The Homebred Steel 29er

After deciding that there is too much seatpost on show on my lovely Boardman HT Pro I decided that I the next bike should be a 29er and seen as I am having to do a lot more university work recently I am also unlikely to be competitive in races which led me to wanting a steel build for comfort. After looking at my options (Cotic Soul, Shand, Singular, etc.) none of them really did it for me and the price was still a fair amount more than I ideally wanted to pay.

With the success of a friend at university building his own bike out of carbon fibre I had the fatal thought of 'How hard can it be?'. So then I started research, lots and lots of research.

The bike I wanted was able to take a tapered fork, standard bottom bracket and all my existing components from my Boardman (bar the cranks as they are a different standard). It had to be steel and if I was buying new wheels anyway I had to go with a 142x12 rear through axle.

Unfortunately there are a whole heap of standards that are closely guarded so if you are thinking about building your own bike here are some useful links to standards.
Rear IS spacing standard
Chainline and Q factors for common shimano cranks

After finding these I then decided that the drop outs should be from Paragon machine works in the US as they are the only 142x12 drop outs that I could find. All of the main frame tubes including head tube will be from Reynolds as a direct order (Reynolds 853 to make it easier to braze) because its very easy to get all of their tube dimensions if you just e-mail them directly. The rest of the components like cable guides, bottom bracket and the like will be ordered through a company in the UK called Ceeway (who also sell the brass rod and flux that I shall be using as well). The chain stays would be very difficult to bend as thin walled tubing has a tendency to crush when being bent so pre-bent columbus chain stays are being used.

Unfortunately then comes issues with things like a frame jig, which will be discussed and built in a separate post. Thankfully that was actually the easiest part as buying some aluminium profile and then making some threaded cones should hold the frame almost perfectly and won't distort/burn with the heat from a oxyacetylene torch.

After stealing much geometry from Niner, Cotic, Charge and On One I came up with the below, which will hopefully be passed off by the people in the know about frame geometry!

As of the moment no calculations have been done to check that it would pass BS testing, but pedalling fatigue looks very complex so likely hood is that the calculations will be done for vertical and horizontal fatigue (even though this design is exempt from vertical fatigue testing).