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EB18: Drivetrain Trends – We’ll be changing more than gears one day

CeramicSpeed Driven concept shaft drivetrain with roller bearings and flat cassette driven by a carbon shaft
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The Ceramicspeed Driven concept showed us that there are ideas beyond the chain and derailleur. Rotor showed us that there’s room to add more gears with their 13-speed group for any type of bike.

But is that really what’s next?

sram eagle 1x12 xx1 and x01 mountain bike group technical details
Eagle and XTR push the limits of how big of a gear you can use, in part because the derailleur hanger can’t get much longer without creating clearance and stability issues.

Is it really about adding more gears? Or more range? If you look at the range available from SRAM Eagle or the latest Shimano XTR, those already have more range than your typical road bike drivetrain.

Campagnolo Super Record 12-speed Movement 12 mechanical shift hydraulic disc brake carbon road bike groupset Cannondale Synapse new twelve-speed drivetrain

With such a big spread on tap, the issue becomes the steps between gears. That’s why Campagnolo ratcheted it up to 12-speed too, while retaining the same gear spread and front derailleur, smoothing out steps in between. It is also why 3T’s Strada 1x road bike needed a 2x option for their pro team. They needed to be able to improve the gear steps so the riders could maintain an optimal cadence. What’s counterintuitive, though, is that it’s not the massive jumps at the big end of the cassette we’re talking about. When you have a 46 jumping to a 50 (or more), that sounds like a lot…four whole teeth!!! But that’s only an 8% percent jump.

3T Strada Bailout and Overdrive wide range road bike cassettes
3T Bailout and Overdrive road bike cassettes give you different gear steps within the same wide range.

Look at the other end of the cassette, though, and if you were to add a 9 tooth cog to the bottom and that’s more than an 11% jump. If you’re particular about cadence, which most roadies are, that’s a massive jump that would screw up your rhythm. One solution is to simply increase the size of the chainrings to make a 10 or 11 tooth cog enough to hammer at your highest speed. But then you need bigger cogs at the other end to ensure you’re not grinding up the climbs.

Which means the next real drivetrain advancement is figuring out how to get smaller jumps between all gears, particularly at the small end of the cassette, while keeping a wide range. Maybe it’s an internally geared hub. Maybe it’s a planetary, CVT-style mechanism. Or something entirely new.

The Pinion P1:18 gear box transmission has 18 finely spaced gears and a 636% range. Where that starts and stops depends on the gear and cog used with it.

Assuming we do move away from a traditional cassette and derailleur, the trick then becomes how to describe it. What if we no longer need to say it’s a “12” speed or “17” speed drivetrain? We can’t just say it’s a 500% or 600% range drivetrain. Because that tells you nothing about the lowest or highest ratio. So it will have to be something that describes the lowest and highest points, and, if it’s not infinitely adjustable between those points, it will have to describe what those steps are. Ideally, it’ll just be something that moves freely between the entire range. Because then you eliminate any downside to a massive range.

Internally geared systems will have to improve to be viable alternatives, mainly by dropping weight and reducing drag. Like every component group, though, they’re getting better every year. Whether things move inside the frame, hub and bottom bracket or find a new way of shaping the current chain and sprocket sets, one thing is for sure: The industry has realized the limitations of a big cassette and derailleur and they’re trying to figure out what’s next.

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Larry Falk
Larry Falk
4 years ago

What we need for the road (eventually) is a 1x type of drivetrain with a low/high geared internal bottom bracket to replace the front derailleur. That way we have the simplicity of 1x without the negatives of the front derailleur. How you make this, I don’t have a clue!

Ryan
Ryan
4 years ago
Reply to  Larry Falk

truvativ hammerschmidt

Shafty
Shafty
4 years ago
Reply to  Larry Falk

This idea, like many others before it, overlooks the inherent efficiency of a chain drive. We’re already at the lightest and most efficient type of drive, we simply need to continue refining the overall concept, while looking past fad or marketing driven ideas. It may be time to revisit a different chain pitch, like Shimano 10 pitch, to really get the gears we want. That way the small and inefficient 9T/10T sprockets wouldn’t be needed and the next gear would be closer.

2x drivetrains really are the best compromise of efficiency and range.

Patrick Fowler
4 years ago

I agree, and have contended that the chain driven derailleur is the next area that needs to be replaced by better, cleaner more efficient systems. Good luck to the better minds than mine working on this!

muddrock
muddrock
4 years ago

An interesting piece, but you don’t draw any conclusions.

Maybe because it’s the newest thing, but the Ceramic Speed prototype looks like it has the most promise. It’s relatively light, with an aluminum “cassette”, it’s clean and dirt-free like a belt drive, looks like a mechanically simple mechanism, so reliability should be a plus. Drag, and final weight, is TBD.

That pie plate would be a delicate component, if you fell on your right side.

Dinger
Dinger
4 years ago
Reply to  muddrock

It looks neat, but it’s got a lot of shortcomings. It’s very environmentally sensitive, so it’d need to be fully shrouded, which will add weight. The pitch of the teeth on the cassette don’t appear to be any finer than that of a chain, so gaps probably won’t improve. The entire thing will require absolute stiffness and strength.

