Mono Wheel Trailer project - ideas and parts

jamesappleton · Sep 17, 2015

Over the winter months I plan to build a mono wheel trailer but already I'm having difficulty sourcing some essential parts here in Northern Ireland.
What I have in mind; a front wheel & spindle etc from a moped/scooter (12" diameter or so), fabricated swingarm using one light shock absorber (damper) and a tubular framework for the main structure.
The hitch will be a universal joint off a propshaft.
Rather than having an enclosed body/tub, I plan a wire mesh floor that will have an aluminum box and dry bags attached - lightness is key to the design.
Bits I need are the wheel and damper, easily sourced from ebay UK, but most won't ship to NI.
What I need is a local breaker, but these seem to be like hen's teeth !
cheers

Bigmak96 · Sep 17, 2015

Cool, I liked mine. In fact, still have it for some day when the 1100 is road worthy again. Stop laughing you guys,,,it could happen. ;>)

Oldbikefixr · Sep 17, 2015

jamesappleton...just make sure the wheel assembly you select is rated for the maximum speed you intend to use when in tow.

sirepair · Sep 17, 2015

I used a standard 8 1/2in trailer tire, with axle, bearing and hub all sourced from Tractor Supply (large retail chain of farming stuff) Makes it easy to find a replacement tire/wheel so I don't worry about a spare.

I've pulled it hundreds of miles running 70+ mph and it has seen triple digits without issue.

I used a plastic "job box" and bicycle shock for suspension. See link below for pics of build.

gmast1100 · Sep 18, 2015

Bigmak96 said:
Cool, I liked mine. In fact, still have it for some day when the 1100 is road worthy again. Stop laughing you guys,,,it could happen. ;>)

jamesappleton · Sep 19, 2015

Thanks for that SIRepair, the use of a trailer wheel and bearing had crossed my mind - does the 'squareness' of the tyre/tire profile not affect the handling ? (the way a well worn rear would).
Can a scooter type tyre be fitted to that type of rim ?
Ta

ScubaDave · Sep 19, 2015

James, A common trailer tire does not affect the trailer. If you want to see what I did take a look at my album for pics of my build a few years ago. I have pulled it many thousands of miles with not a single issue.

ST1100Y · Sep 19, 2015

jamesappleton said:
...front wheel & spindle etc from a moped/scooter...

If memory on Euro regs serves well, must wheel, tire(s) and other parts be certified to the V-max of the towing vehicle...
Unless you get a homologation limiting your permitted max speed to like 80kph (and you have to install a big [80kph] badge to the tailgate of the trailer)...

sirepair · Sep 19, 2015

jamesappleton said:
Thanks for that SIRepair, the use of a trailer wheel and bearing had crossed my mind - does the 'squareness' of the tyre/tire profile not affect the handling ? (the way a well worn rear would).
Can a scooter type tyre be fitted to that type of rim ?
Ta

The squareness really doesn't matter. I don't think there are any scooter type tyres that would fit that rim. I opted for that size tyre because it is readily accessable at many retail locations.

jamesappleton · Oct 20, 2015

Well, here's where I've got to... sourced a wheel from a 125 scooter and a swinging arm from a pit bike to get me started. I used a universal joint from a car propshaft, but even though it felt tight on the bench once welded in place there is too much sway (movement) at the trailer wheel for my liking. In the process of a plan B - 2 rose joints and 2 rose track rods instead. The single suspension unit isn't heavy enough either, so going to revert to 2 shocks on the swinging arm.

ScubaDave · Oct 20, 2015

Looks like a great start

klaproth · Oct 20, 2015

Looks fantastic so far....nice design! I have often thought of building a trailer as well, will be following this to see how you resolve your ideas!

Bigmak96 · Oct 20, 2015

Nice.

jamesappleton · Oct 21, 2015

I now have the rose jointed 'universal joint' fabricated and it appears to be much more rigid/stable than the car u/j - next step is a short road test with both a video camera and someone following. All nuts will be nyloc nuts when finished of course.

jamesappleton · Nov 8, 2015

This is where I've got to now. Done a short road test before I upgraded the rear suspension unit to a 125cc unit (I was using one off a 50cc scooter, but it was too light). All went well with a 25 kilo bag of sand strapped on instead of the box. Planning another road test with 30-40 kilos in the box to check out the handling. Currently waiting on a rear mudguard to arrive and then I can start looking at LED lights. It had better all work 'cause I've already booked it on the ferry to France for next year!

ibike2havefun · Nov 8, 2015

jamesappleton said:
I now have the rose jointed 'universal joint' fabricated and it appears to be much more rigid/stable than the car u/j - next step is a short road test with both a video camera and someone following. All nuts will be nyloc nuts when finished of course.

Would it make sense to run the bolts in the opposite direction so that loss of a nut would not also entail loss of the bolt?

Belt-n-suspenders: you could drill through the bolts below the point where the nut ends and insert a cotter pin as an added safely measure. Just a thought.

TOS · Nov 8, 2015

I was going to comment...Be certain to keep center of gravity low and make certain the hitch (bike and trailer) are very ridged.
Your already past those points, looks good!

ST1100Y · Nov 8, 2015

ibike2havefun said:
Would it make sense to run the bolts in the opposite direction so that loss of a nut would not also entail loss of the bolt?
Belt-n-suspenders: you could drill through the bolts below the point where the nut ends and insert a cotter pin as an added safely measure.

+1...
At least use nylon stop-nuts for additional safety... (not a big fan of cotter pins myself... ;-) )
Looks like a fun project, hope you'll get it flawless through registration and MOT.

jamesappleton · Nov 8, 2015

Thanks for the comments guys. Yes, all nuts will be replaced with nylocs on the final assembly. The two nuts that secure the swivel to the towbar on the bike will be some sort of quick release nuts with R clips yet to be designed. Trailers in Northern Ireland don't have to go through any official testing before use but do have to fulfill certain construction criteria. Keeping the main weight low was always part of my criteria - heavy items in the alloy box and lighter stuff in a waterproof cargo bag that will strapped onto the top.

Bigmak96 · Nov 9, 2015

Looks good. Are there plans to shorten the tubes the bolts run through on your mount? It looks like a pinch point should you hit a substantial dip in the road.

Mono Wheel Trailer project - ideas and parts

jamesappleton

Bigmak96

R.I.P. - 2021/08/07

Oldbikefixr

sirepair

Let's RIDE!

gmast1100

Gettin old sux

jamesappleton

ScubaDave

ST1100Y

sirepair

Let's RIDE!

jamesappleton

ScubaDave

klaproth

Bigmak96

R.I.P. - 2021/08/07

jamesappleton

jamesappleton

ibike2havefun

Still above the sod

TOS

ST1100Y

jamesappleton

Bigmak96

R.I.P. - 2021/08/07