speed diff and speedo gear ?

[kps36]

My son is having new BFG ATko's put on his truck in a few days. My question is: He is going from 225/70/14 to 27/8.5/14. What would be the speedo error ? Also, if I were to replace the speedo gear, how many teeth does it need to have with the new size tires?
thnx.

 

[lonewolf]

What year is the Ranger? 98(I think) and newer do not have speedo gears, it is an electronic spedo head controled by the ABS system sensors. Before that they did have gears. Check out www.TheRangerStation.com , they have a section on spedo recalibration.

If it is the computerized newer ones, then you just need a ford tech to reprogram the ecm. It is a quick 10 minute job but I have heard that it can be pricy. I need to get mine done and a friend who works at a gealer will do it for me gratis.

Hope that helps.