I have maybe a question for you that may help have you changed the size of your tires?? If so it changes everything.
Also:
How much does it over-read?
If only by a slight amount, say 5 or so MPH:
If the Speedo read under the speed you were doing then when you got pulled over and issued a speeding ticked (citation) by the Police, you would sue the car maker.
As a result, all car speedos read a speed above the speed the vehicle is actually going.
The size of tires can effect that accuracy of a speedometer. Larger tires will cause the speedometer to read less than you are actually going.
The speedometer in any vehicle does not stop a car from going faster, which many cars can go much faster than the speedometers highest number. Sometimes vehicles are limited from the factory to achieve a speed lower than that on the speedometer like my 2006 silverado says 120 but does only 99. However your truck can go faster than 85 mph.
Could be that the wrong size tires are installed, or that somewhere along the line, a different rear-end gear ratio was installed.
yes they are going to make a new dodge car it is going to be a dodge ev, that means electric vehicle
no However, you will very likely be fined for speeding, for not knowing what speed you are going without a speedometer!
It will affect the speedometer. For example, bigger rims will make you go faster than what the speedometer is actually reading. If it say's 50mph with regular rims, then with larger rims you will be going faster.
Do you have the correct size tires/wheels on the vehicle? Look on the driver's door post or in your owner's manual for the correct size. Incorrect size tires will effect the accuracy of the speedometer. If you are running the correct tires then the vehicle speed sensor (VSS) may need replacing.
If you change the size of the diameter of the original size of tire , YES If you go LARGER in diameter , you will actually be going FASTER then your speedometer indicates and If you go SMALLER in diameter , you will actually be going SLOWER than your speedometer indicates
Acceleration is not represented on a speedometer, however, when you look at the speedo, if the needle is moving, you can get a rough idea of acceleration like this: If the needle is going clockwise (of generally indicating faster speeds) - you are accelerating. If the needle is going anticlockwise - you are decelerating. Speedometers measure speed. You would need an accelerometer to measure acceleration.
Speedometers work by measuring rotations of the wheels. The more rotations, the faster your going. But they can't measure in reverse.
To get a quote on a Dodge vehicle you can start out by going to your local Dodge dealership. That should give you a starting point. From there you can look at sources such as Consumers Digest and Kelly's Bluebook.
The resistance is greater the faster the vehicle is going.