bbballard11

I just installed the Bilstein 5100's and larger tires, 275/65/20 Nitto Terra Grapplers. Ford did all of the work with exception of the tires. I requested that they calibrate the computer/speedometer to the new tire size. They "said" they did it. I picked it up and noticed it was off by 6% by my gps and pacing my wife's car, so I took it back and asked them calibrate it again to the proper tire size. They obviously didn't do anything the first time and just charged me the $25. After having the truck for a few hours, the service manager called saying their computer could not program the tire size any larger than the stock tires, 275/55/20, and that was the highest Ford's system would go.

Has anyone had this successfully done? I can't imagine Ford not being able to calibrate the computer on these trucks to a larger tire size than the stock tires.

Questions for those who know more about this topic than me:
1. Are there negative consequences associated with the computer not being calibrated to the actual size tires on the truck? Ie; performance, shift points, mpg's, etc.
2. Is there another option to recalibrate the computer other than by using a tuner?

I have searched the forum and couldn't find the answer to my questions. Any feedback would be greatly appreciated.

Thanks!

MPD165

I assume your truck is a least a 2009.

Unless they drastically changed the computer, which I highly doubt, they should be able to reprogram the speed-o-meter for the new tire size, or at least get it close.

I had a 2006 that had 255/65/17's on it, factory OEM, and when I replaced the tires I put 275/65/17 on it. The service department was able to reprogram the speed-o-meter with no problems. They actually told me they did it after they reprogrammed it.

I now have a 2009 that I just replaced the 17's on and went with factory OEM size 20's. They wanted to charge me $100 for the reprogram. So, it can be done.

I really dont have an answer other than they just dont want to do the work to find out what the revs per mile are. You can always look on tires101 and see if you can find a tire size with the same or close to the same revolutions per mile than your new tire size.

Post an update to your results.

MPD165

AC Man

There was a thread on this subject just yesterday. In a nut shell, Ford can only chose a tire size that is available from the factory. to program your truck. All you have to do is get the diameter of your tire,and pick the closest one that Ford offers. I have 315 70 17 tires which is the largest they offer on the Raptor, so they are able to program mine exactly.

Wyocountrykid

Im also looking into this right now. Here is the link to my thread I started yesterday. If I find anything else out I will post it. So far what I think it comes down to is if you have a good tech or not. You can read through my post and if it helps.
https://www.f150forum.com/f38/dealer...2011-a-135091/

Jaba1974

I had a leveling kit installed with bfg 285/65r20. I think it has affected my navigation. The arrow isn't centered on the road. Who can help me with this? Has anyone had this problem?

smgfx4

I had the same thing. I had to buy a hypertech speedometer recalibrater. Bought it from my dealer for about $200. It took about 5 min to install. I would have bought a tuner but my dealer will void my warranty with a tuner. The hypertech will not.
It also corrected my navigation.

Jaba1974

Can you give me more information about the hypertech item you got? Did you install it yourself? I see you said it corrected the navigation arrow.

Keith460

iTrader: (1)

I don't know if it will correct s navigation error since the system relies on satellite feed to the roof antenna. But, I was able to correct speedometer errors with the HyperTech Speedometer Calibration device I found and bought for $160.00. Easy to do and doesn't void warranty.

smgfx4

I think this is the same thing I used. It looks just like a programmer, it just doesn't change anything but tire size and gear ratios. If you want to add performance tuning to this you can have it added by hypertech anytime you are ready. All you do is plug it in and follow the instructions, 5 minutes in all, maybe.

As for correcting navigation, it does that too. For some stupid reason fords navigation works off of satellite and the speedometer. Your speedometer has to be accurate for it to work properly.

mrv99

I had this problem on my Nav as well. Do a few turns and you are not on the road. The solution which was suggested is disconnect your battery for 30 min and it will fix it. I did just that and my Nav has been spot on. I have 305/55/20's so they are far from stock size. B