tire size and speedo

[born2drive]

Hello - Im sorry if i'm double posting, I honestly don't know what to search for. So if you could kindly redirect me to the correct post or tell me what to search for... (or you could answer the question. That would be the best)

If I get larger than stock size, would the Speedo be correct? If it would be, how would I get it correct?

Also, is the stock tire size of my "93 X be 31x10.50x15?

Thanks Again!!
John

 

[jimbo74]

stock 235/75/15 converts to be about a 28.8 inch diameter tire

check out www.4lo.com for conversion calculator

the speedo will be off, but it will probably actually be almost perfectly accurate

 

[Nicaraguense]

NO NO NO NO

If you change the size (height) of your tire your speedometer/odometer WILL NOT BE accurate. THE WILL BE THROWN OFF. However, if you have a newer model your speeedometer is probably electronic (mine is) if so, you might check into a hypertech or (I can't remember any other brand name) preformance chip. Using one of those you connect it to your OBD II sensor. It will ask you a series of questions one of which the size of your tires. When you enter in the new tire size the chip will reprogram your ECC computer and adjust your speedometer/odometer accordingly. Or, when you put new tires on, you should be able to go to your local Ford Lincon or Mercery dealer and have the speedometer adjusted to compensate for the taller (smaller God forbid) tires. If your speedometer is electronic, it should only cost 1hr. of labor to adjust it. $60 cha-ching in this area. ¿Does this answer your question?

 

[Mike Mac]

Slightly off the beaten path but do the math, on my '95 Ranger, I replaced P225s with 30x10.5s and my speedometer was 9 miles per hour off, just enough to draw attention from the local law enforcement and their radar toys.