While living in England, I bought a bicycle and I used it to move around in my daily errands. To me it’s just a brilliant form of transport, although for many out there is much more than that. But what about the materials used in bicycles, do you know them? I’ve been asking around and it seems a lot is going on in the fascinating world of bicycles. So, let’s do a quick tour looking at materials used in the different parts of a bicycle, to then move to the newest trends in design. Of course, I’ll have some interesting examples of what you can do with the old but never aging bicycle.
Looking for general information about bicycles I’ve found this great image in wikipedia, which saves me explaining all the different parts you can find in a modern bike. If you want to look at other great bicycle images, follow this wikimedia commons link.
bicycle diagram. Source: wikipedia, author: AI2
Materials
There are many available options for a bicycle designer. I asked a fellow blogger, James Thomas, author of Bicycle design, about the materials currently used in bicycles. Here is his answer, which gives a good starting point:
As James explained to me the criteria to choose a material depends on price and the particular applications the bicycle is going to have (commuting, mountain, speed, jumping around). As for the frame itself, density of the material has to be reasonably low, so the overall frame is not too heavy. The frame is the main structural support of the bicycle, so the material used to construct it needs to be strong and endure such a tough life. The most used material in frame construction is steel. I asked through Linkedin about this topic, and Peter Gale got back to me with a lot of detail, but when it comes to the old steel, Peter had the most detailed answer of all:
plain old tubular carbon steel welded, dipped and coated. The uncoated steel parts are 304 stainless because it can be welded or 410 for blanking and other steels in the bearings, the chain and the brakes. The body is extruded, cut, then welded, dipped, cleaned, painted and baked. – Peter Gale, design engineer at EM
Other metals used in frame construction are aluminium or titanium, the latter being quite expensive. Composites of various types have also been explored, as they could provide lightweight and stiffness to the frame. Its use is limited and in general expensive. Composites used in frame construction include ceramic matrix composite, also used in aviation, carbon fibre composites and even carbon/flax fibre composites.
dandy horse. Source: wikipedia. Author: Gun Powder Ma
But by far the most renewable is the bamboo bike, which I’ve already mentioned in other posts. The bamboo bike project aims to examine the feasibility of implementing cargo bikes made of bamboo as a form of transportation in Africa. If you think it not possible, think again, because one of the first two-wheelers, the Dandy Horse (1820), predecessor of the bicycle, was made with cherry wood and softwood. Bamboo wood is strong, but light as it is hollow.
concept technologies
There are so many great things about bikes that I just had to make this post. I think the same about many other objects about which I would like to write, like planes, boats or conceptual cars, but I have to go one by one. The materials I’ve discussed up to now are great examples on how materials can replace each other in the same type of product. But bikes can be inspiring just because of the technologies used in them, regardless of the material used to execute the idea. For example, Velorution, a British blog dedicated cycling, emphasises the importance of monocoque (or made in one piece) frames and James Thomas already explained above the importance of new processing methods, like hydroforming, to improve performance. Again, through my question in Linkedin, I got this great info on new technologies for bicycles from Jody Wilson, Acudyn Inc:
Systems
- hydraulic brakes
- power system; regenerative shocks, brakes, wheels
- magnetic bearings
- magnetic shock absorbers (for electric adjustment)
- automatic shifting, or electronic shifting
- shaft driven (opposed to chain) wheels
- single sided wheel supports
- spherical shaped wheels, bearings
Austin Brown, whom had very interesting ideas for this post (sorry Austin, I didn’t have time to discuss decal and painting fo bicycles, but i keep the idea for some other time), added all these concept technologies and kindly provided me with links:
hubless wheels, continuously variable transmissions, automatic transmissions, and electric bikes are all pretty intriguing. There was also a three wheeled vehicle that is on the market (not a bike, i know) but the propulsion system relied on the rider kicking as though he were ice skating. Very neat. Finally, I recently saw a post about a self balancing bike developed in Japan. (2nd link)
Links:
Folding bike
Innovative projects
DuPont and Tag Wheels
Most wheels have tires made of rubber, with rims and hubs made of plated steel. TAG Wheels (TAG stands for Technically Advanced Geometry) manufactures composites wheels made in one piece. And when I say one piece, I really mean it, since they are not cut and glued together, but manufactured with a technology called “Lost Core Molding”. The manufacturing process starts with molding a low-melt point metal mandrel. This mandrel is then over molded with a composite thermoplastic. The mandrel or “core” is then melted out leaving behind the hollow-formed composite wheel. Thanks to this technology, TAG Wheels can design complex geometries with varying wall sections throughout the wheel.
Tag Wheels use DuPont‘s material, Zytel 8018 to mould their FRX5 wheels. DuPont commercialises a wide variety of materials, but nylon is definitely one of their core businesses. You can check more sports applications of DuPont’s materials in this Omnexus article (you may need to register, sorry). Zytel 8018 is nylon reinforced with 14% glass reinforcement and it has an outstanding impact strength. And if you want proof of it, just look at this video I found in YouTube (many more if you search Tag Wheels):
Museeuw Flax Bike
Yes, Flax Bike. It may come to a surprise, but flax, the natural fibre, is used as a reinforcement in plastics. Its widespread use in the automotive industry, for example in door pannels, is not very well known. Museeuw Bike, managed by Johan Museeuw, winner of 11 World Cup Races, collaborates with IPA Composites Belgium (design) and Billato Linea Telai (manufacturing) to produce these bicycles. The frame material is a combination of long flax fibres (the longer the fibres, the more resistance the give to the composite) and carbon fibre. If you want to read about a test riding for the Museeuw bikes, follow this link.
Flax is in decline in Europe, since most textiles are now manufactured elsewhere and therefore its use in composites is one way to bring back value to a shrinking market. Other advantages of using flax are:
- safe reinforcement, unlike glass fibre, which needs to be handled with protection
- natural, renewable resource
- existing knowledge on processing and behaviour
- improves shock absorption
Conclusion
The conclusion for this post has to be that I need to cycle more – probably you too! But let’s not forget how sometimes some amazing materials are used in common objects and how design and engineering can improve performance and of course, looks.
