When you see the F, it's both front wheels displayed and the R is the rears. It's not standardized as to left or right, so you'd have to check each tire and compare them to the readout to determine whether the upper/lower number is L or R. May seem silly, but it's that way b/c some people roatte their tires from side to side. On my FX35, it just lists all four presures on the same screen and doesn't specify any position, front, rear or otherwise b/c tires are rotated front to rear. The readout is more just a general indicator; the system is really to allert you of a low tire. You should always check/set them with a gauge.