Adaptive Mountain Bike
To create a new type of adaptive mountain bike that redefines the levels of maneuverability and accessibility in this field.
AD3 linkage
please see orange bikes for further details:
Interview with Alex Desmond, Orange Bikes Senior Design Engineer, Director of DezMotoRacing and creator of the AD3: Adaptive 3 wheeled mountain bike.
Describe the AD3 in a nutshell.
The AD3 is an adaptive mountain bike that’s designed to feel like a conventional bike whilst offering the rider independence and accessibility. The balance component is transferred to the upper body allowing riders to stationary balance and maneuverer at low speed without using their lower body. The wheels are as narrow as the pedals which opens up single tracks usually inaccessible to adaptive mountain bikes. It is customisable to each riders needs and preferences. The AD3 enables riders who can’t or choose not to ride a conventional bike to ride something that behaves and feels like a conventional bike.
More details on the AD3.
A lot of riders with disabilities still want to ride single tracks, berms, jumps, technical roots, rocks and ruts. The AD3 opens up this kind of riding to them. It looks similar to the three wheeled motorcycles that people may have seen around but there are two key differences. The linkage is designed so that it can be fitted to existing bike frame designs without changing the geometry of the original bike. The second difference is the balance element. Other three wheeled bikes don’t have a way of balancing without using your legs.
The AD3 is a patent pending design that uses a pair of cantilever linkage arms to join two additional head tubes. There is then a second steering linkage element connecting the two forks to the original steering head tube. I have developed multiple versions based around this cantilever front end that achieve upper body balancing in different ways. Some use a second set of handle bars that are fixed, another has a second steering set, one locks the lean mechanism and I have a design that incorporates the balance and steering into a single handle bar. Different solutions suit different people depending on their individual needs, their level of injury and their preferences. All solutions allow riders to achieve stationary and low speed dynamic balancing, stopping or moving slowly on almost any incline or terrain.
The leaning three-wheeled design means that if riders’ loose traction or reach the limits of lean they understeer instead of falling over like on a conventional bike. The leaning linkage is also designed to protect the legs if the rider does fall. The lean limit is dependent on the set-up, on Lorraine’s bike it’s 40 degrees lean angle. I found that it’s pretty difficult to get any off-road bike past 30 degrees without losing traction so this gives you a good margin. It also means the bike can be ridden along inclines around 40 degrees which are pretty tough to even walk across. The front-end linkage can ride up over obstacles up to 175mm, plus the suspension travel of 170mm meaning the total clearance for one wheel on Lorraine’s bike is around 345mm. The double front end also reduces suspension input to the rider by 50%. This means it feels like a magic carpet ride over roots and ruts. Having the second front wheel also increases grip by 50%, making the bike a lot more secure.
The secondary seat suspension allows the rider to change their centre of mass on the bike, enabling them to jump or pump the bike. All these attributes mean that you can ride it like a conventional bike but still be able to balance with only your upper body. When we tested it, no-one could keep up with Lorraine when flat cornering as she just had more grip on the AD3. Plus… she is pretty dam fast. There’s a reason she’s called the pocket rocket.
What does it feel like to balance using your upper body?
It’s obviously different to balancing with your legs and can take some practice. It’s a subconscious skill that some people pick up really quickly and others take a little more time. It feels a bit like doing a track stand on a bike but physically it’s a lot easier. I’ve had someone with a complete T7 spinal cord injury jump on, strap themselves in, grab the balance linkage and ride off straight away like they’ve been doing it for years. Other people take a bit more time which is fine too. Lots of people working at the Orange bike factory wanted a go on the prototype and everyone got the hang of it very quickly. It’s also important to remember that the balance bars are only used at very low speed or when stationary and most of the time riders are on the regular bars and it’s just ridden like a conventional bike.
Where can you ride it?
Most places a conventional bike can go. A limitation of many adaptive bikes is they need wider tracks. A lot of purpose-built tracks for people with disabilities don’t have gnarly features like jumps, steep berms and technical descents which a lot of adaptive riders still crave. I really wanted to build something that could use existing single tracks so the AD3 has a 350mm track width. Because of the AD3’s ability to ride on an incline you can also ride it along tracks narrower than 350mm or down ruts with one wheel in the rut and one wheel out. You can traverse up to 40 degrees incline on Lorraine’s bike, but I have a version that can achieve 45 degrees lean angle if you want to go that far.
The whole purpose of the AD3 is to provide a bike that allows adaptive athletes to push the boundaries of their riding abilities without being restricted by the bike.
Why two wheels at the front?
