Kit Trailer - Stress Cracks

[DrewsBrews]

This appears to be the same type of kit besides 8" wheels.

You can see the frame rails butt together and is reinforced by another piece that surrounds that connection point and extends for and aft. The spring hangers then attach under that surrounding piece, the bolts assist to hold the rail pieces together. Though you can also see that the axle is only placed roughly 5" rearward of what appears to be the center line. This is not great, especially when the heavy galley is hanging out past the rear of the chassis like ian_cad's design. This puts the axle probably directly under the very center of the total length of the trailer (minus tongue). If you expand the photo in post #8 you will see what I'm talking about.

Given the design of the chassis. I think one could retrofit an axle move by leaving the bolts in the existing position, but removing the spring hangers. Then drill new spring hanger bolt holes farther back and reattach the hangers (with more bolts purchased seperately). However, the rear hanger would then only be attaching to a single layer of steel. If this seems not strong enough, then IMO a length of angle iron could be added underneath the chassis rail (hugging the chassis) that spans at least from the front hanger to the rear hanger. Maybe sandwich a spacer piece between too to keep everything parallel. Finally drilling new holes for the fender mounting. This would realy only require an angle grinder with cutoff wheel and a drill with bits to fabricate such a solution.

 

[KCStudly]

That trailer will never be right. This looks like the perfect example of a company, probably a sheet metal fab shop that makes computer cabinets and the like, trying to extend their market by branching out into a new product field that they have no practical knowledge in, but are hoping to leverage their existing fabrication tooling and processes. Piercing thin sheet metal with square/rectangular shaped dies, bend said sheet metal right on said cutout and then passing a big load straight through that same stress riser without adequate strength to carry the load is a horrible design. Then they obviously didn't do near enough test and evaluation before shoving the product out onto the market. Now I bet they are having complaints from most, if not all of their customers about failures. Just replacing the crap design part with the same thing isn't going to fix the root cause. Uni-strut isn't really a structural solution as it has its own set of built in "flaws". And even if you make a new tongue and move it under the front xmbr, the weak point is still the existing front xmbr. Even if you have a welder fill in the cutouts by fully welding in filler patches, it just looks thin to me. Photo makes the xmbr and tongue appear to be less than .125 thick by a fair amount.

At this point it would probably be cheaper to replace the whole thing with a Northern Tool kit than to have a fab shop replace the front xmbr and under sling the a new tongue with properly designed box tube. Sorry, that's just how I see this issue, not worth continuing down that path.

 

[TimC-TNT]

...

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.

You might be right about the axle placement/weight distribution. It makes some sense. When I assembled my trailer (same model) I relocated the axle mounts. It took some doing. Adding more through holes drilled in the frame wasn't real comforting but it has held up OK, except the tongue which I mentioned previously. Of course I'm at under 700# and mostly highway travel. What backroads I travel I drive like an old grampa. Which I am!

 

[TimC-TNT]

...

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.

It is an odd design as far as axle location. I did the same as QBill on my other NT 5x8 trailers. Worked well. On this light trailer it required adding some reinforcing brackets. Essentially I added several heavy Sampson Strong Tie angle brackets to where the axle was supposed to attach. If interested I can add some photos of that process. But I don't think ian is focusing on axle placement right now. Maybe he should, I don't know but adding weight in front of the axle is one easy solution that should help other than improving tracking behind the tow vehicle.

 

[TimC-TNT]

That trailer will never be right. This looks like the perfect example of a company, probably a sheet metal fab shop that makes computer cabinets and the like, trying to extend their market by branching out into a new product field that they have no practical knowledge in, but are hoping to leverage their existing fabrication tooling and processes. Piercing thin sheet metal with square/rectangular shaped dies, bend said sheet metal right on said cutout and then passing a big load straight through that same stress riser without adequate strength to carry the load is a horrible design. Then they obviously didn't do near enough test and evaluation before shoving the product out onto the market. Now I bet they are having complaints from most, if not all of their customers about failures. Just replacing the crap design part with the same thing isn't going to fix the root cause. Uni-strut isn't really a structural solution as it has its own set of built in "flaws". And even if you make a new tongue and move it under the front xmbr, the weak point is still the existing front xmbr. Even if you have a welder fill in the cutouts by fully welding in filler patches, it just looks thin to me. Photo makes the xmbr and tongue appear to be less than .125 thick by a fair amount.

At this point it would probably be cheaper to replace the whole thing with a Northern Tool kit than to have a fab shop replace the front xmbr and under sling the a new tongue with properly designed box tube. Sorry, that's just how I see this issue, not worth continuing down that path.

