Wrong Hubs?

[rkochanowicz]

Hello,

I have a 2012 North Trail 32Buds and recently had a hub failure. In fact, it is still stuck and abondoned in a public parking lot 5 hours from home while an axle and hub replacement is located. I'm being told it could be 2 weeks or more for the replacement parts.

That brings me to my delima... while finding replacement parts the wheel/axle specialists say the hubs look too small for the application and after some research we found something strange.

The camper has a GVWR of 8600#
It has an GAWR of 4400#
It is equipped with an axle that is rated for 4400#
It is equipped with bearings that sized correctly for the weight

The wheel hub brake assembly is part number ST-BD-65535-17

 

[jbeletti]

...That brings me to my delima... while finding replacement parts the wheel/axle specialists say the hubs look too small for the application and after some research we found something strange.

The camper has a GVWR of 8600#
It has an GAWR of 4400#
It is equipped with an axle that is rated for 4400#
It is equipped with bearings that sized correctly for the weight

The wheel hub brake assembly is part number ST-BD-65535-17

If you have 2 axles rated at 4400# - you have 8800# of axle carrying capacity. Then a bit of weight carried by the tongue. So it sounds like the axles are correct.

Are you suggesting the axles are undersized or just that the hubs seem to be the wrong ones for the axles?

Are they Lippert? If so, please call them now to discuss this. They are on Eastern time. Their number is 866-524-7821. They should be able to tell you quickly your components are correct.

 

[rkochanowicz]

Hub failure - question about possibly mismatched wheel hub and weight ratings

Hello All,
I hope you are all having a great season and are enjoying great times and making memories in your campers!

I have a 2012 Heartland North Trail 32 Buds.
I recently had a hub failure that also damaged my axle. In fact, the trailer is still 5 hours away in a public parking lot abandoned and unable to be moved.
While we are trying to find replacement parts and get things squared away with the aftermarket warranty people, we found something odd…

While trying to find the replacement hub/brake and axle we found something that I would like the forum’s opinion on…

Immediately and initially the axle/wheel repair people looked at the hub and quickly said it looked too small for the application.

When looking up the replacement brake/hub assembly it was samped with part number Axletek BD-65535-17

The description on this brake/hub assembly shows it as being a 6 lug - 5.5 bolt pattern -3500# capacity per axle – 1750# capacity per wheel – that tends to make sense based on the part number. We found where these hubs are made and imported from China and they are listed with a maximum capacity rating of 3500# per axle (2 wheels) and 1750# per individual hub/wheel.

I know the following facts:
The trailer had a dry weight of 6995#
It has a GVWR of 8600#
It has a GAWR of 4400#
It weighed at 8300# loaded

Research from authoritative sources provides the following info:
The wheel hub is the section that bears the entire weight of the vehicle, includingthose of its passengers and cargo and connect the vehicle and its wheels.That's why car manufacturers warn owners not to overload their vehicles becausethe wheel hub has only a finite capacity. If that capacity is greatly exceeded,especially when it happens frequently, the wheel assembly could break and youcould lose control of the vehicle.

Overloading a hub creates similar conditions as over-tightening the hub. The excessive weight forces the lubricant from between the bearing rollers and bearing raceson the loaded side of the bearing causing localized heat and fatigue.

Do not exceed the capacity of yourtrailer's running gear. Overloading can seriously degrade the life of thevarious components, result in unsafe braking and may lead to catastrophic failure.

The Gross Axle Weight Rating (GAWR) of your running gear is determined by the lowest rated component in the assembly.The capacity of the wheel, tire, axle, brake, springs/rubber and hub are all considered.

The axle is rated at 4400# and per LCI Lippert the bearings areproperly rated to support the listed weights on the 4400# per axle. However, this brake/hub assembly seems tohave a maximum weight capacity of 3500# PER AXLE and only 1750# PER WHEEL. To be properly rated to conform with the GAWR,it seems these hubs should have a minimum rating of 2200# per hub assembly for a minimum total of 4400# per axle.

Assuming all weights are distributed equal, the camper has 4 tires with each hub assembly seemingly rated for a max of 1750#. Take the max rating of 1750# per wheel and multiply it by 2 and it adds up to a max axle weight GAWR of only 3500#, but the camper is stamped with a 4400# max axle rating. Now multiply that times 2 axles witth the same 3500# rated hubs and that only gives me a 7000# max GVWR on a camper that was 6995# when it left production and was 8300# in use and stamped with a GVWR of 8600#

I spoke with Heartland and Lippert and they insist the parts used are correct and would not recommend any other suitable replacements. The person I spoke with from Lippert also seemed to be initially mislead by the hub rating thinking that the individual hub was rated for 3500# and not actually for #1750. As I tried to clarify, they proceeded to argue,insist it was the right part and even asked if I was an engineer – which I am. They are supposed to get me the technical specs on the hub, but I have not received response. If they did misunderstand the maximum rated capacity for a pair of hubs and thought it was for an individual hub, I would think that could be a serious problem.

