Kit Trailer - Stress Cracks

[ian_cad]

Hi All,

My first post here - although I've taken much inspiration from your builds and knowledge.

Recently I took my Foamie out on a road trip (4000km round trip) across Ontario - starting in Toronto and going all the way up to Lake of the Woods. Most of the journey was on a much improved Trans Canada highway - which was largely as smooth as butter and driven at a steady 90kmph (56mph).

The trailer used in my build was a kit 5x8 from galvanized steel. It has a payload of 1,250 lbs. Given my build was a foamie I knew I'd be way under the weight limit. Essentially the load consisted of 3.5 sheets of 1/2" ply, about 20 2"x2"s, 7 sheets of 1.5" XPS foam, 2 solar panels, spare tire, small power unit, and a mattress. The kitchen at the back was framed out - but not finished in time for the trip.

When we arrived half way through the trip where the tongue meets the frame had a noticeable bow and cracks had developed on the crossbeam. We had to do a bit of a cowboy fix in order to get the whole thing home which involved bracing the front crossbeam with 2x2 angle iron. It worked and we got home without issue.

I reached out to the manufacturer and they said it was likely caused by too much weight on the front - but in reality we had very little weight on the front. They are sending me a replacement part under warranty so they have been great. My guess is on bumpier sections of the road my SUV was pulling up and down on the tongue causing it to eventually start to crack. Fort Francis has the worst roads I've ever driven on for a city. You might as well be driving off-road! The trailer is quite noisy when towing and I've just learned of a product you can get which can alleviate the rattle of the hitch connecting to the car.

Does all this sound logical or am I way off base? Should I now install angle iron on all crossbeams ? Or could this have been caused by something else. Any insight / advice would be appreciated.

 

[Tony Latham]

Does all this sound logical or am I way off base?

Post some photos of the damaged tongue.

Tony

 

[ian_cad]

Cracks along the top and cracks starting on the same piece on the bottom.

 

[Tony Latham]

Cracks along the top and cracks starting on the same piece on the bottom.

Ouch. That's a serious design and materials flaw. I think you need to find a local fabricator to weld up a real chassis. It'll fail again.

Sorry to be the bearer of bad news.

Tony

 

[DrewsBrews]

The way it bent/seperated.. It looks like the front was trying to pull upwards. Possibly not enough weight on the front actually. I'd think moving the axle farther back would be the primary fix so the rear weight has less torque to try and lift the front on every bump. But the front rail does look weak. Adding a piece of angle iron underneath that rail with holes drilled to use the factory bolt locations should help to strengthen it. But IMO that is secondary to addressing the weight distribution/axle location.

If the spring hanger straps are bolted on, it may be as simple as drilling new hanger strap bolt holes farther back to move the springs and axle and figuring out moving the fenders too... Assuming the tires/fenders are outside the trailer body width. If your axle location can't be moved because the walls form fenders over the tires, then you will need to look at moving weight towards the front and minimizing weight added to the rear.

The constant noise you mention may be the tongue trying to lift off the ball (coupler slamming up and down on the ball). There can be circumstances when this will infrequently happen on alot of trailers. But, if it is constantly happening that is likely another indication there may not be enough tongue weight. IE the trailer is "teeter tottering" on the axle instead of placing primarily downward force on the coupler.

 

[ian_cad]

Thanks for the input.

Yeah that's essentially what we did to get home. 2"x2" angle iron bolted through existing holes to reinforce the frame. See the image.

They are sending me a replacement front piece - but I'm trying to figure out a more sustainable long term fix. Ideally without just scrapping the trailer. I've mulled the idea of something like 2x4's through each cross beam?? Just wondering if other people ran into this issue and how they overcame it.

 

[DrewsBrews]

Looks good to me to keep as a permanent brace. It could even act as a bumper to deflect items in the road that would otherwise hit the forward stabilizers while on the move. But like I mentioned above, I think it is an indication of a larger issue. The extra weight of that steel up front probably helps. But I would have my doubts it is enough.

Do you know the total trailer weight? That can be compared to the weight that the trailer puts on the coupler with a bathroom scale and a block of wood.

Here in Ohio I was required to get the trailer officially weighed in order to get registration. I was able to do so at a truck stop type gas station with a CAT scale.

Appropriate tongue weight isn't just a frame issue, it also has a big effect on the stability of the trailer at speed.

 

[ian_cad]

I don't know the official weight. We'd don't have as many of those CAT scales here. However there is a recycling yard nearby who may let me use their scales. Otherwise a trip to the dump might be in order to use theirs.

