Speedometer off? - Toyota Yaris Forums

randydid · 12-18-2011, 09:38 PM

Hi,

I just put 383 miles on a tank of gas which took 10.22 gallons to fill. That equates to about 37.5 mpg calculated. The gauge reports 33.8. In my neighborhood and other places we have those speed signs that tell you how fast you are going vs. posted limit. My SE's speedo reads 2-3 mph faster than the signs are reporting. Has anyone else noticed speed descprentcies like this? Yes, I have the stock 16's with OEM rubber.

*kimona* · 12-18-2011, 10:02 PM

My speedo was off with the stock 185/60/15's. With 205/50/16's, my speedo is dead on.

traveller · 12-19-2011, 10:02 AM

Here in the U.K. there's a 10% allowance for speedo accuracy. Usually they read a bit high anyway, which I prefer as that reduces the chances of being over the limit!
Yours is possibly indicating that bit more anyway.

KentSzabo · 12-19-2011, 10:29 AM

I have nearly 4100 miles on mine now, and I can tell you the speedometer/odometer is accurate, but the problem is with the Average Fuel economy calculation. On level ground and going uphill it is accurate, but going downhill is a completely different story. The AVG Eco going downhill can not exceed a mileage of 99.9, when in fact the vehicle may be getting anywhere from 120 to 160 mpg during those downhill cycles. Therefore, the entire average computed is skewed downward anywhere from 1 to 5 mpg depending how much hilly terrain you are driving over.
This is evidenced at fill up time if you keep your odometer figures from last fill up. Calculating yourself is the only way in these vehicles with average economy calculators to verify your true mileage. On my 2000 Caddy Eldorado it also has one of these calculators, but it can't exceed 70 MPG going downhill and exhibits the same problem as the Yaris's calculator.

A-Dingo-Ate-My-Baby · 12-19-2011, 11:24 AM

get a scangauge and an GPS unit and program the scangauge to display actual
speed (use the GPS for 30 minutes above 75MPH to get actual reliable moving speed) no matter what the car speed pickup says.

you can dial a percentage offset and get scangauge to read dead-accurate
miles and speed regardless of tire size

12-18-2011, 09:38 PM	#1
randydid Drives: 2012 Yaris SE Five Door Join Date: Dec 2011 Location: Albuquerque, NM Posts: 33	Speedometer off? Hi, I just put 383 miles on a tank of gas which took 10.22 gallons to fill. That equates to about 37.5 mpg calculated. The gauge reports 33.8. In my neighborhood and other places we have those speed signs that tell you how fast you are going vs. posted limit. My SE's speedo reads 2-3 mph faster than the signs are reporting. Has anyone else noticed speed descprentcies like this? Yes, I have the stock 16's with OEM rubber.

12-19-2011, 10:29 AM	#4
KentSzabo Drives: 2012 Toyota Yaris L, 5 speed Join Date: Oct 2011 Location: Grant, CO Posts: 32	I have nearly 4100 miles on mine now, and I can tell you the speedometer/odometer is accurate, but the problem is with the Average Fuel economy calculation. On level ground and going uphill it is accurate, but going downhill is a completely different story. The AVG Eco going downhill can not exceed a mileage of 99.9, when in fact the vehicle may be getting anywhere from 120 to 160 mpg during those downhill cycles. Therefore, the entire average computed is skewed downward anywhere from 1 to 5 mpg depending how much hilly terrain you are driving over. This is evidenced at fill up time if you keep your odometer figures from last fill up. Calculating yourself is the only way in these vehicles with average economy calculators to verify your true mileage. On my 2000 Caddy Eldorado it also has one of these calculators, but it can't exceed 70 MPG going downhill and exhibits the same problem as the Yaris's calculator. __________________ 2000 VW Golf TDI, 5 Speed, 48 MPG 2000 Cadillac Eldorado ETC, Auto, 23 MPG 2004 Dodge 3500 Auto, Dually, 6" Lift, 36" Tires, 4" Dual Stacks, Predator, 20 MPG 2012 Toyota Yaris L, 5 Speed Manual, 46.4 MPG

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12-18-2011, 10:02 PM	#2
kimona Super Moderator Drives: 2014 White VITZ Join Date: May 2007 Location: Huntington Bch, CA Posts: 4,938	My speedo was off with the stock 185/60/15's. With 205/50/16's, my speedo is dead on.

12-19-2011, 10:02 AM	#3
traveller Drives: Anything but Toyota Join Date: Sep 2011 Location: U.K. Posts: 6	Here in the U.K. there's a 10% allowance for speedo accuracy. Usually they read a bit high anyway, which I prefer as that reduces the chances of being over the limit! Yours is possibly indicating that bit more anyway.

12-19-2011, 11:24 AM	#5
A-Dingo-Ate-My-Baby Banned Drives: yaris Join Date: Jan 2011 Location: earth Posts: 364	get a scangauge and an GPS unit and program the scangauge to display actual speed (use the GPS for 30 minutes above 75MPH to get actual reliable moving speed) no matter what the car speed pickup says. you can dial a percentage offset and get scangauge to read dead-accurate miles and speed regardless of tire size