Hacker News new | past | comments | ask | show | jobs | submit login
Shimano’s three-pulley rear derailleur could revolutionise drivetrain design (bikeradar.com)
80 points by giuliomagnifico on Feb 19, 2023 | hide | past | favorite | 98 comments



I don't think this is going to 'revolutionise' anything really. It is just another friction point and part to fail or need maintenance. It is an attempt for Shimano to look relevant.

I have the wireless electronic sram shifting on my 1x Lauf. It is kind of expensive, but amazing and worth the simplicity of it all. It just works and shifts perfectly every time.

I could never go back to cables. The revolution will be to figure out ways to make this same electronic shifting technology less expensive so that it can be installed on every non-e-bike out there.


I’ve have/had mech SRAM, mech Shimano, SRAM Red AXS eTap and the new Ultegra Di2. Well maintained (change cables every couple years), mech just works too and has crisp shifting. While I love electronic and won’t go back to mech on some of my bikes, mech has its place. It has not left me stranded with a dead battery and it hasn’t entered crash mode during a cross race. Mech also won’t brick a $1000 derailleur after a firmware upgrade (it magically came back to life 2 months later, after I had bought a replacement).

I do agree with your first point, I don’t see much revolutionary here.


Electronic shifting is everything I don't want on a bike.

- Another battery to recharge

- Proprietary battery format making replacements difficult

- Needing an app to make simple adjustments. Hopefully it runs and is still compatible after 10+ years of ownership!

Bike components are wonders of precision machining and modern materials but conceptually, they have a beautiful simplicity. Not to get too "give up programming for woodworking" but all of that goes flying out the window the moment you add a proprietary wireless protocol and closed hardware in the middle of it.


Index adjustment on SRAM AXS can be done on the fly from the shifters. Or from the app as you ride without stopping. Try that with cables.

The battery replacement is the real issue as technology gets older. Though to be honest, at some stage it gets more difficult to find parts for any system. I started to run into challenges sourcing several replacement parts for a 8-9 year old bike that had 10 speed Shimano group set, so it got sold and replaced. Batteries are not much different really.


> I started to run into challenges sourcing several replacement parts for a 8-9 year old bike that had 10 speed Shimano group set

I can't say I've had any problems with getting maintenance parts for my 2004 (19 years old) Shimano XTR mountain bike.


Barrel adjusters near the controls are a thing though not all bikes have them.

Example: https://www.amazon.com/Jagwire-Inline-Indexed-Tension-Adjust...


I haven't opened the app since I got the bike... about 2 years ago. You don't need the app to make adjustments... I also haven't made any adjustments in 2 years, so there is that too.


That anyone would think 2 years is a long time for a part not to need adjustment is a symptom of 21st century thinking surely. I'd also suspect you're not riding 100s of km of hilly terrain every week (I do, and have definitely needed to make adjustments, but no more often than on mechanical shifters).


2 years of no adjustments on any bike, is pretty unheard of, regardless of technology involved. Cables stretch, e-shifting gets rid of that issue... there really isn't anything to get out of alignment there.

I've been riding and racing bikes since I was 15 years old and I'm nearly 50 now.


> It has not left me stranded

Not much different than a mech cable snapping or the derailleur not being adjusted correctly by a tiny set screw and the chain ending up in your spokes.

Shit has catastrophic failures... that's never going to stop being a problem.


Mech cable snapping vs forgetting to charge the battery? Yes, end user error with the battery, but I’ve had exactly 0 cables snap and I put my bikes through hell.


I've had a cable snap in a race.


I just watched a NorCal video where guy had to spend all race in little ring because it snapped at the start line. Ouch!


As long as you have access to a phillips screwdriver, you aren't stuck in the little ring - you can tighten the high limit screw to pick your one gear (at least from the higher ones).


(Replying to wmitty) it happened to him at the start line. His choice was between DNS or little ring.


I've never had a rear derailleur cable "snap"; they stretch, fray and may eventually break right at the pinch point but these are either slow delays with obvious warnings or easily fixed on the trail. Compared to a connectivity or battery issue? They don't have nearly as high of likelyhood.


