It would be fair to say that mountain bikers everywhere have had a bad experience with a derailleur at one time or another, which is what drove Cedric Eveleigh of Lal Bikes to create the Supre Drive, a drivetrain system that separates the two functions of the standard derailleur (shifting and tensioning the chain), while also placing the purpose-built derailleur out of harm's way. The Supre Drive's four key elements are durability, efficiency, chain damping, and a lower unsprung mass, all on a high pivot suspension platform.
The idea popped into the Canadian mechanical engineer's head one day while he was catching his breath on a ride in the spring of 2019, and he immediately set to work building a stationary prototype drivetrain. Cedric has patented the Supre Drive in Canada, and while the patent is pending internationally, he is already working with a major mountain bike company to create a frame that will use the system. The prototype in the launch video is limited in range, but the current version can accommodate a 10-51-tooth range cassette and only has two specific requirements; a 52 mm chainline and a T47 bottom bracket.
A derailleur’s first job is to push the chain across the cassette cogs to change the gear ratio. Secondly, the pulley cage tensions the chain when slack is created by shifting to smaller cogs, keeping it from jumping off of the front chainring and cassette as the bike bounces down the trail. Cedric has placed the cage-less derailleur inboard on the swingarm and moved the chain tensioner to the middle of the bike, above the chainring. Although it uses a conventional hub and drivetrain parts, the frame must be designed around the entire system.
The tensioner pivots around the bottom bracket axis and extends counter clockwise to provide more slack in the chain when the derailleur shifts to the larger cassette cogs. Conversely, when an upshift is made to a smaller cog, the tensioner is pulled by a cable towards the front of the bike by a cartridge in the downtube, controlled by a spring and damper. Most intriguing is the system keeps the chain tension nearly identical across all gears. Conventional drivetrains increase tension in the lower gears, causing an increase in drag.
Add in a shorter section of free chain and as Cedric claims, "Speed-sensitive tensioner damping that outperforms any derailleur clutch on the market", and you get an extremely quiet and damped drivetrain. The Supre Drive also uses the same number of jockey wheels as a conventional high pivot idler bike, but reduces the friction since those wheels have a larger number of teeth than the typical derailleur.
As for the unsprung mass debate, the system saves roughly 130-grams of unsprung mass, but adds 100-200 grams of total mass. Like Pinkbike's Seb Stott discussed in his recent article about why you shouldn't worry about weight much
, there are potential benefits to increasing that sprung to unsprung ratio by adding more weight to the front triangle and less to the rear.
After meeting Cedric back in August on his venture through B.C. from Chelsea, Quebec, I was presented with the opportunity to parking lot-test the second Supre Drive prototype. In a blindfolded test, I would not be able to tell the difference in the shifting system versus a traditional layout. If anything, the Supre Drive should shift even better on the trail, because the derailleur is mounted at two points and therefore does not rotate around on the B-knuckle pivot.
The fact that there is no B-tension adjustment needed and no special tools are required to assemble the system helps simplify setup. The positioning of the derailleur also gives more chain wrap around the cassette because the jockey wheel is clocked much higher. Almost hidden in plain sight, the derailleur also has abundant ground clearance and is further protected by being nestled between the chain and seatstay. Adding to the benefits of the system, the chain is kept further away from the elements and won't contact the ground under oscillations.
Production for the drivetrain components will be headed up in Canada by Lal Bikes and incorporated by Cedric. The brand name comes from Pierre Lallement who was credited by some as the inventor of the bicycle. Where does the Supre Drive get its name? Cedric explains, "Supre means above in the Esperanto language. This refers to the Supre Drive being above other drivetrains, both physically and performance-wise." He genuinely wants to make the mountain biking experience better and more reliable.
As you can imagine, the creation of this idea didn't happen overnight, but Cedric is extremely savvy and highly educated. The mechanical engineer by trade has a masters in Engineering Physics and taught himself how to TIG weld by watching YouTube videos and built on his machining practices learned in school. This is not the first time he's put his passion to improve bikes to the test. Back in 2012, he participated in Pinkbike's Reality Redesigned innovation contest and submitted a Pinion gearbox-equipped downhill bike design.
There have been a lot of wild and wacky drivetrain iterations throughout the years; Honda's RN01 "derailleur in a box" with a continuous drive chain, Zerode's high pivot design centered on an internally geared hub, Cavalerie's belt-driven gearbox DH bike, Lahr's CVT project, Allan Millyard's single-sided swingarm DH bike that enclosed the chain in an oil bath. The industry has never seen anything like the Supre Drive before, tackling multiple problems at once, like exposed derailleurs, chain kickback, but still using readily available drivetrain and hub components. All eyes will be on Lal Bikes to see what brand has licensed the Supre Drive, how it will be applied, and who else might in the future.
