Question: Speedometer vs. Odometer

[slick]

I would have to agree with the posters wo report that the speedometer reads higher than actual speed (I forget the %) My question is whether the odometer is recording actual miles or does it record high as well? Thanks.

[rick3000]

I think the speedometer is separate from the odometer. I have one of those police speed signs by my house and I average +2-3. So when I am going 43MPH it says I am going 40MPH. But that could just be my car or the speed meter being off. No way to really now without taking it into a shop. My sister has a Mini and always tells me I go 5 under.

[porsche986spyder]

Originally Posted by rick3000

I think the speedometer is separate from the odometer. I have one of those police speed signs by my house and I average +2-3. So when I am going 43MPH it says I am going 40MPH. But that could just be my car or the speed meter being off. No way to really now without taking it into a shop. My sister has a Mini and always tells me I go 5 under.

I would not go by the police speed sign meter. Those things need to be re-calibrated every so often. Same as the cops radar/laser guns they use. They can be off by a few mph.

My speedometer and the digital read-out are in sink, but weather they are both off from true mph is another story. It could have allot to do with your wheel and tire set up too. Depends on how extreem you went with a plus size, like a set of 19s. Could make your readings off a little from the actual speed showing.

[husker boxster]

I have come to the conclusion my speedometer is off by 3mph also. Curiously it doesn't seem to be a percentage based on the speed but appears to be a constant 3mph across the board. This is based on the speed signs, but from different cities and states. Would they all be wrong by exactly 3pmh? Seems too coincidental. Except for the set of tires I currently have, the previous sets were to factory specs. I have not checked speed with the new set I have on now which are a size or two larger than stock but still 18's. I also wondered if the odometer was registering more miles based on the "higher" speed, so I checked using mile markers on an Interstate. I went 10 miles and the odometer said exactly 10 miles to the tenth.

Is there any way to correct the speedometer?

[FrayAdjacent]

I checked my indicated speed with my GPS when I was coming back from Phoenix.

At 80mph as indicated by the speedo, GPS says I was doing 76mph. A little faster, and the difference was about 6mph.

It's been rumored before that Porsche sets it's speedometers to indicate that you are going a little faster than you actually are.

Mine is off by 3 mph too.

[rebeltown]

I read recently where a certain Japaneese maunufacturer was being sued via class action because their odometer readings were reading higher than the federal codes allowed( I think it was plus or minus 5%). The new car owners were complaining that they were being cheated out of their full warranty coverage. The manufacturer agreed to give them credit for the overcharged mileage...

[Chills]

I've noticed mine is about 3mph off as well. I base this on the GPS I have in the car.

3mph isn't bad at all. In the sportbike world your speed may be off by 10% or more than indicated. That's on a stock bike, too.