wheel location for Hauling dog
 

Hi everyone,

I am building an electric bike and trailer but am not sure what diameter wheels to use on the trailer. It is so I can take my dog to the park on the weekend without having to drive.

These are the plans so far.
http://www.caninefostercare.org.au/bike03.jpg
I can experiment moving the wheels forward or backward to balance out the tipping effect, this is okay.

http://www.caninefostercare.org.au/trailer01.jpg

I was thinking of using a 16" (400mm) wheel, something like this:
http://www.surlybikes.com/uploaded_i...003-747194.jpg

Will the trailer tip over easy in a sideways direction [with a 16" (400mm) wheel]?
Or should I increase the diameter of the wheel, say 20" (500mm), and run the axle over the top of frame using a bracket like this? (I can make this bracket)
http://www.caninefostercare.org.au/bracket01.jpg

It is not a major problem to use the bracket setup, because my dog likes to stand while in transport, she enjoys riding in my ute with her head out the side. But I would still have to pad over the axle in case she decided to lay down, and of course it will be awkward/uncomfortable.

I use a burley kid carrier to take out dogs to the park. Sometimes with my solo, sometimes with our tandem. It works OK, but I have had some thoughts on how I'd change it if I were building a trailer for that purpose.

The problem with a dog hauler is that a standing dog has a much higher center of gravity than a seated kid. Also, when turning, most of the dogs weight can be thrown to the outside, and this certainly happens if (when!) the trailer starts to tip over. Bottom line is that stability is much more of a problem with a dog trailer, than with a kid trailer.

The center of gravity needs to be ahead of the axle, otherwise the trailer will be really trying to turn itself around backward. If you balance the trailer so that it has 10% of the total weight on an axle hitch, or maybe 7% on a seatpost hitch, it should be fine.

The 20" wheels on our Burley seem big enough. It would be better if the floor were 3-4" below the axles. Look at many of the DIY designs on the web to see how this can be done. The through axle has the advantage of forcing the wheels to be paralell, but rules out using standard bicycle wheels. If you use larger than 20" wheels, lowering the floor becomes very important. The wheel track (width) needs to be more than the dog needs for stability, but limiting the enclosure is OK, as this keeps him from shifting outward in turns.

Finally, come up with a decent kickstand or center stand. This is very handy when loading the dog, and having a trailer attached can really limit your leaning options.

http://i64.photobucket.com/albums/h1...eRyan/pdub.jpg
Princess thinks that you have a good lookin' dobe there.

As for the trailer- do you have to use a solid axle? what about a design more like this:
http://www.instructables.com/files/d...SSD.MEDIUM.jpg

Go with BMX 20 inch wheels as there are more around and easy to get tyers
Slope the wheels in at the top and you'll never turn it over

If you use BMX wheels with thicker axles [just bolt in each side]
slop the wheels like I did on this trike
Happy building :)

http://i228.photobucket.com/albums/e...s/Gabby009.jpg

Is that trike front wheel drive and front wheel steering? how does that work when going around corners?

Make her lay down while rolling or do something like Ryan's plan. We use a converted Burley 20", and rolling is an issue w/ the dog.

Yes
front wheel drive
turns well
3speed with a coaster brake
Girl has no use of her legs so we made her one she can peddle by hands

wow, thanks everyone for your posts.
I will go for the 20" wheels. I shall see how they go with normal bolts, if I need too I will swap it for a tilted wheel design.

I might try use a plastic tub with my current design. The plastic tub would look like this (but more heavy duty) (ignore the trailer, just look at the tub);

http://www.instructables.com/files/d...7WW.MEDIUM.jpg
image: rocknrollskwurlo

This way I can still keep the design simple, and the tub can lift out for cleaning. I can't really weld any tube up, I am an aluminum person. I might just put the bolts through the frame, and the tub will lower the finished floor 3-4" below the axle like kevbo suggested.

HandsomeRyan thanks for the photos, if only dogs could see 2 dimensional pictures!

I shall post some pictures for everyone at a later date...thanks again.