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At How Many Cogs Does the Madness End?

  • At 12-spd road/13-spd gravel (what it is now).

  • At 13-speed everything.

  • 14-speed

  • 15-speed

  • 16-speed

  • 18-speed

  • 20-speed

  • More than 20 (!!)

  • “Something something CVT” (even though that doesn’t answer the Q, and CVT is heavy).

  • I’m terrified to even guess.

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Banned Sock Puppet
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Might be a fair concern. Current 12-speed chains are already barely wider than 3/16”.

As we keep narrowing the chain, where’s the breaking point? Both figuratively and literally. 💥

Or short of that, when do we get to a ridiculously short lifespan/replacement cycle.
But parts wearing out faster is good for the economy, right? The only other option is for wider hubs which of course causes issues with chain line in extreme gears.
 

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Discussion Starter · #43 · (Edited)
But parts wearing out faster is good for the economy, right? The only other option is for wider hubs which of course causes issues with chain line in extreme gears.
Yup. And wider hubs also obviously mean wider chainstays, so your heels and/or cranks can hit them, unless they spec a wider crank (high Q-factor) along with it.

Which many ppl don’t want, as it impacts pedaling efficiency and aerodynamics to be in a more splayed-out position like that. 😕

So, it kinda mostly falls to narrower cog spacing to shoehorn more gears in there.

Though rim-brake road could go to 135mm frame spacing w/out the poop hitting the fan.
 

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Yup. And wider hubs also obviously mean wider chainstays, so your heels and/or cranks can hit them, unless they spec a wider crank (high Q-factor) along with it.

Which many ppl don’t want, as it impacts pedaling efficiency and aerodynamics to be in a more splayed-out position like that. 😕

So, it kinda mostly falls to narrower cog spacing to shoehorn more gears in there.

Though rim-brake road could go to 135mm frame spacing w/out the poop hitting the fan.
So no 148mm Boost spacing for road bikes?
 

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Discussion Starter · #46 · (Edited)
So no 148mm Boost spacing for road bikes?
Road bikes usually have short chainstays, which make very wide hubs difficult to accommodate without causing the problems discussed earlier.


Edit- for anyone still unclear on why that is, note how your chainstays flare outwards and get farther apart along their length.
 

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Road bikes usually have short chainstays, which make very wide hubs difficult to accommodate without causing the problems discussed earlier.
True. So if we want more gears, we need to have paper thin chains and gears or bring back the quad rings.
 
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How about an eight speed internally geared hub with a cassette and thirteen more gears? That's 104 gears with one chain ring, 208 with two and 312 with a triple.

There'd probably be some duplicate gears in there, but I'm not gonna try and sort that out.
 

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Discussion Starter · #49 · (Edited)
How about an eight speed internally-geared hub with a cassette and thirteen more gears? That's 104 gears with one chain ring, 208 with two and 312 with a triple.
The slam on IGHs are that they’re simply not quite as efficient as chain drives, aka they lose watts— though a high-quality IGH such as Rohloff can narrow the gap a good deal (for a price/$$$).

Interestingly, looking it up… CVTs are even less efficient than IGHs. 🤔

This kinda leads me to think that the ‘Day of the CVT’ for bikes (at least non-electric ones) is very far off, if ever. The added weight was already a turnoff.
 

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Discussion Starter · #50 ·
Interesting test/comparo on the efficiency of various IGHs, CVT, and single-speed chain drive:


And also one on 1x chain-drive efficiency vs 2x:

 

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Interesting test/comparo on the efficiency of various IGHs, CVT, and single-speed chain drive:


And also one on 1x chain-drive efficiency vs 2x:

Great articles!


Sent from my iPad using Tapatalk
 
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Discussion Starter · #53 · (Edited)
That’s really interesting… a hybrid IGH-chain drive approach.

