I received a question about irregular wear on trailer tires. The owner said that all four tires showed indications of abnormal wear in some locations.

This is definitely “brake flat-spotting” from trailer tire lockup. Higher force on relatively light-loaded tires can cause this. Once there is a spot, the next time you hit the brakes the tire is more likely to stop at the same spot again.
Here are examples removed from passenger cars.

If you lock up the brakes on your car, you will probably feel a new vibration. But if you lock up a tire on a trailer or on a toad, you will not feel anything. Unless you do a close visual examination, you will probably continue driving.
You need to adjust the brake setting to decrease the tendency for lockup. If you discover this on a tire, you can continue driving on it. However, you need to keep an eye on the level of wear as once you have a flat-spot, the tire is more likely to stop on that spot and continue to wear faster there.
Have a tire question? Ask Roger on his RV Tires Forum here. It’s hosted by RVtravel.com and moderated by Roger. He’ll be happy to help you.
Read more from Roger Marble on his blog at RVtiresafety.net or on RVtravel.com.
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Flat spotting might cause the loss of a few dollars in replacing tires but the most dangerous part of locking up the wheels on your trailer is it can cause your trailer to try and pass you, causing a serious accident or death.