jbollt — Toyota's specifications for the 2007 TCH's speedometer (both US and metric versions) are given on page ME-39 of the attached document from the Repair Manual. You'll see that the metric speedometer's tolerances are generally +/- relative to "dead on," whereas the US speedometer's tolerances are + only. The design certainly appears to be skewed towards over-reading in the US version, but not so much in the metric version. My metric (Canadian) TCH's speedometer is generally within 2% of GPS speed readings, and this isn't a problem.

Stan

 

The Yaris I rented was a 2009 4 door automatic.

 

Chill JBOLT.There are much BIGGER things to worry about in this world !..

Of course, I am in Florida on vacation right now, so am an authority on 'chillin'


WillyBill

 

Thank you!
Again, does anyone have any information how the US government sets the speedometer regulation?

Ken@Japan

 

MY bet would be with the "market" determining that.

The ODO on rental cars MUST be correct.

Speeding tickets would be useless if speedo's weren't accurate within reason.

Within reason.....??!!

Cold (underinflated...) tires starting out in the early cool morning versus....


You would need GPS or RADAR to have a more accurate speedo.

 

I have always heard only the patrol cars have a certified accurate speedometer. In the old days that's all they had to clock someone with, before the radar guns came out.

I feel near all our speedometers are about 2 mph fast at 60 miles per hour. Could be a gas mileage trick to help conserve gas.

You can check yours when when on a highway. Located the mile makers on a straight highway if you can. Driving at 50 using the cruise I count each post as 1 minute 5 seconds apart. I think that's correct. Driving at 60 which for me is harder to time the passing marker would be a post at ever 60 seconds.

Ever 4 or 5 miles I up the cruse once to add one mph. If the post don't match the second hand then up one more mph. I got mine down to 10 post and was only off by about 15 feet.

It's faster to start out at 51 mph or maybe 62 with the cruise then count the post seconds. It's best to allow a passenger do this while you concentrate on driving.

 

Many years ago I beat at least one speeding ticket by forcing the officer to testify to the court that his speedometer certification process consisted of a bench test wherein only the accuracy of the speedometer head ALONE was certified to be correct.

Too many variables in the vehicle for any reasonable level of "certification", tread wear, tire inflation level, tire HEATING.

 

I should have used that in the old days to get out of my speeding tickets. I had a handful when I was about 20 years old. Two suspensions slowed me down. In fact after I stopped drag racing my 57 chevy, I went all out for gas mileage. I'm glad as over the years I have saved lots of money.