I’ve seen cable breaks happen, though not frequently. I’ve also seen chains break a lot more frequently, I know of 5-6 instances where it happened last year alone locally. All of these were a result of complete lack of maintenance as you point out, though I suppose it would be possible for a newer component to not show signs of wear and still fail.


Can you expand on your idea of why you think Shimano doesn't look relevant now? Not to play favorites, but they seem to be the biggest manufacturer of high-end bike parts in the world. On road, every World Tour team, save 3 are running Shimano. Campagnolo seems the company that's becoming irrelevant, with SRAM being second, but doing some interesting stuff.

In my experience, jockey pulleys don't add too much friction, as they're not under a great amount of force and don't fail all that often - for the same reasons. It's the derailleur arm itself that's very likely to take damage from abuse (by bending out of spec).

I would say the use of a clutch on a rear derailleur - something your SRAM 1x most certainly has, leaks more watts (tho v. v. little) - the compromise is certainly worth is, especially for the gear cluster spread you're running on the back.

This design looks just to be an improvement of some sort of clutch system, with purpose to try and move the derailleur arm out from being so low, where lovely things like rocks can hit it. That seems like a win to me, given my own assessment of how these things become worthless paperweights.

SRAM actually seems to be all-in on making rear derailleur replaceable in piecemeal, which seems to be a nice improvement over the design, in a very Right To Repair kinda way.

https://bikerumor.com/next-gen-sram-eagle-direct-mount-derai...

I'm not sure why such a design can't be run wireless if that's your preference. Looking at Shimano's offerings, even the 105 is electric these days.

But again: this is just a patent for an idea - it's not the first time Shimano has done this obviously

https://www.bike198.com/shimano-gearbox-patent/


I mean relevancy in the abstract sense by the way. It is trying to solve a problem that nobody really has, by adding an additional component to the system. It also makes your chain a tad bit longer... added weight and links.

> Can you expand on your idea of why you think Shimano doesn't look relevant now? ... On road, every World Tour team, save 3 are running Shimano.

They all use electronic shifting. This is not the way to compare relevancy, given that it is a sponsorship. Next year, sram comes out with a better financial deal for the team than shimano and they go with them.


I would think this is focused on the MTB crowd, where the derailleur is a very fragile piece of the kit. As 1x's get ever more expansive, derailleur arms get longer, and there's just so much room to grow. Seems like Shimano is looking into ways to grow into that. If an ever-expanding range of gears or tighter steps between is relevant or not to something is I guess a personal call. I've ridden across the states on a single speed mountain bike, so I may be the wrong person to ask!


Came in here to say just that - I wouldn’t judge relevancy based on the amount of sponsorship a company is willing to throw at a world tour team.


I'm not judging relevancy on just the amount of sponsorship but it is a sign pointing to "relevancy". No World Tour team would use Shimano if it's 1% disadvantage over brand X. Seeing Campy not being used at all is again: another sign of this company being relevant, when paired with their loss of market %.


By that logic, you would see very little variety in types of components used by world your teams. Teams are in the business of making money, if SRAM offers them a better deal, team owners will find it hard to say no.


The logic I'm displaying is using a variety of different metrics in order to come up with a conclusion. I also never said that SRAM is irrelevant, only questioning why Shimano seem irrelevant to the the original poster I replied to - and I also mentioned how much product they push in the second sentence.

But the business of World Tour temas is also to win, as winning means being invited to the big races, which actually have coverage for the ads-on-wheels that riders are to get eyeballs on. If they can't win because of crap gear, they won't use said gear, no matter how much money given to them.

It's a fine balance, right? Some riders of high talent are also pretty controlling on the gear they use, and will bring their own bike sponsor into a team as part of the deal of transfer. Chicken and egg I guess: if the gear is irrelevant, you'll never see it on the Pro Tour.