I also had the chance to catch up with Cedric and throw a few questions his way once he was finished dumbfounding industry folk in the Sea to Sky area.
How and when did you get into mountain biking?
I’m fortunate to have grown up with XC mountain bike trails out the back door, so I’ve been mountain biking since I was about 7 years old.
What was your first bike?
My first proper bike was a Norco Bushpilot hardtail.
What did you study in university?
My undergrad was mechanical engineering, and my master’s was engineering physics (both in Canada). A highlight of my undergrad was a couple of internships in Berkeley, California. My master’s was especially fun; my research project was on corrosion-resistant coatings for use in molten salt nuclear reactors, and I got to do a research internship in Shanghai.
When did you realize the flaws in the mountain bike drivetrains?
I’ve been aware that derailleurs suck for a long time. I remember upvoting all the pro-gearbox comments on Pinkbike around 2010, so it goes back at least as far as that.
What does the sales model of the Supre Drive look like and how do you see manufacturers incorporating this into their product line?
Lal Bikes will manufacture the derailleur, chain tensioner, and idler pulley in Canada (probably coastal BC, and maybe also in Europe later on). The sales model is the same as other drivetrain companies: sell to bike companies that spec the Supre Drive, and also sell directly to mountain bikers, etc. I'm currently collaborating with a major mountain bike company for them to develop a bike with the Supre Drive, and I plan to collaborate with many more.
What sparked you to tackle such a project?
After my master’s, I decided to switch my focus back to mountain bike engineering, which is what got me to sign up for mechanical engineering in the first place. The most glaring issue with mountain bikes is derailleurs, so I focused on that. While brainstorming possible solutions, I got some motivation from seeing the outside-the-box thinking of Ceramicspeed Driven. The eureka moment for the Supre Drive happened while I was out on a ride, and the idea was promising enough for me to switch from brainstorming to building prototypes.
How did you learn the manufacturing skills to build your own working prototype and what was that process like?
I’ve had to learn a variety of fabrication skills for this project, both for frames and the drivetrain. Most of this was learned on the fly during the project but some of it was learned beforehand in student machine shops at university. Some skills like 3D printing are quite accessible, but others like CNC machining and TIG welding have a much more difficult learning curve. I’ve learned a lot, but I still have a lot to learn, especially for switching from prototyping to manufacturing. I’m looking forward to having others join the team who are knowledgeable about manufacturing.
To answer your question about what the learning process was like, it has been friggin' great. With 3D printing, the accessibility of information online, local makerspaces, and other things, there’s never been a better time to invent.
What are some of the downsides or constraints of the system?
The Supre Drive requires the idler pulley to be farther forward than on most other high pivot bikes. This is because the front section of the chain needs to be forward enough to allow for the range of motion of the tensioner arm. The forward position of the idler pulley constrains frame design. It’s still possible to design frames that perform as well as the best frames out there, but some previous suspension systems might not work well with the Supre Drive.
I was lucky enough to pedal the proto around the parking lot. Can you explain how the derailleur is able to shift across the cassette if the tension is at the front of the drivetrain?
For shifting gears, the basic function of derailleurs is to guide the chain from side to side from one sprocket to another. There’s no need for the derailleur to also tension the chain. The upper pulley (guide pulley) of conventional derailleurs guides the chain from side to side just like the single pulley on the Supre derailleur. If the lower pulley (tension pulley) of conventional derailleurs doesn’t play a role in shifting, why not move the tensioner arm to somewhere safe?
Why not go with a gearbox, since this is not a traditional drivetrain anyways?
I’m not aware of a way to make gearboxes as efficient and lightweight as derailleur drivetrains. However, the Supre Drive is efficient and lightweight like a derailleur drivetrain—well, it is a derailleur drivetrain—just a tough one.
What were some of the reactions when you presented the Supre Drive to industry directors?
The reactions have been very positive but also amusingly vulgar. These two are verbatim:
“This is f****** fascinating and terrifyingly ambitious.”
“I’m not easily impressed, and this is f****** impressive.”
When do you think we will see the first production version of the Supre Drive?
For a first production version, I'm aiming for 2023. I have a lot of testing to do to make sure that I put out top quality parts. Also, frames need to be developed to go with the Supre Drive. It'll be some time before the Supre Drive becomes commercially available, but I'm working hard to make things happen fast.
What does the future hold for Cedric Eveleigh?
Plan A is to build a big manufacturing operation in Canada, and to make the Supre Drive as affordable, durable, and high performing as possible. I’m stoked about the task of getting a team of people together to build the Lal Bikes company, and I’m also looking forward to collaborating with more frame companies. And of course, the future includes a lot of mountain biking!
Photo and video credit: Chris Snow
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