I went with two wheels at the front after working on and riding a few bucket seat bikes (a conventional bike with a sit-ski style seat on). Bucket seat bikes are cool, but adaptive riders need a lot of support to use them. They can’t independently get in or out, if they stop they’ll fall over or they need a wall or person to lead on. Rider’s centre of mass is also fixed on a conventional bucket seat bike which restricts how the rider can move their weight around and means they often need more grip than a non-adaptive rider doing the same speed around a corner. The end result is a lot of falls. On a bucket seat bike a riders lower limbs are very exposed and I’ve had a few friends break bones and injure themselves on what looked like minor spills.
I did two things to address these issues. Having two wheels at the front increases the front-end grip by 50% and it means you understeer instead of low siding. In addition to this I designed the linkage so it locks up at maximum lean and forms a protective cage around the riders’ legs. Having 2 wheels also turns the bike into a tripod which, combined with the patent pending linkage and balance mechanism I designed, allows riders to independently stop or manoeuvre slowly, which you couldn’t do with two wheels at the back. I also added a seat post suspension to give the riders some centre of mass movement, allowing them to pump and jump more easily.
How much does it weigh?
How much the AD3 weighs depends on the specification of the bike. A normal E-bike weighs in at around 20-25 kg depending on battery size and the level of build. The AD3 has two front ends and a bucket seat rather than a saddle so this increases the mass. Lorraine’s build weighed about 30kg, but it could have been much lighter. For example, Lorraine went with for 38 Fox forks to get a really robust build as she wants to do downhill runs in the Alps and that was more important to her than keeping the weight down.
How strong is it?
The front end is designed to be as strong or stronger than the original bike frame, with the tubes sized accordingly. Given that this was a 170mm travel Orange E-bike to start with the AD3 front end is designed to deal with the same loads as the base bike. I used Finite Element Analysis (FEA) and destructive physical testing extensively during the development to ensure the design was strong enough for it’s intended use. The prototype has thousands of miles on it now and ive had no issues so far.
What’s it like to ride?
It just feels like a conventional bike when you’re moving. The front-end design means one wheel can actually clear an obstacle of up to 345mm. This means you pick a route and ride down it like a conventional bike and the AD3 does the rest of the work. There is some difference in thinking about where the two wheels will end up but honestly, it’s not something you don’t tend to think about, your brain just works it out for you. I tend to teach people to balance the bike without the seat post suspension installed as it adds another variable to get used to. If people want to find out for themselves, they can get in touch through my website Dezmotoracing.co.uk or by contacting Orange bikes to book a test day.
This all sounds like a lot of work, what motivated you to design the bike in the first place?
The person that taught me how to ride a motorcycle had a stroke and couldn’t ride anymore. that really shifted my focus to wanting to design something to enable people to ride after injury. The project goal was to give rider’s their sense of freedom, independence and inclusion in a sport that means so much to them.
I was partly inspired by seeing Martyn Ashton’s “down not out” video and relating to what I would want if I was in the same position. I couldn’t find anything on the market that would fulfil what I would personally want if I was an adaptive rider. Martyn’s bucket seat bike is a conventional bike with a motor for power and a sit-ski seat which holds the rider securely. Bucket seat bikes are great but they are not without limitations. They require lots of people to help the rider get on and catch them when they stop because they have no stationary balance, have a high risk of injury and are poor at jumping because of fixed rider position. I felt these barriers could be overcome with good engineering and I was interested in the challenge. I was motivated to design and build something entirely of my own conception after years of engineering for large corporations.
Most adaptive bikes on the market mainly focus on safety and independence. They tend to be low and wide which means the rider is not on the same level as their riding friends, can’t use all of trail network and they don’t give the same sensations as a conventional bike to ride. They are great for people whose priority is independence and safety, but others just want something that feels like a conventional bike but need one that they can balance and use independently. You can still fall off on the AD3 but it’s a lot more stable and secure than a conventional bikes and it does help to protect the rider if they do fall over.
How long?
I actually started the AD3 6 years ago in my free time, at one point I lost my job due to covid and focused on the project for a solid year. During that time I have worked with lots of riders with different levels of spinal cord injury including Steve at Can’t Quit Cartel and talked to Martyn Ashton about what he would want too. I’ve invested a lot of time and money in the design and prototype and went through 6 main iterations, trying different set ups for different people. I brought my own CNC machine and started making pretty much everything myself. I couldn’t have done it without help from friends though, especially Paul at Ride Works, not only did he make a lot of the initial prototype parts but he taught me how to program so I could make my own CNC parts.
How did you meet Lorraine?
