dump trailer frame channel or tube?

[jwnpgh]

Which is better?

I wonder about the strength and the rust resistance.

 

[BruceWard]

You can paint the inside of channel.

Tubing has greater twist resistance.

I believe that a 4" channel with the long side vertical can withstand a greater vertical load than 2" tubing. Both have 4" of vertical side but I beleive the single 4" vertical is stronger than 2 2" verticals.

 

[Diamondpilot]

I was a firm believer in tube trailers for a long time until I had a tri axle 18,000# boat trailer built. That cost. Anyway after talking to 3 different custom trailer builders they had 3 different ideas on brakes. One liked Disc surge, one liked stainless electric, and another liked electric over hydraulic. I opted for Surge Disc.

Anyway one liked Tube. The other two liked Channel. One guy made a good point that sold me. He said tube was for finish work. Channel, I-Beams, ect are for structural. He said how many large semi trailers, GN's, or even sky scrapers you seen built from tube steel? That sold me.

So my answer to you is I would go with Channel.

Chris

 

[jwnpgh]

Great comments.

although most mass produced ones are tube. Well at least ones sold here in southeastern PA.

I am looking at Griffin(dump max), cam superline, and sure-trac. All have tubular frames and cross members and are similarly priced for 7x12 10,000#. All are around $5500.

I spoke to a custom trailer guy and visited to see his. He used channel iron and his trailer costs over $8000.

So, you do get what you pay for.

As for the trailers I mention, some are 7 gauge thick tube, at least the one manufacturer mentions thickness.

One must consider that big buildings hold much more weight. If the tube can hold the weight, then it holds the weight.

thanks for the input!

john

 

[BruceWard]

Semi trailersm GNs and sky scrapers are designed to handle defined stresses.

I can see why tubing could be used to resist twisting in a dump trailer. I imagine that stress occurs in unexpected directions during the dump. On a slope wieght transfers from one side to another causing a twisting force. When dumping that force would be concentrated on a small area.

7 guage is 3/16ths so it is middle weight tubing.

What are the outside dimensions of the tubes?

I would assume the commercial trailers are desinged by an engineer. If I were building a dump trailer I would try to follow their design.

 

[CurlyDave]

He said how many large semi trailers, GN's, or even sky scrapers you seen built from tube steel?

Where I used to work we made lots of frames to support heavy, but oddly shaped items where even small deflections could cause a problem. We used mostly square tubing to make up the frames.

If you don't know exactly what the forces are and just want to make it "strong enough" square tube is a good thing.

 

[Skyco]

My concern with tube is the inside can rust out and one may never know until it is too late.
My dump trailer has a channel frame but all the box supports are tube. One day I noticed rusty water dripping from a few spots. Seems the welds aren't always perfect letting rain water, road spray, etc seep in. I drilled about a 3/16 hole in every single section to let any water accumulation out. I was really surprised how much rusty water drained from some.
I've been trying to figure a practical way to fog the inside of each member with an oil mist or something...

 

[wushaw]

My 8X16 duall tandem dump trailer is "I" beam frame, It'll hold 11tons no problem and dump it.

 

[RickB]

I think heavy duty trailers use channel for two reasons.
1. All surfaces can be treated and cleaned to minimize corrosion.
2. Channel WILL deflect without cracking and transferring stress to welds better than tube profiles. There are many instances in manufacturing where rigidity is not preferred over controlled flex. Trailer frames are a prime example.

 

[Egon]

Design parameters and cost of materials and construction is usually the deciding factor.

 

[Diamondpilot]

My concern with tube is the inside can rust out and one may never know until it is too late.
My dump trailer has a channel frame but all the box supports are tube. One day I noticed rusty water dripping from a few spots. Seems the welds aren't always perfect letting rain water, road spray, etc seep in. I drilled about a 3/16 hole in every single section to let any water accumulation out. I was really surprised how much rusty water drained from some.
I've been trying to figure a practical way to fog the inside of each member with an oil mist or something...

I am in the trailer business and see this a lot. Especially with trailer hitches. Mainly on late 90's early 2000's GM products. I know of 2 that failed while in tow last season. At that point the safety chains do no good and the whole load goes for a ride.

