Tires: tire conversion, rim diameter, rim width

Question
sir,
i have a set of tires sizes hr78-14
what is the tire size in modern sizes.

thank you
                john

Answer
John,

An HR78-14 deciphers this way:

H - 1775# at 32 psi.

78 = aspect ratio

14 = rim diameter

It also mean that the diameter is 276" and a width is 8.6" on a 6" rim.

A 225/75R14 deciphers this way:

225 = section width - 8.3" on a  6 1/2" rim with an allowable rim width range of 6" to 7 1/2"

75 = aspect ratio

14 = rim diameter.

It also means an overall diameter of 27.3"  and a load carrying capacity of 1797# at 35 psi.

So while this isn't quite an exact equivalent, it is close.