RV/ Camper trailers. Check your spring mounts!

[ebinmaine 67,506]

While doing research about the flatbed trailer that we are rebuilding I've been finding that the spring perches or mounts have been a trouble zone for a good many years.

I've also been finding that over the last maybe 5 to 8 years? It's become a much worse problem, or maybe just better publicity?

On tandem axle or triple axle trailers there's quite a bit of twist amongst the shared axles as these trailers are being turned or parked.
Obviously the frame and suspension takes up massive amounts of weight in the total capacity possibilities.  
Manufacturers need to be able to sell these trailers to people that are more concerned with options than long-term strengths. 

There are products on the market and DIY add-ons that can be done to greatly increase the strength in these weak problem areas.

[lynnmor 7,306]

I did considerable work to my travel trailer to make it usable.  I replaced the cheap tires with LT load range D Goodyear Wranglers.  The cheap steel wheels were replaced with wider aluminum ones to match the tire width.  The skinny and bent 2-3/8" axles were replaced with heavier wall 3" tubes.  The bent, broken and malformed springs were replaced with some from a farm store.  The cheap too thin shackles were replaced with ones I made from 4140 HT steel.  The bolts were all replaced with wet bolts so the new bronze bushings could be greased.  Framework was added to beef up the frame and stop the cracking that I had in four places.  Monroe gas shocks were added and fastened to the framework mentioned.  All tires, wheels and drums were balanced as assemblies, because factory drums are not balanced at all.  A TPMS was added to keep track of tire pressures and temperatures.  Plus much more.

 

Edited July 19, 2023 by lynnmor

[6wheeler 603]

Good Info. It is the same with self propelled RV,s. My class C is way heavier than the factory components of the chassis are made for. Even though ours is an older coach?  One of my co-workers has a 2 yr. old machine? He has made the same changes I have made. Both machines handle 150% BETTER than when new. In the case of both of ours. Which are 33 years apart in age, with similar mileage (mine 1988 w/12,500 mi. his 2021 w/14,300 when purchased) both are Ford Cutaway E-350 chassis. We both have made upgrades to the springs with overloads. Heavy duty RV shock absorbers. And heavier stabilizer bars front and rear. I put a steering stabilizer on mine also. These changes made both of these "White Knucklers" handle like they should. During regular maintenance I am always on the lookout for cracks and changes in the coach whether it be cosmetic or mechanical.

[lynnmor 7,306]

5 minutes ago, 6wheeler said:

Good Info. It is the same with self propelled RV,s. My class C is way heavier than the factory components of the chassis are made for. Even though ours is an older coach?  One of my co-workers has a 2 yr. old machine? He has made the same changes I have made. Both machines handle 150% BETTER than when new. In the case of both of ours. Which are 33 years apart in age, with similar mileage (mine 1988 w/12,500 mi. his 2021 w/14,300 when purchased) both are Ford Cutaway E-350 chassis. We both have made upgrades to the springs with overloads. Heavy duty RV shock absorbers. And heavier stabilizer bars front and rear. I put a steering stabilizer on mine also. These changes made both of these "White Knucklers" handle like they should. During regular maintenance I am always on the lookout for cracks and changes in the coach whether it be cosmetic or mechanical.

The motorized RVs are considerably better than the towable junk.  Yes, they cut what corners they can, but major companies like Ford and Chevy will not take the chance to put total junk on the road.  The RV industry just doesn't care, if they get in trouble they can just change the name and keep on going.  If you want a real eye opening, just tour the factories in Indiana where most are made, if they still allow tours.  It is beyond sad what goes on.  BTDT.

[6wheeler 603]

28 minutes ago, lynnmor said:

The motorized RVs are considerably better than the towable junk.  Yes, they cut what corners they can, but major companies like Ford and Chevy will not take the chance to put total junk on the road.  The RV industry just doesn't care, if they get in trouble they can just change the name and keep on going.  If you want a real eye opening, just tour the factories in Indiana where most are made, if they still allow tours.  It is beyond sad what goes on.  BTDT.

