"It's not what you do; it's how you justify it."
-Me; over and over again - sardonically.
When reading this, keep in mind that I have been working as a mechanic in a bike shop since 2004 and had been working on bikes in a home shop since 1997. I know that I only see stuff when it goes bad; I've seen a lot of stuff go bad. If I had to come up with a mission statement it would be:
Keep Riders Riding.
I made decisions when making the prototype. Some of the decisions could be seen as going against the principles stated; I can back up almost all of the decisions with a reason why the decision was made and will simply admit when something happened “just because”.
In many cases what is advertised as an advantage could be seen as a disadvantage in a different context. I have a hobby of wording statements to let them be ambiguous by simply stating fact and letting the reader decide advantage v. disadvantage.
Read that enthusiastically; filling in the blank with the word BEST.
Read that while rolling your eyes; filling in the blank with the word WORST.
MAKE IT EASY TO:
The most complex part of the frame is what I called The Foot. Given the original consideration of wanting it to be easy to convert my pencil and paper drawings to CAD, I based the part on a small number of key points based on the corners of rectangles. The part itself is then a series of intersecting circles. This made it extremely easy to manufacture the part on the manual machining equipment I ended up using.
A friend gave me the advice: "Make it easy for someone to make it for you".
I stopped with the swoopy curves and such and ended up making the prototype drawings based on cuts and mitres instead of bending tubing, I specified dimensions that allowed for common stock tubing. I picked 6061-T6 tubing since it was easy to get from local metal suppliers and it was the material used by the two Canadian companies still welding high end frames in Canada.
How easily I could jig the parts for welding, the way several pieces would actually snap together or hold each other in place and the way that using square tubing allowed me to nearly let the parts be their own jig was a tipping point mentioned in the PROCESS section of this Website. Most of the parts are also designed to be machined from one side only. This eliminates the step of flipping the part or the need for more impressive machinery than I have.
This does leave an unfinished side of the part. In the case of the Feet that means the left side isn't very pretty - that's ok, you photograph bikes from the right side. A Note About Symmetry I designed the parts for the frame in such a way as to never have a left or right of something. I know that in CAD it is easy to make a mirror image of a part but then you're stuck with two of that same sort of thing that aren't interchangeable.
I've actually been in the conversation between rider and manufacturer where the customer is upset that they asked for a left drop out and got the wrong part, the manufacturer was perplexed that the rider received a derailer hanger instead of a brake mount. The rider then said that was the problem, they wanted a derailer hanger, not a brake mount. The rider's quote: "Wait, do you mean the BIKE's left?". As it turns out the manufacture was perplexed initially since they had lots of brake mounts but were out of the derailer hangers.
The TrebuChat has two Legs and two Feet.
When the Foot is on the right side of the bike, the narrowing to 8mm at the Toe allows the derailer to line up properly.
The Leg has the cable guides on the bottom when it is on the right side of the bike to have the derailer cable route smoothly.
The guideline was to make a frame that you would never have to take to a bike shop for service.
That's right; I'm employed as a bike mechanic and I thought it would be a good idea to make sure what I manufactured was completely user serviceable.
When the dream was still to actually produce bicycle frames and sell them directly to the public, I had the idea of shipping the frames disassembled to make it easier to ship and reduce damage. The plan was actually to visit a local shipping company and ask the people that load and unload the trucks what the best shape box would be for the purpose of protecting the contents.
This made the requirement of being able to assemble the frame in a series of simple steps using minimal tools. The instructions and assembly process were designed with the intent that no special skills would be needed to assemble the frame.
Other than the bottom bracket, there was intended to be no threading in the frame. If you stripped out or cross-threaded a bolt, you could drill it out and replace it without damage to the frame. I did end up threading one part. The PROTOTYPE section will confess to this and explain why.
I've actually been working on my own bikes since about 1977. In the '80's I was into BMX, the first time it was cool. I remember going to the hardware store looking for fasteners… we got the same answer every time: "I've told all you kids before - if it's for a bike - we don't have it; bikes use metric, we only have imperial".
Fine. Bikes use Metric.
I specified Metric bolts - M8x1.25 threaded into M8x1.25 nuts.
The difference between 8mm and 5/16" is only 0.0625mm (0.0025", round up and say "3 thou" in conversation). For perspective this difference is about the thickness of a red headed human's hair.
Run into the ghost of the guy behind that hardware store counter from the 80's when you're looking for an M8x1.25 bolt for your TrebuChat? Just tell them that you also need a 5/16" bolt (and nut) to fix a picnic table.
All the bolts for this project were sourced from the local outlet of a large Canadian hardware store chain. Some of the bolts in the prototype are actually 5/6" Grade 5 bolts.
I originally wanted to use A4-90 stainless steel M8 hardware but I learned from looking up tensile strength that the 12.9 M8 hardware had a higher strength even though it gives up corrosion resistance. For the prototype I used the easier to source 12.9 M8 bolts.
USE STANDARD COMPONENTS
Bicycle Industry, that word you keep using, I do not think it means what you think it means.
Let me try to establish this as Use The Most Common Component Specifications; there I'm ok with that.
At the time this project started (2009) the most popular specifications for a DH bike were as follows:
I designed the bike around these specifications.
Things changed as the project went on but I was happy to stick to the specifications.
A Press-Fit BB would have made it easier to manufacture (I threaded my own shell on my lathe - I understand a motivation for Press-Fit).
If I had used a 8.75"x2.75" shock I could have saved some weight but as it turns out analysis and luck lined up and I was able to purchase a stray 9.5"x3" shock from the local bike shop - where I work.
