biggest tires

[sod40sport]

i just did the shackle and tt on my 98 sport. From you guys experience what would be the biggest tire i can fit? Im thinkin of goin with a 265 75 16. These damn 16 inch rims makes things complicated, but dont have the money right now to change them. Oh by the way i have 255 60 16 on right now. thanks

 

[01EB5.0]

265/75R16 should fit fine. Arn;t the stock ones 255/70? not 255 60?

 

[sod40sport]

im not sure about stock sizes, but the 60 series is what i have on there right now, its how i bought it.

 

[01EB5.0]

ahh...thats kind of odd. yeah the 265.75 will fit fine though...you'll have to get your speedo computer recalibrated

 

[sod40sport]

about the speedo thing. do i have to bring it somewhere like a dealer to do, or can a transmision place do it. Oh and about how much does it cost. Ok one more question, will my speedo still work (even though itll be untrue) when i put the tires on?
thanks

 

[01EB5.0]

Your speedo will work, but it'll be off as you assumed. the computer reprogramming happens at the ford dealer. I think it is around $100 i doubt a tranny shop can do it..they cam notmally change out speedo gears, but yours isn;t like that..yours is electronic.

 

[Robert]

Your transmission will also shift badly if you don't get your speedometer recalibrated. It is hard to explain how it felt. I just remember that the week that I drove it before changing mine I didn't like the way it was shifting. Someone makes an electronic calibrator for your transmission now. You can use it to change the calibration of your speedometer as often as you like. The Ford PCM can only be changed a certain number of times before it can't be changed anymore. The calibrator is more expensive than one calibration at Ford. If you do it twice though, it's cheaper to get the calibrator. I think summitracing.com sells it for about $150.

 

[01EB5.0]

I don;t think it'll hurt the trans to drive on ther new tires before the calibration. when I did my converion i noticed it shifted at different speeds, but thats expected of any drivetrain change

 

[Robert]

In the short term, I am sure that driving on it without recalibrating won't hurt a thing. Long term though, I wouldn't want to chance it. I just coudn't put up woth the annoying shifting for any longer than the week that I did. Since the Explorer transmissions are already notoriously weak, I wouldn't want to subject it to anymore stress than necessary. Shifting it at a speed that it wasn't designed to shift at isn't good for it. We are probably only talking very minor stress so instead of a transmssion lasting 100K it might only last 95K. Who's to say what caused it.

 

[01EB5.0]

I think bigger tires in general could add stress to a tranny no matter if you reclibrate the speedo or not...some people never recalibrate...some guys i have talked to didn;t know how to recalibrate and have been driving with the speedo off by like 4-5 MPH for years. It's just when you get bigger tires your truck and you both have to change your driving charectoristics. I know I can just tell when my truck will shift from the many years of driving it. Now when I go drive someone elses truck it feels like it's shifting wrong, when it isn't....it's just my perception. The truck has a momory that remembers your driving style and this memory changes. say you tow a trailer for 3,000 miles. The memory will change the shifting habits to account for the added weight. you take off the trailer it'll feel like it shifts different for a while. Saem thing with the tires. they are an added stress and if you drive on them for a while without recalibration, the truck's computer and you yourself will get used to it. i'm not saying thats the right thing to do, but personally I think it won;t do any damage to the tranny...all the tranny does is shift....the only thing that might not be good is if it was shifting in and out of overdrive a lot because of the added "weight", but thats all I can see happening.