I didn't mean the vehicle manufacturers do anything wrong ie; FORD CHEVY DODGE and all other chassis builders. They are delivered to the coach builders as a rolling chassis. Capable of handleing exactly of what is designed to do and equipped to do just that. Then, as you stated. These builders throw all of their stuff on it . Granted, it is within the weight rating of the machine. But, it makes them extremely top heavy and turns them into a giant sail. 

[ranger 1,750]

One thing I think many people “Don’t” take into consideration with heavy multi axle trailers is the stresses imposed on the framework, etc when being towed by a big truck with stiff suspension. A single axle trailer is relatively unaffected by ‘Pitching’ movement between the vehicle and trailer, but a multi axle trailer is. Tremendous stresses can be placed on frames and drawbar/tongue? If the trucks suspension doesn’t move easily to accommodate trailer movement. A popular towing accessory over here is a towball mounting called a ‘Shocklink’? Which absorbs movement of the trailer in a vertical plane when the truck’s stiff suspension doesn’t.

[lynnmor 7,306]

57 minutes ago, ranger said:

One thing I think many people “Don’t” take into consideration with heavy multi axle trailers is the stresses imposed on the framework, etc when being towed by a big truck with stiff suspension. A single axle trailer is relatively unaffected by ‘Pitching’ movement between the vehicle and trailer, but a multi axle trailer is. Tremendous stresses can be placed on frames and drawbar/tongue? If the trucks suspension doesn’t move easily to accommodate trailer movement. A popular towing accessory over here is a towball mounting called a ‘Shocklink’? Which absorbs movement of the trailer in a vertical plane when the truck’s stiff suspension doesn’t.

 

You mean something like this while making a U-turn in a gravel parking lot?  This is before I did the modifications mentioned above.

 

Here is one of the four frame cracks where the cross members tried to punch thru the incredibly weak main frame beams.
 

[Pullstart 62,884]

6 hours ago, ebinmaine said:

I've also been finding that over the last maybe 5 to 8 years? It's become a much worse problem, or maybe just better publicity?

On tandem axle or triple axle trailers there's quite a bit of twist amongst the shared axles as these trailers are being turned or parked.

There’s always going to be a finger pointer, but at the end of the day the RV manufacturers’ Engineers spec a frame, Lippert builds them to spec.  Lippert’s name is on the frame, but they were paid to build a chassis not knowing what would end up being built on it.

[ranger 1,750]

2 hours ago, lynnmor said:

You mean something like this while making a U-turn in a gravel parking lot

Not exactly. What I’m referring to is the trailer trying to ‘rock’ and pivot around the axle centre. On a single axle there’s no problem. A multi axle trailer tends to take weight off one or the other axle over undulations. Again not a huge problem if the towing vehicles suspension is ‘matched’ to the trailer and can move easily, if the coupling/hitch end is effectively solid, I.e, very stiff truck springing then excessive stresses are applied to the ‘A’ frame etc.

Edited July 19, 2023 by ranger

[ebinmaine 67,506]

8 minutes ago, Pullstart said:

There’s always going to be a finger pointer, but at the end of the day the RV manufacturers’ Engineers spec a frame, Lippert builds them to spec.  Lippert’s name is on the frame, but they were paid to build a chassis not knowing what would end up being built on it.

 

Absolutely agreed. 

 

[squonk 41,118]

6 hours ago, lynnmor said:

  If you want a real eye opening, just tour the factories in Indiana where most are made, if they still allow tours.  It is beyond sad what goes on.  BTDT.

I spent a week at the Winnebago plant in the 80's. I was amazed at the amount of GM bare "P" chassis went through the plant in a day. First thing that was done to them the front frame was cut right behind the rad and extended. Same color wire was used throughout on some of them. When the spool ran out they would grab a spool of a different color and keep going. Lots off spray glue holding things together.