It is pretty simple though. Top end campy isn't wireless.


in the short run this system might make sense for some use cases, the future it is not. chainless systems will take over for e-bikes, e.g. https://www.schaeffler-industrial-drives.com/en/news_media/p... First used here: https://www.golem.de/news/free-drive-schaeffler-baut-kettenl... (german only, sorry). 250W is low, so there needs to happen some development for more use case.


>figure out ways to make this same electronic shifting technology less expensive so that it can be installed on every non-e-bike out there.

But why bother when ebikes are already cheaper? BAFANG motor with battery conversion kit is 2/3 of the cheapest SRAM kit available($1.2).


There are plenty of people who don't want e-bikes, but want electronic shifting. People who race bikes are a great example. The whole bi/triathlon industry.

Given that electronic shifting is still $1.2k, it would be nice to lower that cost a bit so that all price points can participate more easily.


I like shimano. I have an early di2 and loved the perfect shifting. But I have always wondered why wireless is even a thing - it just seems like a way to spread out batteries everywhere and allow signal variability to creep in.


People like clean cockpits, and threading cables and wires through the headset is a PITA if you ever need to adjust the stem, handlebars, fork, etc.


That's exactly it. I have two "cables" on my bike now and that is it... for the disc brakes. It is super clean and simple.

The batteries in the levers last a long time since they are just used for a button press. They are worth it. Never had an issue with signal or shifting.


Battery-powered anything on a bike is a fad that will pass.


DI2 came out in 2001. How many years do you think this 'fad' will last?


How's market adoption?


A question with a question that's easy enough to google? Come on.

https://www.prnewswire.com/news-releases/bicycle-gearbox-sys...

Still growing at a nice rate and every single pro team has been using it for years now.

All I see now around where I live, which is heavily bike centric, are e-bikes...


I’m not sure that is the correct metric to look at. As it is a very very high end product.


Precisely. If it was a truly innovative, no-brainer upgrade like dropper seatsposts, you would find almost one every recent-ish bike. I have seen one (1) live so far. And it was a ultra high end road bike.

For the same reason, what the pros do on their rigs is no concern for the 99.9% of mountain bikers.

I wouldn't bring anything I can't repair or troubleshoot directly out in the mountains, let alone anything that can discharge and not work anymore.


I have three bikes with electronic shifting in my basement. None are “ultra high end road bikes”.

Shimano also brought electronic to their 105 line and SRAM has it on Rival. Neither is high end, never mind ultra high end. I’m not a MTBer so I’m not aware of how that market is, but electronic shifting is definitely prevalent in road, gravel and cross.


If you’re talking DuraAce/Red then yes. Otherwise it does not truly qualify as “very very high end” or even “high end“ for Rival/105.


You cannot complain about points of failure and praise electronic shifting in the same breath. I have a bike with downtube friction shifters and 2x8 gearing on an old deore group. Its liberating.


That would surely help dealing with the effect of bumpy ground on chain tension: the first and second pulley (as seen from the travel direction of the chain) can be freely positioned relative to their pivots for balance, without affecting the distance between sprockets and the pulley responsible for lateral chain positioning.

But two-pulley designs solve some of the radial movement required for the "selector" pulley (the one responsible for lateral) to deal with a wide range of sprocket radii by the offset between pulley and cage pivot: The line between upper pulley and pivot is at a considerable angle to the line between pivot and the other pulley. In a three pulley setup, I'd expect everything to become far too unpredictable if they still kept the selector pulley offset from its closest pivot. If balancing two pivots with a B-screw is difficult, imagine having to balance three pivots with a "B" and a "C" screw! And I'd imagine the impact of imperfect balance to be far worse in a three-pivot situation... (with two pulleys/pivots B-screw adjustment is more nice to have than requirement)


You make a great point about how hard this may be to tune perfectly. I think the answer though is, "it'll be electronic and the app will guide you on which screws to turn, if any". Since we're at 12 speeds and going on 13, this is quickly becoming a difficult dance to perform even with current tech.


Hardly revolutionary, its still a fragile derailleur hanging off the frame exposed to the elements.

I'm amazed with hub gears and when Honda simply put the derailleur and freehub in the frame with their old downhill bike, that this is still the best solution on the mass market.


