MTB brake system for finger amputees (university project)

alex_gunn

Hello, I’m a final year undergraduate student at Bournemouth University studying product design. For my major project I have decided to develop a product for mountain bikers with a finger amputation who struggle to use the bicycle’s brake levers.

I have created a short questionnaire with google forms that takes 5 minutes to complete. If you are a mountain biker with or without a finger amputation it would be a great help if you have a spare 5 minutes to complete the questionnaire. This will provide a clearer understanding of how such a product may be used.

You do not need a google account to complete the questionnaire.

Link to the questionnaire

Thanks for your time

steve_sordy

To all: The link looks genuine, I completed the form.

To @alex_gunn: What a great idea for a research project!

You may get some ideas from other work that has been done for amputees. A couple of years ago, I saw a guy riding a bike with only one arm! He had both brakes on the right side and the left side of the bar had only a grip (for safety). He was considering removing the left side of the bar completely, down to the stem, because when he came off the left side bar end usually poked him in the ribs. Yikes.

I also saw another guy who had no hand at all, off at the wrist.
He was a bit better off ( ) because he could use his arm to stabilise the steering. He had an attachment to his stump that fastened him to the bike. He had a quick release device in case of an off. Double brakes on side as before.

Both guys needed to master having both brakes and the shifter operated by one hand. Some customisation of the mounts was necessary to put all those levers in the range of one set of fingers. 1x shifting was essential of course.

I was so blown away by the awesomeness of both guys that I completely forgot to ask about whether they had a dropper post.

For quick release devices, take a look at clipped in pedals.

@alex_gunn I wish you well with your project and I hope something comes of it. With sufficient misfortune I may need it one day!

alex_gunn

Hi Steve_Sordy, thank you for completing the form

It is amazing how these riders are able to overcome the challenge of remaining in control of the bike. It must require a lot of perseverance.

Thanks for all the suggestions, I'll have a look at how the release mechanism in pedals works.

All the best,
Alex

steve_sordy

@alex_gunn There are all sorts of quick release devices, ranging from dead man's handles on locomotives to throttle kills on jet-skis.

I saw the one-armed guy put his whole bike in the back of his car! It was that which alerted me to his condition. He promptly removed the bike from his car to show me his controls. He was a big guy and I sure wouldn't have challenged him to arm wrestle!

I have also chatted to an ex-army guy who had had his foot blown off. He had a special lower leg just for MTB, complete with its own riding boot that had a special quick release on it. He said it was different to the standard Shimano SPD release because he couldn't twist sideways by the amount required for ejection.

Sticking with the "special legs" theme. I once worked for an Austrian guy who lost his leg at the hip in a motorbike accident when he was 18. He had a leg for walking about, but it had a special lock at the knee that he could release to allow for increased range of movement when he wanted to sit down or get into the car. Compared to the high-tech ones our injured ex-forces people are being fitted with, it looked definitely low-tech to me. His hobby was scuba diving and he had a special leg for that! Obviously seawater proof, with neutral buoyancy, and it came with its own flipper! He had other legs too, but he didn't volunteer what they were for (maybe bike riding?)

I suspect that the existing industry that serves disabled people will prove to be a rich seam of information and ideas for you to mine.

alex_gunn

Hi steve_sordy,

Incorporating the principle of a deadmans handle would be a nice way for a prosthetic arm to detach from the handlebars in the event of a crash. Maybe the mechanism could act when pressure is released from the other side of the handlebars or one of the pedals.

Also thanks you for the suggestions, it has been helpful to research existing products to find inspiration for how a potential solution may work. Its interesting to see the differences between each prosthetic which allows the individual to complete a particular task

steve_sordy

@alex_gunn I am assuming that you are a biker (hence your project), therefore you will know that relying upon a conscious action to detach yourself from the bike may not be fast enough. Frequently I have been involved in an "unplanned dismount", or an "OTB excursion" that came totally out of the blue. It is one of the reasons I stopped riding clipped in.
The final straw for me was this: I got trapped under the bike with both feet still clipped in and unable to detach because of the angle of my legs. I was in a gulley with a deep drain hole underneath me and I was surrounded by nettles. I had been riding a 2x uphill at the time and the larger chain ring was embedded in my calf muscle. I needed help to get out of that without incurring further injury. Luckily for me I was in a group.

me-109

Depending on the nature of the riding (as in aggressiveness) or rider preference, you could use a single lever and master cylinder to activate both brakes, use a brake balancer to 'automatically' split braking force (which is normally done to load front brakes more to prevent rear wheel lock up), or use a thumb lever for one (usually rear) and normal brake for the other.
Lots of options - quite a few tried and tested - but braking would be intrinsically linked to actually holding the bars and retaining control. There's no one-size-fits-all option. I don't see an option to use feet or some other alternative as you might with a motorbike.