Adrian at Swarf cycles was a friend of Orange bikes Switzerland, as was Lorraine. They asked Adrian if he knew anyone who could design an adaptive bike for Lorraine. Adrian knew I had been working on the project for years so put them in touch with me.
How is Lorraine’s bike different?
Lorraine was riding at top level Enduro World Series (EWS) and was a very fast, hard rider. They don’t call her the Pocket Rocket for nothing! She had a crash wile racing EWS that resulted in an acquired brain injury. Designing a bike for Lorraine has been a bit different to designing for someone with a spinal cord injury and it’s bespoke kitted out for her needs. Lorraine is a wheelchair user and has some partial paralysis on one side, plus she gets fatigued very quickly especially when completing complex physical tasks. She has cognitive loading issues, so if she does too many things at once, for example pedalling and steering at the same this can lead to spasticity in some of her limbs. This is one of the reasons you see her resting the bike up against a tree or wall at times just to give her brain a complete rest.
I wasn’t sure how the bike would work for Lorraine so I drove the prototype to Switzerland for her to try. She pretty much jumped on, balanced independently and rode straight off. Within minutes she was trying to slide the back end around but, with the brakes revered for UK setting, she ended up doing an endo. I was chasing her down the road begging her to take it easy. It was clear straight away she was going to be a perfect test rider and take the bike to its limits.
How do riders get on and off the bike?
I make bucket seats (sit-ski style) custom to fit the rider’s size and needs. Some riders prefer having a back on for extra support, some like more length on the base, whilst some like it shorter. This influences how easy it is to get in and out. The AD3 doesn’t need to have a bucket seat and can be ridden with a saddle, although most adaptive riders need a bucket seat to stabilise their core. It’s possible to lock the linkage and pull yourself onto the bike using the balance bars for stability, similar to when a wheelchair user transfers into a car. Alternatively, you can use a hoist or the help of another person. I’ve designed a set up that works out the back of a car, as well as a custom bike rack. With practice and the right set up it’s possible to transfer independently. This is quite different to a conventional bike with a bucket seat on where at least three people are needed to support the rider getting in and also catching the rider if they stop because they can’t stationary balance. Lorraine is able to get the bike in and out of her garage and go for rides independently. She’s also learned to get the bike upright again and back on if she’d crashed, perhaps when she’d been testing to see how big a back end slide she can manage before she goes down (thank you Lorraine for your extensive help in testing every limit of the bike- not good for my nerves but certainly good for my engineering!)
The height of the AD3 does make it harder to get in and out, although this is what enables it to feel and behave more like a conventional bike than is possible if the rider is lower to ground level. Riders can also stop and balance at the same level as non-adaptive riders which makes riding with friends feel more natural and inclusive. We found a solution for Lorraine that didn’t require anyone else’s help and within three weeks of testing she covered over 200km of trail and did over 7,000m elevation gain. The AD3 can climb very well depending on the specification. I struggled to keep up with Lorraine going uphill even when I was riding an ebike. It has enough torque to do some impressive technical climbs.
How far can the battery go?
The battery life depends on many factors including whether it’s set up as a mobility device or an e-bike, rider weight, riding style, terrain, battery specs and motor specs. Lorraine’s bike has a handlebar throttle and was built with a 504wh battery and a 1.5kw continuous motor with a 2kw peak and with around 150NM of torque. I also have a 635wh battery design too. Lorraine has a small bike frame so I wanted to keep the battery compact. Lorraine found she could do about 700m of technical climbing on one battery and about 25km of trail. She carried a spare when she wanted to go further which easily fits in a backpack and takes seconds to change. If you were just riding fire roads or doing descents it would go a lot further on one battery. We did a day using gondolas to get elevation and Lorraine did a few Verbier Bike Park trails, then rode home on one battery. This included 25k of trails, mainly descending and traversing with over 2500m elevation drop.
How did the connection with Orange Bikes come about?
Orange Bikes Switzerland is run by Lucy and Phil who we stayed with whilst Lorraine was testing the prototype. When that went well they put me in contact with Orange Bikes UK to see if they would manufacture a bike for Lorraine using my AD3 design. Obviously they have to protect the integrity of their brand so they wanted to check it was good enough for the Orange logo. I took the prototype to the Orange factory and they were really impressed. Orange said they’d only make it if I agreed to work for the company. I actually said “I’ll think about it” as I was so busy working on the adaptive bike. I got halfway down the M6 before it clicked that the adaptive bike cost me money rather than made me money at that point and I was like “bugger, I need a job and Orange is basically THE British MTB company, they were there at the start”. I’d seen Orange bikes hung up in shops when I was 13 and lusted over them so to have the opportunity to work with them was a dream come true…. It just took me a while to process!
