What is the Supre drivetrain?
We've already covered Lal Bikes' Supre drivetrain, including the First Look in November
of last year, the results of their efficiency test
, a deep dive into the patent
, and a podcast with the man behind the design and prototype manufacturing
, Cedric Eveleigh. Nicolai even debuted a production bike, the wild-looking Nucleon 16
, equipped with the Supre drivetrain in June, but that German monster won't be available for months.
In the meantime, Cedric is at Crankworx with his own prototype, a steel hardtail to test the latest 12-speed version of the Supre drivetrain. Better yet, he lent the bike to me for a few hours so I could gather some early riding impressions.
We've explained it a few times before, but here's a basic breakdown of what it is and why it exists. The Supre drivetrain splits the traditional derailleur's duties - shifting and providing chain tension - into two components that live in different places on the frame. First, the low-hanging derailleur that we're all used to seeing is gone, replaced in part by a mini-derailleur that's tucked up safely into the swingarm. You know, where it's far less likely to get ripped off or bent.
The other main component, the tensioner, rotates around the bottom bracket and does the job of the now missing derailleur cage - to add chain tension.
Supre works with mostly conventional components, including a Super Boost hub, normal-ish T47 bottom bracket, cranks, cassette, chain, and shifter, but it does require a purpose-built full-suspension design that uses an idler pulley... Or a purpose-built hardtail in the case of my test bike. There's also a general DIY theme that underlines Eveleigh's approach to everything, from machining his own idler pulley wheels to 3D-printing his own mini-derailleur out of polycarbonate at his shop on the Sunshine Coast of British Columbia.
He estimates that he's made thirty to forty prototype derailleurs at this point, and put in three and half years of full-time work, including a trip to Germany in order to lab-test the drivetrain's efficiency.What's it like on the trail?
If I had never met Cedric, didn't know anything about the Supre drivetrain, and had only seen photos of his prototype hardtail, I'd probably tell you that it seems like nothing but trouble, to be honest. There's a whole lot of chain, an idler wheel, another pulley that's spring-loaded to act as the clutch, and a homemade derailleur that looks like it's missing some important pieces. None of that says smooth sailing and trouble-free to me, but that's exactly what Eveleigh is promising with Supre - durability, efficiency, chain damping, and a lower unsprung mass.
But once I was rolling to the trailhead and running through the gears, I realized that it felt and shifted surprisingly normal. His derailleur is proprietary, of course, but it's controlled by a normal 12-speed Shimano shifter, uses a Shimano chain and cassette, and shifts, well, very much like a Shimano drivetrain. Shift speed is on par as well, which makes sense given the chain and cassette, and it doesn't require any more (or less) force at the paddles than you'd expect. So far, so good.
I usually try to avoid riding while blindfolded, but I wouldn't have been able to tell the difference in shift quality if I had hit the trails with my eyes covered. The same feedback applies to shifting under heavy load on tricky climbs, with the whole thing simply working well despite my best efforts to be a complete meathead.
I have a rollercoaster relationship with idler pulleys, including plenty of shit talk when they add obvious friction and I can easily feel them rumbling through my pedals, especially when they're covered in grimy mud. But I've also recently ridden a couple of bikes with well-thought-out designs that were essentially invisible when the drivetrain was clean and lubed. The key is to use as big of a pulley wheel as you can to limit friction, which is exactly what Cedric has done with his prototype. The result is surprisingly (to me) smooth action across all the gears, even when in the smallest or largest cogs when the chain is at the most angle coming off the idler pulley. Part of the reason for this, Cedric told me, also comes down to how far forward the idler sits relative to the chainring and derailleur which allows that angle to not be as drastic as it might be if the idler was in-line with the seat tube. The caveat here is that it's bone dry and dusty in Whistler, and I'd like to see how it feels when plastered in sticky mud and grit.
That said, I did manage to derail the chain from both the 'ring and the lower spring-loaded pulley, but I had to engage full-on meathead mode to make it happen by shifting through eight or nine gears while back-pedaling like a complete goober. Without a guide of some sort to act as insurance while goobering, the chain finally came off. I'm not sure how fair that was - no drivetrain acts nice when you do that - but people do some strange things in the real world, including myself.
With more chain running so close to the bike's seatstay, I had expected to hear some rattling as I pinballed my way through minefields of pointy rocks on his hardtail, but that certainly wasn't the case. Instead, the bike was quieter than most of the full-suspension rigs I've ridden, despite it being a proof-of-concept prototype equipped with homemade components. It was covered in enough rubber to silence even the Grim Donut, though.Does all that mean I'm convinced?
I've probably written a few too many mean things over the years about gearboxes that shift comically bad and rough idler pulleys, but there's a good reason for that: I simply don't break many derailleurs, don't bend many hangers, and have generally had pretty good luck with the status quo. But I'm also aware that I'm often using fancy, expensive things, and that my test miles are usually spread out over many different bikes. Contrast my saddle time with many riders who are doing nothing but park laps on rocky trails, pedaling through rockier terrain than I see, possibly using less expensive and less reliable components, and also putting more time on a single drivetrain that needs to last a long time.
If the production version of the Supre drivetrain works as well as what I used today in Whistler, and if it proves to be trouble-free over multiple seasons of abuse, I can certainly see a place for it on some riders' bikes. Those who aren't mangling derailleurs on a semi-regular basis probably don't need to think about purchasing a new bike designed around a proprietary drivetrain, but there are definitely riders (and trails) for which the Supre drivetrain will make a lot of sense.
What's your take on Supre - is there room for another type of drivetrain, or is it trying to solve a problem that you don't have to deal with?