have a2017 dodge ram with 20 " tires just by chance found out my spare is 235-70-17 and dodge is putting temporary spare tires on there trucks always was told not to put different size tires on the same axle dodge said there is no problem is this correct thank you
Chances are your 20s have a lower aspect ration than the 17 and the outer circumference is very close to being equal. Even then the spare is just to get you to a place to repair or replace the faulty tire.
There is no problem. Dodge installed the 17 inch spare in your truck. Dodge designed your truck. Why would we ever contradict the people who designed your truck?