What is the best and most cost-effective material for a trailer?

[Monument]

Hi everyone,

I am buying the trailer in the attached picture. As you can see there is no surface on either side of the central channel. I need advice as to what material will easily bear weight 100kg+ and be able to withstand weather. I wish to achieve a balance between budget and effectiveness. 

All help would be very much appreciated.

Cheers.

[TedBear]

@Monument now that I understand why you want the floor, I suggest using steel or aluminium floor grating
It is often used for steel steps, so that width will likely be good for standing on while attending to the bike, as well as low maintenance, wind drag, water pooling and affordable. You should be able to attach them with long U bolts to go around the frame.
The following websites are suppliers in Perth that will be able to give you a quote for floor mesh cut to required length.
https://www.totalsteel.com.au/perth.html
Or try
https://www.maddingtonconcrete.com.au/products/galvanised-steel-channel-drain-grates

Alternatively, go back to the marine ply suggestion, making 2x 300-400 mm wide "running boards".  Screw a timber strip underneath on both sides of the front and rear cross frames, so the boards can't slide back and forth. They will also reinforce the boards there so you can sink the heads of bolts (with washers) that go down through short steel plates (or angle iron) running under the frame to lock it all in place.

(Just trying to keep it cost effective.)

[Monument]

@TedBear  I have purchased the nutsert set. Do you think Aluminium checker plate will be too heavy for the flooring on this particular trailer?

[r23on]

If you have a look at the back of the Action Aluminium catalog link provide you will find the checker plate will come in around 4kg The weight of 2mm aluminium sheet is 5.4Kg m2 a sheet of 12mm 2400 x 1200 formply weighs around 19kg with out knowing the length and width of your needs a good guess is around the same as checker plate difference one will last longer than the other. I would use formply over and above AA marine ply as t still needs to be sealed.

as a point of interest drag, the following needs to be taken into account:-

Drag Coefficient 

Cd = Fd / 1/2*p*V^2*A

• Where Cd is the drag coefficient
• Fd is the force due to drag
• p is the density of the fluid
• v is the velocity
• A characteristic frontal area of the body  (m2)

Given the design and shape of the trailer the drag coefficient will be affected by the shape and aerodynamics of the tow vehicle the combined weight of trailer and tow vehicle  plus the fluid density (the density of air on the day of travel) Given the trailer has no large front to prevent free air flow drag will be so small regardless of what you put as flooring. At a guess the air flow over you vehicle would drop at the back of the trailer. Regardless of which method you use drag is subject to the above. This also applies to all forms of motorised racing.

Which rivet nut set have you obtained?

I hope this helps in your decision as which method

[Monument]

I got the nutsert set via ebay and the brand is Topex. From appearances and weight of the materials it appears to be suitable for the application.

I don't believe drag will be an issue. The trailer will be towed by a subaru wagon and any airflow would only pass by the bike. By design the bike is aerodynamic - it does not have rear view mirrors or anything else of the like to interrupt airfow.

I would be more concerned about the narrow track of the tyres at higher speed. They are only 4 x10  4 ply tyres so the foot print is very narrow.

The checker plate surprised me as to low weight so If availability is not an issue I will take that option up ( I approximate 350mm width on either side of the channel but I can't determine length. It appears the toolbox will fit and it won't be of sufficient weight to cause a centre of gravity issue.

I'll get back to you when I know the OD of the tubular frame and advise which size nutserts would be suited to fixing the plate and toolbox.

Thanks again.                                                                                                                                                                                                                                                                                                                                                                                                                                                                         

[TedBear]

@Monumentthat depends on how much you put on, but I doubt that 2 strips will be too heavy.

It has the advantage of being durable without needing any coatings and should be easy to fit with those Nutserts (although I haven't personally used them, but the idea looks great.)

And as you have already figured, the drag wont be a problem.

[r23on]

It really does not matter what brand of nut inserts you use they all do the same job accept for the really cheap ones, the wall thickness of the insert matters

centre of gravity requires both linear and angular momentum of weight through distance and I do not believe you are going to mount a tool box of any size above the height of the bike. Because the bike and trailer basically becomes one mass the formula to calculate centre of gravity is complex due to the varying shape of the combined mass.

I do not confess to understand all aspects center of gravity so I will leave it at that. feel free to research the subject.

The screws for the bolting down of the floor I suggest you use are stainless pan head toque or allan wrench head and the size will be subject to frame diameter. the other tools I suggest you have will be a step drill and centre punch. the step drill is for drilling the tube standard twist drills catch when drilling tube 

https://www.bunnings.com.au/craftright-3-piece-step-drill-set_p0027584  these will do the job not the best quality but will pass

[r23on]

Here is an interesting article on tyre foot print pressure, a bit of high school maths there may be some better tyres out there another cost is there someone in the racing area who could advise where or what  

https://surjan.substack.com/p/16-weighing-a-car-with-tire-pressures 

[TedBear]

@r23on , that was an interesting article on attempting to find weight by tyre pressure. The results seemed a bit academic in the end, given that the $12 weighbridge method was much simpler and more reliable, but fun to work on from a problem solving perspective. I think he should have used a more dynamic method and measured change in contact area against change is pressure. That way he could have ignored errors in measuring the actual tyre contact area (the error would be the same for both pressure measurements).  But fun to contemplate, so thanks for supplying the link. 

[TedBear]

Hi @Monument , if your concern is about the bike tyres jumping out of the central track during the journey, can you simply tie them in using short tie-down straps?

[r23on]

As the trailer tyres are 4 x 10 4 ply and narrow foot print are the concerns and the tyres performance and durability at height speed. Hence the article is more about weight to ground ration and the amount of rubber on ground. The weight distribution across the surface of each tyre. All the weigh bridge did was weigh the total mass.