I didn't adopt tapered head tube (I almost typed technology there)… tapered head tube specification.
The design I picked made it easy to manufacture my headtube and it will adapt to almost anything.
I didn't adopt 157mm rear hub spacing since it would have required flipping the Foot piece in manufacturing…
TRENDS ARE NOT TECHNOLOGY
Yes, I have what everyone seems to think are narrow handlebars… I'm ok with that.
The reason for this is that I WILL NOT ACCEPT CHANGE without being forced or convinced.
Yup, I'm an inventor that won't accept change. I don't use a wider handle bar because since I embraced this as my favorite geometry (circa 2005), the only parts of my geometry that have increased in width are irrelevant to holding the handle bar.
The fork that I have on my prototype is from 2004. I have not yet found a fork that feels better to me than this make and model (though I was ok with the 2005 version). On principle I would never design the internals of a suspension fork in nearly ANY way that this fork is put together… never… couldn't make me do it. It feels too good to change. I can also tune it in a particular -I'm not giving this secret away here- way.
The brakes are from the turn of the Millennium. My affinity for these brakes is well enough known locally that I got these from a friend that buys used bikes to refurbish them these were on a bike that was selling for twice the price I paid for the brakes… most of the rest of the bike was scrap.
The drive train is 10-speed. My previous bike ran a cassette of four (4) cogs. I called those cogs: "pedal?", "ride", "feeling zesty" and "broken derailer cable". If I put anything other than what is standard issue these days I figured that you would figure that it could ONLY handle a 4-cog cassette. I picked the brand and model because I like the idea of an affordable full featured derailer and shifter… I work in a bike shop - there's a sideways glance here.
The cranks and bottom bracket are from a Canadian manufacturer. My previous cranks were from the same manufacturer and survived enough use that my ankles wore noticeable notches in the arms. I prefer a caged v. full complement bearing for a bottom bracket but I will get over this.
The chainring is from the same manufacturer as the cranks and bottom bracket. There was a U.S. Patent Pending from another company for the alternating tooth profile. I didn't want to support intellectual property infringment. While I could have simply said "I'm in Canada" and let it go at that, I decided to investigate the progress of the prosecution of US application 13/311735. I learned that the process was not going favourably for the applicant. I took an self-educated and informed guess that prosecution would not be successful. I followed the case up to reading the 36 pages of the final rejection*.
Even given the extent to which I tried to reduce waste, there were times I felt like I was a making toothpick out of a tree trunk.
Let's get the paint issue out of the way.
No it's not painted. Bicycle companies need to survive, their employees need to be able to afford food and shelter. This means bikes have to sell. When I help someone buy a bike I know that how it looks is important. I know that next year's paint colour or graphics help sales. My approach to this was: The most environmentally friendly paint booth or finishing process is to not have one. That was the real push. Yes, I clear coated the steel swingarm in my shower uh… paint booth.
I looked into plating or powder coating options but found them to be too energy consuming. I was so set on avoiding paint that I had originally designed, lined up material sourcing and tooled up to make it out of Titanium - strictly to avoid paint…
The way I would pitch this after the main reason behind no paint:
Easier to see a crack in the material
Never worry if it's this year's colour
Reduce the stagnant stock aspect.
Maybe raw will be cool again!
Without any polishing and clear coat it will tarnish - but then again, we all do.
The second round of prototype drawings changed slightly in specification.
I discovered Schedule 80 Pipe! Seriously, Schedule 40 and Schedule 80 pipe dimension tables are going to be printed out, framed and hung in my machine shop.
I changed the specification of a 6001 bearing for the Knee pivot to a 6003 when I couldn't find either Schedule 40 or 80 pipe to match the dimensions I needed. This let me make the bearing cup out of a common and locally available 6061-T6 pipe instead of machining the cup from round bar. This sacrificed the "use all the same and very common 6001 bearing" principle but kept me from making a tube out of a tree trunk.
I made my rear axle out of ½" 7075-T6 round bar turned down to a nominal 12mm axle (11.84mm?) and threaded a hole drilled into each end to avoid turning down a larger round bar to make a more common type of bolt style axle.
The head tube, seat tube and bottom bracket shell are all Schedule 40 and 80 pipe.
The rounded cable and hose guides are cut out of the piece of material cut away from the tube in the area I call the Tummy Tuck. The squared off guides were cut from a reclaimed (I don't like the word scrap) piece of flat bar
My recycle bins are separated as follows:
It's great to be able to say that I've managed to collect a high percentage of the swarf produced but it won't count for much until I can find a recycler that will make maximum use of the small amount of separated material.
I am very lucky that I was able to source much of my Metal (6061-T6 Aluminum and Brass) and my Machinery (Lathe, Mill and most tooling) from suppliers not only within a 10km (6 mile) radius but in the same direction. I was often able to combine trips although this occasionally led to making an excuse to drop by the Machinery supplier when headed to the metal supplier. That sounds really good but the truth is that the metal came from various US and overseas locations. The machinery and tooling was almost exclusively of overseas origin. I didn't have to go very far but the commodities I purchased closest to home came from furthest away.
My steel was sourced from an online supplier with a Canadian location 575km (350 miles) away.
My tooling was also sourced from an online supplier with a Canadian location 475km (295 miles) away.
Welding was done primarily at a welding school 10km (6 miles) away.
Heat Treating was performed by a company 200km (125 miles) away.
I made selections in material and tooling based on availability and budget. To make ethically driven choices of local sourcing can be impeded by availability, service and cost.