get different tires/wheels. __________________

08-18-2009, 08:20 AM	#19 (permalink)
zZSportZz A True Z Fanatic Join Date: Mar 2009 Location: Maryland Posts: 1,095 Drives: 370z Blk on Blk 6MT Rep Power: 18	Mine seems pretty accurate.....its my cruise control I'm worried about. It seems that it can fluctuate a lot. I've been like 6 mph over going down a hill. __________________ --Rick

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08-18-2009, 02:41 PM	#20 (permalink)
drdre8424 Base Member Join Date: Mar 2009 Location: https://t.me/pump_upp Posts: 133 Drives: 09 Pearl 370z Auto Rep Power: 0	mine simes to be about 2 mph off from my GPS, i dont lose sleep over it.

08-18-2009, 08:28 PM	#21 (permalink)
rudi Enthusiast Member Join Date: Jun 2009 Location: Australia Posts: 306 Drives: 370Z Australian Spec Rep Power: 16	A possible reason for the error is Nissan my have calibrated the speedo to suit the 19" rims and not the 18's. Does anyone know if the rolling diameter is different for both wheels?

08-18-2009, 11:31 PM	#22 (permalink)
davidyan Base Member Join Date: Jun 2009 Location: CA Posts: 244 Drives: PG 370Z Sport 6MT Rep Power: 16	the GPS speedometers are usually pretty accurate unless you are accelerating hard or slowing down in which case, there is some lag in the calculation. I had a portable Garmin and used it in 5 different cars (sometimes I drive my parent's cars) and it always seems like the car speedometer is about 1.5 - 2 mph faster than the car.