2014 and still going strong!

It is the end of September 2014 and I have been riding the Plycycle all summer and it is still going strong. Since completion in 2011, I have had to replace the forks as I originally bought cheap ones and I stripped the thread on them. Other than that it is all great.

It is a pleasure to ride, even in hilly old Bristol.

Plycycle - wooden bike out in Bristol 2014.

The wooden frame!!!!!

Here it is, fresh out of its clamps, the two halfs finally fixed together with the metal bits and the rear stays all in ONE PIECE!

The frame all in one piece for the first time.

And a vid of the frame.. all in one piece for the first time.

What this really means is that the project has taken a massive step into the final phase. Sanding off all the resin seapage, and final smoothing to make it ready for varnishing.

I could put it together and attempt to ride it, but really I need to put the saddle in and the final strengthening bolts in the topof the stays. Its going to be tough, but I am going to resist.





Plywood.

Today I started swatting up on plywood for the frame components of my wooden bike. I am lucky that in Bristol there are a couple of very good suppliers, who stock a variety of hard wood ply in most thickness's. I have based my design around 25mm ply, so that is a given, what is not so cut and dry is the wood base of the ply. The one I have my eye on is a 100% mahogany ply. The only problem with that is the cost, £168 per 8x4 sheet. Too much for a test project, maybe if the proof of concept bike works I can make another with the expensive wood. So the question is, what else is out there. Well the main wood in cheap ply is spruce, a soft wood, which although lighter, I have ruled out because I don't think it will be strong enough in the high stress parts of the frame in the longer term. So that leaves other hard wood options. The one that seems best, affordable and made to high standards is birch ply. It is the most commonly available high quality ply, both my local suppliers carry graded birch ply from rough and full of knots to architectural grade.  Best of all, birch ply usually comes from sustainable forestry, something that is harder to to be sure of with the more exotic hard woods. The really good stuff is about £45 a 8x4 sheet, I think this is what I will go for.

The bottom bracket....

I had initially hoped that I could hide the bottom bracket mounting inside the wooden bike frame with a single metal tongue filleted between the two halfs of the plywood frame.  This may still be possible, but I am worried about the amount of torque that will have to go through this fixing, as it is one of the most mechanically stressed parts of the bike. My plan at the moment is to use a two metal mounts that sandwich the wooden frame. This will defiantly be stronger, but I also want to keep the metal work hidden as much as possible. If I can find a way of making this work then that would, of course be best. I had best get the sketch book out.

Bike design, next step.

I took the BikeCAD image below, with its acurate angles, (but designed with a steel frame in mind) and copied it in illiustrator. This llowed me to start plying with the proportions of my wooden bike design. It is amazing how fast little details acumilate and have a knoc on. For example, the only way to maintain the geomtry of the frame that I designed in BikeCAD, and add material for strenght, is to
increase it into the central frame viod. This in turn makes the botom bracket fixing point rather out on a limb, very low down. So that needed tweking and beefing up and so on. The above is by no means the answer, but it isthe first time I have seen what the shapes may actually have to look like. This will (I hope) evolve as I add detail and the inevitable probems arise.

Using Bike CAD

Having been all excited about materials and getting started, it dawned upon me to focus a little more on the actual design of the bicycle. Bicycle design can be just a few sketches on paper, like I did below, but I thought I would have a crack at Bike CAD an on-line bicycle design tool. It is set up with some basic templates for most bicycle styles that are then 100% customisable. So I went with a road frame and entered my hight and

chose some parameters, below is what came out. I have a geared bike and a fixed gear bike and I enjoy both for different reasons, but as you can see here I have gone for a single speed design, mainly because for my first complete build it will be easier.
Bike CAD is set up for steel framed bikes so I am looking at this for basic measurements and geometry. I found it really useful to be able to type in different seat post angles and see the changes to all the other angles straight away. No doubt this will evolve, but I like the basic simple shape of this bike and I hope it will be possible for me to adapt this into wood with out too many changes to the frame geometry.

Insperation.

If my wooden bike turns out half as good as any of these amazing creations, I will be really very happy indeed.

Getting started.

I ordered the first parts today from Ceeway, a plain mild steel Bottom Bracket and a steel head tube. Their web site is a treasure trove of frame building goodies. Its enough to make me want to make a steel frame too, but that will have to wait.
Now that these two parts are ordered it feels like a real start.
I am planning to make the frame from ply wood, but keep the rest of the bike as standard, ie, mostly metal. So for that I need to make the places where the wood meets metal work well. I will make special shaped rear dropouts from mild steel, so that therear stays can bolt onto them. They will be longer than normal to allow a generous spacing of the bolts so as not to stress the wood  at the join. The Bottom Bracket will be fixed to the frame with a fin of mld steel welded at 90degrees to the BB and bolted into the frame. I will try and use the same principal on the head tube. I came up with this soulution as I didnt want to have to machine complex shapes around the metal parts. I think it should work out well. Fingers crosed, as it is at the heart of the plan.
I should note that the famegeometry is based on my 1980's Ralliegh frame on my fixed gear bike. i love the way it feels andrather than take a punt on a new frame design for my first attempt, I thought I would stick with what I know.