i put 32x11.50 tires on my 94 bronco with a 5.8 and i want to calibrate it through the gauge sequence. i know how to do it i just need to find out the calibration ratio. i have the hayne's repair manual and the manual in the truck but i can't find anything about it in them. if anyone knows the figure or where i could find it i would appreciate any info.
thanks.

chris

94 bronco
5.8
k&n
glass pack with duals

 

Chris these are the instructions I got from this board that worked perfect for me when I put my 32" BFG's on. My speedo is right on the money.Just remember you can only change the PSOM 6 times. Superlift just came out with a electronic calibrator you can change as many times as you like. I'll be looking into that in the future when I jump to 35" 's. Hope this helps you out



Locate the dealer mode programming enable single-terminal connector. The
connector is located at the bottom of the instrument panel below the center
of the glove box. On all vehicles, the dealer mode enable wire is Circuit 567(LB/Y).
Insert a jumper wire or alligator clip in service wire and clip other end
to vehicle ground with the key in the OFF position.
Turn key to RUN while holding down the trip odometer RESET button on the
speedometer. Release RESET button.
The Speedometer will prove out(sweep across dial and back). The
English/Metric and revision levels will be displayed. The last number of
the display id the dealer mode lockout count. This count shows the number
of allowable conversion constant changes remaining. When the count is zero
(0), no additional changes can be made to this instrument cluster. If a
revision is required a service instrument cluster must be ordered.
Press and release RESET button again and PSOM conversion constant without
the decimal point will be displayed followed by the word CAL.
The new conversion constant necessary to correct the speedometer can be
found by determining the current percentage error. One way to do this is by
comparing the indicated miles versus mile markers on an interstate trip.
The longer the trip, the better indication of the error since interstate
mile markers are not always exactly 1 mile but the average is very close to 1 mile.
Going to taller tires (indicated miles less than true miles) will mean the conversion
constant must be reduced by the same percentage as the speedometer error and
going to smaller tires (or a numerically higher rear end ratio) means the conversion
constant must be increased.

Press and release the odometer SELECT button as many times as necessary to
change the conversion constant to the correct value. The constant will only
increase (not decrease) when the SELECT button is pressed so reducing the
constant means counting up until the constant jumps to the bottom of the scale
and begins counting up from there.
Note: Pressing and releasing the RESET button to lock in the new
conversion constant reduces the number of times the PSOM can be
reprogrammed by one count. If you change your mind and want to go back to
the old conversion constant, turn the key OFF BEFORE you lock in the new
constant.
When the new correct value is displayed in the odometer window, press and
release the RESET button to lock in the new conversion constant.
Turn the key OFF and disconnect the ground wire and check to see that the
speedo works correctly.


Joe
94 Bronco XLT,5.8,E4OD,4" skyjacker lift,K&N FIPK,Custom SS Exhaust

 

thanks alot for the specific directions. what ratio did u calibrate your bronco with. i mean the actual percent. i would do the interstate mile marker test but i'm kind of limited on time.
thanks alot for the help


chris

94 bronco
5.8
k&n
glasspack with duals
32x11.50 bridgestone duelers

 

I know that I had everything written down but I can't seem to find it.(I did it about a year and a half ago) I remember it wasn't off by much I don't even think it was off 5%. My truck came stock with 265/75 15 tires and the BFG's were only a little taller. If I get time I'll go check my speedo and post the constant that I'm running now.

Joe
94 Bronco XLT,5.8,E4OD,4" skyjacker lift,K&N FIPK,Custom SS Exhaust

 

thanks alot. also my bronco came with p235's, will the calibration be the same ratio as your's that came with p265's

 

did you ever get the calibration for the 32 inch tires if so can you email me the calibration.
thanks
customfoam(No Email Addresses In Posts!)

 

Does it make a difference if I have changed the gears, from 3.73 to 4.56? I now have 35" BFG MT and would like to fix my speedometer but it doesn't seem too far off.

 

It may be a little late but my calibration code for my BFG AT 32x11.50's is 896. My speedo is right on the money. I just put 35" tires on and will be recalibrating soon. I'll post my results

I'm considering getting Superlifts Truespeed calibrator. Any body have any experience with one of these. It is supposed to remember 2 calibrations so you can switch tires and just flip a switch.

Joe
94 Bronco XLT,5.8,E4OD,4" skyjacker lift,K&N FIPK,Custom SS Exhaust

 

If i'm not mistaken this site can help you when changing to any size by giving you the % change in the speedometer:
http://www.miata.net/garage/tirecalc.html

 

to answer the question about gears, it doesn't matter what gears you put in, the speedo should not be affected. i believe the speedo inputs are taken from the anti-lock sensors at the back wheels, so any change in gearing before that point will not be reflected in the speedo. if only my mustang were so simple....

 

 

Here is a good link with lots of tire/ratio calculations:

http://www.zilbandy.com/suburb/gearcalc.htm

I just bought a 2002 F-250 XLT 4-Door V-10 and it came with 31.6" tires and a gear ratio of 3.73. I am planning on lifting it and putting 33.5" tires on. If I understand correctly there is a way to calibrate the speedo without buying the truespeed calibrator? If so could someone go over how to do that or let me know where to find the info?

Thanks,

Brett
(bmf2001@attbi.com)

 

You need to go to the newer trucks forum. The info in this thread applies only to the 92-96 (or 97 F-250).