As for tube versus channel. I see cracked welds all the time on tube trailers and have seen zero on channel trailers. Trailers have much less suspension travel versus the tow vehicle so allowing to flex some is a good thing in my opinion.



Chris

 

[Diamondpilot]

I think heavy duty trailers use channel for two reasons.
1. All surfaces can be treated and cleaned to minimize corrosion.
2. Channel WILL deflect without cracking and transferring stress to welds better than tube profiles. There are many instances in manufacturing where rigidity is not preferred over controlled flex. Trailer frames are a prime example.

You hit the nail on the head.

A small 7K trailer can be made of much anything without too many issues. You get into the 16K range and longer lengths there is much more chance for stress and flex and problems will arise.

Chris

 

[Renze]

I think heavy duty trailers use channel for two reasons.
1. All surfaces can be treated and cleaned to minimize corrosion.
2. Channel WILL deflect without cracking and transferring stress to welds better than tube profiles. There are many instances in manufacturing where rigidity is not preferred over controlled flex. Trailer frames are a prime example.

I worked as a trailer engineer for some years. Dont know if anyone is interested, but here it comes:

-for light mid-axle trailers behind cars and vans, we used 2x2" tube spaceframes because the torsional stiffness gives a smoother ride, and at the same time a lower weight (given that the distance of the longitudinal tubes of the space frame is high enough)
-for the stuff from 7 ton upwards, we used I beams: these were all 5th wheels which are supported at the axle (or tandem gear) at the rear and the 5th wheel dish at the front, which prevents most vibration flexing on the road. But mid-axle tag trailers behind trucks, we also used I beam because the price of an open profile is lower than tube. Also, the torsional flexing problem gets smaller when the weight of the trailer increases.

For heavy equipment trailers, monotube section frames from 3/4" top plates and half inch vertical plates are the norm, also because of their torsional stiffness, as it helps them to better withstand the torsion of unequal loads of odd loads like machine parts and the such. Also, in this class of trailers, the technical reserves are much higher and often a special permit for oversize load is required anyways, so they are not as "engineered to the pound" as box trailers, which are generally constructed out of I beams.

For a lightweight trailer i'd want tubes, preferrably galvanised as it covers the inside too. This because the dirt cheap trailers built from brake pressed sheetmetal you'd find at the Dutch equivalent of Wal-mart, will flex even with just a strong crosswind: looks like you're towing a cardboard box behind...
Tandem and single axle, mid axle trailers, are supported in the mid and at the ball hitch: kinda like a triangle. this allows them to flex over the longitudinal axis.
In heavier trailers, the vibrational frequency of the chassis is much higher, so usually you wont get resonance from road vibrations.

That was a long winded story, but in general, tubes for mid axle trailers up to 7k, and I beams for anything over that weight was the rule of thumb where i worked. Thats my personal preference too, as my current 2.5 ton deck-over trailer, with a space frame from cold rolled C-channel, flexes quite more than the ones we used to build at my former employer.


oh, and one thing about them dumptrailers: open channels are easier to treat on all surfaces, but the open ends can also collect more dirt, which may stay on the flanges of the profiles... lots of pros and cons....

 

[jwnpgh]

Wow

I was away from the forum for a day and there were so many posts.

Seems like a popular topic.

Well unfortunately the mass produces ones all seem to be tube main frames.

I suspect they don't all have engineers designing from year to year and are probably somewhat over engineered.

The brochures don't give all the specs. here are the specs for the Griffin dump max:
GVWR - 12000
GAWR - 6000
Curb Weight - 3450
Payload - 8550
Max Hitch Weight - 1200
Top Frame - 2 x 4 x 11 Gauge Tube
Bottom Frame - 2 x 5 x 7 Gauge Tube
Tongue - 2 x 5 x 7 Guage Tube
Coupler - 2 5/16" A-Frame Ball Coupler
Jack - Coupler Mounted, 5000# Top Wind
Fenders - 14 Guage Formed Tread Plate
Axles - EZ Lube Dexter Axles
Suspention - Equalized Leaf Spring
Tires - 750-16LTLRF
Wheels - 6x15, Silver Mod
Floor - 10 Guage
Electric Plug - 7 Way Round Standard Plug
Finish - Powder Coated Black
Overall Length - 198
Bed Legnth Inside - 144
Bed Width Inside - 80
Bed Heigth Inside - 24" Tall x 10 Guage Sidewalls
Floor Heigth - 29
Coupler Heigth - 18
Gate - 2 Way Combination Spreader/Barn
Hydraulic Hoist - Dual Rams
Pump - 2500 PSI 12VDC KTI Pump System Power Up and Down
Battery - Deep Cycle Marine Battery
Ramps - Heavy 3" Formed C-Channel Ramps Mounted Fenders
D-Rings - (5) 5000lb. D- Rings Welded Into Floor
Body Options - Spare Tire Mount


