Proper Tire Size to Replace F-78-14 tires on 14x5.00j Trailer Rim

Updated 07/25/2015 | Published 07/24/2015

Question:

I recently had tires on rims come into the shop I work at to be changed for a 1968 trailer. The rims were 14 inch with the stamp of 14 x 5.00j. The tires were F-78 14s. Ancient to say the least. After fighting to remove them for 1/2 an hour, when I tried to install new ST215/75/14s, I could not get them to fit. They were too tight. Is the newer tire size not comparable to an F-78? I have not had to deal with this issue before.

asked by: Jenny

Expert Reply:

The modern size equivalent for the F78-14 is 205/75-14, which are compatible with 5, 5-1/2, 6 or 6-1/2 inch rims. Try that size tire, it should fit.

The 215/75-14 isn't compatible with a 5 inch rim, the rim is too narrow (I'm guessing that's what you meant by fitting too tight).

I've linked to some trailer tire FAQ articles.

expert reply by: Mike L