It also doesn’t “work”. It doesn’t actually shift yet and efficiency in the one gear that does run drops above something like 350 watts, so it’ll be draggy even on short rises as it is. Maybe it could be something, but there’s a lot of work yet to do.

talkliketim
talkliketim
4 years ago

We’re living in a time of rapid and accelerating technical (and social) change, which makes it look like almost any existing paradigm can be toppled. Still, I think it’s going to be hard to replace the chain-and-derailleur system that’s been in place for so long. There are several reasons for that. First, makers of chain and derailleur systems enjoy massive incumbent advantages- economies of scale (think factories which crank out millions and millions of standard drivetrains each year for very low prices), users’ and sellers’ trust in traditional drivetrains and their knowledge of how to use and maintain them, and also simply the high level of technical refinement in these systems. SRAM and Shimano can also simply offer to buy disruptors’ drivetrain ideas, removing them from the competition.
The traditional drivetrain has faced challengers before- internally geared hubs have never become widely popular with serious high-end users, and the same has so far been even more true of gearboxes. And these are systems that in fact work and are on the market now, something which is not true of Wild’s 13-speed drivetrain. Also, so far there has been to my knowledge only one drivetrain system which offers stepless shifting, it is the Nuvinci hub.
I am curious to see what happens, but believe it will be more of the same- great chain and derailleur drivetrains with some tantalizing niche offerings.

Padrote
Padrote
4 years ago
Reply to  talkliketim

The only thing accelerating is the amount of money consumers are willing to spend on things with only perceived value, which, just like this drivetrain, will become increasingly garish and useless (see also: a relatively successful company named Lauf). We can pretend all day long that there are significant technological advancements to be made in the bike industry but really the only way anything like this takes hold is people with more money than sense.

Veganpotter
Veganpotter
4 years ago
Reply to  Padrote

I totally love my Lauf fork. And they’re very honest with it’s limitations. CVT transmissions for cars were total junk until recently. A sports cars are forcingd manuals. It’s gonna be the norm at the low end too. That’s how tech works. Hopefully willw eventually have low friction, planetary gears on bikes that aren’t insanely heavy.

Adilos Nave
Adilos Nave
4 years ago

Larry, don’t they already offer that? Think it’s called a Schlumpf drive. You can switch to insanely low gearing by simply pressing the button in the middle of the crank spindle.

King County
King County
4 years ago
Reply to  Adilos Nave

I always wanted to have a bike with a Schlumpf and a kick back hub.

Lyford
4 years ago
Reply to  Adilos Nave

I’ve seen the Schlumpf on a unicycle but not on a bicycle. 1:1 or 1.5:1

http://krisholm.com/en/gear/component/kh-schlumpf

typevertigo
typevertigo
4 years ago
Reply to  Lyford

Schlumpf drives seem like a great option on Bromptons, where introducing more gear steps/range is a little more challenging. Impressive stuff

adamrice
4 years ago

We can already say something like “a 40-108 gear-inch range in 14 steps of 8%” for drivetrains using a Pinion or Rohloff.

barael
barael
4 years ago

I mean, we sent a man to the Moon 40+ years ago. Can’t we have indefinite range with arbitrary gearing next?

Jason Etter
Jason Etter
4 years ago
Reply to  barael

Or did we? 🙂

blahblahblah
blahblahblah
4 years ago
Reply to  Jason Etter

one day the projector going to break and all hell is going to break loose

Paul Mourer
4 years ago

i have my money on 1/4″ chain spacing to allow smaller gear jumps, smaller chainrings, and smaller cassettes (better clearance on mtbs, smaller derailleur cages needed, better cadence’s on road bikes)

VeloKitty
VeloKitty
4 years ago

> Maybe because it’s the newest thing, but the Ceramic
> Speed prototype looks like it has the most promise.

hahahahahah… You are saying that we are doomed then.

David
David
4 years ago

NuVinci hub thingy.

typevertigo
typevertigo
4 years ago
Reply to  David

Precisely what I had in mind. It’s effectively a pedal-powered CVT, and it’s not even all that new. It’s been around for about 5 years now I think.

Dinger
Dinger
4 years ago
Reply to  typevertigo

It’s been around longer than that, but it’s inefficient and heavy. Ok for e-bikes, but impractical for high performance bikes.

JRF
JRF
4 years ago
Reply to  David

The NuVinci is cool. The problem with it is it literally weighs like 5 pounds.

RobertW
RobertW
4 years ago

I was perfectly satisfied with 2×9, and now I have a 2×11. I cannot possibly become more satisfied. Sorry manufacturers.

Veganpotter
Veganpotter
4 years ago
Reply to  RobertW

Perfectly satisfied with 2×9, more satisfied with 2×11. Hate to say it but you’re making the case for 2×13 being even better

DougB
DougB
4 years ago

smaller chains and therefore smaller teeth on cogs, if you halved the teeth size, you’d be able to go from an 18 tooth to a 17 tooth (9tooth to an 8.5) so a much small change in cadence. Time for a new standard in chain size.

talkliketim
talkliketim
4 years ago
Reply to  DougB

That might well be a good idea. I bet it would cost a heck of a lot in retooling, and it probably also would require more precision to manufacture things like correctly shaped tooth profiles/ shift ramps. In other words, it could take a lot of time for that trickle down to low end.

Veganpotter
Veganpotter
4 years ago
Reply to  talkliketim

Less retooling than an xD freehub. And that trickled down fast

slacker
slacker
4 years ago

Advances in manufacturing and design makes this a interesting topic. I am always amazed at how dirty a standard chain drive is and then how often the chain requires replacement.
I would like to see more internal gearing w/ belt drives. keeps the efficiency and makes is cleaner.

Tim
Tim
4 years ago
Reply to  slacker

Cleaner, yes. But as efficient? Maybe. A belt running in dirty conditions is probably more efficient than a chain in the same conditions- but a clean chain is more efficient than a clean belt, no? Plus, internally geared hubs do have more loss than freehubs. These aren’t big differences, but they are noticeable, and they may matter even more than real ones.
Also, people often make the mistake of thinking that technical superiority is what drives the market. Let’s suppose IGH’s with belt drive really are better than traditional drivetrains, that doesn’t mean they will take over the market.

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