anyone work this out in solidworks please?

[Dangle_kt]

Hi,

I'm half way through building my bike trailer, really pleased with it so far, but would like a little confirmation on strength of it please.

It is built very similar to this - minus rear loading ramp.

http://cgi.ebay.co.uk/COLLAPSIBLE-M...rkparms=72:12|39:1|65:12&_trksid=p3286.c0.m14



it is made from 3mm x 40mm angle - 7ft in length, with 3mm flat welded across to make the slats - the gap between the angle is 7".

This is going to be supported at on end by the towbar (fitted to 50mm box) and the middle by the 50mm cross bar between the indespension units.

My question is, can anyone run a simple model through solidworks so I know how much weight the rear end can take (as this bit isn't supported) I'm hoping I can carry a bike up to say 200kg's, but would love confirmation.

Maybe I'm golden, but I;d rather have some experienced person say it rather than guess and hurt someone on the motorway if it fails!

 

[rusty69bus]

my question how much is your bike worth?

my home workbench is stronger than that, reinforce, reinforce, reinforce

 

[Dangle_kt]

I would like to leave it pretty lightweight so I can take it apart without a crane

Plenty of trailers sell that are less solid than mine, but I would like someone with some either experience or software to confirm.

The one in the advert says its good for 350kgs, and that one doesn't even have the main "channel" made from a solid peice of steel, it's just bolted together.

anyhow - I take your point rusty - but I'm sure it will be ok, I'd just like a rough max weight.

 

[rusty69bus]

Plenty of trailers sell that are less solid than mine

ok looked at the link for the third time,still don't like it especially with all the boucing your bike will do to angle box angle middle joint when your driving down the road.

the design needs to be smart and strong, not light weight and easy to take apart.

perhaps someone else will comment

 

[rusty69bus]

i not having a go, the materials appear to be to light

 

[Dangle_kt]

to angle box angle middle joint

Sorry - to clarify, Mine doesn't have this joint - as I didn;t like it either, the 7ft length is solid - no joints.

My trailer will only brake down into two parts, the channel with the hitch on, and the "axle" with suspension units mounted onto a 50mm box cross bar.

 

[Dangle_kt]

i not having a go, the materials appear to be to light

I know mate, I'd just like it backed up with some maths prior to me binning what i've worked on all weekend

 

[rusty69bus]

sounds a little better but i can just see it bending in use

 

[rusty69bus]

prior to me binning

wouldn't bin it just strengthen it

 

[Paul.]

I would also be concerned about the loading on the middle of the axle tube, all the weight is concentrated on the middle, I was involved for a while with a project making motorbike lifts and knockdown trailers, similar design except that the main front to rear member was a 4mm thick folded section like an upside down top hat section, the axle was an 80 x 40 RHS on edge, my customer wanted to lighten it by fabricating it like a ladder, so I walked away, he's not in business now
Paul

 

[Dangle_kt]

hopefully this explains things a bit better.

I just went in a bounced around on it for a few mins on the axle stands... its supprisingly solid, however IF i need to strengthen it up - would 40mm box along the length of each angle suffice?

be a shame to waste a perfectly good channel, if I can make it more robust.

 

[Dangle_kt]

I would also be concerned about the loading on the middle of the axle tube, all the weight is concentrated on the middle, I was involved for a while with a project making motorbike lifts and knockdown trailers, similar design except that the main front to rear member was a 4mm thick folded section like an upside down top hat section, the axle was an 80 x 40 RHS on edge, my customer wanted to lighten it by fabricating it like a ladder, so I walked away, he's not in business now
Paul

Hi thanks for this - I hadn't even considered that. I have seen lots of trailer with a single peice of box section for the "axle" between indespension units.

The box I am using is 50mm 3mm walled box - it will be 3ft in width with the two peices of angled welded at right angles to it, so that the "ladder channel" mounts onto the angle with 4 m12 bolts.

Can you suggest a more solid arrangement?

I'm all for re-doing the design if needed, but it is only for an MX bike (not a harley) at approx 100kgs. (which IS NOT stored at my house btw - for all you light fingered forum trawlers)

thanks guys!

 

[Paul.]

You could probably double up the axle by stitching another box section underneath, that will give you 100 x 50 section, weld a 5mm folded channel on the top to locate the main ladder section, Make that about 450 long, perhaps my quick sketch helps,

 

[Dangle_kt]

That is very helpful thanks!

I may have the lower box go all the way across as this will raise the whole trailer up by 50mm, which looking at it might be needed to stop the trailer riding too "nose up".

I like the folded 5mm, except I can't do that at home - which increases the cost to silly money to get it fabricated. I could make it from angle and flat though - I guess that would work just as well?

cheers guys - as usual you have spotted flaws in my plans which I hadn't considered, and come back with suggestions that will cost me more flipping money!

 

[wyn]

If it looks right it probably is right.I would go with the jumping up and down on it test.*Roughly more than 1/2 the weight of the bike would be on the front near the towbar the rest on the rear cantilever. if the wheel base was around 58" that's around 2' from the axle. There would also be the forces applied by the tie down straps to factor into any calculations.If you were a bit worried you could welded some of the flat you used for the cross pieces onto the vertical side of the angle iron, from the tail end up to the point where it joins the axle.
Here's a pic of my trailer, no calculations

 

[Paul.]

Fabricated would be fine, flat plate with 2 off 50 x 50 angles or 2 50 x 5 flats on edge,
Paul