The science of better bicycles

There is a huge amount of science related to bicycles. In our research publications database you can find thousands of papers. In the better bicycles project we are focused on one aim, creating better every-day or city bicycles for transport and leisure. The science of better bicycles has three steps:

  1. First we consider the questions we ask when trying to design these better bicycles.
  2. Next we review the literature to see if we can answer these questions using current data.
  3. Finally we consider what new science is needed to answer any remaining questions

Scientists and engineers can get involved to help with all stages of this work. Cyclists can also help us with the new science aspect by taking part in studies. This page provides an overview of the current science of better bicycles with links to more detailed pages for each topic.

What's better?

The first question to be answered is what exactly do we mean by a better bicycle? The Better Bicycles project is not about designing bikes that will win races. It’s about creating better bikes for everyday use. That means bikes which are fast, safe, secure, desirable to ride, comfortable in all weathers are practical in a range of situations.

We haven’t defined exactly what this will mean but it will almost certainly be a folding bike with relatively small wheels. It might have integrated luggage which improves aerodynamics and visibility. It would probably have integrated lights spread out over a large area. A bike like this would not meet the UCI’s regulations and so would not be allowed to enter races. It could, however, be considerably faster than the bikes you see in the Tour de France. It would certainly be far safer and more practical.

What's fast?

There is a common misconception that road racing and time trial bikes are the fastest designs. They aren’t, they are just the fastest within some very tight entry rules. But the fastest bikes, such as record holder Aerovelo at 89.6 mph (144 kph) are completely impractical. The question we really want to answer is how can we get the most speed from a practical bike? Analysis of factors influencing speed must, therefore, consider issues of practicality.

Finding an ideal configuration for a practical every-day bike involves trade-offs. The research questions are therefore really about how we can quantify these trade-offs. Specific questions are:

  • How can we quantify the trade-off of rolling resistance (larger wheels are better) against weight and aerodynamics (smaller wheels are better)?
  • How can we quantify the trade-off between weight, traction and rolling resistance when selecting tire width and pressure?
  • What are the aerodynamic gains from different riding positions?
  • What is the biomechanical efficiency of different riding positions?
  • What are the aerodynamic gains from practical partial fairings?

A brief summary of what we already know:

  • Smaller wheels (less than 20” diameter) can come close to, and sometimes exceed, the speed of larger wheels. This was demonstrated by Moulton in the 1960’s.
  • In theory, wider tires have less rolling resistance but more drag.
  • More horizontal riding positions reduce frontal area and therefore drag.

What’s safe?

Consideration of what makes a bike safe must start by considering what the risks are, we can then examine the most effective ways to minimise these risks. We know that the best way to keep cyclists safe is to keep them away from cars. We fully support the development of cycle-ways which achieve this. However, our focus in this project is the bikes themselves. Assuming that we need to ride on roads with motor vehicles, how can we make the bike safer? Specific questions are:

  • What are the most common and the most dangerous accidents?
  • What is the cause of these accidents?
  • What types of injuries are typically sustained?
  • How can these accidents be avoided?
    • How effective are different methods of making cyclists more visible?
    • How effective are different methods of improving cyclists’ visibility?
    • How significant is bike braking and handling to accident avoidance?
    • How important is defensive cycling and can sensors help cyclists to ride more safely
  • How can riders be best protected in the event of an accident?
    • How effective are different types of helmet?
    • What other forms of protection are effective?

A brief summary of what we already know:

  • Many accidents occur because drivers don’t see bikes
  • Cyclists should actively avoid drivers’ blind spots
  • Cyclists should try to be highly visible and use lights at night
  • Many lights are not visible enough from the side leading to a lot of accidents

Read more about the science of making safer bikes

What’s secure?

How can we prevent our bike being stolen?

  • How effective are bike registration and tracking schemes at deterring theft?
  • How effective are different forms of locks at preventing theft?
  • Do folding bikes get stolen from their storage locations?

What do people want to ride?

What can research into peoples’ behavior tell us about how to make bikes that people will actually want to ride more?

What is comfortable and practical in real life?

What does a bike need to be able to do to make it useful to people in their every-day lives? This is closely linked to the previous question.

  • What luggage and/or child carrying capacity is required?
  • What weather-protection is required?
  • What level of maintenance is acceptable?
  • What is an acceptable storage size?
  • What is an acceptable time to unlock, unfold and go?
  • What is the most ergonomic and practical form factor to move around when folded?

How can we put it all together?

The answers to the above questions will equip us well to design a better bike. However, there remain some questions of trade-off between the topics discussed above. For example:

  • What are the best riding positions? This question must consider a wide range of factors: aerodynamics, biomechanics, comfort, visibility to other vehicles, ability to see other vehicles, maneuverability and enjoyment.
  • What type of fairings should be fitted? This question must consider aerodynamics, weather production, luggage carrying and foldability.