tire/rim size swap questions

[dougray]

hello i have a 2001 explorer xls it has the stock rims/tires P235/75R15 . i have a chance to swap out these for a set of rim/tires from a 1999 ford ranger xlt but the ranger has P255/70R16's i know if i just swap these the speedometer will be off but my questions are what size tire would i need to purchase for the 16" rims so the speedometer will be close on the 2001 explorer or could i simply change out the speedo gear (take the one from the ranger?) the explorer and ranger have the same engine/tranny? both are 4 wheel drive,etc. any info on this will be great...thanks in advance.

 

[rwenzing]

The 255/70R16's are about 1.2" taller than the 235/75R15's. This will make the speedometer read about 2.5 MPH lower at 60 MPH than it does with the stockers. The speedometer is electric so there is no gear to change. If you want to have it exactly right, a dealer can use a special tool to change the tire revs/mile parameter in the 4WABS Module.

If you want to find a tire with a comparable outside diameter to the originals, you can try different number combinations on this calculator:
http://www.miata.net/garage/tirecalcold.html

 

[dougray]

....

thanks for reply, yes the tire that is close is the P235/70R16 i am going to check out the dealer programming thing first.