I plan on replacing my 17" wheels with the stock 255/65R17's and replacing them with someone's take-off OEM 20's. Probably from an FX4 or Platinum. What would the tire size on the 20's need to be to maintain the same overall tire diameter?

 

255/50 R20

But try different combinations at http://www.1010tires.com/tiresizecalculator.asp

It depends on if you want to go wider.

 

This is the correct size.

 

Don't forget to have the tire pressure sensors swapped over to the new rims.

 

How hard it is to do that? Last set of tires I changed out was on a '99.

 

Do you have the TPMS system? If not, you won't have to worry about the sensors and, if you are going with OEM 20's there's a good chance they will already be present...you will have to have them reprogrammed though. I did the same swap on my '05 Lariat - went with OEM 20's from an '08 Lariat (replacing my stock 18's) and there was less than a 5% diff in overall tire/wheel diameter. One word of caution, my '05 Lariat was a 4x4 and the 20" OEM wheels/tires made it ride rougher. I liked the firmer handling (got rid of the "pogo" feeling from the tall sidewalls - but it did ride noticably stiffer..was fine around town - but I did notice it on the SoCal Freeways...

Good luck!!

 

yea it has the TPMS, sounds like it may be more trouble than it's worth, I like my stock wheels well enough, just thought 20's would look better.

 

Since you have an 09, you can use your TPMS sensors on the 20's. The most you would have to buy is valve stems for under $20.00 worst case. You might be able to re-use the stems and sensors and buy nothing. You can re-use the sensors for sure.

 

thanks for the input, how hard is it to reset the TPMS to match the PSI of the new tires?