When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
Most likely the truck originally came with 18" rims & a Previous Owner installed the 20" rims and neglected to get a 20" RIM & tire for a spare. I upgraded my original 17" rims to 2014 20" Platinum rims and have yet to find a single 20" rim for sale so I have a correct spare
By varying the aspect ratio, a mounted 18" tire and wheel assembly can have the same diameter as the fancy looking 20" tire and wheel combinations having lower profile tires.
why does f-250 have a 18" spare tire ,when truck has 20" tires
So when you get a flat and put the spare on, you have a reminder to get that flat repaired.
Almost all vehicles have a steel-rimmed spare tire, and those generally aren't made in larger sized rims (generally).
You also must remember that, as stated above, by varying the aspect ratio you can get pretty close to the same OD regardless of rim size.
There won't be any fitment issues, either. Your spare is generally the smallest size that can fit over your braking system without rubbing, regardless of what wheels are actually on the truck.
Most likely the truck originally came with 18" rims & a Previous Owner installed the 20" rims and neglected to get a 20" RIM & tire for a spare. I upgraded my original 17" rims to 2014 20" Platinum rims and have yet to find a single 20" rim for sale so I have a correct spare
Incorrect.
I had a 2011 lariat and still own a 2013 lariat that came with 20" chrome clad wheels and both had/have an 18" steel spare with 275/70 tires. Both were purchased new, both had the 20" wheels on the window sticker. It's a money saving feature as mentioned previously.