I’ve been towing campers for 10+ years and have never experienced a hub failure. I am very careful with my tow weights and maintenance for hubs and bearings. I do not think there is anything that I have not done or have done incorrectly to cause this, but am concerned that I am going to continue to have failures due to these hubs being overloaded for this camper -and seemingly not being incompliance with the GVWR and GAWR listed values.

Am I missing something, or does it seem that these hubs are not sized correctly for this application? I can watch the wheels flex in and out a significant amount when turning in a parking lot and the amount they bend does not seem normal - wheel flex can also be an indication that the hubs are not rated correctly.

Thnoughts?

Thanks,

 

[danemayer]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

Hi rkochanowicz,

Sorry to hear you're having this problem. No one wants to go through something like you've described.

One thing I'm not clear on:

When looking up the replacement brake/hub assembly it was stamped with part number Axletek BD-65535-17

The description on this brake/hub assembly shows it as being a 6 lug - 5.5 bolt pattern -3500# capacity per axle – 1750# capacity per wheel – that tends to make sense based on the part number. We found where these hubs are made and imported from China and they are listed with a maximum capacity rating of 3500# per axle (2 wheels) and 1750# per individual hub/wheel.

Is this a Lippert part you're describing, from the Lippert spec sheet, or from the part on your trailer? Or is this a part that the repair shop's catalog is saying is the appropriate replacement?

 

[rkochanowicz]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

What I know is that the 6553517 is the part number for the hub/brake assembly that is stamped onto each wheel hub. It appears this part is manufactured and imported from China and supplied by Lippert.

The part is listed as being rated at 3500# PER AXLE / 1750# individual capacity.

In my application with a GAWR listing of 4400#, it does not apear that these hubs would meet this requirement.

 

[rkochanowicz]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

[h=1]Import Hub Drum 6 on 5 1/2 in Bolt Pattern - 3,500 lb - 1/2-20 Press In Studs (Yellow) (Dexter-Quality Hub Drum)
Here are the specs for that part number:[/h]Drum Size: 10 in x 2-1/4 in
Bolt Pattern: 6 on 5.50 in
Capacity: 1,750 lb per drum
Bearing Size: 1-3/8 in x 1-1/16 in

http://www.trailerandtruckparts.com/Trailer-Brake-Hub-and-Drum--10-in-6-on-550--3500-lb-Axles-BD6553517_p_1433.htmlOn a lot of the sites it is listed only as Trailer Brake Hub and Drum - 10 in, 6 on 5.50 - 3,500 lb Axles #BD6553517

Yes, 3500# Axles and an individual capacity of 1750#

How can these components possibly have a safe GAWR of 4400#?

 

[rkochanowicz]

Some additional information from Lippert:


Description:
Entered on 07/11/2013 at 15:15:44 EDT (GMT-0400) by Connie Wilfong:
The 4400# axle has the 10" brakes that are used on the 3500# axle, but they are sufficient for the 4400# axle as well. It is designed this way for the smaller wheels. This axle is built with a 3" beam used on the 5200# axles with the 10" brakes and 2200# springs.

This did not really answer my question about these stock hubs being overloaded. I also understand that the hub/brakes may technically fit and work, but if the manufacturer has rated them for a capacity and they are being used in an application that is rated higher than their capacity, then htere is a safety and reliability issue.

 

[danemayer]

If you get any additional clarification from Lippert, please let us know.

 

[berky]

As I read the wording in the link to the BD6553517 part, it is basically saying "This is the hub you want to buy if you have 3500# axles". It doesn't necessarily say the hub housing is limited to 3500#. In fact it's probably rated somewhat more than that, since it will accept 15" wheels and D-range tires good for 5080# per axle.

I have the same axle and ran into this "problem" while researching the parts I needed to replace my bearings and seals. I found that:
- the axle tube is 3" OD and not the 3500# axles 2-1/2" OD, as Lippert noted.
- one of the bearings (I forget which one) is larger, i.e., higher load capacity, than the standard 3500# bearings.
So I haven't been losing any sleep over my axle ratings.

You didn't mention in what way the hub failed. Can you tell from the damaged part what the root cause was?

 

[rkochanowicz]

When researching the hub, it lists a capacity of 1750# per hub and 3500# per axle.
Bolt Pattern: 6 on 5.50 in
Capacity: 1,750 lb per drum
Bearing Size: 1-3/8 in x 1-1/16 in
If I have a 4400# axle and hubs that are only rated at 1750# each, then my GAWR would only be 3500# and not 4400# like the axle is rated. Correct?

