Renovo by Pure Timber.. How it happened

by Christo

Renovo Bikes is owned by me Christo, who also owns Pure Timber LLC. Many of you have asked about how Pure Timber became involved with Renovo and I'll discuss that here, along with some wood working philosophy that made this a perfect fit...I first met the founder of Renovo, Ken Wheeler, about 12 years ago when we were both at the Port Townsend Wooden Boat Festival. My slant was decidedly more nautical than Ken's. But it got me interested in the product, and when Ken's business went bankrupt, I pursued and secured the assets and intellectual property. I knew I had a technical and production advantage that would make my ultimate success with the business much more likely. That probably needs a bit of explanation so I'll try to elaborate on it for you.

Pure Timber is not a Timber company, and definitely isn't a saw mill or lumber yard. The name is a reference to our engineered flexible hardwood that can be used for Extreme Woodbending (TM). This engineered wood we create is solid hardwood, but compressed so that it can stretch when it bends. Wood can't stretch, so we engineer stretch into the wood under controlled conditions, and with heat and lots of pressure. What we do to hardwood is like taking a straight plastic drinking straw, and turning it into a flexible hospital style drinking straw. We are putting the bellows into the cell walls of the wood, and later, when we bend it, it can stretch out again. And speaking of plastic, the wood seems to be like some kind of soft plastic, so I named it Pure Timber to avoid the frequent questions about it being sawdust and glue, or plastic wood, or something like that. It's not. It is 100% solid hardwood, engineered to make it extremely flexible. By the way, after we bend it, we dry it in a kiln, and that fixes the shape permanently.

We use this engineered hardwood to make many precision products and parts. This includes musical instruments, organically shaped furniture parts, organically shaped architectural fabrications, and now wood bikes. The woodwork we do is very precise. If I could hire dentists, they would probably be really good at this kind of thing. Luthiers are good at it. And the detail, geometry and perfection required for a bike frame is exactly what we have been doing for 20 years. 

Wood is an amazing material for making bike frames if the properties of wood are considered for the shape of the part being made. I can design a frame that looks like it was made out of carbon fiber as far as the shape goes. But I have far more flexibility to change and adjust on the fly, or from bike to bike. Most bikes are popped out of molds. It costs a lot of money to make a mold, so it has to be used to make a lot of bikes. Renovo used to have a similar problem to this. Because it cost a lot of money to program the machine to cut this bike. 

Which leads me to another wood issue... using aerospace cutting technology on it. It sounds like a good idea, until you consider that wood does not behave like aluminum. I'm not talking about plywood. This is about solid wood. It has a grain, or a direction in which it is very strong. But it also has a direction in which it is very weak. Cutting a curved line through a straight piece of wood gives you some strong wood, and some weak wood. On the other hand, bending those parts, like we do, keeps the strong part of the wood exactly where it is needed. It is like using unidirectional carbon fiber in a curved part. 

There is another problem with cutting wood on a machine that is used for metal. Solid wood won't come off the router in the shape you think it will. Wood moves. It is still like something living. It breathes. It expands and contracts. It moves more in one plane than in the plane 90 degrees to it. This makes it very difficult to cut wood parts to a specific file, and then put those parts together. The wood parts won't think it is a very good idea, and they'll tell you so. I find myself having all these silent conversations with wood. And if the wood disagrees with my idea or position, I'll loose. 

When I choose wood for a bike frame, my customers often think that I am selecting for color and grain pattern. And I am, but only to a point. I'm also selecting the wood for the part I'm making, and choosing the wood that is going to agree with me that it is going to be a good idea for it to be a different shape. I could cut it and sand it and make it be the shape I want, but the piece will be full of tension and stress. This is not what I want for your bike frame. By bending the wood for the curved parts, I am teaching the wood to be the shape I want it to be. And I've done it long enough that the wood generally goes along with what I ask it to do, if I ask the right way. And be the best mentor I can the wood. It learns. It's a give and take. Not just brute force and saw blades and router bits.

I do not use the "clam shell" method of production for wood bike frames. Renovo did this until 2018. I've changed that. My inner triangle of the bike frames is made from a single piece of long, bentwood. It becomes the backbone, or structure for the rest of the bike. Everything is built off of it. Think of it, a triangle, in one piece of wood. No end grain. No grain run out. Only strong grain running around the triangle. This is the biggest change I have made to Renovo bike production. And it is the secret to a very strong, and very beautiful frame. One piece of wood, bent around a triangle to form a closed part. 360 degrees around. Three tight radius bends. And one nearly invisible scarf joint right about where the water bottle is going to go. This is my production secret. I build from the inner triangle, out to the rest of the bike, and it starts from this very strong foundation, and ends with a functional work of art, strong, and free of stress.

Renovo used to use the "clam shell" method of production. There were two halves, hollowed out on one side, then joined along a center line. There are other wood bike frame builders out there, and most of them learned, and went along with this clam shell method and do it themselves. I'm here to say that it is not a good idea. The parts don't always line up, because wood can move from machining operations, there is a lot of waste, and the weak end grain and sloped grain part of the wood created by this method is put right where you need the most strength at the joints between the top tube, seat tube, down tube and head tube. I've repaired many of these frames, and replaced that weak wood with strong bent parts.

The main triangle, as I said is not a 2 piece clam shell. It is a 3 layer part, with the strong mid bend layer (like unidirectional carbon fiber), and a layer of show wood on either side of the bent unidirectional bent spine. This 3 part build is stable, strong, efficient, stress free, and light. People will come over and just pet it, like it is alive. And it kind of is. It's a living machine.