jwkiss0

i have a 98 F150 4x4 stepside pickup that came with 235x70x16 tires. there are two optional factory sizes for that year 255x70x16 and 245x75x16. my question is since the vss sends a signal to the pcm and speedometer and measures the rotation of the transmission output shaft or the ring gear on the differential and sends an ac voltage signal to the pcm which determines the corresponding vehicle speed. does it matter which size tires i replace the ones on my truck with? can i use any size without affecting my speedometer operation?

89F150

i'm not to sure, i had a look at this site
http://www.eunos.com/tirecalc/
and there doesnt seem to be too much difference
you go a little faster than the actual speedo reading with those tyre changes