Project Stage 1 - Building the 4' x 8' Chassis

[Adz_4]

Hi All,

The first stage of my teardrop project is building the 4' x 8' trailer chassis out of 1" x 2" mild steel tube with approx 3mm wall thickness. The suspension units I am using are http://www.towsure.com/product/7112-Suspension_Units_with_Cast_Hub_-_10_inch_-500kg_10CWT and rated at 500kg (1102 lbs), do you reckon these would be suitable for a 4' x 8' Benroy style teardrop??

The most recent picture I have of the chassis is it clamped up ready to be welded:



Although it has now been welded. I will get some more recent pictures of it soon.

[Ron Dickey]

Frame looks very simplistic and to the point. Nice Job

where will you run your wires?
Will you have brakes?

Ron D.

[doug hodder]

Just curious...why did you use the tubing with the long side horizontal? Doug

[Adz_4]

Frame looks very simplistic and to the point. Nice Job

where will you run your wires?
Will you have brakes?

Ron D.

Thanks !

I am going to run the wire for the rear lights along the tounge then up through the first piece of plywood and along the cavity between the 2 peices of plywood which are going to make up the floor.

This one is unbraked, the suspensions I have ordered are rated for up to 500kg and I am hoping the whole thing is going to weigh around 400kg, so brakes wont be required .

[mikeschn]

Just curious...why did you use the tubing with the long side horizontal? Doug

That's my thought too! It should be vertical. It also looks too narrow.

However, that can be remedied with a gusset underneath. Andrew would have to tell you how much additional support you might need.

Andrew?

Mike...

[Adz_4]

Just curious...why did you use the tubing with the long side horizontal? Doug

Originally I was going to use 2" x 2" steel box section but I want this teardrop to sit as low as possible to the floor so decided to go for 1" x 2" box section with the long side horizontal (I know its only an inch lower but it all makes a difference ). The steel box section I got it really strong and there is no flex in the chassis .

[Adz_4]

Just curious...why did you use the tubing with the long side horizontal? Doug

That's my thought too! It should be vertical. It also looks too narrow.

However, that can be remedied with a gusset underneath. Andrew would have to tell you how much additional support you might need.

Andrew?

Mike...

It does look narrow in that picture however it is exactly 4' wide by 8' long, which is how big I want the footprint of the teardrop to be.

[doug hodder]

I'd be concerned on the tongue strength, but that's just me. If the tongue were vertical you'd pick up close to 70% more vertical strength with no additional weight and the trailer wouldn't sit any higher than it is now. You would have to come up with something to adapt the coupler width however. ..just my thoughts. Doug

[Adz_4]

I'd be concerned on the tongue strength, but that's just me. If the tongue were vertical you'd pick up close to 70% more vertical strength with no additional weight and the trailer wouldn't sit any higher than it is now. You would have to come up with something to adapt the coupler width however. ..just my thoughts. Doug

It is certainly something to be aware of. I may weld some bracing on to the underside of the tongue to give it a bit of extra strength.

[angib]

Welcome, Adam - I must be fairly close to you (in Newcastle).

That tongue looks a bit weak to me, though I have no problem with the rest of the frame being that way round. A 1x2 tube (laying down) is about 80% as strong as two 2x2x1/8 angles, which is what some teardrops have, so we're not talking about anything extreme - though being only 35% as strong as the typical 2x2x1/8 tube makes it look a bit more scary.

I'm guessing from the photograph that your frame is 32" or 800mm from the front of the body to the centre of the ball. According to the Australian trailer design rules that would make your 1x2 tube sufficiently strong for a 340lb (155kg) trailer but my rule of thumb is that teardrops are abused much less than other trailers and so I think it's safe to double that rating for a teardrop.

Now 680lb (310kg) is light but not exceptionally light, so it wouldn't be hard to stay under that weight with careful building. I would be a bit worried that the tongue wouldn't be stiff enough (ie, too 'springy'), rather than not strong enough, but I must admit I've got no proof that it wouldn't.

A simple mod to really increase the tongue strength without adding too much weight would be to add a second 1x2 under the tongue, extending 16" (400mm) in front of and behind the front of the body (so a piece 800mm long).

Andrew

[Adz_4]

Welcome, Adam - I must be fairly close to you (in Newcastle).

That tongue looks a bit weak to me, though I have no problem with the rest of the frame being that way round. A 1x2 tube (laying down) is about 80% as strong as two 2x2x1/8 angles, which is what some teardrops have, so we're not talking about anything extreme - though being only 35% as strong as the typical 2x2x1/8 tube makes it look a bit more scary.

I'm guessing from the photograph that your frame is 32" or 800mm from the front of the body to the centre of the ball. According to the Australian trailer design rules that would make your 1x2 tube sufficiently strong for a 340lb (155kg) trailer but my rule of thumb is that teardrops are abused much less than other trailers and so I think it's safe to double that rating for a teardrop.

Now 680lb (310kg) is light but not exceptionally light, so it wouldn't be hard to stay under that weight with careful building. I would be a bit worried that the tongue wouldn't be stiff enough (ie, too 'springy'), rather than not strong enough, but I must admit I've got no proof that it wouldn't.

A simple mod to really increase the tongue strength without adding too much weight would be to add a second 1x2 under the tongue, extending 16" (400mm) in front of and behind the front of the body (so a piece 800mm long).

Andrew

Hi Andrew,

Yes I work in Newcastle so must be very close . Thanks for the advice, I may have to look at some kind of bracing to strengthen the tongue, although I was hoping that due to the weight balancing of the trailer (heavy stuff in the galley at the back behind the axle), I would never have more than 30kg on the ball/tongue when towing ( ) and when the trailer is parked there will be no weight on the tongue at all, as I am fitting legs to the front bar of the chassis. Do you think this will be okay?

Adam

[Billy Onions]

Hi Adam

I wouldn't worry about the section being laid on the flat too much when you consider that most of the tears are built on the HF / Northern Tool chassis. Maybe the only concern I would have is when welding it doesn't twist too much, even then as with the drawbar / tongue it wouldn't be a problem to put right.

Seems to be a bit of a Teardrop thing going on in the Geordie/Mackem/Smog region of Blighty.

Good luck with the build.

[angib]

Adam, you don't want to have a desperately light tongue weight as it reduces stability - or, more exactly, reduces the speed at which the trailer will start to sway.

I don't think you can rely on a light hitch weight to reduce the maximum load in the tongue - this will occur probably when the back of the tow vehicle moves sharply upwards over a bump and then the tongue has to rotate the trailer up at the front/down at the back. This load will depend more on the whole weight of the trailer rather than just the load on the hitch.

Andrew

[Adz_4]

I've just got my chassis back from being powder coated and im really please with the outcome. They also used a Zinc based primer to give it some extra protection, here is how she looks so far:





I am going to add another 1" x 2" metal box section underneath the tounge to give it some extra strength.