Orange partnership:
Orange is the only bike company that actually make their own aluminium frame tubes in the UK and that gives me the flexibility to design exactly what I know will work for the AD3. I’m passionate about showcasing the ingenuity and creative engineering that comes out of the UK. The frame, linkage and most of the components are designed, engineered, manufactured and built in the UK. Orange aligned really well with what I value, designed and built in Britain in a sustainable and environmentally friendly way using recycled, recyclable materials. We have a shared goal to make the best performance product to meets customer’s needs. I can see an exciting future working together with Orange, merging our expertise in different areas like bringing my FEA background to Orange and them sharing their tube forming knowledge with me.
The Orange bike:
The Orange Phase was the perfect starting point. It has a choice of wheel sizes, frame sizes, an integrated motor and battery and 170mm of travel. Bucket seat bikes to date have been conventional bikes with aftermarket E-bike motors bolted on. This isn’t an ideal solution as conventional bikes are not designed to deal with the loading of an e-bike and it makes the batteries hard to package, and the motors don’t have good ground clearance. I worked with Paradox for the motor as they have some different power options available that suited Lorraine’s needs. I custom designed and 3D printed the battery out of partially recycled material which was cool too. This means the centre of gravity is much lower than other bucket seat bikes and the battery is protected whilst also having over 300mm of ground clearance for the motor.
What were the biggest challenges?
Keeping everything in mind. For example it’s no good having a system that can achieve 45 degrees lean but only 45 degree’s steering. Specifically, I had to design my own steering and leaning linkage so the bike could achieve up to 45 degrees lean (depending on set up) in each direction and nearly 90 degrees steering angles in each direction. The design could not change the bike geometry or make it too wide and had to allow for ergonomic handle placement. Then I had to make it robust enough, stiff enough and light enough and then enable fitment of different forks and common bearings. You can push every limit individually but coming up with something that’s good at everything is the difficult bit. All this was really just to deal with switch backs too, let alone everything else that you can throw at a mountain bike. The AD3 can turn and can be reversed in really tight spaces and on inclines which is sometimes necessary when you’re out on more natural trails where you make navigation mistakes and have to deal with gates and obstacles. The first time you strap in and ride up to a closed gate you realise pretty quickly how controllable and manoeuvrable it needs to be otherwise you end up hitting the dirt. When it’s ridden it needs to rail berms, jump, slide, endo and be stable at 50kph down rough tracks. Then you have to be able to manufacture it, make it serviceable and cost effective to build.
Could someone without disabilities ride one?
Absolutely, it’s really fun and confidence inspiring for anyone to ride. In fact, someone has already expressed interest in buying one to ride the alps in winter as the AD3 design has more grip and stability than conventional bikes in slippery conditions. There’s a version that pedals like a conventional e-bike but has the advantage of increased grip and stability. This can also allow for progression in certain types of injury recovery, with a bike that can be adapted as the rider’s needs change over time.
What is the logo?
Its my dog, when I started doing the bike, she always came out with me on test rides and became a sort of mascot. My dad John Desmond is an artist and he drew this caricature of her for one of his books. I liked it and thought it would be a good tribute to her and him.
What now?
I’ve been working in secrecy on the AD3 for 6 years so I’m really looking forward to seeing what the reception is. My hope is that it can create a new type of adaptive bike and that anyone who wants one gets in touch with Orange or me at Dezmotoracing.co.uk and we can sort you one out.
What does Lorraine think?
She is really happy to have something that’s gives her independence back. She takes her assistance dog Largo out for a walk with it and goes to the bike parks at the weekend. We have even been on uplift days with her, and she is just basically loving it. She is also really enjoying the technical side of owning it. I keep getting messages about upgrades, and modifications. She has an Engineering background and really understands how the bike works so she is a great ambassador for the bike.
Hybrid sump design JLR
Working with GRM as our optimisation partner we delivered a hybrid sump design project at JLR which was presented at the 12th World Congress of Structural and Multidisciplinary Optimisation. The project was part APC funded. The project looked at how optimisation methods have been used to design a hybrid sump from scratch. I completed all the Design work, Managed the project and presented the work with GRM at the world congress representing JLR. The link to the report is below.
http://www.grm-consulting.co.uk/hybrid-sump
Husaberg slipper clutch
The standard clutch wore and failure occurred frequently when used for Motorsport applications. I created a one off design which improved on the function of the slipper clutch by implementing a helical ball bearing path. The design removed the inherent weaknesses of the original and was successfully tested across a race season.