Bearings, how hot is too hot?

Broadside · 24 May 2019, 06:27

I have recently replaced the taper roller bearings on my hubs, the nut has been done up finger tight and then locked in place to remove all slop but the wheels rotate freely. I towed it 20 miles yesterday and felt the hubs afterwards, they were warm to the touch but not hot.

I can understand why they are warm but how much it too much? I’m now wondering if I have slightly overtighened them. How much heat is too much?

Last Tango · 24 May 2019, 07:43

Will no doubt start a debate with differing opinions but I try to tighten them to the point where there is still a "just perceptible" amount of play at the wheel rim.

jeffstevens763@g · 24 May 2019, 08:47

just warm is ok if too tight they will get hot the old way was to tighten up then slack off 1/4 of a turn tyers generate heat all that transmits into the rims etc.

Broadside · 24 May 2019, 08:50

I should have mentioned that one wheel is tightened so it just has the slightest perceptible amount of play, the other wheel has no play at all. They both get warm, but the tighter one slightly more!

If it’s normal for them to get a little warm then that’s ok, I will keep an eye out in case they get hot. Thanks for the replies.

jeffstevens763@g · 24 May 2019, 08:57

if new bearings they will have to bed in anyway i change mine every year normal taper bearings i travel to scotch corner about 100 miles and check they are always warm. it's always recommended to wait until the bearings have cooled down before launching so its normal

Bern Hanreck · 24 May 2019, 09:26

Perhaps also remember that some of that heat comes from the hub ( brakes ) and the tyres . Ideally the brakes will be " evenly " adjusted from side to side and your tyres should be in decent nick ( and never more than about 7 years old - even if they look ok ! )

Broadside · 24 May 2019, 10:50

Thanks all, you have given me a bit of confidence that warm is ok but it’s a problem if they get hot.

Broadside · 24 May 2019, 10:52

Quote:

Originally Posted by Bern Hanreck

Perhaps also remember that some of that heat comes from the hub ( brakes ) and the tyres . Ideally the brakes will be " evenly " adjusted from side to side and your tyres should be in decent nick ( and never more than about 7 years old - even if they look ok ! )

Thanks, the tyres were 8 years old but in good nik, but I have chosen to put new ones on anyway last week. I don’t need the aggro of a flat when towing.

Bern Hanreck · 24 May 2019, 10:55

A wise move I reckon ! ( It's not really about a flat tyre , total break up is a distinct possibility ,with dire results )

Dr. Hook · 24 May 2019, 11:05

Yes, ageing tyres that, on inspection, appear to be in perfectly good condition can suddenly delaminate on you under normal conditions (not nose heavy, over speed or hot). The whirling rubber can do quite a bit of damage, even to relatively heavy section steel.

Orwell boy · 24 May 2019, 20:03

Without stating the obvious the tyre must be muti ply trailer load carrying tyres not car tyres ,if you got proper tyres you can run at max psi rating ,maybe 60 or even 80 psi which will in tern reduce the surface resistance ,which will reduce heat and even fuel consumption ,plus make the trailer easier to push about , if the police stop you they may even base your trailer load capacity on the addition of the tyre max capacities

willk · 24 May 2019, 22:14

Quote:

Originally Posted by Broadside

Thanks all, you have given me a bit of confidence that warm is ok but it’s a problem if they get hot.

Do you have brakes? These can dial a LOT of heat into a hub. If no brakes then you should run relatively cool. If you have brakes then they should be adjusted to the point that they do not make contact while the rig is rolling. A braked rig will warm very quickly if making multiple "hard stops" or long gradient descents. Anything you can hold your pinkie to for extended periods is OKish IMO. If it feels toasty then it's too hot.

Broadside · 25 May 2019, 08:51

No brakes on this trailer. I did a 60 mile run with it fully loaded yesterday, the hubs were warm at the end but not worryingly hot so I think they’re probably ok ��

jonp · 25 May 2019, 10:13

I recently took a boat 3200km up the coast for a mate, the one wheel was getting almost to hot to touch. I was going to back the bearing nut off but the owner I was delivering it for said not to worry, if it had been mine I would of done it. We were in a hurry trying to outrun a cyclone.

Phil and Jane · 25 May 2019, 17:51

We do a 450 mile none stop tow to our destination and return, twice a year (my wife is driving as we speak on part of the outward leg). We stop after the first 20 minutes and the bearings will be warm, like luke warm coffee. We stop every hour and recheck for the next nine hours and they stay at the same warmth. (It’s a braked trailer). Anything hotter and we’d be concerned. The bearings are good for 4,500 miles the manufacturer states, but we change them every 3,500 to 4,000.

jonp · 25 May 2019, 22:28

Every boat trailer has bearing buddies fitted here, I assume you guys use them in the UK too ?

paintman · 26 May 2019, 10:10

They - & similar - are available but I've not seem many fitted with them.

ETA I've always adjusted taper roller wheel bearings so I can JUST feel play when gripping the wheel at 12 & 6'o'clock. Never had an issue with overheating or - on cars - with the MOT.

Last Tango · 26 May 2019, 14:50

Quote:

Originally Posted by jonp

Every boat trailer has bearing buddies fitted here, I assume you guys use them in the UK too ?

I've got them fitted but "jury's out" on whether they make any difference.

I still just change the bearings twice a year and there's always evidence of a bit of rust starting on at least one of them.

two stroke mick · 26 May 2019, 18:14

A cheap it thermometer is a great tool to ha in the car generally I check the hub when towing any get circa 25 deg c. I have an unbreaked trailer and pull the hub every year. I do about ten outings a year round trip 30 miles

Tsm

Ribtecer · 27 May 2019, 08:02

Quote:

Originally Posted by Last Tango

I've got them fitted but "jury's out" on whether they make any difference.

I still just change the bearings twice a year and there's always evidence of a bit of rust starting on at least one of them.

I am in the middle of a rib refurb and as the boat was off the trailer I took the opportunity to give the trailer some much needed love, and during the process I have fitted these;

https://www.trailertek.com/bearing-buddies-50-25mm-dia

Other than a PRV there are no moving parts, not sure how effective they will be, but they are made by Bradley which is normaly good stuff.

Time will tell I guess