Wheel bearings !!

everything camper trailers, trips, tips, tricks & mods

Moderators: krp102, Coxy68, robcaz

Post Reply
tigger384
Posts: 5
Joined: Sun Jul 12, 2020 6:20 pm

Wheel bearings !!

Post by tigger384 » Fri Jul 24, 2020 2:30 pm

Hi Guys

I am relatively new to trailer camping, we have done a few trips and just love it. I am looking to some more adventurous trips including the Simpson desert in the next year or two and as such have become very interested in making sure that my Emu Trax off road camper is up to the task and I have the correct spares for it. I have found the tech info here very useful, thank you to all those who contributed to the tech tips. I checked the specs of my camper trailer and it is fitted with Ford SL type bearings so far so good. But in reading the article on axles and bearings I have some questions.

1) according to the table Ford SL bearings have a load rating 1.2 -1.8 tonnes depending on axle size and or tire diameter. Is this per bearing or across the whole axle? so does this mean that the trailer total weight can be 1.2-1.8 tonnes or each wheel bearing is rated to 1.2-1.8 tones ( therefore total weight capacity for the trailer theatrically would be 2.4-3.6 tonnes) ?

2) The table also mentions tire diameter affects the capacity rating of the bearings. I think I read somewhere else that increasing wheel size reduces capacity by 20% So if I match the trailer wheels and tires to the same size as my tow vehicle (777mm) from the original trailer size of 734mm that I must reduce the overall weight of my trailer to the 1.2 - 1.6 range (dependent on axle spec) according to the tech tips table. So as my trailer has ATM of 1450kgs would I be compromising the margin of safety by matching my trailer wheels/tires to the same as the tow vehicle.

many thanks

Steve

User avatar
MrBeardie
Posts: 12
Joined: Thu Oct 17, 2019 8:16 am
Location: The hills east of Melbourne

Re: Wheel bearings !!

Post by MrBeardie » Sat Jul 25, 2020 3:14 pm

Hi Steve,

I'm unable to find the tech tips page you're referring to but I'd like to read it before making any comments. Could you please post a link to it? Thanks.

John
Not there yet

tigger384
Posts: 5
Joined: Sun Jul 12, 2020 6:20 pm

Re: Wheel bearings !!

Post by tigger384 » Sat Jul 25, 2020 4:28 pm

Hi John

Here is the link https://www.campertrailers.org/axles_bearings.htm


Thanks Steve

User avatar
MrBeardie
Posts: 12
Joined: Thu Oct 17, 2019 8:16 am
Location: The hills east of Melbourne

Re: Wheel bearings !!

Post by MrBeardie » Sat Jul 25, 2020 6:50 pm

Ok, thanks for the link. I've had a look at it and tried to go to the original source page but the later is not responding. I'll start by saying that the information on that page is somewhat simplistic, incomplete and somewhat misleading due to the lack of relevant detail.

e.g. In regards to your question about the load carrying capacity of those SL bearings, the chart states the maximum bearing load is 1.8T, yet it also states that the maximum spindle (in this context that means the axle) load is the same. That makes sense only if they're referring to one end of the axle and mean a bearing set, rather than each bearing, because there are two bearings per set/per side. The absence of qualifying detail throws into question the numbers on the page. They don't even say whether the spindle load rating is for the entire spindle or just one end, although context suggests they do intend to mean just one end.

I know the above is no answer to your questions but, especially when it comes to stuff that can affect your safety, don't just accept what you read on the Internet, unless you know the data is from a first-hand reputable source. For info on bearings I always talk to either the bearing manufacturers (hard to get an answer if you're not a big customer) or a specialist bearing wholesaler, who will have the technical data books and should be able to give you good, accurate information.
Not there yet

User avatar
robcaz
Posts: 1150
Joined: Sat Oct 12, 2013 4:07 pm
Location: Stockton NSW
Contact:

Re: Wheel bearings !!

Post by robcaz » Sun Jul 26, 2020 2:32 pm

As far as I know the bearing & spindle load rating is per axle not a side, so if the bearings & spindle are rated at say 1800kg, it would be suitable for use with an axle that is rated at 1800kg.

