What speedometer gear comes w/ the 265/70/r17 F150's?
 

Does anyone know which speedometer gear (how many teeth or color) came stock on the 1997-1999 F-150's with the 265/70/R17 tire/wheel combo?

I'm thinking of bumping up my tire size to 265/75/R16's which would be the same overall size as what I listed above. My problem is I've read that some people are using the 19 tooth speedometer gear for this particular size but all the "calculators" I have used on various websites show I need an 18 tooth. The calculators all show that 235's (29" tires) use a 20 tooth gear, the 255's (30" tires) use a 19 tooth gear and the 265's (31.6" tires) use a 18 tooth gear. I can verify that I have a 20 tooth speedometer gear in my truck now, I originally had 235/70/R16's which I replaced a while back with 255/70/R16's.

So, I guess to take the guess work out of it, does anyone know which gear came stock on the 1997-1999 F150's with the 17" rims?

I have a 1997 F-150 4x4, Auto transmission, 4.6 V8, 3.55 LS Differential.

It is so easy to access the VSS gear that you ought to just check it yourself. The gear is accessed by removing the bolt (forgot what size, but know it is standard and not very big) on the driver side of the tranny. After removing the bolt just pull the plug out and the gear is right there. I did mine in the parking lot of my Ford dealership! As far as how many teeth you subtract, my truck came with 245's and it now has 285's. I subtracted 2 teeth and now my speedo is within 1-2mph of being right. By the way, my gear had 21 teeth.