Ok guys here is the question. Currently on the truck is a 255/70/17. If I put a 265/70/17 on will I need to have my speedo and tranny recaled? Im looking at the Pro Comp All Terrains. Thanks for your help. I have talk to a few shops and they say that it could cause some issues with the computer but there not sure. Thanks for the help.

 

i don't think so. that's not a real big change, so i think those guys are wrong. i'd try some different shops.

i went from stock to 285/55/20 to 305/65/17 without needed to recalibrate the speedo.

 

It's a taller tire, so your speedometer and odemeter will be off. Get a tuner, it will correct it and provide much more performance too.

 

People change by a much larger percentage than that without adusting computer settings. You'll be fine.

 

No need to reprogram for that small a change. Difference is just over 1 mph.

 

Thanks for all the input. I was thinking the same thing but just wanted to check. thank again.

 

a few good tire sites, enjoy

http://swatt.j.porter.name/tech-cent...ire-calculator
http://www.discounttire.com/dtcs/infoTireMath.dos
http://www.bmwtips.com/tires/calc.htm
http://www.car-videos.com/info/tirespecs.asp
http://www.tirerack.com/tires/tiretech/tirespecskey.jsp
http://www.1010tires.com/WheelOffsetCalculator.asp
http://www.dakota-truck.net/TIRECALC/tirecalc.html

 

Just to be clear, the change is relative, so it will be a percentage off. 1 MPH @ 60mph, 0.5mph @ 30mph, 1.5mp @ 90mph. Likewise, the odometer will read lower by 1.77%. So, for every 1000 miles your odometer tells you, you actually drove an extra 17.7 miles.

 

Yes, I should have stated just over 1mph diff at 65. Actual is 1.15mph at 65 per the tire calculater at www.discounttire.com.

 

Would I be able to bring the truck to ford and have them recal the computer? The only reason I ask is because I have to sign a form stating that the odometer is correct when I trade it in. I haven’t purchased the tires since im waiting for them go on sale in Oct. buy 3 and the 4th free from pro comp. Thanks again for all the help. I didn’t know that going from a 255 to a 265 would make such a change. I guess it all is relative to the .1 difference in the height.

 

Yes you can get it corrected, and one of the tire sizes available on the list is 265/70R17. Not all tire sizes are available on their programing. I just had mine done recently and my dealer did not charge me, but don't expect that to happen in all cases. I have heard of charges of up to $80 to have it done.

 

kingfish51 that is correct on the 80 bucks just called one of the local dealers and that is what they said. 80bucks if they can reprogram it. Kind of odd that they dont know if it can be fixed. You would think that since ford likes to use these odd ball tire sizes they would expect this. Although i guess its not just a ford issues guess alot of the car companies like to do that. Thanks again for all your help. I like the pro comps because there actually a truck tire rather then a car tire. Im not looking to buy a programmer for a one time use so I guess ill pay the 80 to ford, plus that means that I can screw up the computer.

 

They programming is set up with tire sizes that are OE. Not for aftermarket. On the list I saw when it was being programmed, I saw the 235/75r17, 255/70r17, 265/70r17 and 275/65r18 and whatever the tire size is that is on the 20" wheels. Maybe a couple of others. The tire size I put on my truck, 275/70r17 is not on the list, but it happens to be the same diameter of the 275/65r18, which is what I had them set it to.

 

cool so i should be good with the pro comps 265/70/17 awesome makes life a littler easier. now i just have to see if it is better to buy now or in Oct when its buy3 get 1 on.