With the main goal to be a 1x drivetrain with 2x gearing ratios, courtesy a 2-speed hub that provides a ‘virtual small chainring’ in one speed, and ‘locks up and gets out of the way’ for the other speed (‘virtual big chainring’).

IOW, they’re using a 2-speed hub to get rid of the front derailleur and second chainring.

Pretty neat, and probably more efficient than any pure IGH drive, even Rohloff.

But, the cost is a bit of a shocker (2400 GBP, which is about $3400 USD) for everything you need, including their rim (why are you required to use theirs only?).

Plus, no matter how much they insist otherwise, it’s likely not as efficient as a chain-drive, as it has both chain-drive and IGH frictional losses to contend with (just less of each).

It’s cool, but the price alone likely ensures it’ll remain niche.

Honestly, it’s really hard to beat good old-fashioned chain drive (aka, The Champ going on 136 years now)… it’s simple, robust, cheap, and highly-efficient.

All that, unless you fark up and design it not to be. 😕
 

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Discussion Starter · #54 ·
This thread…

3000+ views
13 votes in the poll

Sigh. 😕
 

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This thread…

3000+ views
13 votes in the poll

Sigh. 😕
Lurkers will lurk. I wonder if it keeps track of lurkers who don't have accounts.
 

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That’s really interesting… a hybrid IGH-chain drive approach.

With the main goal to be a 1x drivetrain with 2x gearing ratios, courtesy a 2-speed hub that provides a ‘virtual small chainring’ in one speed, and ‘locks up and gets out of the way’ for the other speed (‘virtual big chainring’).

IOW, they’re using a 2-speed hub to get rid of the front derailleur and second chainring.

Pretty neat, and probably more efficient than any pure IGH drive, even Rohloff.

But, the cost is a bit of a shocker (2400 GBP, which is about $3400 USD) for everything you need, including their rim (why are you required to use theirs only?).
This is a pretty cool concept. I'm sure the cost will come down over time. But being proprietary... I don't see it going anywhere.
Ridley bikes is supplying bikes with them though.


Plus, no matter how much they insist otherwise, it’s likely not as efficient as a chain-drive, as it has both chain-drive and IGH frictional losses to contend with (just less of each).
It definitely can be more efficient.
In the 1:1 ratio, the hub is locked. So there's no loss in efficiency. But you have a straighter chainline from the 1x, so it would definitely be more efficient than a 2x setup.
When the hub is unlocked in the 0.7 ratio, you'll lose a bit from the internal gears. But you still have the benefit of a straighter chainline. And you also have a larger front ring, which is more efficient than a small ring on a traditional setup. So it could be a wash.

While a few gear ratios in the unlocked mode may be less efficient, the overall average efficiency is most likely equal or higher.
 

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Discussion Starter · #57 · (Edited)
[The PowerShift hybrid IGH-1x chain drive] definitely can be more efficient [than chain drive].

In the 1:1 ratio, the hub is locked. So there's no loss in efficiency. But you have a straighter chainline from the 1x, so it would definitely be more efficient than a 2x setup.

When the hub is unlocked in the 0.7 ratio, you'll lose a bit from the internal gears. But you still have the benefit of a straighter chainline. And you also have a larger front ring, which is more efficient than a small ring on a traditional setup. So it could be a wash.

While a few gear ratios in the unlocked mode may be less efficient, the overall average efficiency is most likely equal or higher.
I remain a bit dubious about that.

For one thing, 1x drivetrains do not overall have a straighter chainline than 2x. Because with 2x, you have some duplicate ratios to play with, and thus can be strict and eliminate the (likely rubbing anyways) cross-chain gears, and the ones adjacent to them too.

IOW, with 2x, the chain only has to span part of the cassette with each chainring. But with 1x, it has to span the entire cassette with its single ‘ring. There’s no efficiency advantage for 1x here.

In fact, it’s generally the opposite. When you compare the efficiency of 1x gears vs the gears in a 2x setup that actually get used, 2x comes out ahead:

Rectangle Slope Plot Font Line

(^ Tap to make larger. Input power was 250W).

