Last night towed boat home after beach about 20 miles. Smelled something burning when at a red light close to my house. When got home found out smell was coming from the trailer tires. Felt the wheel bearing area and noticed that 3 were hot (just more than I could touch) 1 was very hot (burned me) and 2 just warm. I am joing to get a infared temperature gun to verify. my question is how warm/hot do wheel bearings typically get? Also if getting hot what is normally the cause/causes?

that's wayyyyyyyyyyyyyyy too hot, you have a problem, fix it b4 you go anywhere else

mine run about 30* over ambient and never exceed road temp using an infrared gun, tire temp is about 5-10* warmer then bearing temp

Which ones were the hottest? Was it the wheels furthest-forward? Was the truck sagging?

This happened on my trailer once. I had to borrow a truck (Ford F250) to move my boat across town. The rear suspension couldn't support the tongue weight so it sagged pretty bad. By the time I got home the wheel bearings on the two front wheels on the trailer were hot. I suspected it was because they were supporting the majority of the weight.

First and only time it had ever done that.

Brakes dragging?

On the hottest days pulling through 100+ you should be able to hold your hand around the cap without being burnt. Whenever I stop to fuel I do a quick walkaround and touch each hub. You can feel the difference between the axles with brakes and the idlers. If they are too hot to touch you have issues. Temp gun is nice but not required...

Not that we need an excuse to by a cool tool but nice to have one

A little off subject but an infared gun would be a cool tool to have in the box. Where do you buy these? And what are the good brands to own?

I've seen them at Napa and Advance. You can buy them online too.

It's a priceless tool when it comes to troubleshooting. You can spend between $35 and $85 bucks on one.

I check the bearings, brakes and tires every stop.
The best test is uniformity. If anything 1 part is 10-15 degrees or hotter than the same part anywhere else, you've got a problem. Only difference is the tires that are in the sun vs. the tires that are in the shade are usually 10-15 degrees hotter accordingly based on sun exposure.

Bearings too hot to HOLD onto are either running dry or adjusted too tight or starting to pit. Pull em and replace em is your best bet.

Raytech is best make sure you get the one with the laser pointer so you know where the temp is taken from.