I too am worried about corrosion from the inside.

john

 

[Egon]

Renze; nice explanation.:thumbsup:

 

[jwnpgh]

In regard to rust prevention, some manufacturers offer undercoating.

I imagine Zeibart could do that including treat the inside of the frame tubing.

Has anyone had any of these extra services done?

What about a spray in liner for a trailer that won't be "over" used with things like large rocks. If it is primarily a dirt hauler or gravel, seems like a spray liner would be of some protective use.

John

 

[Pops15]

I think moisture on the inside of box tube frames is from condensation. If it's from porous welds then those trailers have bigger issues than rusting!
I have a 1968 jobsite trailer that has a box tube frame. After reading this topic this morning I checked the frame today. It's solid as can be.

My B&B 14K dump trailer has a 2X6 box tube frame. It's very rigid and gusseted very well. A trailer that short doesn't need to flex like a semi trailer does. If you're considering a dump trailer I highly recommend spending the extra and getting a B&B. I looked at several brands before I bought and decided on the B&B because of the higher quality construction and the single ram set up. The only down side to B&B is the price.

My home made flatbed trailer has an I beam frame. Hmm, actually it's a cut down house trailer that we doubled the I beams and welded them making kind of a box tube with flanges. Anyway, that trailer will flex a little torsionally but not end to end. We built it in the mid 80's and it's still holding up well.

You can get box tube or Channel that will carry the same load. The channel will have to be taller to carry the same load. That means the deck height of the trailer will be higher.

I wouldn't recommend Zeibart (are they still in business?) or any other rust proofing where they'll drill a bunch of holes in your trailer frame. Those holes are just entry points for water and salt to get in. Spray on rust proofing leaves allot to be desired.
Also don't spray line the trailer. Dirt will cling to it when you're trying to dump. The powder coat is still in decent shape in the bed of my dump trailer after 5 years and I don't baby it at all. It has some scratches but considering how it's been used it's in remarkable condition. I've read about plastic skid plates for dump trailers. I don't have one, but if I was going to do something different to the box of my dump, thats what it would be.

 

[jwnpgh]

thanks again for advice.

B&B's website leaves much to be desired as far is details go. They don't list construction details.

As far as a spray in liner, like Rhino, you can opt for the smooth finish without grit. Would the dirt really stick? so much that it prevents flow?

I have seen some of the UHMW style liners for addes flow properties, but these are figid lines that are "molded" to the dump. Also expensive.

You said your dump powder coating is still intact after years, what do you haul/dump typically?

I will be doing dirt and gravel .

thanks

 

[Pops15]

thanks again for advice.

B&B's website leaves much to be desired as far is details go. They don't list construction details.

As far as a spray in liner, like Rhino, you can opt for the smooth finish without grit. Would the dirt really stick? so much that it prevents flow?

I have seen some of the UHMW style liners for addes flow properties, but these are figid lines that are "molded" to the dump. Also expensive.

You said your dump powder coating is still intact after years, what do you haul/dump typically?

I will be doing dirt and gravel .

thanks

B&B's website is terrible. Give them a call and I'm sure they'll be very helpful.
My powder coat has lots of scratches but it's held up far better than I expected. I mostly haul construction debris....broken concrete, ceramic tile, plaster, etc. I've hauled dirt and stone too. I use it for my business and don't baby it like a weekend warrior might.

 

[Renze]

Does any of the N.A. trailer builders galvanise their trailers ? It is standard on 99% of all european trailers, because galvanisation is payd per pound, painting per foot: on light, thin walled trailers galvanising is just cheaper, and more durable. Its hard to find a painted (wet or baked) trailer under 3.5 ton in Europe.