Uneven Bearing Temp

[Car1800]

I have run into a situation that I have not seen before. The bearings on the rear axles are about 30-40 degrees warmer than the front axles using temperature gun. I have pulled the bearings and no problems. They are not overheating just running warmer. I have never seen this much difference before. The thing that changed is the truck, from a 2011 Ram to a 2019 Ram and a B&W hitch. The truck is higher of course. The camper is sitting 2 inchas higher in the front by using a level and tape measure. Is anyone seeing higher temps on their rear axles under this type situation? The rv has Trailaire suspension.

[Cummins12V98]

ScottG wrote:
Level and recheck.

YEP !

[Car1800]

Thanks for the replies. I leaned toward the nose high condition causing the temp. difference put I was not certain. When I worked in maintenance years ago the first thing asked was what changed, is anything different? In this case it is the truck. We have owned this camper for ten years and I never saw this before. I have looked at the suspension saw nothing wrong. I use high temperature grease and the temp. does not get anywhere near the max. The B&W hitch is at the lowest position and I am going to check about adjusting the kingpin to a lower position. It looks as if I do that I will have about 5 inches of clearance between the truck bed and camper. We are to the point now that we have a seasonal site and only pull it there in the spring and back in the fall. I know the roads and am not concerned about the camper hitting the truck with that much clearance.

[Lwiddis]

Out of level by 2 inches? Too much for me.

[ScottG]

Level and recheck.

[Thermoguy]

Understanding temperature is so important for so many things in industry. Measuring bearing temps is huge in a factory. Load balance is one issue the can sway the temperatures of bearings doing the same job. As almost everyone has said, this could easily be caused by the trailer traveling not level. You are putting more stress on the rear wheel bearings over the front wheel bearings. The only unknown item, what temp can the bearings handle. It might be well within their tolerance and not an issue, or it could be outside of their tolerance and you are prematurely causing a failure. Sorry, I don't have any knowledge of what temps trailer bearings can run at. But a simple solution seems to be to find a way to get the trailer to ride level.

We did an experiment looking at semi truck and trailer brakes and bearing temps. What we found is that all manufacturers have a different tolerance to temp and we could not use a standard to determine if they might fail. The only temp we could use was the lack of temp - a failed brake or bearing has no temp (or just ambient temp) so that was failed. We were working with the LEO's so they pulled over trucks with failed brakes and made them fix them before returning to the road.

[Cummins12V98]

Rear tires and bearings can run a bit warmer because they get less air flow but usually not that much warmer!

Get your RV leveled out and make sure your suspension is working properly.

Then again it could be the RAM and B&W. 😉

[BurbMan]

You don't mention what year the 5er is, but I would look at the equalizer links if you have a leaf spring suspension. I had a blowout on my TT after many years of towing with no issues, and after getting new tires I was monitoring temps and the new tire in that position was running hot too.

Turns out the Trail-Air equalizer on that side was rusted and frozen in position. Since it couldn't pivot it wasn't allowing the weight on that side to be shared between F/R axles and was overloading the front tire.

Yes, running nose-high will put more weight on the rear trailer tires, but also check all suspension components (not just bearings) to be sure that everything is working as it should.

[MFL]

I can see the R/A bearings running a bit warmer, due to carrying more than 1/2 the load, but 30-40 degrees, seems excessive. Is your FW loaded to close to GVWR, and your rear axle maybe at RAWR or slightly over?

I have noticed bearings 10 degrees warmer, one side to the other, caused by sun, or more than normal slope of road.

I've noticed that a bearing set, that has been hand packed, will run 10 degrees cooler than the one next to it, that has the hub filled from EZ-lube use.

I will mention, before someone else does, it could be the new B&W hitch! 🙂

Jerry

[Lynnmor]

If you have torsion axles the trailer needs to be level, a leaf spring trailer will have an equalizer that compensates to some degree.

[Likes_to_tow]

Is your new truck a 4 wheel drive? Since 2011 there seems to be a race by automakers to see who could make the tallest truck with the deepest bed. I had to buy a 2WD Ford F250 to keep my rig level. My old tow vehicle was an 05 Ram 2500 2WD and I wanted to get a 4WD this time but could not believe the height difference!! The bed on my new truck is 2 inches deeper thus allowing for even less space between the truck and the bottom of the 5th wheel. Some people flip the axles on their trailer or add larger diameter tires to compensate. You can also remove some of the spacer blocks between the truck axle and springs. This will give your truck a more level appearance.

[n0arp]

If you're nose high, your rear axle is going to be bearing more of the load. More load = more heat. Simple as that.

[mooky_stinks]

If the trailer is running nose high then it would make sense that there is more weight on the rear axle possibly making the bearings run warmer on that axle.