I have the stock factory 20's on my truck. I just bought the Saleen 23's. Do I have to re-calibrate my PCM for my speedo and odo. I was told that I have to do this and the dealer want's $120 plus tax to do this. Your opinions, please.

 

It's not the wheel size that matters. It's the height of the tire. For instance, if the oem tire is 33 inches tall it would not matter if you installed 33 inch tires on 17 or 28 inch wheels.

 

Yes, determine the difference in the height of the tires and calculate the % difference in the speedometer. If you need to recalibrate, why not apply the cost to a tuner that will do it for you?

 

I know nothing about tuners. My truck is stock. If I have the dealer put the wheels on they should know what to do from their correct? I'm wondering what is it that they exactly do.

 

You can lower your tire size. But to be safe, i'd just get the company calibration done. So then you wont have to worry about being a few miles off.

 

Like I said I have the factory OEM 20's now with the Pirelli tires (I don't know the tire size but from a pic on my computer it looks like 275/55/20) that came on my 07 FX2 Sport


I just placed an order for the 23 Saleen wheels. I will be using a 305/40/23 tire. Can one of you geniuses do the math for me. I might not need a calibration.

 

I knew nothing about tuners either. Now, I would not be without one. The Gryphon and the Edge are simple to use and give you gauges. Plus, I can change back to my stock wheels or change tire size and recalibrate myself.

 

I'm listening, tell me more. How does this work, websites, etc. I would love to change wheels for the winter/summer without giving the dealer $120 plus tax each time.

 

What will the dealer do when they re-calibrate my PCM and how long will it take. HELP

 

My favorite.

http://dygytalworld.ehost-services139.com/php/

It comes with 3 canned tunes that you can use instantly, or you can run your stock tune and just use the gauges. You can monitor over 20 things. All the temps, voltage, ect. You also get 3 custom tunes that you can order later after you decide what you might want such as performance, economy, towing, 87, 91, 93. Bill makes these trucks hum and the shifting, downshifting is awesome.

 

305/40/23 is 32.6 in tall
275/55/20 is 31.9 in tall

so the 305 is 2.2 percent bigger

so at at speedo reading of 70 you are actually going 71.54
not something that I would worry bout.

 

Holy ****, thanks alot. What will this do to my odo? Isn't my mileage going to read a little higher than it really is.

 

will read slightly lower

your mph and odometer readings are based of rpms of the tire. They are configured for a certain size tire. Since you are going with a bigger tire you will covering more distance per rotation of the tire and thus will be going slightly faster and farther for a given rpm of the tire than your truck thinks it is.

 

I have a question about my sensors. My current sensors are on a 20" band and my new wheels are 23" I'm going to buy the 23" bands from Saleen but do you think that my currents sensors will work?

 

First, the difference in the two tire sizes you listed is not enough to worry about.
As for the sensors, you can have your oem sensors removed from your stock wheels and installed on the Saleen wheels but you will need to buy new mounting bands. I believe Tire Rack sells these for less money than Ford. You don't have to install the TPMS on your Saleen wheels but you will have to put up with the idiot light on the dash burning.