Agree. I "upgraded" mine since I wanted to get it on the road. It is very light material and yes, you are correct. I believe Westbrook started out building greenhouses (commercial and otherwise).

Since assembling mine and continuing to use it I have encouraged others to look elsewhere for TD chassis. If you have one, like me, and can't just swap it out for a better chassis please just take it easy and inspect, inspect, inspect. Every time you prep for a trip.

There are the obvious weaknesses of this design but also the fact that when I emailed my concerns about the placement of grommet holes I rec'd no response. Maybe that would appear to be admitting that they have some design flaws.

I regularly crawl under my trailer to inspect the fasteners and frame. I'm not an expert but I feel I can tell if something is starting to fail. Just trying to help others that have this trailer or are looking at it as an option. It is not a POS and they make some interesting products but maybe look elsewhere. You might save a couple hundred bucks up front but chances are good you'll pay later.

 

[QueticoBill]

Following up on Drewbeers and my post about moving axle, use one of the cross pieces cut into halves to reinforce side rails for relocated axle and replace it with a 2x4 or whatever sized 2by fits.

 

[ian_cad]

Sorry for the delayed response here. Busy busy!

I think you guys are right. After inspecting it last night, moving the axle can probably be done easily enough. Moving it about 6 inches to the rear will hit the 60/40 ratio. I'll be double checking that math though!

Secondly, I'll be re-installing the angle iron at the front.

Thirdly, I plan on 3D printing super tough nylon blocks/wedges that sit perfectly into the weak point joints on both sides. They should really bolster the strength there. I could order these from PCBWay (or similar) if I wanted commercial grade printing.

And then as Tim said, I'll just babysit it and keep a good eye on how things perform.

Hindsight is 20/20, but at least where I live there is no other trailer option that comes close in terms of cost. The difference might be upwards of at least $1000 unless you get really lucky on Facebook marketplace.

 

[TimC-TNT]

Sorry for the delayed response here. Busy busy!

I think you guys are right. After inspecting it last night, moving the axle can probably be done easily enough. Moving it about 6 inches to the rear will hit the 60/40 ratio. I'll be double checking that math though!

Secondly, I'll be re-installing the angle iron at the front.

Thirdly, I plan on 3D printing super tough nylon blocks/wedges that sit perfectly into the weak point joints on both sides. They should really bolster the strength there. I could order these from PCBWay (or similar) if I wanted commercial grade printing.

And then as Tim said, I'll just babysit it and keep a good eye on how things perform.

Hindsight is 20/20, but at least where I live there is no other trailer option that comes close in terms of cost. The difference might be upwards of at least $1000 unless you get really lucky on Facebook marketplace.

I think just the fact you are aware of the limitations and are taking steps to address those you are way ahead of anyone that doesn't do any preventative maintenance. Good luck and good traveling!

 

[ian_cad]

Little bit of an update.

Trailer is largely fixed now. I did end up welding some things - but not the galvanized steel - I don't want to die. After some research it turns out that flux core welders are VERY affordable on places like Amazon, and they do a great job. I did welding from the age of 14 so for me it was like riding a bike. Not the cleanest welds I've ever done but I suppose a bit more practice wouldn't go amiss.

This allowed me to weld up a frame to bolt under the trailer. It feels very solid now. I just took it out for a test drive and there is a very noticeable difference. Gone is the constant rattle with every slight bump - now it's a much duller slight sound as I roll over actual bumps in the road. The front of the trailer is also heavier now which will hopefully result in a smoother ride.

This weekend I hope to replace the plywood for the trailer that got tore out - also going thicker on that. Then once that's all water proofed I'll slide on the camper and we should be good to go!

 

[DrewsBrews]

Putting my flux core welding to shame.. and I built the whole frame

 

[TimC-TNT]

Just curious... what did you do to the tongue and coupler? Is that beefed up too?

Asking for a friend

 

[ian_cad]

The new frame support (c channel) runs all the way up to the bar the coupler is attached to. There are two large bolts that attach the main trailer chassis to the coupler section. The C-Channel is bolted to this now. In the middle image in my last post you can see the holes for these bolts on the small galvanized triangle.

Essentially what we end up with is a continuous bar from the coupler running down the centre of the trailer frame.

 

[ian_cad]

Just an update on this fix. The support channel seems to be working well. No issues so far - after a recent 700km (435 miles) round trip and plenty of bumpy roads. So if you do get a kit trailer frame from Home Depot (Canada) I would recommend doing this minor upgrade before building your trailer on top of it. Princess Auto sell the C channel at a reasonable price, that's where I got mine.