Adjusting Comp. for Larger Wheels

**nstaricha** · 05-15-2009, 12:06 PM

Has anyone upgraded wheel size and had their truck settings changed to reflect the new tire size? I plan on getting larger wheels and am curious if shops such as Americas Tires/Discount Tires will make the change or if I will have to buy a tuner and make the adjustment myself.

**Pete95Sierra** · 05-15-2009, 06:36 PM

a shop will not change your speedo or anything for you. you will have to get a programmer or something to adjust for the new tires

**TRPLXL2** · 05-15-2009, 06:53 PM

When my friend had his truck put up on 33" tires his speedometer was off by about 10 mph, so he bought a tuner/scanner and adjusted the difference that way. In the event that you want to go way out of the box, to say a set of 44" or bigger tire or a set of gears that are bigger than 4.10 then check this link out. This is an in-line calibrator that stays in the truck, you can reconnect with it anytime with a USB to OBDII port cable which you hook to your laptop. This is what I have in my truck and I love it, this is especially nice if you go to say a 4.56 or 4.88 gear and you have the problem of the dealer not being able to calibrate it for you. Anyways check it out for kicks, but the regular programmer will do the trick too!.............AMY

http://store.summitracing.com/partde...5&autoview=sku

**masterfoxscout** · 05-15-2009, 11:40 PM

x2

I've tried programming with a handheld for 35's and 4.56 gears. It confuses the ABS system b/c the VSS (controlled by the PCM which is what gets programmed) and the WSS (controlled by the EBCM or ABS computer) read different speeds and get confused setting an ABS code.

TRPLXL2, are you running stock programming for gears/tires and using a inline to fix the speedo?

**TRPLXL2** · 05-15-2009, 11:55 PM

I have the in-line to correct the speedometer and it also picks up on the re-gearing, the idea of the in-line is to work in conjunction with a tuner such as the one that you and I have. (Hypertech Hyperpac). It is the same as a PCM module from Jet, it plugs right into the PCM and takes over feeding it the correct info for what your running. The minute you take it off you will have every fault in the book come on, I have never taken mine off but I can tell you that when I had the re-gear done the guy suggested one so I bought it and I never had any problems with lights or whatever coming on. It basically reads and sets your new running gear automatically, and if you think about it that's a $800 combo from Hypertech to get the truck to run right.

I forgot it also has to be calibrated through a laptop with that cable that you can buy seperately, I have never fooled with mine after it was put on but it's cool looking for sure. It might work for the problems your having for your truck too, I am just skeptical about recommending PTM stuff I guess.

**masterfoxscout** · 05-16-2009, 12:02 AM

Through the PAC, did you program your gears and tire size or did you just do it on the in-line?

The advice I got was: Use stock tire/ratio settings and an inline to fix the speedo for new gears and tires and not to program the tire/ratio size with the PAC.

Basically, I programmed 35s/4.56s with the PAC and I got the ABS light of doom...

**TRPLXL2** · 05-16-2009, 12:09 AM

The only thing I use the Hyperpac for is live monitoring, everything else is done in-line. I can understand why you have the ABS light on with that setup, I know I would have it on mine too if it wasn't for that setup. I waited until they went on sale and I got one for $199, which is what it would cost you to take it somewhere and have them mess with it. The nice thing is if you ever change gears again or bigger tires, it is completely changeable to whatever you get to ALL extremes.