Frame strength of small TT's

[Gjac]

I have read on here about frames welds cracking and axles bending. Are these problems basically with longer heavier TT's driven on bad roads or is this prevalent with short TT's, 18-22ft 3500 lbs or less UW also? I can't find any info on frame thickness or material on MFG web sites. I would think that the frame thickness would be the same on a 22 ft vs a 27 ft TT, making the frames stronger on shorter TT's, but that is just a guess. Also I see where Winnebago uses huck bolts instead of welds to attach frame structures together is this process better than welds?

[tibbitts]

I had a "22" model that was actually 23.5 ft. It was a "lite" trailer. The frame never bent that I know of but towing the trailer bent the frame of my half-ton pickup where the receiver attached. A higher-rated receiver (Reese sent me an upgraded model for free - outstanding customer service) solved the problem. So I wouldn't assume the trailer frame would be a weak link.

[Gjac]

Maybe some better questions to ask is what frame thickness should a 22ft TT have? I assume the frame is just plain carbon steel is that correct? Do any use a higher strength alloy? Are any made from Aluminum? I realize the shape of the cross section of the frame pieces are also important with a box beam being stronger than an I beam and an I beam being stronger than an C section per a given weight. So are there any short TT's made with box or I beams rather than C sections?

[goducks10]

You get what you pay for. Best thing to do is crawl under the TT and look at the frame and suspension parts. The lesser expensive light weight TT's will have thin frames, thin spring hangers and no gusseting at the spring hanger locations. They will also have smaller axles with only the minimum for tires.

With that being said if the GVWR of the TT is low then you don't need a thick frame with beefy components. IMO though overkill is better with TTs and 5ers.

[deltabravo]

Lynnmor wrote:
All manufacturers are looking to reduce weight and cost, so many use frames that are very weak.

The exception is the three brands built in LaGrande, OR: Outdoors RV, Nash and Arctic Fox.
They build their own frames instead of outsourcing them to Lippert (LCI) like so many other TT manufacturers do.

Outdoors RV Factory Tour

[JBarca]

Gjac wrote:
I have read on here about frames welds cracking and axles bending. Are these problems basically with longer heavier TT's driven on bad roads or is this prevalent with short TT's, 18-22ft 3500 lbs or less UW also?

I can't find any info on frame thickness or material on MFG web sites. I would think that the frame thickness would be the same on a 22 ft vs a 27 ft TT, making the frames stronger on shorter TT's, but that is just a guess.

Also I see where Winnebago uses huck bolts instead of welds to attach frame structures together is this process better than welds?

Bending and cracking of travel trailer frames is real. It may not happen a lot, but it is real. I have had to deal with 5,000# to 10,000# GVWR rated campers which had frame cracks/failures.

The weight itself is not the issue, the reality of what you are buying and how it is made, is the issue.

You seem to be talking about a TT with a single axle in the weight range of 3,500#. Again, weight in this case is lower and the frames are made lighter and thinner. The end result is, the frame needs to be made strong enough for what the load is to be and where you load cargo/water. You have some level of control where cargo is placed. Left to right loading in the camper is determined by how the floor plan is, and where you can place items. Soon after you load the camper, weigh the camper to get a total axle weight, then weigh each wheel. Do not overload one side of the camper, each side needs to be at or less then the allowable axle weight rating GAWR. You may find, you are under the total weight but over on one side.

The comment about the use of axles/tires and wheels being installed less then the total GVWR, is also real. Not all brands do this, but it can be common in lower priced campers. I myself will not buy a camper where the sum of the axle GAWR is less then total GVWR. There is very little safety margin in these cases for off center loading. And you can have lower cargo capacity, yet a very long camper.

The huck bolts are not a problem if used and size right. They act like rivets of years ago. In thinners frames, the Huck bolt can reduce weld stress and welder error.

A welded frame, designed right, welded right, is not a problem.

As others have said, the RV industry is looking to save weight and taking it out of the steel frame is an easy choice. This does not matter what size or weight range. Cost to produce also comes into the equation.

The 22ft verse 27 ft frame, this depends. Some manufactures put tandem axles on both a 22 and 27 ft frame. Now a days, a 22 ft an be on single axle and very low cargo capacity. There is no rule of thumb on length and frame strength that fits modern day campers.

When the use of a weight distribution hitch is needed, that creates other stress issue in trailer frames, mainly the A frame and header area. Do not oversize the WD bars, make sure the dealer and the manufacture (especially them) will warrant the frame when a WD hitch is used, and what is the max WD bar they will allow? If they tell you, they will now allow a WD hitch, and your tow vehicle cannot handle the weight without one, well, now you know going into the sale, you have a problem to start with.

Hope this helps.

John

[Nv_Guy]

My experience has been that the lightweight trailers tend to have the most frame cracking issues. I attribute that to the lighter materials as well as the manufacturer not allowing for any overloading or hauling on less than perfect roads. I have see frame cracks on larger non lightweight 5th wheels, so nothing is guaranteed.
Nothing wrong with huckbolts, they eliminate the issues that welding can cause, especially on thinner materials.

[QCMan]

Basic rule of thumb that is not a guarantee but an idea - ultra lite and lite trailers will have a thinner/smaller everything steel. That is the biggest weight saving a builder can get. That does not mean they are bad but just that there is less steel. Those trailers will also usually have less cargo carrying capacity so you do not overload it.
RVIA rules have changed also to ensure a safety margin on tires and axles. It appears rhe engineering for rv's is sound but the execution sometimes leaves much to be desired. Thus the recalls over the years.

[kellem]

I always make frame inspection part of PM.
What I've found amazing through years of trailer ownership is how the manufacturer uses axles rated below the the trailers GVWR.
Their way of thinking is the tow vehicles hitch and trailers Jack will distribute the weight off the axles.....still comes across as a shortcut but I'm OCD.

[Lwiddis]

Frame strength is directly related to trailer cargo capacity. Buy a TT with 900 pounds of cargo capacity...water, batteries, propane and stuff eats that up pretty quickly...and your running at or more likely over frame capacity. My current TT has over 3000 pounds of cargo capacity...strong axles and frame. I motor down the road with 1700 to 1800 pounds of unused capacity.

[Lynnmor]

All manufacturers are looking to reduce weight and cost, so many use frames that are very weak. I have welded mine in four places. Look carefully how the main front to rear beams are constructed, if you find that they are pieced together and welded, run. Look at the cross members, they can cause cracks as they resist the twisting. You don't need to be an engineer to determine if the frame might be adequate, but you do need to craw under with a powerful flashlight, you will know junk when you see it.

[Guy_Roan]

I am on my third travel trailer - a 19 footer, a 25 footer and now a 37 footer. All the frames were welded and I never have had a problem

The 37 footer is in a permanent spot and I snow bird in it. I wouldn't tow it for all the tea in China ! It has about a 16 foot over hang behind the rear axel and I cringe every time I think of it being overloaded in that area- going down the interstate at 60 or 65 and hitting a bump.
I have never heard of the frame cracking, but then may be people don't publish it when and if it happens.

Guy
I

[TurnThePage]

In the case of my old 24 foot trailer, yes the shorter trailer shares the same frame rails as some of the the longer models. To a point. I believe that makes my trailer stronger foot for foot.