> amazed with hub gears

I've never seen hub gears on light or even medium weight hybrid/city ALU bikes. Which suggests there is a problem with hub gears. Maybe they are heavier, or more expensive, or harder to maintain, but they are not popular.


I have such a bike.

The downsides:

* It's heavier than a derailleur/cassette

* More drivetrain losses

* It's expensive.

Upsides:

* Maintenance is replacing the oil about once a year.

* You can shift from a stop.

* Easier to adjust.


They're expensive, and ones with as many gears as a derailleur system are hideously expensive. Folks worry that they won't have the gears that they need for hills. Also, I think the bike makers are timid about marketing them -- an entire line of bikes might have exactly one with a hub gear, on a bike with "city" styling.

I've got a couple of bikes with old Sturmey Archer 3-speed gear hubs, and they're utterly bulletproof. I've had each one open exactly once, when I got it and wanted to make sure it was in good condition before putting it on a wheel. Plus I was curious.

The other thing in my opinion, though I love hub gears, modern derailleur systems with a zillion gears aren't all that bad. Especially with indexed shifting, which we've now had for decades. They're exposed to the weather, but most people don't ride in bad weather.

Since you mention hybrid/city, that's my category. I use my bike for commuting to work, shopping, and weekend recreational rides. I'm in no way fast nor competitive, so the weight and efficiency issues are secondary for me. But also, the 3-speed is a sweet spot where its efficiency actually rivals derailleurs.


Weight is important to me with that usage because bike thefts in the area around my office means I want to carry my bike up stairs...


Similar situation for my kids, both in college. Both have built up single-speeds. They can lock up their bikes on campus and enjoy "security by obscurity," but at their apartments, they have to bring their bikes in or hide them well.


They are heavy and don't shift under high load. Maintenance is minimal, though. Great for a commuter but not practical for road racing or mountain biking.


They don't shift under any load, as far as I'm aware. Maybe Rohloff's are different but IME, you need to stop pedaling entirely to safely shift without damaging anything.


Certainly true for Sturmey-Archer. If you try to upshift under load, you'll feel the cable resisting. If you downshift under load, it'll wait to shift until you back off on the pedals just a bit.

Compensating for both things becomes a habit. Likewise, remembering not to shift at a stoplight becomes a habit with derailleurs. You reach a point where you begin to think like your bike.

Given that I'm a casual cyclist on a non-sporty bike, I just live with the slight awkwardness when I'm halfway up a hill and realize that I chose the wrong gear.


They need very little maintenance. But they are very expensive.

e.g. https://www.sjscycles.co.uk/rohloff/


You picked about the most expensive option, there’s quite a few that are fine for commuter bikes, but cost substantially less. The Shimano Alfine series for example.

But except for the Rohloff, they all have a smaller gear range than a derailleur, so there are tradeoffs.


But you still don't see them on very pricey bikes ($15k+). So they are very expensive, without being premium, which is a weird place to be.


Bikes in the $15k plus range are probably targeted at professional sport cyclists, who need to adhere to UCI equipment regulations, which include the requirement for a chain-derailleur drive.

If you want to know what's premium for everyday utility cycling, look at the ebike space, where people are shelling out thousands for bicycles just to use them a vehicles. Hub gears are not dominant, but are very well represented on price points over $2k.


There are also triathlon bikes in the $15k plus range which don't comply with UCI rules. But the efficiency loss makes hub gears useless for that market.


The $15k+ bikes are race bikes, which are probably never going to have internally geared hubs because they're too heavy and add too much drivetrain loss. Rohloff hubs are fairly common on high end ($5k+) bikepacking and touring bikes.


I've mostly heard of them being used for people doing giant international tours where they want something that just will not break. Seems like a very niche market though!


I personally can't get over how you have to stop pedaling to shift using internal gear systems. People told me you "get used to it," which is true, but the awkwardness never goes away.


