• Question: i have a few more questions if you don't mind answering :-) 1. does the smaller wheel size of the bike effect the performance 2. do you have any advise on starting out in engineering 3.do you think you will venture into purpose built bikes e.g mountain/road

    Asked by JoeDavies to Eleanor on 8 Mar 2016. This question was also asked by pajj.
    • Photo: Eleanor Sherwen

      Eleanor Sherwen answered on 8 Mar 2016:

      1. Yes. When you cycle the wheel deforms (changes shape) as it presses against the ground. That grips the road, and you push the wheel so the next bit touches, pushing you forward. The amount of wasted energy (that didn’t make you go forwards) is called the rolling resistance. A small tyre has a higher rolling resistance, because you have to deform a larger % of the shape to get the same grip as with a large tyre. So of a large tyre and a small tyre at the same pressure, the large tyre is more efficient. But, we make our little tyres with more pressure to compensate. 100 psi instead of 70-80 psi. So the deformation in shape is less again, reducing the rolling resistance and making it more efficient. Also, as long as the gear ratio on a small wheel bike is just right, you don’t notice the difference in efficiency very much at all anyway. So that is how we limit the effect. To go really really fast, big wheels help. To get a bike folded up and on a train, little wheels win!

      2.My advice on starting out is try to get lots of experience, ask if you can go to workshops and factories or engineering firms and look around. Ask lots of questions and find out how they do things. That really helped me when I was young, there were lots of older engineers who explained and taught me. Engineering is very practical and still has a culture of apprentices and learning gradually in the workplace, so A levels and University degrees help but it’s not the whole picture.

      3. It would be a bit tricky to – there are only two large bike manufacturers in the UK: Brompton, who make folding bikes, and Pashley, who make traditional style bikes. I specifically like folding bikes so Brompton suits me fine, I like touring bikes as well but that’s a real niche market. Some of my colleagues are into mountain biking or road biking and their absolute dream job would be working on those bikes, but they can’t in the UK. One colleague recently moved to Canada and started working for a mountain biking company, so it can be a route into that.