DIY Mono Wheel Trailer

[KoffMixtures]

What stops the hitch hitting the floor? It doesn't appear to have any support?

The hitch completely detaches using the quick release pressure fittings.

Alternatively, I'm working on a quick release cotter-pin so the hitch stays on the bike, where it will hinge up and clip to the rack.

Remember the whole assembly pivots vertically at the bike end.
As the trailer is long, the effective pivot arc is minimal in practice.

 

[Deleted member 26715]

The hitch completely detaches using the quick release pressure fittings.

Alternatively, I'm working on a quick release cotter-pin so the hitch stays on the bike, where it will hinge up and clip to the rack.

View attachment 688978

Sorry I think you misunderstood what I was asking, or I didn't ask correctly, the towbar for the want of a better word it is connected to the axle, but this looks like a pivot point, what stops it going further towards the floor?

What stops it ending up here?

 

[KoffMixtures]

Sorry I think you misunderstood what I was asking, or I didn't ask correctly, the towbar for the want of a better word it is connected to the axle, but this looks like a pivot point, what stops it going further towards the floor?

What stops it ending up here?

View attachment 688979

The connection has it's own bolts, above the axle.
That is the vertical pivot point for the entire trailer.
The hitch connects/locks to the trailer via the adapted bottom bracket. This is a vertically rigid assembly.
The whole thing is supported from the wheel to the bike, moving freely up and down.
The bottom bracket connection allows the trailer to pivot horizontally.

Due to the complete unit being vertically rigid, there is no danger of a 'collapse' at the joint.
As the last photo shows, if the hitch is left on the bike, it pivots up and will be clipped to the rack.
A temporary rubber band indicates where the clip will be.

Hope that helps?

 

[Deleted member 26715]

Maybe I'm just having a bad engineering day, but I would have concerns of failure at the arrowed point unless additional strength was added.

 

[KoffMixtures]

Maybe I'm just having a bad engineering day, but I would have concerns of failure at the arrowed point unless additional strength was added.

View attachment 688982

The adapted bottom bracket spindle and pedal are substantial steel drop forgings and well capable of taking the loads I intend to be carried, which would be far less than a rider applying his/her entire weight to the same components.

I am aware the weakest point potentially, is the joint just ahead of your arrow.
If that becomes an issue, it can be further supported by a mod as and when required.

Any future developments will be reported here.

 

[presta]

I would have concerns of failure at the arrowed point

Me too.

loads I intend to be carried, which would be far less than a rider applying his/her entire weight to the same components

Carrying a rider on a pedal, the load on the crank is substantially in tension, the load as you have it is in bending with a very long torque arm, for which it's much weaker. Bob have a substantial amount of triangulation at the pivot on the Yak.

 

[KoffMixtures]

Me too.

Carrying a rider on a pedal, the load on the crank is substantially in tension, the load as you have it is in bending with a very long torque arm, for which it's much weaker. Bob have a substantial amount of triangulation at the pivot on the Yak.

View attachment 688991

Presta, thank you.

had looked at the Bob trailer among others on the market and considered my options based on materials available.

I agree with your comment/observation and am quite prepared to make modifications, such as adding the lower pedal to a better braced hitch.

I'm going light shopping locally, NOT mountain trekking with all the gear to last a fortnight.

At the moment this is a proof of concept project, done at minimal cost, so I am rather pleased it has got this far.
(It nearly got made of wood!).

Thanks to you and everyone's encouraging interest and likes.

 

[Deleted member 26715]

My thoughts were meant as simply that my thoughts, if you thought they were criticism then apologies they were not meant as that.

 

[KoffMixtures]

My thoughts were meant as simply that my thoughts, if you thought they were criticism then apologies they were not meant as that.

Constructive criticism is always welcome!

Your comment gave me the opportunity to describe more detail and justification of my methods.

 

[KoffMixtures]

Re 'presta' comment #21.
Riders forces on a pedal crank is substantially compression, with secondary torsional force.
My configuration is more than adequate to take the bending forces, taking into consideration the relative low intended weight of the loaded trailer....which will be considerably less than an adult of average stature.

 

[chris667]

This looks like it would work really well to me. Excellent stuf! There's going to be plenty of fear of litigation in the Bob design.

I plan to make something like this myself over the winter if I can't buy what I want.

If it did turn out to need strengthening, I wonder if you could simply make the pivot extend upwards and have some cables under tension supporting the load bed?

 

[KoffMixtures]

Hi Chris.

My trailer was cobbled together using available materials and is a one off for my own use.
It has bugger-all to do with any commercial product. There's a cycle at one end and a wheel at the other, with my own ingenuity in between.

Good luck with your own endeavour. be sure to share.

 

[chris667]

My trailer was cobbled together using available materials and is a one off for my own use.

Of course - and a very good effort it is too! It looks like a really excellent bit of work. I'll be delighted if mine turns out so well!

 

[albion]

Not much of a disaster if it fails anyway, at least not in the intended use scenario.

 

[biketrailerguy]

Hi, am all for diy trailers using scrounged / available resources (and currently use one) - just wondered why you decided on a single wheel one rather than a 2 wheel version? I've made several 2 wheel ones over the years, using bog standard simple tools (no welding) and materials?