speed ohmeter is fast

Thanks for all of the reply's. The tires are the correct size, I might try a shop and have them check the calibration. It is not huge issue, just kind of annoying.

On my Chevy Kodiak chassis the speedometer was reading off from GPS. The ScanGaugeII read correct for MPH to GPS. Removed gauge cluster from dash. Removed needle from step motor and positioned to more correct location. Speedometer now reads within 1 MPH of GPS.

Nobody's speedo is right on, you have to look. Is the error constant or linear. Meaning is the error always 5 or is it half of what you see at 70 when you are at 35??
The constant error can be fix as above, more the pointer on the shaft. If it is linear, then call a Ford dealer. Manufactures often have different speedo pickup gears for this. When they build a transmission they don't know what the final drive will be and the driveline people don't know what tires will be on the assembled vehicle.

Matt

Matt_Colie wrote:
Nobody's speedo is right on, you have to look. Is the error constant or linear. Meaning is the error always 5 or is it half of what you see at 70 when you are at 35??
The constant error can be fix as above, more the pointer on the shaft. If it is linear, then call a Ford dealer. Manufactures often have different speedo pickup gears for this. When they build a transmission they don't know what the final drive will be and the driveline people don't know what tires will be on the assembled vehicle.

Matt

The faster you go, the greater the difference,

99 Ford's use an electric speedometer. They can be reset by you to read accurate for tire size changes. Type in 99 e350 speedometer on {YOU TUBE}. It will give you instructions on how to. Get the value that your speedo is presently set at and start from there.

CaptainCal wrote:
99 Ford's use an electric speedometer. They can be reset by you to read accurate for tire size changes. Type in 99 e350 speedometer on {YOU TUBE}. It will give you instructions on how to. Get the value that your speedo is presently set at and start from there.

Thanks for the information