Now that i have 35s how bad is my speed-o off

 

when im doing 50 im actually doing about 60+ mines pretty jacked up.

 

superlift has a programer thing that re-calibrates your computer to your new tire size. I know nothing about this product....but its called something like "Speed-Cal" or something like that.

I believe Bamachips has this option.

 

when my speedo says 40 its actually ~42, 50 or 55 its about 5 over, when it says 61ish im doin about 67.. then around 66-67 im goin about 74. and anything under 40 isnt anything to worry about

my 0.02... unless you were planning on getting a programmer, don't buy it just for this reason lol

 

according to this "speedometer to tire speed calculator" that i've got, if your truck originally had 245's, and now you have 35's (305's) your speedo should say 65, but your tires are doing 75. however, ford rangers are noted for having their speedo's set a few miles faster than the truck is really doing. my truck, when new, was going about 3 mph less than what the speedo actually read. so, when i went from 245's to 265's, my speedo is now dead on with what the tires are actually rotating at.