Ive owned boats for around 15 yrs. Never anywhere as hot as arizona in summer. Middle of summer it can be 115 to 120 driving on the freeway home. I repack my bearings every spring. I read on the internet they should not be more than 120F but mine average 135F with a heat gun driving 3 hrs at a time one way in those summer temps. Should i be worried that they are averaging those temps? Thanks. 

Are you getting those temperature readings by a IR thermometer?  And if so, are you aiming at the axle grease cap or somewhere else?

If you inspect the bearings regularly, you don't have to worry.

Pretty sure you have nothing to worry about as long as there is the proper amount of grease in there.  

Been pulling RV's for 30 yrs and never a bearing failure by following your maintenance intervals......your good. 

135 degrees in the AZ HEAT? Yeah you are good. You start looking at ISO and Reliability standards for heat on bearings and they talk about 20 degrees over ambient as being well within spec of a bearing. If you are packing them with synthetics, that grease won't break down until 400 degrees...mineral based is cooked at about 175-180.

 

A boat fishing buddy of mine carries a spare in a ziploc bag. They are usually pretty inexpensive and if it is on your mind...you could carry a spare.

On 4/27/2020 at 1:27 PM, CountryboyinDC said:

Are you getting those temperature readings by a IR thermometer?  And if so, are you aiming at the axle grease cap or somewhere else?

I always aim at the cap and on the rear seal. 

12 hours ago, Armtx77 said:

135 degrees in the AZ HEAT? Yeah you are good. You start looking at ISO and Reliability standards for heat on bearings and they talk about 20 degrees over ambient as being well within spec of a bearing. If you are packing them with synthetics, that grease won't break down until 400 degrees...mineral based is cooked at about 175-180.

 

A boat fishing buddy of mine carries a spare in a ziploc bag. They are usually pretty inexpensive and if it is on your mind...you could carry a spare.

Thanks appreciate it. Ya i use synthetic grease also. 

1 hour ago, brgbassmaster said:

On 4/27/2020 at 4:27 PM, CountryboyinDC said:

Are you getting those temperature readings by a IR thermometer?  And if so, are you aiming at the axle grease cap or somewhere else?

I always aim at the cap and on the rear seal. 

I'd guess that's probably close to the temperature inside the hub.  As others have said, I don't think there's anything to worry about, particularly considering the ambient temperature.