The nuvinci hub is really interesting. I suspect it is not as efficient as a derailler at transferring power, but it is more efficient at getting power out of your body at the cadence you want. Some bikes pair it with a non-metal chain and it is very quiet.


I bought one and ended up not even making a wheel from it. It was brutally heavy and just playing around with it I could see it would be power-robbing. On that bike I stuck with my shimano 7 speed internal gear hub.

For high-end mountain bikes, makers are actually experimenting with removing gears from internal gear hubs[1] because for less mass, they want to keep the full range of gears but use less in the middle.

[1] They are not very common but there are some high end downhill bikes that use an internal gear hub, located near the bottom bracket. They are simply too heavy and expensive to appear on other types of bikes.


I had an electric cargo bike with a nuvinci, since it was the only option with a belt drive. It works for that application, shifting under load is a nice thing when going up the hill with a heavy bike. But the downsides are pretty big. It’s lossy, so riding the bike without assist was tedious. The gear range is tidy, so I was always missing some on the upper end. I picked a different combination for the next bike.


Compared to a 7 speed, yeah, a CVT is better for getting your cadence where you want it. 11 and 12 speeds? I've rarely felt like I've wanted intermediate gears with an 11-34T cassette.


Yeah, I wish they sold derailleur hangers in six-packs. I've always wanted a Rohloff for commuting, but they aren't cheap.


In six-packs, because you break them often? How does that typically happen?


They are kind of a sacrificial part in crashes. They can also get bent going in/out of bike racks. Crashes are a lot more common racing FWIW.


What is cheap, definitely enough for commuting (well except dirty dozen type one) and rides amazingly well are 3 speed Sturmey Archer hubs.


Problem on 3-speeds is that they are always installed wrong. Number 2 gear is direct connection and lossless and it should be the one you use most.

I had to go extreme measures to find 1:3 sprocket set for my 20' folding bike. Originally I was constantly switching between 1 and 2 and never using number 3.


That situation is actually pretty common. The problem is that the gear spacing is quite wide, so there's rarely a use for more than 2 of those gears in a lot of regions.

Also, 3-speed bikes in the US were sold with no gearing options. Schwinn geared them too high in my opinion. In England, the bike dealers were instructed to work with the customer to choose a cog that was appropriate for each rider's terrain and physique.

I've geared mine based on the realization that my top speed is likely to be limited by wind resistance and my own physique, and I don't need gears that are faster than I can ride.


Yeah, I was looking at the cassete-combo version of the Sturmey Archer 3-speed, but I believe it would be obviously better if the top gear was direct connection (100/70/50% ratios, not 133/100/75%).


You can offset for that with a smaller chainring and you gain some ground clearance. Win win!


When you simply, it's kind of true, but the space to do this is really limited and there's no good solution seen yet to keep a wide range of gears in that system.


Some of this might be intended for the pros, and with time modified to be more robust for the retail consumer market.


Mountain biking is interesting in that the consumer usually gets to buy exactly what the pros are using.


Same with road biking. If you are willing to pay for it, you can get the exact same set up as any of the pros, of course, with the exception that some of it might be prototype and exclusive.


People who shrug and claim Shimano is "not relevant" compared to SRAM or others need to review the price and performance of Shimano's drivetrain. Wide range 1x Deore vs SRAM NX? There's no comparison. You basically get top of the line performance at the lower end with Shimano, with the differnce being tool-free adjustment, weight and carbon fiber. This is what product differentiation that aligns customer demands with price should look like.


I suspect this is a workaround for 1x drivetrains. 1x drivetrains require absolutely massive cassettes to get a useful gear range. With 1x being a trend and cassettes being a very visible component, huge cogs have become super fashionable for now. Derailleurs are a limitation, because the whole assembly needs more length to get around those enormous cogs, plus the long jockey lever arm to accomodate the full slack range of the drivetrain. The whole assembly eventually gets pushed further down where the chain and fragile jockey arm are exposed to the bits of nature they can snag on. Splitting the jockey arm over a third jockey wheel like this avoids that problem. So this design might allow even huger cogs.


It would be nice to be able to change gears while pedaling hard uphill. Seems like you can’t have much tension to change gears.


