Intro & Motorcycle trailer

Greeting to one and all, I'm a newbie to the forum but not to life, also I'm a mechanic by trade but have been out of the business for over quarter of a century due to a back injury which has slowed me down (a lot) but hasn't stopped me yet.

I have read this trailer forum from cover to cover and have picked up a great number of valuable tips along the way, but I'm now preparing to build a motorcycle trailer and wanted to bounce a few ideas around to see what others think. The goal I'm aiming for is a bike trailer which can handle the usual 3 motorbikes BUT alternatively be used to carry a chook-chaser as well as both of my kid's quad bikes.

After a lot of measuring and thinking (as well as me tiring of drawing and reworking hand-drawn plans in the past), this time I decided I needed the help of some type of CAD package which didn't need a degree to understand, or use, AND wasn't too expensive. The mention of Sketchup had me intrigued but I admit I was very hesitant to try it out, I finally installed Sketchup and after watching the intro videos, decided to dive in head first, much to my amazement in under 24 hours I was able to put my cerebrally stored plans onto a medium that others can see and critique.

The following pictures are two designs I have come up with, with both having a bed 3100mm long and 1370mm wide, with outriggers at the front and rear which make the width 1800mm wide (mudguards and other side fixtures have not come into the equation yet). The drawbar, side rails, front and rear cross-members are 75mm x 50mm x 3mm RHS and the inner cross-members are 50mm x 50mm x 2.5mm SHS... now where the difference lies is within the number of cross-members.

Attachment 204350 Attachment 204351

As you can see, one design has three cross-members, these are spaced at 712.5mm apart, this is the lighter of the two designs. The other design has four cross-members with spacings of 560mm apart, now while this would be heavier, the idea behind this design is to have a hydraulic motorcycle lift built into the floor. My question is: "Do you think the design with 4 cross-members would be too heavy?"

I'm currently leaning towards the four cross-member design, if I go this route, I don't have a final design for the motorcycle lift so I am open to suggestions regarding the design of this.

Cheers,
Glenn

Hey Glenn, welcome aboard.

The extra weight in another cross member would be negligible, so if you're happier with four, then that's the way to go. As far as spacing them, if you're considering any sort of solid flooring on this trailer, then you really want the cross members to be on any joins.

Hi Yonnee, thanks for the welcome.

I decided to go with hardwood decking timber in between the three motorcycle channels and this is why the cross-members are only 50mm in height compared to the 75mm height of the surrounding framework. I was also thinking of welding some 5mm thick angle across the inside of the front and back cross-members to bolt/screw the ends of the decking timber to.

I was just wondering if the weight of the timber AND the 4-cross-member design would be getting towards the heavy side and whether it would be getting close to requiring electric brakes? :?

Cheers,
Glenn

If you're adding 20mm of timber over the entire floor space, and then your lift... you could be running into a weight capacity that would require brakes, Electric or other. At almost 10' X 4'6", your not that far off the size of a small car carrier, so I would guess you could be somewhere around the 300 - 350Kg mark empty, which leaves only 400Kg payload capacity. And that's if the tow vehicle has an unbraked towing capacity of 750Kg.

No worries Yonnee, Thanks for the info :2tsup:, it'll be interesting to see what it weighs when I build it.

Cheers,
Glenn

Hi all,

I have now updated my Sketchup design by adding springs and a drawbar and I was wondering, does the drawbar length and axle placement look about right? :?

In this design, the drawbar length was determined by measuring roughly 5' from the front cross-member of the floor/bed of the trailer, I will probably round the size off to the nearest 100mm during the actual build.

Attachment 205106

Does anyone have any comments or ideas about this design so far?

Cheers,
Glenn

Looks spot on to me. :2tsup:

You would have a little lee-way with your drawbar length as your cutting list would give you more than enough;

2 x 8000mm lengths

1 x length:

• 2 x 3000mm side rails
• 1 x 1800mm rear cross

1 x length:

• 1 x 1800mm front cross
• leaves 6200mm for the drawbar

So you've got enough to do 3100mm for your drawbar...