Leinster

I guess not, and I presume it’s been looked at. But it appears to bring the best cases of 1x (you can use a single narrow-wide chainring, no issues with front retention) and 3x (you can have a close-spaced cassette and still have wide range)

I would argue that having a smaller cassette might even offset some of the weight penalty, too.

We saw at least one company in recent years throw a lot of marketing budget and effort into a rear hub that mixed internal gearing with rear derailleur shifting, and call it a “front derailleur killer.”

spelger

oh please! at least one ME here has stated he was not insulted etc. stop arguing for the sake of arguing. my comments were quite simple and not meant to insult anyone. now leave me alone.

Ironfish653

The fundamental flaw with that idea is that to shift from the non-tensioned side, you have to move the chain after it is engaged on the chainring teeth. You'd have to move the chain over, and at the same time, lift it off of the current ring, while under tension.

The way FDs currently work, it doesn't so much pull the chain off the current ring, as it does feed the chain on to the intended one. Once you have enough links engaged on the new ring (about 1/4 rotation) the FDs job is done, and the rotation of the crank finishes off the rest of the shift, using the chain tension to your advantage.

Shifting "from the bottom" would mean pulling the chain over, and lifting it off of the chainring teeth against the tension which, I imagine, would require a much more substantial and complicated mechanism than existing FD designs.

I suppose you could get around the chain tension issue by backpedaling during the shift, but the whole point of a derailleur drive train is that you can change gears without stopping pedalling

njkayaker

They were "simple" indeed.

Maelochs

Anyway ..... lots of very good reasons why having a dozen chain rings and only two cogs is not at all a good idea and not at all an improvement.

Also ... one way of describing the "stagnation" of a long-used machine is ..... "perfection."

If no one has come up with anything better, maybe .... we should be glad we have what we have.

Front derailleurs meet a certain definition of mechanical and engineering "elegance" in that they are ridiculously simple and ridiculously effective. To be "better" a device would have to either shift significantly more smoothly or be even smaller, lighter, and/or simpler, or all of the above.

I am willing to stipulate the electronic derailleurs might be "better" for most uses, even though they are not nearly as simple ...

Sure, there are designs for internal-gear hubs, gearboxes, etc, but in terms of what makes the best engineering sense ..... light, cheap, strong, simple, reliable, effective ..... I am sure some day scientists will concoct some sort of readily moldable, incredibly strong and flexible unobtanium compound which can be used to make bike frames with tubes the diameter of pencils and ten times the strength of steel or carbon fiber or whatever .... and I am sure someday someone will develop a miniaturized, piezo-electric fully automatic bicycle gearbox is smaller, lighter, and more reliable than modern derailleurs ... and cheap enough to be fit on Walmart bicycles. And we will all fly down to Walmart in our hovercars to buy them.

In the meantime ........

tyrion

There's plenty of room for improvement of gearboxes (weight, efficiency, cost, standardization). Seems like a logical place for the industry to develop THE NEXT BIG THING THAT YOU ABSOLUTELY MUST BUY.

StanSeven

Let’s stop with the accusations and insulting posts. This thread is pretty good and we don’t want to close it.

HTupolev

It's both.
On upshifts, if the front derailleur were to magically disappear before the chain is meshing with the next ring, the chain would tend to go back to doing what it was doing on the initial chainring.
But on downshifts, the chain needs to drop in height before it can mesh with the new ring. This generally won't happen until after it stops engaging with the initial ring.

Changing gears without stopping pedaling is nice, but I don't think I'd call it "the whole point." Even a derailleur that requires a large disruption to pedaling rhythm can be far less disruptive than, say, getting off the bike to move a chain to a different cog.

Even when a derailleur doesn't require that a rider stop forward pedaling, they generally work better if pedal pressure is eased off. Various advancements have reduced this, but even modern rear shifting can sometimes get crunchy at full stomp.

Historically, there have been commercially-produced derailleurs that required backpedaling. This was especially true for racing designs from the 1930s, which often put forks or paddles on the top of the chainstay. These designs include the original Osgear Champion, the Vittoria Margherita, and Campagnolo's early derailleurs.

The earliest well-documented commercially-produced derailleur, the Gradient from the late 1890s, used a mechanism to lift the chain off of the rear cluster while changing gear. In some forms of the system, the chain-lifter was engaged by backpedaling.

PeteHski

I presume you mean the 2-speed Classified Powershift hub, which I really do like but it is very expensive and limits your wheel choices. But if one of the big players took it on along with plenty of wheel and cassette choices then I would be very interested. But a more simple 1x13 is very tempting for me on a road bike and an electronic version can’t be more than a couple of years away. I very nearly built a road bike with Ekar last year, but component availability at the time put an end to it.

Trakhak

Here's an example of box-free thinking about front shifting: the Browning Transmission. Post no. 8 is from an industry guy who gives an insider's perspective.

https://www.bikeforums.net/classic-v...nsmission.html

Polaris OBark

You just need to know where to look:

tcs

Read the first couple of chapters of The Dancing Chain by Frank Berto to learn about the early days of derailleur gearing (1895~1935) and what was tried, what didn't work, and what lasted.

kyselad

As someone who doesn’t give much thought to how much my bikes and various components weigh, that still looks heavy. Also, it’s gorgeous and I love it.

kyselad

I’d like to see that thing in action. I can only find one video of it being operated, but it’s not mounted on a drivetrain so sort of misses the point for me.

njkayaker

https://www.renehersecycles.com/comp...ntuple-cranks/

Look at the date.

