11/11/2011 | 12 comments
Homebrew bikes continue with a super slack 4130 downhill hardtail, the BTR Mark 1
Paul “Burf” Burford tells us all about his super slack downhill hardtail project and his plans to turn his passion into a career.
Burf: I started racing DH when I was around 14 and have wanted to start my own frame company for as much of that time as I can remember. I was pretty all right at the old DH game, raced in expert for the Muddyfox team back when Stanny, Simmonds, Molloy and the Atherton’s were on it too. Reckon if I put the effort in I could have got onto the World Cup circuit but I guess I kinda realised I wasn’t going to be pro and make anything of it. So while my mates (Ash Loram, Alex Evans, James Mcknight and others) were all doing seasons in Morzine, I took my self to college and Uni to do engineering so I could learn how to make a sick ass bike.
I went to Oxford Brookes Uni to do Motorsport Eng. where I met up with the dudes at K9. Tam Hamilton was on his sandwich year being the CAD engineer there and we just became good mates from then on. We found out that we both wanted to start our own company. Time went on and I flunked out, Tam did his dissertation and then carried on working for K9. I was then basically on the Dole for 6 months till I found a job in a sheet metal place where I learnt to TIG. Then one random day Tam rung me up and said “Are we gonna start this company or what?” That was March 2010.
Tam designed the frame and I started making tools (jig etc.) I managed to land a sweet job where the bosses don’t really pay much attention to what I do, so I did many a ‘homer’ in order to make the tools I needed.
I had repeatability in mind so I made a tube notcher and a fully adjustable Jig.
The tube notcher is an insane bit of work; I still don’t really know how I managed to make it work so well. Made out of offcuts and bits of scrap from work and made in my shed. It’s basically a belt sander and took forever to make it all line up so I could notch the tube accurately. I was pretty excited when I got it running.
I made the jig at work while the bosses were away at a show in America, and the rest of the work force was throwing Ninja death stars at a bit of wood for two weeks. Told you it was a sweet job!
It took ages to find 4130 tubes in the right diameter and at the right cost. The tubes (6m) for the top and down tubes and the sheet metal ended up coming from Holland. We got the chainstays, headset cups (integrated 45), seatube (seatpost size) and bottom bracket from Ceeway (Framebuilding One Stop Shop). The sheet metal bits were laser cut into gussets and dropouts.
A hell of a lot of Internet searching was done on what I needed to use as filler metal when welding 4130. You don’t need heat treatment if you use the right one, which saves a massive pain in the neck.
Welding the frame was pretty hard. There are some crazy places you have to get into and you can’t slow down or you’ll blow a hole. I finally finished the frame on Saturday the 27th August this year.
Why a hardtail? I switched from DH bike to hardtail (DMR ExAlt) when I packed the racing in to concentrate on College/Uni. I figured it would teach me a hell of a lot about riding a bike and there was also no need for an 8in DH bike on the South Downs ( I live near Brighton) or in Oxford. Never gone back really. Only in the Alps do I pull the DH bike out from under the bed now.
So the frame is designed as a DH specific hardtail because I can’t buy one and I wanted one for years. 150 rear axle, 83 bottom bracket. Slack as you like head angle.
I couldn’t believe it when I first rode it. It feels just like a DH bike. In the corners it feels like you can squish it like you do on a full suss. It’s so stable and yet still feels light and flick-able.
It feels so good ripping some turns and drifting on a frame you made yourself. I’m basically just trying to break it now. What with it being the first frame I ever built I expected something to go on the first ride but it’s doing pretty good. Had a couple weekends riding and raced it at Porc the other week
Still no cracks
It’s taken a long time from when we first decided to make a frame to when we could ride it. I’ve hardly ridden or seen anyone apart from work people and my girlfriend for over a year. Trying to figure out how to make the tools I needed has been the most fun. I had an Idea of what I wanted them to do and then started building, figured each bit out as I went and the feeling you get when it does its job is awesome.
As I said we are hoping to turn this into a company so at the moment I’m building another frame, making a website and doing lots more Internet searching.
We have a Facebook page: www.facebook.com/BTR.Fabrications
If you want to learn how to weld, get welding info, or you are a welder, go here: www.mig-welding.co.uk/forum/index.php
Like what you see? then get in touch with Burf: firstname.lastname@example.org
If you’ve made your own homebrew bike then get in touch with Billy