Hello!

I heard that a bigger tire size would afect the accuracy of the speedometer and cause problems with other things. Is this true?
I have a stock 1997 F-150 ext. 4x4 with tow package. I was told that 285/75/R16's would look better than the stock tires. With this choice would I experience those problems, or would there be no problem?

thanks

mike

 

I have a 99 4x4 with the 16" rims and i currently run 285/70/16 BFGoodrich All Terrains on it. It definately looks nicer and tougher. It doesn't create that much of a change, at least to me. At first it seemed a little doggier off the line, but then again; i didn't buy it to race.

I haven't had any problems whatsoever with this size tire. And the BFG's are flawless in my opinion so far.

Best of luck

 

The previous owner of my truck had changed from the 235/70R16 to 265/75R16. Only downside I see is the loss of some oomph when going uphill. If I towed something it would probably make a bigger difference. I had the dealer check the speedo when I got it; the mechanic ran it alongside another truck and it was right on the mark. He said that 97's can be reprogrammed by entering a formula into the computer that compensates for the change in size; 98 & later trucks use a different method. Personnally I think a 245/75R16 is the smallest tire that should come on these trucks with my favorite being anything in the 265/75R16 range; no experience with the 285s.

 

It depends on what size your OEM tires were as to how much the spedometer will be off. My Screw came with 255/70s and I went to 285/75 BFG AT KO's. My spedo now reads 5 mph slower than I am actually traveling. I beleive on the 97's you can change the spedo gear in the transmission and correct it for a few dollars. If you post your OEM tire size and gear ratio someone may be able to tell you which gear will correct your spedo , or at least get you close. By the way 33's (285/75 or 305/70) look a lot better than any of Ford's OEM tires! You won't regret going bigger.