Ok, here is the deal, my new truck came with 265 75 16's, I want to put a 285 or 295 tire on it. I know that this will make my speedometer read wrong so I call a couple of my local Ford dealers to see how much to recalibrate the speedometer. Get this, one service guy told me that the computer would actually "learn" the new tire size and automatically re-adjust the speedometer, to this I replied "Ok, thanks for the info" hung up and promptly called another dealer that I hoped would actually know what they were talking about. The next service guy I talked to told me that the truck could only be recalibrated if it was run on a dyno. Now, I am not a complete idiot when it comes to mechanics, I do all my own work that I am able to, but I also admit that I am far from knowing everything. Now the last time I read a magazine a dyno was still used to get hp and torque numbers not recalibrate speedometers. I can't believe that these guys are service managers and don't seem to know the first thing about actual mechanics. If I am wrong, and what I was told is actually true I will be the first to admit I was wrong, but I really believe all it takes to redo the speedometer is a quick hook up to the PCM to input the new tires size. Am I wrong in this thinking Please help me out here.

 

superlift has that dealy bopper that will adjust all your computers to your own tires size, gearing. It runs about 170$. I know that on the pre-superduty series you could recalibrate it yourself, however i have not heard if that is possible on the superduties. Ive been wanting to get the superlift thing for a while now, cause it woul fix the speedo, and also the overhead mpg reading. best of luck

 

Your on the right track about the PCM hook up thing. Around here there a couple of dealers and only one does it. The others told me that it was computer controled and it couldn't be adjusted. Anyway I think they can adjust it up to a 35" tire. My truck came with the 265's and with my 315's on it i'm only about 6mph off at 65. I don't think 285's would change it enough to worry about (atleast for me). I did buy the superlift truspeed and a GPS to set mine. If you cant find a dealer to do it I wouldn't spend the extra money on the truspeed unless you plan on going with 35" tires or bigger.

 

these are notes i made in '99.tell ford tech.to go to special service message 11789 and 11790. OASIS will spell it right out.this is from a guy who took delivery with 295's on.there was some caution for an auto trans.if a tech gives you a hard time tell them circumference is 2pi times the radius.... 2pi[r]....pi=3.1416.
this guys 295 BFG'S[33.5 diam.] worked out to 00602.radius being 16.75 ideally.BFG also gives a static diam. based on sidewall.

 

I just had mine recalibrated a second time at the dealer. The first time, they didn't have the right RPM (Rev's per mile) number for my specific tires 305/70/R16.

I went out to Nitto's website, and they have the RPM's for each of their tires. I went back to the dealer, and they set it to the proper #...

From what I could tell, they were just plugging in to the PCM and entering the #.

By the way, I'm in the Houston area, and I only found one dealer that would do it. Several dealers I talked to didn't have a clue as to what I was talking about...

 

Thanks for the responses everybody. It sounds like I am not the only one encountering less then perfect service departments I agree with not buying the controller to change the speedometer myself. I don't have any other mods and I don't see spending the kind of money the companies want for one of those controllers just to change my tire size only once. I guess that I will just keep looking at other dealers until I find one that will acutally do the recalibration for me. One thing that I am lucky about is the abundance of Ford dealers in my area, in about a 50 mile radius there is 8 or 9 nine dealers. This is truly Ford country in NW Arkansas

 

Search for "revolutions per mile". A guy posted the actual Ford print out for the procedure, listing the service card to use and all. I called 5 dealers, finally one listened to what I was saying and realized they could adjust for up to a 35" tire, which is code 00601. Made the truck drive so much better it is unreal. No more downshifting and better mileage.

But, I have also read that Ford has changed the ability to re-set the revolutions per mile on the 2002 and up models so you cannot cheat the odometer.

 

I put 285's on and my local dealer said it would cost $65 to recalibrate. I just haven't done it yet because I know they will want me to leave it most of the day for the 5 min. fix.

 

Texdoug,

I just set up an appt with my dealer. It took about 30-45 minutes to do. I think most of that was just sitting around doing nothing, then 10 minutes to actually hook up to the PCM and recalibrate...

 

Took mine to my local dealer last saturday and had mine recalibrated. Took about 5 mins then we took it out for a test ride. I went from the stock 265 to a set of 315/70. Which according to his computer is 612 rev per mile. No more down shifting on little hills going down the highway.
Had to make a run down the highway yesterday and in 50 miles on the speedo I went 51 according to the mile markers, I can live with that. The only thing that was hard to take was the $ 62.00 that they charged me to do it.

 

I installed a Superlift TruSpeed unit 2 years ago and absolutely love it. Around $170.00 and 1 to 2 hours to install it. I'm currently running 285's and my mileage on the interstate is dead on the mile markers for 20 miles. Check out Stans site for more info. http://www.eurekaboy.com/f250/truspeed.htm

The beauty of the TruSpeed is if you decide to go bigger in the future all you do is re-calibrate the unit.

If you want good info. on F-250's spend some time on Stan's site. Probably the best F-250 specific site out out there.
http://www.eurekaboy.com/f250.htm

Enjoy...

Mark

 

So, I lifted my truck 4 inches and put 325/65R18 Nitto tires on the truck. Then I was an idiot and thought..."why not kill two birds with one stone" and so I bought the Triple Dog E3 Diesel because it said it could recalibrate my speedometer and I figured the fuel economy was an added plus.

But, the fine print that is only found in the manual says that it only works for 05 through 07 6.0L engines. Great, so I wasted $350.

Then I stumble across this thread and I am thinking that I am dense but I have to ask the question. Why would I buy the Truspeed unit which requires me to modify the wiring of the truck and add one more thing that can fail when the Ford dealer can reprogram the truck. From the posts, it is clear that it is hard to get the dealer to do it, but it sounds like it is possible.

But, why not buy something like the Hypertech Speedometer Calibration that costs the same as the Truspeed and doesn't add another point of failure. No insult to anyone here, but what am I missing? Why is the Truspeed a better choice?

Scott

2003 F250 6.0L SD Crew SWB, Helo 821, Nitto 325/65R18, Skyjacker F9402M/F940S/FA499/7199/H7041/H7079

 

On the plus side, I called Bully Dog and they said that they would take the unit back so I need to send it back to RealTruck.Com | Truck, SUV & Auto Accessories & Performance Parts.

But, in my research for a solution, I stumbled on AOD, AOD Performance Transmissions from PATC, AOD Transmission, AOD Mustang, AOD and it seems that I can replace the driven gear for the speedometer to achieve the same thing as the TruSpeed except it is not variable. Since I run the same tires all year, wouldn't this be an alternative. Labor and all involved it will end up costing the same as the TruSpeed unless I can do it myself.

The only challenge is figuring out how many teeth were on the original gear without pulling it out first.

 

I talked to someone this morning at Bully Dog that said that the Triple Dog E3 Diesel will not recalibrate my truck. RealTruck.com got involved and got me in touch with an engineer that said that they have an update in the works that will allow it to work with my 03 F250 6.0L and that it should be out by the end of next week.

Scott

2003 F250 6.0L SD Crew SWB, Helo 821, Nitto 325/65R18, Skyjacker 4", Line-X bed

 

bddo is right. They input the revolution per mile not the tire size and can only got up to a set # equivalent to about a 315/75/16 size.