Eng-Tips is the largest engineering community on the Internet

Intelligent Work Forums for Engineering Professionals

Register Log in

RV's! 4

Status
Not open for further replies.
XR250

XR250

Structural
Jan 30, 2013
5,202
0
36
US
I don't understand this industry.
Seems like one company, Lippert, makes the majority of the frames for Rv's in the USA. There are so many incidents of these frames cracking. Fifth wheel frames cracking inside the front of the trailer. Regular tow behinds cracking if you use a weight distributing hitch and go down a bumpy road. Spring shackles bending and pulling off.
Lippert claims they build the frames to the manufacturers specs. Manufacturers claim it is Lippert's problem but they spec the lightest weight frames they can so they don't overload the axles and can fit more amenities inside.
Do any of these companies employ structural engineers for the design? Most of these large RV's are always pushed up against their axle and tire ratings. Can't imagine this is safe.
Are there any ASTM or SAE standards for any of this. Does it ever get enforced?
OK, that is my rant for the morning.
 
Replies continue below

Recommended for you

Sort by date Sort by votes
My hobby involves towing motorcycles around and sleeping overnight at race tracks. (I just got back from a track day at Mosport, err, Canadian Tire Motorsports Park.)

It's very common nowadays for people to haul "toy hauler" RV trailers behind a pickup truck of some sort. Build quality is a nightmare.

I use a Ram ProMaster a.k.a. Fiat Ducato van that I have built out to suit my needs so as to not have to deal with a trailer. It hauls the bikes, I sleep in it, it is my change-room, it is shelter from the weather. The downside is that I don't have a built-in washroom or kitchen, and it isn't "fancy". Oh well. But I don't have to deal with RV headaches, and winterisation, and storage, and towing, and my petrol consumption is probably half.

Quite a few people use a plain ordinary box cargo trailer that they've built to suit the same purposes - not as fancy looking as the RV trailers, but by building it themselves, they're the quality control.

Registration and licensing is a factor for the bigger trailers. Using a cargo trailer puts an upper bound on the total weight rating that can legally be driven on a standard driving license and without registering both the tow vehicle and the trailer as commercial vehicles (with annual inspections and the associated costs). RVs, unfortunately in many ways, are exempt from all this ...

The driving license is one reason why enormous trucks towing caravans (or RV trailers if you prefer) aren't commonly seen in Europe. Their license classifications are tighter than ours. Many heavy-duty pickup trucks on their own, without even considering a trailer, are beyond the 3500 kg weight-rating limit for a standard driving license in Europe.
 
Upvote 0 Downvote
BrianPetersen said:
My hobby involves towing motorcycles around and sleeping overnight at race tracks. (I just got back from a track day at Mosport, err, Canadian Tire Motorsports Park.)
Click to expand...
I was a track day junkie for a few years (SV 650) but hauled with a trailer and slept in a tent.
 
Upvote 0 Downvote
XR250 said:
I was a track day junkie for a few years (SV 650) but hauled with a trailer and slept in a tent.
Click to expand...

Until about 10 years ago, I hauled my bike on an open trailer behind a diesel VW Jetta and slept in a tent. Getting too olde for that ...
 
Upvote 0 Downvote
GregLocock said:
I think we have a terminology problem. In Australia a vehicle chassis with a house built on the back is an RV. A trailer with a house built on it is a caravan.
Click to expand...

Yup, in the US, they are all RV's
 
Upvote 0 Downvote
3DDavwe said: "AFAIK the only people in the RV industry to ever truly suffer for their actions was Goodyear, who sold tires to it. They make a truck tire for low-range vehicles that works perfectly; got to move furniture or a bunch of lumber 20 miles? Great. They can do that until the rubber rots. Then some bean-bag said "why not corner the RV market? Unlike delivery trucks...... "

That was only part of the story. The chassis's involved were made by someone else, and that type of chassis is used almost exclusively for local delivery and the tire applied by that chassis manufacturer was perfect for that.

But when the chassis's were purchased by the RV manufacturer, he didn't replace the tire with something more suited for the intended service. The fault was the RV manufacturer, not Goodyear.
 
Upvote 0 Downvote
Maybe.

"Until the release of the G670 RV, recreational vehicle owners seeking a Goodyear tire usually purchased the G159," the release said. "A solid performing tire, the G159 was designed for pickup-and-delivery trucks in commercial service."

Whether or not the explicit announcement played a role, three months later, in May 2000, Fleetwood told Goodyear it was going to switch to Michelin tires because of the reported problems with the G159. Goodyear wasn't pleased, according to evidence disclosed in court.

When motorhome maker Monaco started asking similar questions that same year, Goodyear had an almost identical explanation for the issues. (Monaco didn't respond to a request for comment.)

