Speed is the measurement of distance over time. Originally Answered: How do cars measure their speeds? It works by measuring the rotation speed of the wheel. On older cars, this was done mechanically using a cable connected to the transmission. The odometer is the device which is used to measure the distance travelled. The speedometer is used to get the speed for instantaneous speed measuring. An odometer is a device that is used for measuring the distance traveled by a vehicle.
An odometer may be digital or mechanical. The first way to detect odometer rollback fraud is to compare the mileage on the odometer with the mileage number on the vehicle maintenance or inspection records and CARFAX vehicle history report. Reparations and inspections normally record the mileage number. Check for physical signs of odometer tampering — Inspect the odometer to make sure that all the numbers are readable, there are no gaps between the numbers, and the numbers do not appear crooked.
Any of those signs point to a high possibility that the odometer was rolled back. Begin typing your search term above and press enter to search. Press ESC to cancel. Skip to content Home Engineering Where does speedometer cable connect to transmission at? Ben Davis February 5, Where does speedometer cable connect to transmission at? How do you install a speedometer cable? Is the speedometer connected to the transmission? What is the problem if the speedometer is not working?
Police officers use radar to measure your speed which involves a laser beam that bounces off of your car and back to its source, thus telling the machine how fast you are moving. Did you know that there is more than one type of speedometer? They accomplish the same things but do so in different ways. As you press your gas pedal, the wheels of your car spin faster or slower according to how much gas is being supplied to the engine cylinders.
When you want to check how fast you are going, you check your speedometer, which tells you the speed in kilometers and or miles per hour. The cable will measure the rotation and feed back to the speedometer turning a magnet.
The magnet is able to rotate freely within the speed cup which also rotates. The speed cup is connected to a wire coil and to the gauge itself and dictates the speed reading. So the speedometer cable attaches to the drive train. As it spins freely with the transmission, it turns a magnet at the same speed. The spinning magnet is located within the speed cup and within it creates a magnetic field that varies with the speed of the vehicle and with the cable turning. What happens from here is that the speed cup generates electricity.
Electricity that really has no where to go. This is where the mechanical speedometer gets its nickname Eddy Current Speedometer. The speedo cable consists of an inner cable running inside a protective outer sheath. The ends of the speedometer inner cable are squared off, and fit into squared holes in the drive pinion at the gearbox and the drive in the back of the speedometer. As the pinion rotates, driven by the gearbox output shaft, it causes the inner cable to rotate with it.
The other end of the cable fits to a drive shaft leading into the speedometer. On the end of this shaft is a magnet. Positioned close to but not touching the magnet is a cup-shaped metal drum that is attached to the needle giving the reading on the dial. A small coiled hair spring holds the needle at zero. The drum is attracted by the magnet so, as the magnet turns, the drum turns too.
The faster the car is travelling, the greater the pull of the magnet on the metal drum and the further the needle moves round the dial. But the restraining force of the hair spring also increases as the needle moves round the dial. One on the cable and one in the tail shaft in a turbo for example.
Your local tranny shop should have a chart to show what gears work together right. You may have to switch 1 or both gears. I'm goin 90mph on the speedo when really doing about 70mph. So at 30mph I should really be doing That seems about right.
I'll have to go play with one of them speedtrap lightup signs that show my speed and swing by the shop. Not sure if its that bad of a thing though. Thanks Joe. Joined: Feb 6, Posts: 3, Profile Page. When you go to the speedo shop they'll put your car on rollers connected to a calibrated speedometer. Then they'll tell you to bring it to 60mph or so on your speedo. If the difference between your speedometer and theirs can be corrected with transmission gears they'll install them.
If not, they make up an adapter that goes between the cable and transmission to bring it in spec. Make sure that you have the tires you plan on running on the car, because different size tires will change the calibration. Mutt , Apr 28,
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