I got 255/70R16 on my truck now and wanting to get a slighly taller tire. possibily 265 or 275, i am just curious if it would affect the speedo if any or anything els for that matter thanks

 

Changing to alarger tire size will change the readings of your speedometer/odometer. It will read slower than actaul. The easiest way to find out how much would be to drive it on a highway with mile markers, and see how far off your odometer is compared to the mile markers. Example: If your odometer isslow by 1/10th after one mile, your off by 10%, i.e., when the speedo reads 60 MPH, you're actually going at 66 MPH. Odometer slow by a 1/2 tenth would make the speedo slow by 5%, and so forth. Check it over a few miles, to get an accurate check. There are formulas to determine how much various tire sizes will affect accuracy of the speedo.