My gut tells me you are right about there not being enough weight up front. After adding on the angle iron up front it did seem to tow better in my mind at the time - but it could just have been me wanting it to tow better (placebo!). It wasn't 100% quiet all of a sudden. As the camper part is removable I hope to get that off this weekend and do a full inspection of the frame and see what if anything came loose or is also showing weakness.

I just realized I've yet to show the full build. See attached before we hit the road! Note this is before I fully secured the camper to the trailer.

 

[DrewsBrews]

If the trailer is overall very light you could probably even put a bathroom scale under a tire, then under the other tire, and finally the tongue. Add all three measurements to get a reasonable approximation of total weight, then compare to the single tongue measurement. Note, would need to be on pretty level and stable ground and not be sitting on the stabilizers at all. Just prop the tongue up with a board while you are measuring under the tires.

The protrusion of the galley section out the back adds to the length behind the axle. The galley also tends to be the heavier end because of all the cabinetry and stuff that fills them. Based on what I see, I'd still say moving the axle back should be high on the priority list. Generally I hear 10-20% tongue weight is a reasonable ballpark to shoot for. On a very light trailer, toward the higher end is probably more ideal. Too high and that begins to be a question of what can your vehicle handle. Mine is closer to 30% (maybe more when loaded) but I'm towing it with a full size truck that could handle twice that amount.

 

[TimC-TNT]

This is very interesting. I have what I think is the same trailer kit, four by eight, with a foamie on it. I'll leave the name and model unreported but available to anyone that wants to PM me. I don't feel like it's my place to slam any manufacturer. I'm more interested in helping those that buy this model to recognize the limitations for use as a TD build.

My total weight is under 700#. On my first long trip from northern WI to southern IN and back I had a serious bend in the tongue. I ordered a new longer tongue, shortened it about a foot and reinforced the channel with a piece of wood that fits snuggly from front to back. I know, I know... not exactly a professional repair but it has worked fine since. Back when Paintsalot started his build he mentioned he had the same kit. I advised him to reinforce the tongue somehow. Though not necessarily how I did it.

In my post I encouraged others to look elsewhere for a chassis. I am not impressed with the design of this chassis. In my post, and in a message to the manufacturer, I pointed out that there are penetrations that have questionable locations that might compromise strength. For instance there is a large hole for a wire grommet (I'm assuming) that is in the same location but 90 degrees from a through bolt hole for bolting the front frame member to the triangular tongue brace. In the below photo you can see there is not a lot of meat left in that area which I can only assume is a high stress point. There are two of these grommet holes at the point where the triangle meets the front frame member. The tongue does not attach directly to the chassis frame but attaches to the front of this triangle.

Not only are there three holes in that area but if you look close the tongue triangle member slips though the front frame member during assembly. So the only meat left on that frame member is the top and bottom one inch of thin galvanized steel. I don't remember the price difference between this and other bolt together frames but I am willing to bet I saved maybe a hundred dollars up front. Most of that was blown when I purchased a new tongue. Live and learn...

I wrote a very respectable email to the manufacturer concerning this "grommet" hole placement. I did not receive a response. So I still encourage others to avoid this chassis for anything but hauling a few bushels of grass clippings to a compost site.

To the original poster... do whatever makes sense to reinforce the frame and tongue. And don't go off road too much.

 

[DrewsBrews]

If I had access to a less expensive and galvinized kit, I'd be very tempted too. I don't blame you guys. I got galvinized wheels. No worry about paint flaking and excessive rust.

 

[ian_cad]

Thanks for all the great info Drew, Tony, & Tim. It's going to be a busy few weeks to try get this mended and back out again during Fall.

Tim – I'm 99% sure you are correct, and it's the same manufacturer. I won't list them here either but I will say in their defence the customer support didn't push back at all when I requested a new part. So kudos to them for that.

 

[TimC-TNT]

Thanks for the input.

Yeah that's essentially what we did to get home. 2"x2" angle iron bolted through existing holes to reinforce the frame. See the image.

They are sending me a replacement front piece - but I'm trying to figure out a more sustainable long term fix. Ideally without just scrapping the trailer. I've mulled the idea of something like 2x4's through each cross beam?? Just wondering if other people ran into this issue and how they overcame it.

That's probably what I should do with mine. Nice upgrade to the existing frame. I am going to see if I can find a galvanized angle to do that.

As far as 2x4s inside the frame members. Yeah, it's worth a try. It certainly will beef up the frame without too much weight added. I can't remember the inside width of the frame members but you could always rip a 2x to fit snuggly in there.

