And i could be wrong but you dont have to buy anything to fix the speedometer. its a built in system with the truck. you do something with the mile tracking buttons next to the speedometer to change the ratio of the tires. but before you do that download a speedometer app on your phone and see how accurate your speedometer is. it turned out for me that my speedometer was more accurate with my 31' tires than when i had the 235/75's on there. so i didnt change anything.

 

yeah you dont buy nothing to make the speedometer show the right speed. http://www.fullsizebronco.com/forum/...d.php?t=207131
this should tell you how to recalibrate it

 

Go for some 30x9.5r15

 

oh but you can buy something to re-calibrate LINK, and if you go the truck route you only have like 6 trys before you cant do it anymore.

 

on another note too, if your only going up a few sizes your wasting time and if you don't do it right messing the speed on your speedo up all together.

I went from a 235 (29") tire to 36" mud tires and my speedo is only off about 5 mph.

 

Is there anyway to recalibrate the speed on an 88?

 

There's little gears in the back of the gauge cluster or something you replace to recalibrate an 8th gen. Only costs a couple bucks I think

 

Just find out what speed gear u have in the t case and figure out how much a tooth gives u for speed increase