Wheel bearing temperature

[3Ts]

There is another thread about the "light on a trailer axle", but the question I have is just how hot can a wheel hub be and still be safe?

Here's what I saw this weekend. The parking lot (concrete) temperature was 140*, the tire side wall temp was 120*, the wheel hub was 220*. To me the 220* seems to be reasonable, but is it? The truck front hubs were 175*, rear hubs a little cooler.

Now, one more thing, the 220* was on the left rear of the trailer, the other three wheel hubs were in the 170* - 180* range, so the one definately needs to be looked at. However, it will be awhile before I can get to it and I will probably have to make the trip again before I can check the bearing. This is on a 7000# rated trailer carrying ~4000# so loaded trailer is ~6000# so is under max weight but not by much. Trip was about 3 hrs at highway speeds with 15 min break after about 2 hrs on the road.

Thoughts?

 

[Bearsixty7]

Been months since I pulled a trailer very far but I keep an infrared handheld thermometer in the truck and sounds like you do the same thing I do. As soon as I stop I jump out and measure all trailer hubs and look for an outlier. I don't think any of mine were over 200, I was actually thinking they were closer to 140-160 so that 220 would cause me to break it down and check the bearings and repack if they felt ok, more than likely replace them. The other issue is many people over tighten the axle nuts causing too much friction on the trailer bearings, you may just need to loosen the 220 one.
To tighten a trailer axle nut I always spin the tire while gently snugging the nut then back off and repeat a couple times then just snug and back off enough to get the cotter key through the castle nut.
Some axles have a torque spec to tighten to then back off, I think 5k axles are 50ft-lbs.

 

[radios1]

I remember one time I tried marine grease on the front axles of a car, it's supposed to be very usable, but what a big mistake that was!. the whole wheel got red hot!. you could smell and see it at night!. possibly marine grease has special wheel bearing formula for axles, the grease from a grease gun is no good for that!.. it don't dry out, or be affected by water like lithium grease, so I thought it would be excellent..

 

[Bearsixty7]

I remember one time I tried marine grease on the front axles of a car, it's supposed to be very usable, but what a big mistake that was!. the whole wheel got red hot!. you could smell and see it at night!. possibly marine grease has special wheel bearing formula for axles, the grease from a grease gun is no good for that!.. it don't dry out, or be affected by water like lithium grease, so I thought it would be excellent..

Marine grease is for boat trailer axles so they don't wash out when they get submerged when launching and retrieving boats. I only use marine grease on my boat trailer and never had a hub get warm in 20 years, ok 18 years, I haven't trailered it anywhere the last 2 years.

Bearing & Chassis Grease - AMSOIL

Resists water washout and degradation. Unparalleled protection for boat trailer wheel bearings and other components frequently exposed to water. Stays in place, lubricates and protects against rust.

 

[radios1]

Marine grease is for boat trailer axles so they don't wash out when they get submerged when launching and retrieving boats. I only use marine grease on my boat trailer and never had a hub get warm in 20 years, ok 18 years, I haven't trailered it anywhere the last 2 years.

Bearing & Chassis Grease - AMSOIL

Resists water washout and degradation. Unparalleled protection for boat trailer wheel bearings and other components frequently exposed to water. Stays in place, lubricates and protects against rust.

I did a proper cleaning of all grease leftover from the lithium bearing grease, using kerosene, and the only grease that didn't make the axles hot was lithium wheel bearing grease, which is a lot thinner!..

 

[RoyKing]

If you can't keep your hand on it too, hot. Most bearings are china and are hit or miss. If you can find a timken bearing it will last.

 

[RickB]

If you can't keep your hand on it too, hot.

Agreed.

 

[oosik]

If the "standard" is - too hot to hold your hand on...... then 120F would be the absolute upper limit.

 

[nisaacs]

You might have a brake dragging on that one or works better than the other 3. They all seem too hot. I would turn your brake controller down some. I would also check into it, sooner than later.

 

[LouNY]

If you can't keep your hand on it too, hot. Most bearings are china and are hit or miss. If you can find a timken bearing it will last.

Yep, I don't tow a lot but when I do every stop is a walk arourd and check the hub temperatures with my hand as long as I can touch them for a second or two and not get a burn life is good.
I have regreased a bearing in an auto parts store parking lot, easier there then haveing to try and repair on the side of the road.