I mentioned adding a piece of lumber inside the tongue channel. That also would be a good upgrade. I ripped a 2x treated board to fit but maybe you should stick with untreated or hardwood. I'm not sure if the treated will play nice with the galvanized (mfr calls it "Galvalume", whatever that is). I know that using certain fasteners on treated lumber for decks are not a good choice. That might go for galvanized channel as well. Maybe some of our metal experts here on tnttt will chime in and give some advice on that.

 

[ian_cad]

Another option for support which I have actually used is 3D printing blocks that fit perfectly in the channels. When I was going to attach the stabilizers I was worried that the bolts would pinch the channel so I printed up blocks with holes in them for the bolts to pass through.

If you know anything about 3D printing you know you can infill shapes with a customized amount of plastic and pattern. I think I went with 15% infill, and a basic pattern to keep plastic usage and printing times down. It worked perfectly and the stabilizers are on the frame - rock solid. They are surprisingly strong. Plastic also will not react with the galvanized steel. I wasn't too worried about UV degradation as these are inside the channels under the trailer and will get minimal exposure. If you are worried about that you can get UV resistant filament - it's pricer and harder to print - but I found standard PETG to work perfectly.

In conclusion - perhaps I might print a block for each section where bolts pass through the frame. I can make customs block shapes very easily for the unusual parts of the frame where cross beams meet the tongue. It'll take way longer than using wood though! Hmmmm food for thought!

 

[QueticoBill]

In my kit trailer - Northern Tools - the tongue is a "Y" under the frame, not through it like yours appears. I added a 2x2x1/4 (1/8 would probably be fine but had 14") more than halfway back. Brick outhouse strong now.

 

[ian_cad]

Quick update on this fix. I basically had to take the whole trailer apart in order to swap out the broken front crossbeam for the new one. Before I reassemble it fully I want to reinforce the trailer to help prevent future issues.

I'm thinking of doing the following:
Bolting a length of Unistrut (10 feet or so) down the centre below the frame. Unistrut is galvanized and isn't as heavy as a steel c-channel. But is it too weak?

If I do run a length of Unistrut I would have to cut my angle iron to accommodate it - thus weakening the support across the front. Hmmmm what would the engineers here do? Should I run the angle iron all the way across and then run a length of unistrut up to it (not all the way up to the tongue?)

 

[DrewsBrews]

What is it you are trying to attain by doing this?

If it connects out to the coupler then it would help the tongue bars that appear a bit weak due to the wire gromet holes in them right at the flex point. But if you only have it running down the length of the frame perimeter then I don't see the point in it. It wouldn't realy help anything and would only reduce clearance for you axle movement over bumps.

I still say the main original cause of this whole issue was the axle placement/weight distribution. And that is typically a bigger safety issue for trailer stability. Hense me still bringing it up. I'm surprised the 60/40 axle placement guys aren't beating their drum here.

 

[Tom&Shelly]

Just throwing out an idea: Maybe redesign the trailer so the tongue is right below the trailer frame, like most trailers? Get a new piece for the front of the frame, without the cuts in it, new metal for the tongue without the wire holes Tim mentions, and rebolt the tongue to the new front and the sides. That's what we have, with welds instead of bolts.

I'm an engineer, but an electrical engineer, not a mechanical engineer, so speaking as a civilian here.

BTW, Tim mentions "Galvalume". I think that's a brand name for a type of galvanized steel. It makes a fine roof (17 years and going on our cabin). Not sure about something as thin as your pictures show for a trailer. I've never heard of it being used for anything but roofs.

Tom

 

[ian_cad]

Thanks for the valuable input.

The goal here is to get the kit trailer to a stage where it's usable and safe. Unfortunately I can't do things like moving the axle back further or welding things together. The axle mounting points essential hold the two halves of this kit together. I wouldn't trust that moving them wouldn't compromise the trailer further. I'm limited to mostly working with nuts and bolts and bits of steel to try reinforce this.

Now it could be a combination of adding steel to the frame and always packing the trailer with more weight up front. For instance, I can easily add tie-down anchors to the camper trailer floor to allow me to put a cooler full of food in there up near the tongue.

Maybe I need to sleep on this some more!

 

[QueticoBill]

I think Tom is in the right direction. Cut the A-frame pieces off at the front cross piece, and beef that up with an angle or other. Then add a new wish bone for the hitch. Angles or tubes, directly under the existing ones. You ought to be able to do it easily with bolts.

I don't understand how the axle wnd springs hold the frame together. On my NT, I simple move my front spring mount to where the rear slipper was - same holes - and drilled new holes for rear slipper. Within inches of 60%. Moving axle was easy. Fender harder, especially to underslung axle.