Hi all,

I am a new member to the forum. I have been viewing this site for a long time, and decided to join because I need advise, and want to share experiences.

I have a question, and hopefully am posting in the proper forum...

The question is:

I just picked up 2006 20" 6 spoke wheels with Pirelli tires, and want to install them on my 2004 F-150 Supercrew 4x4. I noticed that the new wheels and tires are slightly "taller" than the original 18" Lariat wheels and tires that are presently on the truck. If I put the new 20" wheels on, will it mess up my speedo and shift points? Do I need to have a reprogram...if so, can the dealer do it?

Advise sought....and glad to be aboard !

 

Welcome. Yes if the tire is taller, then it will change the speedometer. There is a chart that tells you the percentage of change, it will probably be in the 3% range. Maybe someone can tell you where to get that chart. The dealer can reprogram, but I dooubt I would pay to have it done. One option is a prgrammer to set it yourself.

 

this is the tire calculator: http://www.miata.net/garage/tirecalc.html

but, it seems the 20's are actually a hair smaller than the stock 18's.

stock 18" 4x4 tires 275/65/18 = 32.1" diameter

OEM 20's Pirelli 275/55/20 = 31.9" diameter


I don't think you have to worry about doing anything.

 

Yep, if those are your numbers, I agree.