Here is how to read the information on your tire sidewalls and what it means.
I would think that tire RATIO would have a large effect on trailer tires. A higher aspect ratio would mean the sidewall is taller and (I would think) more flexible causing the sway mentioned earlier in this thread. I didn't see the tire numbers quoted and would be interested in what they are, the 15" vs the 14". You could have 15" tires that are the same diameter as 14" tires by adjusting the ratio. Cest nes pa?
Here is another link very similar but seemingly clearer:
O! O! I just remembered something. When my parents bought their first car with radial tires, we noticed a shimmy in the car. You could actually push the car sideways and it would wiggle a bit in a sideways direction. A radial tire has the cords aligned in a radial direction parallel to each other, hence the name, whereas bias plys have the cords at an angle and crossing each other. The reason for radials is they run cooler and smoother because the threads 'lay down' on the pavement. So probably radials would not be suitable for a trailer and would result in the sway, shimmy, or side to side movement described earlier.
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