What Happens If you Mix a Radial and Bias Ply Tire on a Trailer

Question:

I understand its no advisable to mix an R tire with D tires...but why, what could happen? Whats the actual danger? I have a 6foot x12 utility trailer with a single 3500 lbs. axle. My current tires are aged out but I have a new D spare that I was going to put on the ground and buy one new tire. But, my son-in-law just gave me a brand-new R tire. The trailer maybe sees 500 miles a year in short trips. Im just trying to understand why its not advisable to mix the two. Thank you.

asked by: Rex T

Expert Reply:

I'm going to be perfectly honest...the risk is pretty minimal BUT due to the construction differences between bias ply and radial tires the sidewalls do end up flexing differently which could in turn end up with unpredictable ride quality/handling/performance. Is this going to be an issue in normal, non-emergency travelling? Probably not, but if you were going higher speeds and needed to make an emergency maneuver there's a chance the trailer might not handle the situation as well with mismatched tires. I know people mix them all the time and most will never have anything close to a problem. There's even people that use vehicle tires on trailers which is not a good idea at all but it really comes down to how valuable it is being as safe as possible.

expert reply by: Jameson C