Should I use Radial or Bias Ply tires for my trailer?

It used to be that bias ply tires were considered the only way to go for trailer tires, because their sidewalls are stronger and stiffer than those of radial tires. However, recently radial ST tires have gained widespread acceptance. Both can do the job well, but there are differences. The bias ply tires will still have stiffer sidewalls and therefore be more resistant to trailer sway and so provide more lateral stability. The downside is that a bias ply tire will run significantly hotter than a radial (for reasons discussed earlier in the article). And we know that heat is one of the main enemies of any tire. Which to run is a matter of choice. Some will say that it depends on your towing habits – that you should use a bias ply for towing heavy loads because of the extra measure of stability; and that you should use a radial if you tow light loads at high speeds for long distances, because they run significantly cooler.

Of course, nobody ever defines what a “heavy” load is – is it 5000lbs, 10,000lbs or more?

I have run both radial and bias ply on my 7000lb trailer and can attest that, after 6 hours of towing at 65mph, the bias ply tires are hot to the touch while the radials are cool.

With proper trailer/axle weight rating, loading, tongue weight, type of hitch, trailer brakes, and size/weight of tow rig I don’t feel that sway and stability are a problem and so my personal preference, towing 7000lbs of trailer and buggy, is to run radials because the cooler the tire – the less it will fatigue. Your trailer, load, and needs may lead you to decide that bias ply are a better choice – especially if you have issues with trailer sway.

Do I have to run my trailer tires at Max PSI all the time?

The safest answer is yes, and many manufacturers will state this. However, some believe that IF (and ONLY if) you know the exact weight of your loaded trailer you can achieve a marginally softer ride by inflating the tires to less than the maximum pressure, using a load vs pressure chart for your specific tires.


Info courtey of BillaVista

I would suggest a good radial trailer tire and have them filled with nitrogen. Nitrogen is getting to be available at most all tire stores. It stays alot cooler and does not settle, keeping your tires "round" even when parked. I paid 4 dollars a tire to have my 10000 lb camper done and I have since done all my daily drivers and trailers. It helps your fuel mileage too.