Speedometer Adjustment?

[Gatorboy]

Can it be done? Mine is off by about 5mph

 

[1997chevydriver]

Can it be done? Mine is off by about 5mph

At all speeds?

Or does it get farther off the faster you go?

Sent from somewhere in MN

 

[Tempted]

First thing to do is figure out why its off. What size tire are you running?

 

[Gatorboy]

Stock 235s for tires. Seems to be off the whole range of speeds but ill hook it up again on my way home from work to check again.

 

[Tempted]

235 is the width, what is the aspect ratio? With 31x10.50s my speedo was perfect at 60mph. Anything over 60 showed lower on the speedo and anything under 60 showed too fast.

If you have 235-70s and the truck came with 235-75s then your speedo will tell you that you are moving a little faster than you actually are. Shorter tires = speedo to read too fast.

 

[Bearcat91]

At all speeds?

Or does it get farther off the faster you go?

Sent from somewhere in MN

If it get farther away from actual its most deff tires or gears if you changed those...i went from 308 to 373 and tires a 295/45-20 and my speed is off by about 15% so its more accurate at slower speeds and less accurate the faster I go. Depending on trans will depend what you do http://www.transmissioncenter.net/speedometer_calibration_______va.htm

 

[KReePiN]

there is pins in back of the guage cluster........you will have to mark the concrete.........roll your truck forward on complete revolution.....then mark the concrete again where you stopped.......so you have 2 marks......stArt and stop......you measure the distance and look up in the gm service manual which pins need to be added or removed behind the cluster.....