[lynnmor 7,306]

2 hours ago, squonk said:

I spent a week at the Winnebago plant in the 80's. I was amazed at the amount of GM bare "P" chassis went through the plant in a day. First thing that was done to them the front frame was cut right behind the rad and extended. Same color wire was used throughout on some of them. When the spool ran out they would grab a spool of a different color and keep going. Lots off spray glue holding things together.

My favorite wiring observation was when I saw 5/8" holes drilled thru three sides of a 1" x 1" aluminum tube right at the apex of a corner, then a single wire was run thru the seriously burred holes to a clearance lamp.  The integrity of that frame member was destroyed so I pointed it out to the tour guide who dismissed it as not being a problem.

[ri702bill 8,322]

5 minutes ago, lynnmor said:

My favorite wiring observation was when I saw 5/8" holes drilled thru three sides of a 1" x 1" aluminum tube right at the apex of a corner, then a single wire was run thru the seriously burred holes to a clearance lamp.  The integrity of that frame member was destroyed so I pointed it out to the tour guide who dismissed it as not being a problem.

 

Sadly, the tour guide WAS correct at that point. It would only become an issue after it left the factory........

[wh500special 2,184]

On 7/19/2023 at 1:31 PM, ranger said:

... Again not a huge problem if the towing vehicles suspension is ‘matched’ to the trailer and can move easily, if the coupling/hitch end is effectively solid, I.e, very stiff truck springing then excessive stresses are applied to the ‘A’ frame etc.

That’s an interesting point, and one I’ve seen mentioned elsewhere.  
 

The “typical guy” tendency is to get the heaviest truck possible (in the USA at least) to tow a trailer so that he “doesn’t even know it’s back there.”  But the super stiff suspensions can give the trailer a rougher ride than is necessary especially when the trailer is mated to the truck with an overly stiff weight distribution hitch (not something you see in Europe).  The result, so I’ve seen on some RV trailer forums, is a lot of undue stress in the trailer frame that manifests in broken components and disheveled contents. 

 

On 7/19/2023 at 1:23 PM, Pullstart said:

There’s always going to be a finger pointer, but at the end of the day the RV manufacturers’ Engineers spec a frame, Lippert builds them…

 

I know there are real engineers at a lot of the trailer companies, and in fact I used to pal around with an engineer who worked at one of the higher-end camper manufacturers in Elkhart, but I’m not convinced they put much effort into structural analysis or any kind of optimization. RV’s tend to be built As toolsheds-on-flatbeds with the most engineering emphasis really being merely CAD design to make sure parts fit together and to generate an accurate bill of materials so the cost can be quantified.   From the outside looking in, it generally appears that very little actual “engineering” is done or, at least, is adopted by the accounting departments. 
 

There are exceptions of course.  Oliver comes to mind for the soundness of their construction, but even they don’t look to have poured a ton into suspension and some other details below the surface.  Even Airstream has lost a bit of their reputation for being at a higher level in recent years, but they do offer a fundamentally more balanced platform as a result of taking a unique approach to their construction. 

 

This built-to-a-price point strategy isn’t unique to the RV industry.  And, in fact this relative cheapening probably isn’t really driven by any particular industry as consumers predictably migrate to the lowest price options when given a choice.  Evidenced by Walmart, dollar general, harbor freight, MTD, bass tracker, and any of the ubiquitous conglomerate RV brands.  
 

The unfortunate thing is that even in the premium brands that cost more - for instance with my Lund boat - if you dig a little you find places to be disappointed.  I recently had the floors and decking out of my boat to do some repair and maintenance and the rat’s nest of wiring and excessive amount of construction debris still trapped under there 20 years later would embarrass even the biggest brand loyalist or factory rep.  
 

That said, most do offer real value commensurate with their pricing.  So, there’s that…

 

Steve

Edited July 21, 2023 by wh500special

[stevebo-(Moderator) 8,330]

One thing I found when replacing a complete axle on 24’ enclosed was that the spring/shackle pins are non grease able and only had a plastic shim. The cost to upgrade to a grease pin was like $15 for all pins. Imo these should be standard on all trailers.