Having a 1x drivetrain in my Trek Xcaliber and living up a steep hill, when changing up gears I have to sit down, do a pedal stroke like just letting the weight of my leg press the pedal and switch gear at the same time to avoid that hard snap in the chain. A little inconvenience but it does the trick, it changes smoothly


Tom Boonen (former race bicyclist) is ambassador/investor in a company that solves that problem.

https://www.classified-cycling.cc/


Hmm - looks like it gets rid of the front derailleur with a very proprietary rear hub, but that solves only one shift - small chainring to big is sort of an issue under heavy load (big to small, not so much) (so nothing to do with the cassette.

There was an American cyclist (which I shall not name) who had a high cadence style and would attack on the hills. Part of his attack was quickly going into the big ring. They accomplished this with a down tube shifter that was perfectly set to just flip them into the big ring (STI existed but suffered from shifting under a high load - as well as being somewhat heavy for a high climb bike), while they were already quickly dancing on the pedals on the small, so a high load was less of a problem.

Quite clever, actually.


I have an old di2 and it seemed to allow that.


Looks like it positions the usual two pulley wheels closer to where chain slap happens, while adding a pulley wheel that remains close to the cassette.

In the usual case, you have pulley wheels both shifting and tensioning the chain. Fine for most road bike use cases, but that leaves lots of room for chain slap in gravel and mtb use cases.

The viability of this design depends, it seems, on whether it adds less drivetrain loss than a clutch, and if added weight can be kept low.


Putting the chain on the opposite side of the B-pulley is going to make shifting sluggish on the small cogs.



It looks like a gimmick for mountain bike configurations that have huge cassettes in the back, requiring the derailleur to have a long cage to pick up slack.

I don't understand why you wouldn't just get off the bike and walk instead of shifting to some 42T+ cog. It would be less embarrassing.


This is way off-topic (and, I know, language is arbitrary and often inconsistent, so it’s not “wrong”), but… am I the only one who thinks it’s inelegant that we spell “derailer” the French way (dérailleur) but pronounce it the English way?

As a personal stylistic choice I always write “derailer”, which is the same way all Americans pronounce it.


There's at least one other person that agreed, Sheldon Brown (who else)

> I am on a one-man campaign to replace the foreign spelling "dérailleur" with the English spelling and pronunciation "derailer."

https://www.sheldonbrown.com/derailer.html


Some people I know pronounce it the French way, for whatever that's worth. And these are not all people that speak French.


Do you mean they just pronounce the "eur" part like in French? Or do they actually say day-rye-eur? It would sound really weird to pronounce the word like in French.


"Duh-rail-yer" is the only pronunciation I've heard, which is presumably some sort of half-hearted attempt to keep it sounding "foreign" without using phonemes that most English speakers would struggle with (particularly the 'r').


That's common in English. Spelling is digital so it's easy to error check, and remains static. Pronunciation is analog and drifts.

English spelling often gives hints about where words were at the time of the Great Vowel Shift, when printing was just starting to standardize orthography. We got a mishmash of various places, and words that entered after can be spotted from words that entered before.

This is of course a much more modern word. But the French were the innovators in cycling and they got to set the word, and mostly the spelling (though we did lose the diacritical mark).

You can try to update the spelling, but that rarely works. Autocorrect will likely entrench weird English orthography further.

Oddly, if I type dérailler, my phone automatically adds the accent (because I have a French keyboard installed. That is a different French word, or rather, it's the infinitive "to detail". It's pronounced duh-rye-a.


I would also accept "Disraeli"

https://en.wikipedia.org/wiki/Disraeli_Gears


I’ve been doing bike maintenance for a long time and didn’t know about derailleur clutches?


You only see them on Shimano mountain bike rear derailleurs made in the last ~7 years.


They also exist in Shimano’s GRX gravel series as well


My SRAM Force (CX) and Red (road) have clutches.


Even microshift has them now.




Guidelines | FAQ | Lists | API | Security | Legal | Apply to YC | Contact

Search: