Hello,

I have an XLT with the 18 inch factory rims. There is a set of the 2012 20 inch OEM rims/tires for sale near me that I'm thinking about buying. Do they just bolt right on or do I have to do something with TPMS? Thanks

 

You can get 20"s on the truck as OEM so it should be no problem

They say a 6.7" or 170mm bolt circle for a SRW

If you have TPM's on current tires and not on the 20"s you'd probably want to add/swap into the new tires

 

Thanks.
I'm not sure if I have TPMS on the tires now....I'll have to test it out.

 

I just checked Ford's website, it says that TPMS is standard on 2012 XLT's. So that means that I have it already. Can I swap out the tires myself or am I better off going to a tire place and letting them deal with the TPMS?

 

What's your gear ratio with the 18"s?

 

I have the 3.73's

 

The TPMS are inside the tires. So as long as you have the proper tools to break down and remount your tires, You could do it.

What are you paying for the 20" rims? I bought a set of take of tires from the local Ford dealer and they came with the Lariat Chrome 20" wheels, All I wanted was new tires, But dealer said the price he quoted me was with or with out the rims. Same price. So I took them with the rims and figured I get something out of selling the rims. Need to figure out a fair price and get them sold.

 

The 18's have a diameter of 33.2 inches (11.2 width)
The 20's have a diameter of 34.4 inches (11 width).

Does this mean that my speedometer is going to be slighty off?

I would be buying the tires and rims together so they just need to be put on the truck.

 

Yes, your speedo will be off. You will need a programmer or a trip to the dealership to update the PCM. At over 1 inch diff it might be more than "slightly" off.

 

At 34.4" diameter, the circumference is 108". At 33.2, it is 104". 4"/104" = 3.8% more distance traveled with each rotation than stock. At 60 mph indicated, you would actually be travelling at (60*1.038) = 62.3 mph.

Your opinion of the importance of your speedometer's correction may vary.

 

Thanks for the info guys. I'd probably check it out with a GPS after the install. If it's close I'd leave it as is. If not, then I'll have to have the dealer update it.

 

It's not a big deal for the dealer to reset it for the OEM 20" tires. But they can't always reset the sepeed for tires bigger than the OEM tires.

I don't know if it is a problem resetting the computer if you have the 18" and go to the 20" Just ask your dealer.

 

My speedometer always read about 3mph fast so when I changed from 275's to 295's it is exact now(Checked with my gps). If you have a gps you may just want to put them on and check it against that.

 

I've yet to find any vehicle with an accurate speedometer

Bike or car or truck

 

My point being he may not need to worry about having the dealer try another setting as it may be more accurate now.

To the OP be aware that if the dealer changes the tire size to a size that was not available from the factory on your truck it will throw a CEL. Many of us with 18" wheels and 3.31 axles are running into this.