Speedometer Calibration

[aces full]

Has anyone using BFG 285/75/16 TA's re-calibrated there speedometer, and gotten a dead-on accurate reading??? I'm about to install the tires Sunday, and I'm going to F**D dealer to do the ABS adjustment.

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00 Excursion Ltd, Oxford White, PSD, 4X4, 3.73 LS, WD Chip & Air Filter, Weld SS II's w/BFG 285 AT's, Turbo Lifefaver w/F1 Module, Hellwig Anti-Sway Bar, Stull Grill, Clear Lenses, Burlwood Dash, Cladding Removed

[kflaig]

I have BFG 295/75x16 TAs on my Excursion using stock 7" rims. My GPS says that they make my speedometer and odometer read about 3.7% slow. That's not enough difference for me to worry about recalibration.

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'00 Excursion PSD 4x4 3.73LS, 295 BFGs, Bilsteins, Rancho steering stabilizer, Hellwig sway bars front and rear and Banks PowerPack, Amsoil air filter

[H ED S]

Say hey Aces and Kflaig.

If my memory serves me right I think the speed sensor feeds your PCM and this in turn sends info. to the way your engine operates and could also affect mileage power, etc.

s and the best

Ed

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Y2K"X" LTD. PSD 2/WD FIBERGLASS RUNNINGBOARDS SUNVISOR &other goodies.LIFER NRA,TX.ST.RIFLE ASSOC.& GOA. MEMBER NRA\ILA.
I DO VOTE!

[kendall69]

When your dealer goes blank, byasking fo rthis service, give him this:
8. Calibrate Speedo for tire size

Special Service Message 11789 & 11790 from 7/29/99.

1) Ensure all harness connections are plugged in.
2) Using NGS and Version 3.2 or higher Service Card, Plug into the DCL connector.
3) Turn Key on w/Engine Off.
4) Select Service Bay Functions
5) Select ABS Module or 4WABS Module depending on application.
6) Select Tire Size/Axle Ratio Configure.
7) Select Tirs Size. If tire size is not listed use Formula of: 63360 Divided by the Circumfrence of the
tire measured in inches. Add 2 zeros in front of the solution. Enter this number into the NGS as the
REV.PER MILE figure.
8) Select Tone Ring size and verify that 120 is programmed in.
9) Select <Option> and press TRIGGER.
10) Select <Vehicle> and press TRIGGER.
11) Press <Done> and the Module will be reprogrammed.
12) Check Speedo accuracy.
Circumfrence is 2pi*Radius.Pi=3.1416
So for 33" Tires, using theoretical radius, it's, 2Pi*16.5=103.672
63360/103.672=611.158(611)
Add (2) zeros in front of that 00611 and enter it when prompted.
I had it done and it actually makes the rig run better, seriously.

[tbbux]

aces,

WHAT'S THE ABS ADJUSTMENT? I have a set of 285's I'm taking off to put on 35's.

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2K Black 4x4 PSD 3.73 Limited 285/75/16, Edelbrocks AIS, SuperChip, Badges, Hellwig Anti-Sway rear/front, Loaded (except kitchen sink..although there's room)

[aces full]

<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:</font><HR>Originally posted by tbbux:
aces,

WHAT'S THE ABS ADJUSTMENT? I have a set of 285's I'm taking off to put on 35's.

<HR></BLOCKQUOTE>
this entire thread concerns ABS adjutment, which is how you callbrate your speedometer.

[Tailgate]

Question:

Is the Speedometer re-calibration covered under the bumper-to-bumpe warranty?

I would suspect "No" because of voluntarily changing your tires out with a non-stock size. Anyone know if the dealership will do this under warranty?

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Tailgate
2000 Excursion Ltd, 4x2, 7.3L PSD, limited slip axle, K&N Filter, PSD Badging, Deep Satin Green with Medium Parchment leather interior

[aces full]

forgetaboutit!!!!! Not only is in not covered, but the difference in price charged for this service at the various F**D service dept's is all over the map. If you do it, I'd talk to the service writer, and tell him that you'll pay, but you want the right to come back and re-enter the values for no charge, in the event you want to "tweak" the number---I say this because I think you'll find that the variables on each truck, and tires, will mean that there is no one perfect number for each combination. I went to Harpeth F**D in Franklin TN, and they honored that request. I had the callibration done, went out on the hwy, drove 10 miles, returned to do it again, and then a third time, all within one day, and they were cool about it. The charge was $40. Performance F**D in Nashville wanted $150. I think they pull these numbers out of their a**. The first time the guy at Harpeth did it for me took less than 10 minutes.!!!!!

Aces

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00 Excursion Ltd, Oxford White, PSD, 4X4, 3.73 LS, WD Chip & Air Filter, Weld SS II's w/BFG 285 AT's, Billstein Shocks, Turbo Lifefaver w/F1 Module, Hellwig Anti-Sway Bar, Stull Grill, Clear Lenses, Burlwood Dash, Cladding Removed