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Thread: Speedometer adjustment
09-23-2012, 06:26 PM #1
- Join Date
- Sep 2012
- Northern Ohio
How can I adjust my speedometer to compensate for tires that are larger than my factory size. Is this a dealer thing or can i do it myself?
09-23-2012, 09:14 PM #2
I'm unsure how this sort of thing is handled on pre-99 trucks, but on 99 and later models the truck's computer has to be programmed for the overall diameter of the tires. Either go to the dealership and pay them to do it or buy a handheld programmer and use it to do it.
Be advised that the computer is finicky about certain tires sizes and will turn on the ABS idiot light if it doesn't like a size you've set with a handheld programmer. (My tires are technically 34.3" in diameter, so 34.5" would have been a logical setting and it tossed the ABS light ... but it was perfectly happy with 34" as the setting, so that's what I used.)
09-24-2012, 01:24 PM #3
either a programmer or superlift used to sell a speedometer calibrator (which is what I have). It is hard wired in and you can switch between 2 sizes with a switch as well as fine tune it if you notice it is still off a little.David
2004 Silverado 2500 Crew Cab 4x4, AMSOIL EA air filter, Granatelli MAF sensor, Throttle body spacer, Magnaflow exhaust (true dual to 2 in 1 out muffler), 6" ProComp lift (add a leaf and 5" superlift rear block), Bilstein shocks, 35's (Cooper Disoverer ST) and 4.10 gears, Rhino Liner, EGRUSA fender Flares and widow visors, extended stainless steel brake lines, firestone airbags w/onboard air compressor, Pioneer Avic X940BT navigation, Accel backup camera.
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09-24-2012, 02:07 PM #4
That's another approach. What'd that run, @dsfloyd? I ask because if I were going to sink cash into something I'd want it to do more than just the speedo adjustment ... unless it was super cheap. Programmers run in the multiple hundreds of dollars but do all sorts of things. What'd the speedo calibrator set you back?
09-24-2012, 06:31 PM #5
A speedo recalibrator plus OBD II code reader would be a worthwhile investment. I'll probably put over-sized tires on every truck I own so it would be a good thing to have handy.
As for my truck, it came stock with 245-75-16s and I currently have 265-75-16s it. I have driven past enough of those speed limit signs that show you your speed to know that my truck is actually going 2 mph more than what the speedo says.Clint (TX) 2001 Silverado LS 4.8L auto 2wd ECSB [GARAGE]
Gasoline or gunpowder: If you ain't burning one, you ain't having fun!
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09-24-2012, 08:56 PM #6
09-24-2012, 11:55 PM #7
10-05-2012, 11:42 AM #8
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10-05-2012, 12:20 PM #10
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