Hello FTEs!!
Just bought a 2018 F250 XL and acquired a set of take off 20 in Lariat wheels and tires as well as a fog light included front bumper. TPMS sensors were transferred and wheels/tires balanced and installed today; Drives like a dream!!!

So I see I need to update for wheel diameter but not a clue about how; I have read the posts about FORSCAN and see the APP and OBD2 plug in so more post reading for me!!

Any known issues with changing the wheel size other than the speedometer update? The XL does not offer this size wheel/tire as an option so thinking there may be something hiding somewhere I should know about...

I also read that I need to make FORSCAN changes to get the fog lights to work correctly so THANK YOU for posting all the info and I will be spending lots of time searching and reading these awesome posts as well as asking lots of questions!!
FYI, I do have the fog light connector on the drivers side frame rail and plan to install the bumper soon so a few more pics to come.

 

Looks great!

 

THANKS!! Really liked my 03F350DRW but even at the XL trim level these trucks are purty dang awesome!! Looking forward to getting 15+ years out of this one toooo!!

 

 

Gearing...........you're fuel mileage will go down. that's the only down side. But truck looks great, way better than stock XL wheels.

Edit: I assumed it was a diesel. Not sure what gear selection gas trucks have. I know on diesels, the XL trucks are not geared to run factory 20s.

 

Any issues with FORD (service/warranty etc) when making this change seeing as the truck came with the smaller wheels?

 

Gasser as I could not justify the price increase for the diesel; I have 3.73 rear axle gears and one calculator puts the new ratio with the increased tire diameter at 4.04 so MORE reading to see what that is going to do but I can give up a little mileage to look good... The wife likes it so that's more important!!

 

I believe that calculator was saying to maintain your effective gear ratio you need to change your gears from 3.73 to 4.04. With larger tires your effective gear ratio would be higher.
Shouldn't be a problem as a lot of 6.2s come with 3.73 and 20" wheels, mine did. I was getting 13.8 mpg average on the stock 275/65R20s and now average 12.6 mpg with 37x12.50 R20s...

 

What do you mean (XL trucks are not geared to run factory 20s)? I thought all SRW trucks had either 3:31 or 3:55. My XL came with 18" wheels and 3:55 gears. I found some 20" take-offs and had the dealer make the change for the larger wheels. Works a treat, looks good too!

 

I stand corrected, my apologies. My XL diesel has 3.31s. I tried to get 3.55s in it, Ford would not do it. But, my truck is a 2wd truck, not 4wd. Appears you Can get 3.55s in a 4wd XL diesel. My sales guy didn't tell me that, he just told me that I couldn't have 3.55s in my XL. So in my situation, when I put my factory 20s off my Platinum on my XL, it actually hurt the trucks fuel mileage.

 

NICE lookin truk!!

 

Thanks '18 F250 4X4! I really like the machine wheels you picked, I think I would have jumped on a set too! But after 3 months of keeping an eye out for take-offs in Maine its clear, the pickings are slim. Happy I found a set for a fair price, well fair price for around here anyway. Also I 'm getting old and really like chrome...don't tell anyone!

 

Adding a larger diameter wheel results in a numerically *lower* ratio, which means you have less pulling power. It also means the speedometer will read slow, and your odomoeter will not show all the miles you've actually driven. The fuel economy display will read less mpg than what you are actually getting.

FORScan or the dealer can fix the tire size issue through a simple reprogram. Your 3.73 ratio is fine for that size; as others have pointed out, you can option a gas Lariat truck with those tires and that gear ratio. It will pull less hard and be a hair slower than it would be on the standard 17" size, however. Fuel economy might actually improve...lower numeric gear ratio...at least empty on the highway.

Amazing how a new set of rims transforms an XL truck. Both of the trucks pictured look great!

 

Thanks for the info and I plan to get it recoded for the tire change once I get the new bumper installed and fog lights set up.

 

My dealer charged me 50 bucks...seemed fair! A buddy was going to use FORScan, but he was out of town at the time. We were headed camping the next day, and I really wanted the truck to read correct.