Some things are so good that it’s difficult to improve them. The conventional bicycle is an example. For a long time, any attempt to improve on the double triangle frame with spoke wheels, crank pedalling and a chain has been doomed to fail. Many have tried since this concept emerged in the 19th century. This does not mean that the modern version of the concept is not better than the old version, but the basic concept is unchanged, or has been until recently. New materials are now used, which allow (or dictate) new frame shapes, and frame shapes have become a matter of fashion. Diversification of bicycle types, for instance the mountain bike and the electric bike, has created markets with higher selling prices. New shapes were both needed and expected.
Nevertheless, from time to time a creative idea is presented which claims a technical advantage by changing the concept of the bicycle. NuBike is one of those. It targets the heart of the bicycle: the pedalling mechanism. The promotional video claims that the multilink mechanism reduces stress on the cyclists’ joints, that there is less effort by a longer power stroke and longer ‘gravity push’, and an end to the many troubles resulting from chains (dirt, risk of ruined clothing, maintenance).
Reden Makes Sense is normally about numbers, and numbers will be given below. However, in this case we will also discuss some aspects of innovation. After all, Reden’s website claims that ‘We understand innovation’.
NuBike or Ol’Bike?
An important rule of Reden is: “before trial-and-error, let’s do the physics”. This is not always how developers work; a prototype shows the effort put into it more convincingly than some sheets of paper containing a calculation. The benefit lies in avoiding all the prototypes that don’t work, so less visible effort is needed before the final working prototype can be made.
So, let’s do the physics/mechanics on the pedalling system. NuBike claims the effort on the pedals is more constant than on a chain driven bicycle. We don’t go into the question whether or not this is indeed desirable. There is debate on this in connection with oval chain wheels, which have the same aim (see OvalVs Round Chainring - Where The Road Forks). But in the case of NuBike, is the effort really more constant? The figure below shows the height of the biker’s foot and its vertical velocity for a NuBike and a regular chain driven bicycle. The curves are approximate, the geometric data are taken from photographs. The NuBike curve for the position is slightly asymmetric; the down stroke is a little longer than for the chain drive. The velocity of the foot, however, varies all the time, there is no plateau in the velocity curve. The velocity in the upstroke is 25% higher than for the chain drive. The curves are indeed different, but only practice can tell if this makes the NuBike more comfortable. The claim of a more constant load, however, seems farfetched.
The principle of using levers to transmit power to the wheel is not new. The American Star bicycle uses a mechanism with levers, a leather strap and a drum with ratchet to drive the wheel from each side. This mechanism provides a much smoother transmission of force (but I leave the detailed analysis to the reader!). This part of the American Star seems a very nice feature. The steering geometry, on the other hand, seems very strange, with pronounced negative caster.
Note: it is likely that positive caster would not have much effect because the rider sits almost right above the rear axle. This bicycle has a very large trail in the steering geometry; the front wheel touches the road far behind the point where the steering axis intersects the road, and this helps the bike to go in a straight line.
Comparison of the mechanisms of the NuBike and the Old Bike show that the American Star has fewer pivots, but two leather belts extra. The biggest difference in use is that the two pedals on the American Star are independent, and can be pushed down at the same time for power bursts. The up stroke can be much shorter than the down stroke. Again, whether this is a real advantage is not clear. It would be nice to try it out.
Thoughts on innovation
Innovation is about making things better by developing new ideas, or new applications of existing ideas, and achieving better results than current solutions. In the case of NuBike, as described above, it can be argued that not all conditions are met. It is a very interesting bike, but it cannot claim to be 100% innovative.
A good innovation solves a problem better than existing solutions, without creating new problems.
This suggests the following steps:
- Identify a problem. For example, in the case of NuBike: painful knees, damaged clothes, dirt, low efficiency, etc.
- Find out if the problem is recognised by other people, and how bad a problem they find it. This is not always easy, because some problems are only apparent after a solution is presented; the solution creates the problem; the mobile phone is an example of this.
- Look for old solutions for the same problem (patents, the internet in general, old publications).
- Invent something new with the view to solve the problem. Often, inventors jump to this step after step 1, or the process starts here, with an idea. It is worth going back to steps 2 and 3 if this is the case.
- Before ‘trial-and-error’, let’s do the physics first. Much prototyping can be avoided by careful design based on physics (fluid flow, heat transfer, structural dynamics, etc.), saving time and effort and providing insight.
- Check if the new solution does the job, and has the potential to be made into a good and affordable product.
- Check if the product has clear advantages over other solutions. This is often difficult for the inventor, because (s)he is biased. Step 7 is important for that reason.
- Protect the invention by keeping it secret until it is patented. In the meantime, make selected persons enthusiastic, so they can help you. For this purpose, Non Disclosure Agreements can be used.
- Make prototypes to test and prepare the market for the new product.
There was also a manufacturer in Manchester, UK The Claviger Cycle Co., with a lever-driven bicycle, patented in the US in 1889 by William Golding ofLancaster, UK.
It is possible to sell new products which are not innovative, of course, but that in itself is not innovation. The NuBike looks as if it is expensive to make, and there is no reason why it should not work as well as a conventional bike. It is very special, and has the added advantage of easy disassembly, so there will, no doubt, be enthusiasts who rush to buy it when it is offered for sale.
However, it is not a good example of a technical innovation. Inventing and developing real innovations is not so easy.