Most tire manufacturers will give you the specifications for the tire.
Go to the manufacturers website, select your specific time model, there will likely (though not always) be a section within the model page that says "Specifications"
Within the specifications section, look for the size tire that you are considering....then find the wheel rim requirements.
MOST tires of a given "size" will operate within a given range of rim widths. BUT NOT ALL.
You gotta go to the tire manufacturer to find out what width rim works for the tire you are considering.
Oh...then you gotta get one of the wonderful folks on this helpful forum to tell you what the spare rim width is.
Then...you will know if your rim will fit the tire that you are considering.
In other words....245/60/20 is insufficient information to develop the answer. None of those numbers are relevant to rim width, per se.