Camilo

Yeah, I know the theoretical question was multiple gears in the front. But he also mentioned the mechanical difficulty of downshiftig in the back (moving to a larger sprocket). I was simply mentioning that a "bail out" situation is easy with a smaller front chain wheel compared to a larger sprocket in the back. that's all. I have no illusion that multiple (beyond 3) in the front is practical.

Polaris OBark

It was an April Fool's joke from a few years ago. It was very well done.

kyselad

Haha, I actually thought it was some whackadoodle prototype looking for a kickstarter or some such and totally missed the René Herse logo. I still think it would be epic if they made one for giggles.

Ironfish653

Wow, thanks for explaining to me what I just said. Maybe I should have been more specific in my language to prevent so much misunderstanding.

I should have specified that FDs don't lift or push the chain down; all they do is move it side to side; preventing it from engaging on the current ring.
The rotation of the crank is what moves the chord of the derailed chain; in a downshift, it "falls" off the side of the ring, until it encounters the top of the small ring; in an upshift, the chain side plates engage with the teeth, ramps and pins of the larger ring, lifting the chain until the rollers start engaging the teeth of the selected ring.
The chainring actually does the lifting, not the FD

So, what sort of advantage do these historic cambios offer over a modern derailleur/shifter setup? Freedom from the tyranny of cables?

The movement of a couple of fingers and a half-stroke of soft pedaling should allow almost anyone to successfully complete a gear shift on a halfway -in-tune bicycle. It both higher performance, and easier to use. What's the big design shortcoming I'm not seeing?

Leinster

Right; I don’t like the Powershift for exactly the reason you say, because it leaves you stuck with one wheel. The BB shifting lets the rider bring whatever wheels they want and just replaces the FD.

HTupolev

The issue was not specificity, nor do I believe that you don't understand how FDs work. I was clarifying a sentence which, in its context, I think can be read inaccurately. Your description...

"The way FDs currently work, it doesn't so much pull the chain off the current ring, as it does feed the chain on to the intended one."

...is a good description of front upshifts, but can be misleading as a description of front downshifts. "Feed on to the intended one" is suggestive that the front derailleur primarily guides with respect to the destination, but on a downshift, the front derailleur's role is largely around guiding it off the origin.

My objection to your wording was not about how much horizontal versus vertical guidance a front derailleur applies to a chain.

I don't know; I was not alleging any advantages. I was merely arguing that being able to shift without cessation of pedaling is not "the whole point" of derailleurs, as you had stated.

PeteHski

Well that's only an issue while it remains a niche product rather than an inherent problem with the concept. Moving it to the front increases torque and reduces rpm compared to the hub so it might not be quite as slick. Either way you are stuck with a proprietary hub or crank and so it isn't really going to go anywhere unless Shimano/SRAM get involved and it becomes part of a high-end mainstream group. But I think the push to 1xN will probably kill it off in this respect.

njkayaker

Endless reasons it wouldn’t be a real product. Some of which were mentioned earlier before it was posted.

• Q factor.
• No derailleur exists that moves that wide.
• Nothing exists that would move the derailleur (friction would be the easiest option.
• The market is moving to fewer rings (not more).
• Not a big enough market or (maybe) way too expensive or too stupid (even) for kickstarter.
• Etc.

The joke is entirely appropriate here but another give-away is the lack of an actual link.

PeteHski

Modern drivetrains are so good at downshifting the rear that it doesn't really matter. It was hardly a real problem with older drivetrains as long as you thought a few seconds ahead. I climb walls on my 1x12 mtb and it can easily shift down at the rear even when ramping up steep climbs. So there would never be a need to make a 12-speed crankset just to make downshifts go from a larger to smaller chainring. I think it's safe to say that 12x1 will never exist and for very good reason.

cyccommute 

Triples were de rigueur up to at least 10 speed drivetrains. They didn’t fade away when drivetrains when from 6 to 7 speeds nor, for that matter, 9 speeds came around. 9 speed triples were probably the zenith of triple chainring drivetrains.

While a double may have a similar range…a dubious claim if you want or need lower gears…it’s missing the middle of the gearing that a triple provides. I’m often amazed at people who go on and on about how they want single tooth steps between gears so that they can find “just the right gear” and yet they live with a massive jump in gears between the high and low of wide range doubles. The triple allows for that close range gearing in the large ring as well as the middle ring with the ability to have a low gear for when you need it. Shifting a double is akin to going from fifth to first in a manual transmission. The engine is revving too high when you shift and you either have to slow down to catch up or you have to upshift to find the proper gear.

Again, triples didn’t go away at that period. A lot of the reason that triples have gone away is because racers and racer wannabees have always looked down their noses at triples as for “weak people”. I can’t tell you how many times I’ve read someone here on the forums offer the advice of “just get stronger” when someone finds themselves unable to climb a hill with their gearing.

I have lower gearing and, more importantly, higher gearing than you can get with a 1x or 2x wide range system. I’m not “weak”. I’m smart and know how to design and use a very wide range triple system.