Also, the larger chainring on a 1x (compared to the 2x’s inner chainring) plays only a very small role in efficiency, because no chainring is small enough to produce the kind of friction-causing tight bends that the smallest cogs do.

But, 1x generally uses smaller small cogs for the higher gears, and below a certain size (say 15t) you start taking small but notable efficiency hits.

And then of course, there’s the non-1-to-1 speed on the PowerShift IGH hub. Which will knock down the efficiency of all cogs used with the ‘virtual small chainring’. That’s in addition to the 1x being a bit less efficient than 2x to begin with.

Does this mean PowerShift is crap? No, on the contrary, it may be the most elegant and efficient IGH drive yet (albeit only partly IGH).

But, as efficient as chain-drive? No, doesn’t seem to be.

Close enough that you shouldn’t care? Up to the individual. But even if you don’t, it’s still $3400 for everything you need. That needs to come down.
 

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I don't care what anybody else feels that they "need" to buy...My line in the sand is 10 in back, and two in the front.....Back in the 80, I used to race on a 13-18 6 speed freewheel, and I had enough gears. I find that gears that I used to use, I'm no longer able to get rolling. Now I'm using a 12-25, and at times, I'm stressed pushing a 53x25 over rollers. I've got a "thing" about not wanting to use the 39.....There is NO way I'd ever go 1X......The monster cassette you have to use on them, looks ridiculous.....Part of the reason that Shimano and the other guys are making cassette with more cogs, is because of the demand for easier gearing (don't get me started on that subject).....You can't have cassettes with huge gaps between cogs, so they just add more cogs in-between.
I predict that 1x systems will soon have 13, 14, of 15 cogs in back.
 

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Discussion Starter · #60 · (Edited)
I don't care what anybody else feels that they "need" to buy...My line in the sand is 10 in back, and two in the front.....Back in the 80, I used to race on a 13-18 6 speed freewheel, and I had enough gears. I find that gears that I used to use, I'm no longer able to get rolling. Now I'm using a 12-25, and at times, I'm stressed pushing a 53x25 over rollers. I've got a "thing" about not wanting to use the 39.....There is NO way I'd ever go 1X......The monster cassette you have to use on them, looks ridiculous.....Part of the reason that Shimano and the other guys are making cassette with more cogs, is because of the demand for easier gearing (don't get me started on that subject).....You can't have cassettes with huge gaps between cogs, so they just add more cogs in-between.
I predict that 1x systems will soon have 13, 14, of 15 cogs in back.
Agree with most of that.

And I think 1x is getting a lot of ‘new kid on the block’ hype, as in, “Whoaaa dude, maybe ALL bikes will be going to 1x!!!”— when really, it’s definitely gonna be around but isn’t going to conquer all.

I for sure don’t see any reason to turn my road bikes into 1x. Maybe if I lived in flatty-flat-flat Florida, and used it with a narrower-range cassette. 🍊

I gotta wonder though… is the front derailleur really Satan? Ppl nowadays act like front shifts are akin to being water-boarded, lol. 😮

All that said, I bet you’re just happy you don’t have to hit the climbs with a 42/18 low gear anymore, Grumpy. 😥

Oh and FYI, we’re already at 13 cogs in back, thanks to Campy and Rotor. 1x is helping drive this, for better or worse, since a 500% range drivetrain with small jumps all the way through (the end goal, I think) requires about 18 cogs with 1x (but only 14 with 2x).

Startin’ to see why the industry likes 1x so much…. not only is it “NEW!!” and also helping to drive the upgrade cycle, but it can potentially do so in a relevant/useful way for much longer than 2x can.

AKA it might take us another 20-25 years to get to 18-speed, but 14-speed should arrive this decade. 1x takes much longer to ‘get to the Promised Land’, and with all the attendant upgrades along the way… cha-ching!! 💵 💵

Now, where’d I put my fixie?
 
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