Spedometer problems
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Joined: Apr 2006
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Spedometer problems
Anyone know how to set the spedo correctly on a 03 sd? I put 35x12.50x17 bfg muds on my truck and now it is way off. So i go to the for dealer and they dont have that size in there computer so they put 315x70x17 in and now it is still 5 mph to slow. So if im going 60 it shows 55. Anyone been down this road before? Thanks!
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Postmaster
Joined: Jul 2005
Posts: 3,956
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From: Abilene, Texas
I thought that these trucks were still cable type. with the worm gear. I swear I felt under my dash and could fell the cable. I never really looked into it, but I assume that this is why stuff like my bullydog outlook wont recall mine. I dont know maybe Im wrong (good possibility)
Postmaster
Joined: Jan 2005
Posts: 4,743
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From: Peoria, IL
No they are not run off a cable. They run off the ABS sensor in the rear axle. The dealer has to go into the ABS system and change the setting for the new tire size. Most of the programmer companies don't want to be liable for messing with the ABS system so they don't try to calibrate the speedo on Ford trucks.
They actually program it by the number of revolutions the tire makes per mile. The problem is the system will only allow them to enter numbers greater than 600. Wanabe2's tires only rotate 598 times per mile. The dealer should have put in 600 rev/mile and Wanabe2's speedo should be pretty accurate. However, since they said that it wasn't in their system I am guessing the tech was too lazy to look up the proper specs and just put in some other number that they had already wrote down for the 315/70R17 tires.
For people with larger tires the Superlift Truespeed is probably the most popular fix.
They actually program it by the number of revolutions the tire makes per mile. The problem is the system will only allow them to enter numbers greater than 600. Wanabe2's tires only rotate 598 times per mile. The dealer should have put in 600 rev/mile and Wanabe2's speedo should be pretty accurate. However, since they said that it wasn't in their system I am guessing the tech was too lazy to look up the proper specs and just put in some other number that they had already wrote down for the 315/70R17 tires.
For people with larger tires the Superlift Truespeed is probably the most popular fix.
