I put on my 325/70R17 (35") on my 06 F250 a couple of weeks ago and found out with the GPS that my speedo was reading about 5mph slow.

I was driving by the dealer today in my company car so I stopped to order the new style HCFM valve drain and to see about recalibrating my speedo. The not-so-friendly service manager said it was $75!!! (This after a $45,000 truck!) She wasn't sure if they could do 35" (596 rpms) so she went to ask somebody. Comes back and says without recalibrating, my tranny will shift too late and that since it is racking up incorrect miles that my warranty is voided I asked, what do you mean, like for the axles, gears, and such? She says no, the whole warranty WTF? I have been very cautious to not touch my engine (chips, tuner, etc) so as not to ruin my 5 yr/100,000 warranty. I can't believe that adding bigger tires would void my warranty for say a bad injector, or an oil leak??????

I thought that the tires would only change the speedo and the odometer, and that the tranny would self adjust as needed? It runs and drives great, doesn't seem like it is late shifting to me. I am thinking they are wrong on this.

So here is my dilema: Do I go get the speedo recalibrated so it is adding up the correct mileage, or go by another set of tires (I sold the stockers, but kept the wheels) and bolt them on in case I need to take the truck in? Seems like a big waste. I didn't have my truck there and didn't give my name, so they don't know I put the tires on at this point. I am not trying to be sneaky, just don't under stand the logic behind voiding the bumper to bumper for bigger tires

Are all Ford dealers this way? I love the truck, but I don't care much for them. I have been buying my oil and filters at another Ford dealer....can I just take my truck to any dealer that I feel like? There are plenty around, this one just happened to have the truck I wanted at the right time.

 

I wouldn't hesitate to go to a different dealer. You owe them no favors of your business.

 

Sounds like a lot of rot to me. There have been discussion about the warranty and their ability to void it before but usually in the context of something a little more drastic. BTW my speedo is off 3 mph and no change to the tires or anything.

 

I just want to clarify that I have no intentions of dishonesty....I put the bigger tires on and I will take responsibility for anything that this "modification" would damage. Even though I don't think it is possible the tires will cause damage since I have no plans to offroad the truck or work it excessively, I would take responsibility for an axle, gear, suspension, or related problem. I don't see how the rest of the truck and drivetrain would be affected, and for them to make that statement had me in a rage and I had to walk away.

Let em go after the NOS, propane injected, cat removed, straight piped, 12" lift, 40" tire wearing trucks And I mean no offense, just exaggerating my feelings about bigger tires voiding the warranty on this very expensive truck.

Thanks for listening

 

Well hell! Then I want my warranty extended, because when I bought the truck the speedo was 2 - 3 MPH fast. Does this mean I get my warranty pushed up to 40 - 42k.

 

No. Here in Utah virtually all the dealers sell lifted (brand new) trucks with larger tires...And recalibrated speedometers. Find a mod/lift friendly dealer-

 

Come to think about it Utah is right. My dealer was going to lift it and everything.

 

Mine is off too. It reads about 3 mph high according to the GPS.

I agree, find another dealer. Not sure I understand their problem - I thought the dealer gets paid to do work, whether warranty or not.

 

good point!

 

Find another dealer... Sounds like she was having a bad day.

 

You'll want to call around and confirm this, but someone on one of these forums said that they (dealerships) can only calibrate for OEM sizes on the newer trucks. So, before you plunk down that $75, make sure they'll actually get the right numbers in the PCM for your 35" tires.

 

Read your owners manual very carefully!
Then do a search on Magnuson/Morisson Warranty act(Sorry Spelling could be way off) It will explain alot of your questions
Rich

 

the act says ford can not void your warranty based on that alone. they would have to prove it caused a failure. but with ford footing the bill they would find some way to say it caused it.

http://www.ftc.gov/bcp/conline/pubs/...#Magnuson-Moss

 

Find another dealer - when I modded my '96 t-bird with 3.73 gears and Auburn HD LS, with a Superchips, they were more than happy to do any warranty work.

Including finding what was creaking in the rear suspension after I put in the 3.73 gear (myself). Body attachments on the rear K frame...

 

You could find a new dealer but... Since you don't have any problems to speak of yet, I think it would be a hellova lot of fun to push the issue with such an ignorant dealer.

Regarding the callibration: 1) You should recalibrate to get the shift points and RPMs closer to stock. 2) 35" tires is the largest that they can calibrate 3) Even after the calibration, you will still be about around 2mph off. At least that's what I found from my dealer when I went from stock to 33s to 35s on my last truck. They were all off by 2.5mph. My new truck, untouched by any dealer and totally stock, is 2.5 mph off. A this point I like it. I set the cruise to 70 and I'll never get a ticket. haha

Mike