Do Sharp Turns Overload Tandem Axle Tires and Bearings?

[oldryder1]

Tire and bearing failures on RV trailers seem far too frequent when compared to other tire and bearing applications. certainly that is at least partially due to neglect but there are far too many stories by people that were conscientious (or even meticulous) about maintenance that still have horror stories.

I'm wondering if the loading applied to the tires and bearings when trailers are turned very sharply for parking is to blame. Tires distort in such situations and bearing loads must be very high.

If those sharp turns are a primary cause of failures the loading could be eliminated by a relatively simple system to unload one axle for tight maneuvering. a couple air shocks and a small compressor could do it.

wondering if this have ever been considered.

 

[Gary RV_Wizard]

I think it is very likely that trailer axles & wheels get a lot more and different stresses than cars & trucks. Some trailers do have more sophisticated suspensions but they probably only appear on high-end models where costs is less an issue. But even those systems are still going to have higher stresses. The position on an RV trailer axle (nearer the trailer middle than the ends) pretty much guarantees that.

 

[oldryder1]

I think it is very likely that trailer axles & wheels get a lot more and different stresses than cars & trucks. Some trailers do have more sophisticated suspensions but they probably only appear on high-end models where costs is less an issue. But even those systems are still going to have higher stresses. The position on an RV trailer axle (nearer the trailer middle than the ends) pretty much guarantees that.

Gary, thx for reply. My thought was a pneumatic lift that would unload one axle entirely so for the purposes of tight maneuvering the trailer would be single axle.

 

[Kirk]

My thought was a pneumatic lift that would unload one axle entirely so for the purposes of tight maneuvering the trailer would be single axle.

While that may be possible, I think that it could cause more problems due to overloading the tires left on the ground.

a couple air shocks and a small compressor could do it.

I think that is an oversimplification of what it would take. How it could be done also depends on the type of suspension the subject trailer has. Air shocks could be used to add weight to the chosen axle, but I don't see how they could lift an axle and the mounting of the shocks would need to be able to support the entire weight involved.

 

[woof-n]

Tire and bearing failures on RV trailers seem far too frequent when compared to other tire and bearing applications.

In regard to bearing failures. I am seeing a lot of cheap low-quality bearings used RVs. Even when buying replacements from the OEMs. I recently found a badly pitted bearing self-destructing with 15,000 miles. I have been packing bearings for over 50 years and have never seen such quick destruction of a bearing. I did the poor man's hardness test of running a mill file across the bearing surface. The file cut the bearing surface like cheap box store metal. The file should have slide across like a pop bottle on ice. This bearing missed heat treatments if not entirely. When you replace bearings think quality name brand such as Timkin, SKF, Koyo etc. Yes, they are more expensive but so is roadside failures.

 

[Adventurous Traveler]

Bang, I think Woof hit it on the nose. RVs are littered with cheap parts that the naked eye will never see or be obvious, to save a $$-buck here or there.

Instead of an avid RV enthusiast trying to devise a better bearing-axle-suspension setup on typical TTs and 5'ers, maybe the engineering departments could do a better job of designing the build-out of the system these rigs ride on to begin with. But we all know that won't happen because we'd hear "it'll cost too much".

 

[Doc Roads]

In regard to bearing failures. I am seeing a lot of cheap low-quality bearings used RVs. Even when buying replacements from the OEMs. I recently found a badly pitted bearing self-destructing with 15,000 miles. I have been packing bearings for over 50 years and have never seen such quick destruction of a bearing. I did the poor man's hardness test of running a mill file across the bearing surface. The file cut the bearing surface like cheap box store metal. The file should have slide across like a pop bottle on ice. This bearing missed heat treatments if not entirely. When you replace bearings think quality name brand such as Timkin, SKF, Koyo etc. Yes, they are more expensive but so is roadside failures.

Agree based on experience … last year I bought a new 23 foot dual axle trailer and towed from SD to MT to AZ … I read a post about how an owner had to replace bearings on a new trailer during the first trip out. The article convinced me to have the bearings checked on my new trailer too, even though it was new and relatively low mileage. The tech pulled all four bearing for inspection and found one was near failure and the other three were highly discolored. They were all light on grease. I replaced all with properly packed Timkin bearings. Indeed they cost more but so do bearing failures.

 

[Bearcatrp]

Another cause is loading the RV above max weight straining the suspension. Have seen many RVs at campgrounds that has so much crap crammed in the camper. My max is a little over 11,000. I know I’m close to max as my wife has to bring half the house including the kitchen sink. There was a thread about heavier tires. Gary pointed out these tires need to flex on these tight turns. Heavier tires won’t flex as good. It’s sad some manufacturers skimp on cheap parts to make a buck. Best to spread the word on worthless manufacturers.

 

[Mr Lars]

My take is on line with others have theories, axle/weight/bearings, etc. are woefully inadequate. Ratings of 10,000 lbs, 12,000 lbs etc. are not designed to be run at that weight constantly. Unfortunately manufacturers will not install 20,000 lb axles/bearings/hubs and classifying the units at 10,000 lbs like they should(imho).