How hot is “hot” on wheel bearings?

[Deleted User][Deleted User] Posts: 92
edited October 2019 in Trailer & Towing
I have the laser heat monitoring device to check my wheel bearings but how hot is “hot”? If they get too hot, besides letting them cool down, then what? Does that mean you have to grease your bearings before moving? I’m afraid one day I’ll get a hot reading in the middle of a trip and have no idea what to do. 


  • targtarg Member Posts: 75
    +1 on what @WilliamA said.
    Also, IMO, "hot" in this context is essentially what's referred to as "max touch temperature" and is around 130-140 F.  So if you'd prefer not to lay a hand on a hot surface, you can use those values when checking with your laser thermometer.
    The capacity to learn is a gift; The ability to learn is a skill; The willingness to learn is a choice. | -REBEC OF GINAZ
    2019 [email protected] 320S BD Lite, Jeep TJU, Jeep JT

  • ChanWChanW Member Posts: 2,982
    edited October 2019
    This info is a great help. Thank you @WilliamA.
    I'm always in doubt when I adjust my brakes and the 'spin the wheel' test shows a touch of a slowdown at one point on the circumference. So I adjust again, but it seems there's always a spot that touches.
    When on the road, I check the drums for heat (poke through the wheel 'spokes'), after normal braking, and after a hard brake. Never are they hot, maybe a bit warm, so I figure I'm safe with the brakes (and then the doubt kicks in - are they working at all?!?)
    The bearings have been a concern because the outer hub cover (decorative chrome) was pretty warm (not too warm per your description though). They never got any warmer, however, and I never saw any leakage, so I had to figure the warmth was 'normal', though I don't understand where the heat would come from in a properly lubed bearing...
    Chan  -  Buffalo NY (Beau Fleuve)
    2014 S Maxx - 2011 Tacoma 4cyl 
     [email protected]'ll_Do_Ya
  • tabiphiletabiphile Member Posts: 320
    Anyone who regularly tows or runs equipment gets into the habit of checking bearings regularly. Whenever you stop, do a quick walkaround and place your hand (carefully) over the bearing hub and get a feel for what is normal. If you plan to use a temperature sensor take a reading and start to get and idea of the norms. After a few hours on the road on a hot day a good bearing will feel a bit warm to the touch, but not hot. On a cooler day, it may actually feel a bit cool. You'll get the hang of it. As has been noted, brakes are more likely to kick up the temperatures if they are even slightly out of adjustment or if they've been used hard recently. This is why it suggested that you service your brakes when you lube the bearings.
    Unless you see/smell bearing lube, give the wheels a rest and then move on stopping after a while to see if things are pointing towards a problem. You'll know when there is trouble'll feel like you need to pull your hand away to keep it from getting burned.... get your sensor out and measure that!
  • pthomas745pthomas745 Member Posts: 2,095
    I remember my favorite Volkswagen reading "How to Keep Your Volkswagen Alive" back in the day used to have the same type of advice for checking the status of wheel bearings that WilliamA points out.
    2017 Outback
    Towed by 2014 Touareg TDi
  • tabiphiletabiphile Member Posts: 320
    edited October 2019
    I remember my favorite Volkswagen reading "How to Keep Your Volkswagen Alive" back in the day used to have the same type of advice for checking the status of wheel bearings that WilliamA points out.
    yes...after first rolling a cigarette and standing back to take it all in to arrive at the correct frame on mind. 
  • [Deleted User][Deleted User] Posts: 92
    edited October 2019
    This is great info. I’m starting to understand why they say never pull your camper more than a few hours at a time (3.5-4 is what seems to be the max recommended). I suppose that pulling too long just contributes to increasing your chances of overheating your bearings. 
  • jgram2jgram2 Member Posts: 1,531
    LOL-no chance of towing that long with my bladder! (Did I just say that out loud?) I have fun checking all tires with our laser, nodding knowingly at each wheel. So far, nothing over 115’ with fairly equal temps although the [email protected] tires run a little hotter, or was it the 4runner? It’s good to see numbers, recognizing speed, load, driving conditions and ambient temps will make a difference.
    John, Judi, Guinness & OD in PDX
    [email protected]@t 2015 S Max Outback, ‘18 V6 4Runner 

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