speedometer calibration??

[ADV]

I have 285/75R16 tires on my truck and I know the speedometer will be off a bit. Is there a way to fix this and make it right? Will not go back to stock tire size! 1993 f350

 

[Wicked97]

http://bronco.zenseeker.net/Speedo.htm

Calculators and gear part numbers.

Ebay is a good source for the driven gears.

 

[FordGuy100]

Mine is barely off....I dont think you will see a huge difference with those tires. Less than a couple percent.

 

[Wicked97]

What was the stock size?

 

[mobilemech]

no speedo gearts needed in a '93, the speedo runs off the sensor in the rear end. as was stated, the speedo shouldn't be off much.

 

[ADV]

I had these tires on my last 1988 f250 and the spedo seemed to be off around 5 mph. Its not a big deal to me if its off some but just thought if there was an easy way to fix it I would. Stock tire size was 235/85R16

 

[Optikalillushun]

u do not have a driven gear on the 92+ trucks. the psom can be recalibrated up to 6 times. its real simple check this out: http://www.ford-trucks.com/article/...EDOMETER_ON_9296_FORD_FSERIES_AND_BRONCO.html

 

[mobilemech]

the speedo on a '88 may run off a gear in the trans, so tire size changes will affect the speedo reading because the drive line revolutions are different between the tire sizes. on a '93 the speed sensor reads the tone ring in the rear end, so it sends the signal for the correct revolutions from the tone ring, your speedo should be less than 5 mph off

 

[Wicked97]

Yeah I forgot about that rear sensor crap.