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Shimano’s three-pulley rear derailleur could revolutionise drivetrain design
- _Wintermute 4y agoHardly 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.
- mjhay 4y agoYeah, I wish they sold derailleur hangers in six-packs. I've always wanted a Rohloff for commuting, but they aren't cheap.
- FpUser 4y agoWhat is cheap, definitely enough for commuting (well except dirty dozen type one) and rides amazingly well are 3 speed Sturmey Archer hubs.
- timonoko 4y agoProblem 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.
- analog31 4y agoThat 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.
- silon42 4y agoYeah, 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%).
- gomox 4y agoYou can offset for that with a smaller chainring and you gain some ground clearance. Win win!
- cuu508 4y agoIn six-packs, because you break them often? How does that typically happen?
- mjhay 4y agoThey 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.
- 323 4y ago> 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.
- bloat 4y agoThey need very little maintenance. But they are very expensive. e.g. https://www.sjscycles.co.uk/rohloff/ https://www.sjscycles.co.uk/rohloff/
- 323 4y agoBut 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.
- bloat 4y agoI'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!
- wl 4y agoThe $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.
- hannasanarion 4y agoBikes 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.
- Overtonwindow 4y agoSome of this might be intended for the pros, and with time modified to be more robust for the retail consumer market.
- johnwalkr 4y agoMountain biking is interesting in that the consumer usually gets to buy exactly what the pros are using.
- Overtonwindow 4y agoSame 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.
- mcntsh 4y agoI 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.
- m463 4y agoThe 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.
- wl 4y agoCompared 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.
- johnwalkr 4y agoI 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.
- Xylakant 4y agoI 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.
- johnwalkr 4y agoWhen 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.
- usrusr 4y agoThat 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)
- justinator 4y agoYou 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.
- Zigurd 4y agoLooks 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.
- kevin_thibedeau 4y agoPutting the chain on the opposite side of the B-pulley is going to make shifting sluggish on the small cogs.
- soared 4y agoI’ve been doing bike maintenance for a long time and didn’t know about derailleur clutches?
- CitrusFruits 4y agoYou only see them on Shimano mountain bike rear derailleurs made in the last ~7 years.
- dhaulagiri 4y agoThey also exist in Shimano’s GRX gravel series as well
- sasawpg 4y agoMy SRAM Force (CX) and Red (road) have clutches.
- johnwalkr 4y agoEven microshift has them now.
- bilsbie 4y agoIt would be nice to be able to change gears while pedaling hard uphill. Seems like you can’t have much tension to change gears.
- Gualdrapo 4y agoHaving 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
- Luc 4y agoTom Boonen (former race bicyclist) is ambassador/investor in a company that solves that problem. https://www.classified-cycling.cc/ https://www.classified-cycling.cc/
- justinator 4y agoHmm - 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.
- m463 4y agoI have an old di2 and it seemed to allow that.
- School-Cotton 4y agoThis 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.
- CydeWeys 4y agoSome people I know pronounce it the French way, for whatever that's worth. And these are not all people that speak French.
- swimfar 4y agoDo 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.
- wizofaus 4y ago"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').
- jfengel 4y agoThat'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.
- latchkey 4y agoI 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.
- sasawpg 4y agoI’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.
- latchkey 4y ago> 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.
- davidw 4y agoHere's the Suntour one, mentioned in the article: https://www.disraeligears.co.uk/site/suntour_xc_derailleur_3_pulley_system.html https://www.disraeligears.co.uk/site/suntour_xc_derailleur_3... https://www.youtube.com/watch?v=CjdHSPKfiig https://www.youtube.com/watch?v=CjdHSPKfiig
- skeeter2020 4y agoPeople 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.
- nabilhat 4y agoI 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.
- kazinator 4y agoIt 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.