The larger the diameter of the tyres, the more leverage there is to bend the axle. Unless you are packing your camper trailer to the maximum load or more & driving through every pothole like you were late for work, I doubt you would really need to reduce the load in the camper.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


Image
We're just two lost souls swimming in a fish bowl, year after year

tigger384
Posts: 5
Joined: Sun Jul 12, 2020 6:20 pm

Re: Wheel bearings !!

Post by tigger384 » Sun Jul 26, 2020 6:46 pm

Hi Rob

No not looking to load my trailer to its maximum of 1450 kgs of drive every pot hole I can find lol. More really looking at that a lot of advice and or opinions here discuss that Chinese imported trailers are quite often of poor quality, and maybe really only suitable for driving on sealed roads. I purchased an Emu Trax off road camper trailer after looking at a number of trailers at the lower end of the market. I was able to talk to the designer and owner of Emu just before he sold his business and retired. He stated that although the trailer was mainly built in china that he had made sure that the quality control was up to scratch( yes I know he had a vested interest) I really only want to be able to understand what my trailers limits are and work within those so I can enjoy the trips without having to unduly be concerned that its going to fall to bits at the first sign of a bit of rough road. My questions around axles and bearings was really to say that if they are only rated to 1500kgs that I know pushing the trailer to its max ATM at 1450kgs would be asking for trouble with such as small margin of capacity over the trailers maximum rated capacity. Although I am no expert a good look underneath reveals neat and tidy welds decent sized RHS cross members and a more substantial A frame, but at the same time you can also see where costs have been cut around small detail stuff, like wiring not quite fully protected, cheap no name tires, a cheap poly block hitch etc etc. To save weight I really wanted to match the trailers wheels are tires to the tow vehicle but it seems that this would lower the ATM to something like 1220kgs as the overall diameter of the wheel/tire would increase. Swings and roundabouts I guess.

Thanks for your input

Steve

User avatar
robcaz
Posts: 1150
Joined: Sat Oct 12, 2013 4:07 pm
Location: Stockton NSW
Contact:

Re: Wheel bearings !!

Post by robcaz » Mon Jul 27, 2020 8:38 am

Hi Steve,

As you have said there is a difference between made in China & having an article made to specs in China. If you are unsure about anything that you think is not right structurally on the chassis, ask a mate that is in the know or perhaps a fabrication shop to check it over with youfor peace of mind.

When we had the Patrol we had the same rims & tyres all round plus two spares. We also carried a puncture plug kit, a bead breaker with patches, a tube just incase the tyre could not be fixed, 12volt tyre pump etc. http://www.robcaz.net/tyre_repair_kit.htm

The Jeep has a 55mm wheel centre while the braked trailer hub is 110mm, so we cannot have similar wheels all round. We now have a spare for each and along with the complete tyre repair kit I think we have it covered. As long as the tyres are in good condition you would be very unlucky to bugger a tyre that could not be fixed.

Another problem I had was the trailer suspension originally was designed around 16 inch rims & we ran 15 inch to match the Patrol. If I was to put 17 inch tyres on the trailer to match the Jeep it would compromise the trailers good suspension travel.

Hope to catch up with you around the campfire on evening.
happy camping
Rob & Carol
Australian CamperTrailers Group co-owner


Image
We're just two lost souls swimming in a fish bowl, year after year

tigger384
Posts: 5
Joined: Sun Jul 12, 2020 6:20 pm

Re: Wheel bearings !!

Post by tigger384 » Tue Jul 28, 2020 11:26 am

Hi Rob

I might even consider another option in the continuing saga of spare wheels and that would be if push comes to shove it would be more important in an emergency situation to have the tow vehicle covered with two spares ( I am talking about being remote here) and as the trailer obviously doesn't have a diff running different sized diameter wheel/tyre would be doable. So I could replace the trailer spare with a tow vehicle one. I understand that there would be a couple of down sides to running different tyre diameters on the same axle namely that the trailer would lean to one side a little and more importantly braking would be uneven across the axle not to mention the extra strain on the axle components on the larger side. But as a emergency fix and driving with these downsides in mind to get out of trouble would be ok.

But as you indicated maybe this is all overthinking it too much and that when I do my remote travelling that good quality a/t tyres and the tyre repair kit you mentioned. ( with a bit of practice beforehand) will be a better solution.

Kind regards

Steve

Post Reply