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  1. #1

    Default Re-calibrate speedometer

    I bought some Tahoe wheels off a guy the day he brought his truck home. The tires on these wheels are 265/17 & what came on my truck was 245/17. Now, my GPS says I'm actually running 2mph or so over what the speedometer says. How do I go about getting the speedometer to account for the "extra" tire?

    John - Georgia
    Tan '08 Silverado 1500 4.8L
    K&N drop in Air Filter
    17" Tahoe Wheels
    CherryBomb Vortex Muffler
    Bushwhacker Rail Caps

  2. #2

    Default

    Chevy dealer can handle that, or get an aftermarket unit like from www.hypertech.com

  3. #3

    Default

    Quote Originally Posted by bamf_shadow View Post
    Chevy dealer can handle that, or get an aftermarket unit like from www.hypertech.com
    You think the dealer will charge for that? They didn't charge me to "mate" the new TPMS that came on these wheels.

  4. #4
    Master Mechanic
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    Default

    if its only 2 mph over i personally wouldn't worry about it. after i went from 265 to 315's mine was 5 mph difference between the gps and speedo


    2002 Tahoe LT---------TINTED WINDOWS------------7" DUAL DVD INDASH

  5. #5

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    Quote Originally Posted by lancer View Post
    if its only 2 mph over i personally wouldn't worry about it. after i went from 265 to 315's mine was 5 mph difference between the gps and speedo
    I have thought about just not worrying with it, but , if the dealer can do it & not charge me, I guess I'll go through with it, but until I have enough $ for a tuner, I'll just watch the gps. Little things like this tend to bug me until eventually I get it fixed.

  6. #6

    Default

    Something to keep in mind and that is Hypertech also Sells Speedometer Re-Calibrators for Half the Price of what they Sell there Programmer's for and it also can read Diagnostic Trouble Codes.

    Hyper-Tech,

    http://www.summitracing.com/parts/HYP-732003/
    Last edited by 99'HEARTBEAT; 05-13-2014 at 03:14 PM.

    MIKE


    99"SILVERADO
    5.3 l 3.73 l G80
    BLACK BEAR CUSTOM TUNE
    SNUGTOP l COLORMATCH l KATZKIN










  7. #7

    Default

    Quote Originally Posted by 99'HEARTBEAT View Post
    Something to keep in mind and that is Hypertech also sells Speedometer Re-Calibrators for half the Price of what they sell there Programmer's for and it also can read Diagnostic Trouble codes.

    Hyper-Tech,
    http://www.summitracing.com/parts/HYP-732003/

    I'm unclear about these tuners. Do they just reprogram the cpu on the truck & you unplug it, or is it something that's got to sit on the dash (or where ever) & stay there? I guess what I'm saying is I wonder if I could get a shop to reprogram the cpu instead of buying the programmer? Do they have these used?

  8. #8

    Default

    some tuners will have to stay connected, but most wont. I highly recommend waiting and getting a DiabloSport Predator when you can afford it. I was skeptical about how much a tuner could do for a gas engine truck, but the Predator made a night-and-day difference. You just plug it in, program the things you want to change, including your gear ratio if you were ever to do a gear swap, and your tire size, among many others. When you are done, you just unplug it. If you need to take the truck in for warranty work, you just tell it to restore the factory tune (it saves it before it changes anything), and there is no trace of it having been there.

    2008 FORD F350. My new all-around truck.
    2001 Silverado Reg. Cab Not-So-Base -- SOLD
    2003 Avalanche Z71. No Cladding. Check out my Mod thread. - Crashed. Will be rebuilt soon.
    1974 Triumph Spitfire 1500 - Work in Progress
    2003 Sierra 3500 Duramax. The Newer, Better Work Truck -- FOR SALE


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  10. #9

    Default Tuner / Recalibration notes

    I know I'm about 4 years late to the party, but in case someone comes across this like I did, I wanted to share couple things about the recalibrator and tuners. The hypertech speedometer calibrator linked above does not allow you to adjust for gear changes, although it's since been replaced by one that does not have that note, not sure if the new ones do. It may not be an issue for you now, but in my case I blew up my rear axle and replaced it with one that had a different gear ratio. My DiabloSport Predator tuner allowed me to adjust for that, once I got it 'flashed' with the latest firmware. I got one of the first versions that only allowed custom programs if you ran premium gas. With the upgrade it has 87 octane tunes. Between going from 3.83 to 3.42 gears and the stock 16" tires to much larger, newer 17" from a Yukon, my speedo was off 15mph at highway speeds. And although it's not as fast off the line, my gas mileage increased dramatically. I'm not sure about the Hypertech programmers, but with the DiabloSport you upload the program and then unplug it- at that point, the programmer is 'locked' to that vehicle until you restore the stock program to the truck. So you can't borrow one or buy one and use it on multiple vehicles. Before the new firmware upgrade, once you used it on a vehicle, it was permanently locked to that vehicle even if you restored, so you couldn't keep it to use with another vehicle if you got rid of your current one. Thankfully they changed that. Also I can now do free firmware upgrades by downloading them instead of sending it back and paying $100. So while you can now get used ones that will work as long as the previous owner restored his original program, it's probably better to just buy a new one so you don't have to worry about that or whether it has the old firmware.

    I'm looking for a way to recalibrate my speedo so I can keep my tuner and sell the truck, as I plan on replacing it with a compatible vehicle. Don't really want to spend $200+ though, especially since Summit has new Predator tuners for $199 now.

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