 

[rkochanowicz]

I don't know exactly what caused the problem. It never seemed to completely seize as the tire still looks good and does not have any drag marks on it. I was honked at by a passing motorist and when I looked saw a little smoke coming from the wheel area. When I stopped, the smoke was quite profound -to the fact that we were worried something was going to catch on fire. While we poured water on it, a State Trooper that saw us stopped and asked if we wanted his fire extinguisher. The end of the hub broke in several small pieces. I'd upload some pics, but this site does not seem to let me upload photos. I tried to add them to the post, but I do not get the option to upload them after selecting them.

 

[NWILSON]

Here are the pictures of rkochanowicz' failed hub

 

[berky]

Smoke could be either a bearing failure or a brake locked up. Since you said the end of the hub broke into several pieces, I'm going with an outboard bearing failure. My guess is the heat generated by the bearing failure heated the portion of the hub housing the outboard bearing to its failure point.

If it was a bearing failure, it could have been lack of lubrication or poor quality control in bearing manufacture. You should have an experienced mechanic inspect the bearings, seals, and lube on the other three hubs.

 

[rkochanowicz]

In the pics posted a few posts previous, those are the hubs from the drivers side of the camper. One is in ok shape, the other failed. The passenger side is ok too. It does not have a lot of miles on it. Most of our trips are within 1-2 hours from home. I am concerned that the other hubs are going to randomly failed if it is underrated as it appears. No response from Lippert today as to my inquiry on the manufacturers specs and official rated capacities on these hubs.

 

[jnbhobe]

There was a guy in Goshen with a failed hub that looked like that,It was on a Bighorn, was a bad bearing I think. Lipert has had some 7K hubs crack at the bearing race too.

 

[Ray LeTourneau]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

I saw the hub at the rally that was mentioned by Jon. He was a few rigs down from us. He only noticed the crack/missing piece after arrival at the Rally. I don't know the end result of his discussion with Lippert regarding the hub.
If you end up getting larger hubs that work with your existing axles/spindles, that's great. If not, I would suggest you have the remaining bearings on the other 3 wheels serviced asap.

 

[berky]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

Let me say first I am no expert on axles. What I see in the picture is scoring inside the hub, and I see a lot of metal worn away at the outer end of the hub. Is it possible if the castelated nut was adjusted too loose that the bearing could wobble around inside the hub and you would see this kind of wear?

 

[wdk450]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

That picture looks close to what I called a "drum failure" last summer in Idaho on the 7K axle on my Bighorn. My drum neck cracked in a round ring about 1/2 inch wide on the end. I had roadside service come up with a drum, bearings and a seal.

 

[jimtoo]

Re: Hub failure - question about possibly mismatched wheel hub and weight ratings

After many years of auto service experience it appears to me to be a bearing failure. The unit appears to be over 2 years old.. have the wheel bearings ever been serviced, cleaned and repacked? Usually the only time a drum fails is due to a bearing overheating and failing due to lack of grease or maintenance.

Jim M

 

[rkochanowicz]

Here is the response I received from Lippert... Interesting...

4400# Axle​

Lippert Components certifies and warrants that the 6 on 5.50 hub drum isappropriate for use on an axle rated for 4400#. The 4400# axle is new to theindustry and was not previously available. The new axle make up consists ofuprating the 3500# axle bearing set and brake. The bearing set, described below,and brake have always had significant head room to achieve more than thestandard 3500# rating. New tire designs and customer demand have provided apath for the new axle that would have a capacity and price point between thecurrent 3500# and 5200# axle. The hub and brake was married to a heavier axletube and a new leaf spring to achieve the new 4400# axle. All major trailer axlesuppliers now offer this axle capacity/configuration to trailer manufacturers.The 6 on 5.50” hub-drum for 10” brakes, using inner bearing part number L68149and outer bearing part number L44649, is rated for 4400# axles. Bearingmanufactures publish dynamic load ratings for each bearing part number calledDynamic Load Rating. Load ratings for each of the bearings are shown on theattachments. The L68149 has a L10 dynamic load rating of 1,890 lbs based on90 x 10​

6 revolutions and the L44649 has a L10 dynamic load rating of 1,330 lbsbased on 90 x 106 revolutions. 90 million revolutions equates to 121,951 milesthat a ST225/75R15 tire would travel since the tire rolls 738 revs per mile.On a 4400# axle the outer bearing accounts for 40% of the 2,200 lb max wheelload and the inner bearing accounts for 60% of the 2,200 lb load. Therefore theinner bearing only actually sees 1,320 lbs which is 70% of the 1,890 bearing loadrating. The outer bearing actually sees 880 lbs which is 66% of the 1,330 bearingload rating.The specific bearings used on the 4400# axle are more than adequate for theactual loads seen in service. Given proper lubrication, cleanliness, and bearing​

adjustment the bearing set will provide long life and durability.