"At no time did Goodyear disclose to either Fleetwood or Monaco the test results it possessed which revealed heat generated by the G159 at highway speeds was far in excess of 194° Fahrenheit," the Haegers wrote in their complaint. "Rather, Goodyear actively concealed its test data from these two motorhome manufacturers."
Click to expand...


This may be a surprise, but commercial buyers tell the seller what tires to put on. Goodyear lied to motorhome makers and did not disclose the in-house testing that showed G159s should not be used for motorhomes.
 
Upvote 0 Downvote
IME stateside RV = motorhome = driven cut-chassis + can.
Camper trailer = towed can.

I've worked powertrain projects with RV manufacturers who also built camper trailers, but I have no engineering experience on the trailer side. When I was young and still running a wrecker I hauled the scattered remains of many campers on a rollback bc of idiotic driving or age/maintenance-related wheel-end issues - dry bearings, old rotten tires, sticky brakes. No doubt the can itself is cheaply built but I dont recall ever seeing an accident caused by or hearing of major issues with newer chassis. Modern trailer design trends do confuse me tho, today many of the cans are 9' tall and there's no effort to fit wheel-wells or sit the body down over the chassis. They're literally tall boxes sitting completely on top of the chassis, the floor is 3' off the ground and the roof is level with a semi trailer's 12' up. Lousy for aero, lousy for fuel economy, lousy for fitting amongst tree branches, and simply looks goofy IMHO.

The concerning one to me are the RV motorhomes flat-towing small vehicles. I towed quite a few of the smaller vehicles that became detached from motorhomes and have come to the conclusion that most RV drivers simply cannot feel or hear when issues arise due to the size discrepancy between vehicles. I've heard several drivers say that they didnt know the towed vehicle was gone until hours later, including one who thought his Jeep was stolen in another state after it parked itself inside a clothing store. I've read that the problem has gotten worse with newer vehicles due to the electronic controls, if the towed vehicle encounters an electrical or battery issue they'll often default out of "towed mode" and damage transmissions/transfer cases or even lock the brakes/trans unexpectedly.

To answer the original question tho - Yes, FMVSS applies to trailers.
 
Upvote 0 Downvote
Nowadays video systems are cheap enough that the driver can monitor what is happening to the towed equipment as well as overtaking vehicles, but having it come loose is a problem regardless of towing vehicle.

Interesting about the tow mode. Eventually self-driving cars could take care of that by simply following closely to cut wind drag losses. Even better - tell the self-driving car to take the direct route and meet at the destination while the RV is driven on the scenic route (which I have nick named the time-wasting-detour.)

One feature of such things is that many are used infrequently so that the tire tread is not worn much, but the polymerization of the rubber continues. As a result the tires can look brand new but the rubber has lost flexibility.

We ran into this on military vehicles where they may be stored a decade or more awaiting deployment. The tire makers insisted that tires should be replaced regardless of use after 5 years. The tires can be in a humidity controlled environment, kept off the ground by blocking the suspension, kept within a comfortable temperature range and away from ozone. Didn't matter. Sure, the makers want to sell tires, but with increased age comes decreased capacity.

With RVs someone can buy one; go on a couple of trips of a thousand miles or so, then park it for a decade before deciding to sell it. Maybe they got those tire covers to keep the tires safe(r). But those tires are now long overdue for replacement with 90-95% tread remaining and not (yet) a crack in the sidewall, so they still look suitable.

Similar issues no doubt happen with brakes and bearings - corrosion and lack of working the lubricant can lead to unexpected failures. People tend to think of things wearing out from use and not from age.
 
Upvote 0 Downvote
@CWBI

Lot's of videos on the internet about people flat towing and accidentally leaving the vehicle in first gear and, subsequently, grenading the entire drive.
 
Upvote 0 Downvote
That toy-hauler is bigger and fancier than most of the roadracing folks use, but nothing they said in that video surprises me based on what friends have experienced. Our bikes weigh a third to a half of what they're carrying, though.
 
Upvote 0 Downvote
More sketchy-ness in the RV industry...
Bumper pull to 5th Wheel Conversion. Lets add moment to already weak frames on these things.
I love the statement, "AN EVALUATION OF THE TRAILER'S A-FRAME MUST BE PERFORMED BEFORE USING THIS PRODUCT TO AVOID FRAME FAILURE! REINFORCEMENT LIKE THE IMAGE BELOW MAY BE NECESSARY!"
Right - who is qualified to do this? The frame manufacturer if you are lucky and they will def. tell you the warranty is void.

 
Upvote 0 Downvote
Status
Not open for further replies.
Back
Top