Bicycle Bob Trailer: I understand this to be a generic term for a single wheeled bicycle trailer. It gets its name because it they are usually lightly loaded and on some roads they tend to "bob" along.
Parts List: the following is the list of parts I needed for this project.
- An old childs bicycle. I used the front forks, head stem and front wheel. Cost negligible.
- 1.5 metres of 22mm OD steel tube. It costs $5 for 6.5 metres from a local steel supplier. This is the main trailer shaft.
- 650mm x 600 mm of 3mm gal plate. Cost negligible as it was on the scrap heap. 2mm is quite sufficent.
- 1.5 metres (2 x 750mm) of 15mm gal steel tube @ About $10/6.5 metre length from local steel supplier. This is the attachment to the bike.
- 1 bit of 5mm plate about 150mm x 150mm cut diagonally across. Scrounged from cut off scrap.
- Oxy welding setup and consumables - I did this at TAFE as a project, so nil extra.
Around The Streets: I obtained the kids bicycle as abandoned junk in the street.
Initially I attempted to buy steel to mimic the headset sizes so that I could make my own headset, but whilst I scored great with the innner tube (steel pipe) as it was a great fit for brazing on the front forks and headset, it was a hopeless case for the outer tube. A request for 32mm ID was granted and I rapidly learnt what a general steel supplier means when they say "nominal Bore". My 32mm NB turned out to be 36mm ID and the headset cups had a rattling good time.
On the advice of Moz, I looked at just canablising abandoned bicycles for adaptable parts. So when some one had left a broken kids bicycle lying in the local street, I picked it up. {:-). I have since managed to obtain another similar bicycle from the council rubbish collection service. Our local council provides each ratepayer with three (3) free collections each year, so residents using this service typically clean up on the weekend and leave a pile of rubbish of out the front for collection duing the week following. I understand (so I'm told) that cruising the streets on a late Sunday afternoon can uncover some great finds. {:-)
Measure Twice, Cut Once: This is a common saying, but somewhere along the line, it needs another line. When it came time to cut up the sheet metal to construct the tray supports, somehow my brain carried forward the length desired, rather than the widt. Consequently, the tray will take a square load 600mm x 600mm, when I only wanted a tray 350mm x 600mm. Oh well, something to improve for Bob Trailer #2 {:-). Lead or Angle of Vertical Axis Something I picked up in discussion on the Frame Builders List was that the angle of the vertical axis (side to side movement) needs to lead the trailer, i.e. it points slighlty forward a few degrees off square. I understand this to be for the trailer to lean into the corners.
Something Else I'm sure I'll remember what it is soon.