Introducing our first Imagine Project prototype
After an intensive period of research, learning and development we have produced our first Imagine Project prototype, the Imagine 20. Here we share some of the thinking behind our initial design, materials and component choices and how we’re progressing towards our goal of making the bikes ‘circular’ and sustainable.
Materials are valuable
The Imagine Project is very different to a traditional rental model. A principle of a circular economy is that manufacturers retain ownership of their products and therefore responsibility for the precious raw materials. When the bikes are returned to us we will refurbish them and send to the next rider. This way of supplying bikes incentivises us to design for the longest possible life. If the bike is irreparably damaged, or has finally reached the end of its useful life, materials will be separated and reused or redistributed. Rather than ending up in landfill sites the materials pass between users and other industries, maintaining their value and creating a regenerative, circular flow.
The challenge
The Imagine Project bikes are presenting us with a set of new and unique challenges, causing us to rethink the way we have traditionally designed and manufactured bicycles. We recognise that our first prototypes are unlikely to meet all of the requirements to make them fully circular and sustainable, however we are aiming to get as much right as we can from the outset. Here are some of the key areas we are having to consider:
- Materials and components will originate close to the place of manufacture, minimising the environmental impact and energy used in their transport.
- Material composition (including any applied finish such as paint) must facilitate easy separation and reprocessing at end of life and ensure material value is maintained, not downgraded.
- Our goal is to use 100% reused materials, therefore removing demand on finite natural resources.
- Manufacturing to be done by us in the UK.
- We’ve set ourselves the ambitious stretch goal of a 50 year lifespan for each Imagine Project bicycle.
- Zero maintenance for the user during the typical rental period to provide a fantastic, hassle free experience.
Frame and forks
For this first phase we’ve focused much of our attention on the frame. As the heart of the bike it is critical that we get this right as early on as possible, both in terms of our designs but also material selection and joining methods – all playing an important part in the bike’s longevity, sustainability and performance.
There are a number of options available when considering frame and fork material, with steel the longest established. Steel was used on the earliest bicycles produced over 130 years ago and is still popular today. As a result, when used as a bicycle frame steel has very well understood properties. It has a naturally very long fatigue life; in fact the fatigue life is practically infinite below a certain “stress level”. One downside to steel is its propensity to corrode over time if subjected to moisture. Good quality finishing will significantly reduce this, however due to the difficulty in removing paint and other finishes at the end of life, the toxic components and the inability to reuse the removed material, led us to the conclusion that it would be far better to leave the bikes without any paint finish at all. Stainless steel typically has high tensile strength and addresses the issue of corrosion, allowing it to be left unfinished. We have therefore chosen to trial stainless steel for the frame and forks of our first prototypes.
A small number of special one-off tube sets have been sourced and cold worked for us by our friends at Reynolds Technology in Birmingham – a business with a long history of supplying high quality steel tube sets to the bicycle industry. The steel itself is produced in Sheffield, whereas current off-the-shelf stainless tube sets originate overseas. Stainless steel also has the advantage of containing 70% recycled steel already in its production, as well as 80% of stainless steel being recycled, even without incentives in place to do so. This felt like a good place to start but we will insist upon 100% recycled source once we have established the viability of the material for our bicycles.
In terms of frame construction, the tubes are TIG welded together. TIG welding uses a very small, very hot electrical flame (arc) which melts the metals causing the joint to fuse together as it cools. TIG welding has the benefit of not introducing a different material into the joint, therefore significantly improving the ease of separability of materials at the end of life. To be able to TIG weld to the standard required for a bicycle frame requires many hours of practice. Alongside our frame development we are also expanding our in-house manufacturing capability and skills so that when the time comes we are ready to commence with producing the bikes in larger numbers. Our technicians, Ben and Phil, have spent an intense period over the last few months refining and improving their welding technique.
Finish
When the frame is complete the tubes are polished to a shine. As we are not using paint or decals the logos are applied by creating a mask on the frame tubes then bead blasting them in a dedicated blasting cabinet. This results in a subtle ingraining of the image in the surface of the tube. Although yet to be tested long term, this method has proven durable on custom frames built for members of the Islabikes team and should also be easy for us to refresh when the bike is returned for refurbishment. Marks, scratches and blemishes can be easily polished out, meaning the bike will be sent out to the next rider looking tidy and fresh.
Brakes and gearing
The wear rate of parts in braking systems can be significant when a bike is used regularly, and this accelerates with exposure to the elements. As we expect these bikes to be used in all weathers and want them to be maintenance free for the rider, this is an important consideration. Wheel rim braking systems result in wear to the rim which will eventually require replacement. We are attracted to the concept of a brake contained from the elements in the hub and are therefore trialling drum brakes. In a bicycle drum brake the brake shoes and braking surface are encased in the body of the hub, very similar to those found on many cars. Life span compared to a rim brake should therefore be greatly increased due to protection of the wear parts from the elements. The hubs we’ve chosen to trial are produced by Sturmey Archer – once manufactured in the UK but now in Taiwan. This means they don’t meet our criteria in terms of being locally sourced, never mind other factors such as material composition and provenance. However they will allow us to test the technology and move forward if we feel it works in line with our long life, zero user-maintenance design aspirations.
These hubs also incorporate internal gears, a concept we are keen to test as there are many theoretical advantages for bikes of this kind. Enclosure of the gear mechanism in the hub shields it from the elements and protects from damage when compared to derailleur gear systems. Having been available for over 100 years this technology is well proven; however, little attention has been paid to ongoing product development over the last 50 years. We plan to understand the technology and then seek ways to improve it. If you know of anyone who might be able to help us with this highly specialist challenge please get in touch.
Saddle
Islabikes saddles have been carefully designed to provide optimal fit and comfort for growing children. For the Imagine Project bikes our goal is to fit a saddle with the same rider benefits but which has a sustainable construction in line with our circular criteria. Some interesting products already exist on the market, however we have not found anything yet which is available in sizes and shapes appropriate for children.
Established in 1866 in Birmingham, Brooks are famous for their range of bicycle saddles and still manufacture in the UK using many traditional methods. Their ‘Cambium’ saddle is constructed with stainless steel rails and natural vulcanised rubber with an organic cotton top. Designed for long life, they are also fully re-buildable with spare parts readily available. This felt a step in the right direction, so we acquired a saddle and ‘modified’ it to a more child-friendly shape through careful application of a sanding belt! Although more development is clearly required we are pleased with our first attempt.
Having recently shared our Imagine Project with Brooks, we were thrilled with their enthusiastic response and are now working in partnership with them to develop a circular sustainable saddle.
Pedals
We were intrigued when we first came across these unusual pedals. Manufactured from rice husks – a product of rice processing – this Taiwanese produced pedal has sustainable credentials and is a novel way of taking a waste product from a mass production process and turning it into something usable. As an adult pedal they are not currently ideal for a child’s bike and the fact that they are manufactured in Taiwan means they don’t meet our local sourcing requirements. However we are impressed by the results (and the way they smell!) and would like to find out if any similarly inventive manufacturing methods which harness natural waste products exist closer to home.
What next?
Current bicycle safety testing standards are not designed for the very long lifespan we intend for the Imagine Project bikes. We will be putting the Imagine 20 through its paces so that we can determine the physical demands put on the bikes, extrapolate these over an extended period of time and thereby construct a new and unique set of testing standards. We already have some thoughts around how we will do this, but if you have any ideas or expertise related to the areas of fatigue or product testing and think you might be able to contribute, please get in touch.