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This is a hypothetical question that will help viewers (including myself) better understand gears and their limitations. Suppose someone sees a bike they like at a local bikeshop and it just happens to be a 1x10. After riding it for a week or so, he decides that 10 speeds is too much and he only wants 3 gears. Suppose the 10 speed cassette spanned from 11 to 33 teeth. So the bike owner takes it back to the bikeshop where he bought it and tells the mechanic he only wants the 11, 22, and 33 cogs in the back. Question: will this even work? Is there a limit to how many teeth on a cassette it can jump from a cog to the next adjacent cog? The Shimano MegaRange 7 speed freewheel for example goes from 24T to 34T which is a difference of 10 teeth. The idea is the person doesn't want to have to shift thru the intermediate gears but just wants the low, middle, and high gears only and wants the flexibility of being able to change then via cassette technology (rather than a fixed internal hub).

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    I wonder what will happen to your freehub body if all cogs are not connected to the carrier. If you manage to remove them from it and mount somehow in the first place. Maybe go the other way around with front triple and chain tensioner in the back? Jan 20, 2016 at 6:29
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    The jumps between the cogs will be too big for a smooth change of gears. I have a three speed 1937 vintage-bike. The difference between the cogs is 3 and 4 teeth.
    – Carel
    Jan 20, 2016 at 8:25
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    I fail to see the point. Jan 20, 2016 at 13:22
  • If you do this, please remember to come back and tell us how it went. You can post an answer to your own question and accept it as correct.
    – Criggie
    Jan 20, 2016 at 18:59

4 Answers 4

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It would most likely not work without a bunch of expensive finagling. Most inexpensive cassettes come on carriers, meaning removing individual gears is not really that possible. You can still buy individual gears, but they are a more specialty item and very expensive. After you messed with all that, you would likely find that the lower gears tore through your hub body because the hub flanging is designed for cassettes using carriers setup.

After you replaced the freehub body with a more expensive robust one (or got a new wheel), you'd then find that the shifting was horrible compared to most modern systems. If you looked at Shimano's patents you'd find a huge percentage of them relate to ramping shift surfaces on cassettes and crankrings. Your individual rings would likely have none, or have surfaces designed for not the use you were intending.

Hundreds of dollars later you would likely have a bike that shifts worse that the 3 speed internal hub you could have bought for much less time and money.

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  • What a disappointment. I thought cassettes were supposed to be very flexible in both the # of gears and the chosen ratios. It seems like they have many restrictions. This is why I state I am disappointed in the biking industry as a whole since I was away for a decade or so and there are still problems they haven't been solved for a reasonable cost to the consumer.
    – David
    Feb 6, 2016 at 17:38
  • The large manufacturers exist to turn profit and have obligations to their shareholders. There is only so much benefit to cross compatibility. Lack of cross compatibility also creates niche markets for companies who make little odds and ends to make non-compatible things work together. Feb 8, 2016 at 19:12
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    @David Dude, they are not solving the problems because the problems are not problems. No one wants a 1x3 with 11, 22, and 33 in the back. As you say, it's hypothetical. You are disappointed with an entire industry because they haven't contorted to satisfy your hypothetical? Your inventions don't exist because they are are not useful to anyone but you. And their utility to you is actually debatable.
    – jqning
    Feb 9, 2016 at 5:07
  • Speak for yourself. You don't know what other people want in general. Let's suppose someone has a single speed bike with a 22 tooth cog in the back. How would adding an uphill 33 tooth cog and a downhill 11 tooth cog make the bike undesirable? That is some whacked logic if you ask me. I would love to have a wide range 3 speed bike. A 50% increase in cadence is useful shifting to the lower gear. When I ride on pavement and then transition onto grass, I can use as much as a 250% increase in cadence on my bike and sometimes do so. 50% is actually very mild by comparison.
    – David
    Feb 9, 2016 at 10:50
  • The 3 overall gears could be something like 1.13, 1.70, and 3.40. All very useful for a roadbike. 1.13 is a good ratio to get the bike moving from a standstill and for mild hills. 1.70 is my favorite gear on flat pavement. 3.40 would be an excellent downhill gear.
    – David
    Feb 9, 2016 at 10:53
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Seems like a lot of work for little gain. You'd be able to lighten by the weight of 7 cogs, but the shifting action will suffer. My early megarange was quite bad at the last change, which was 26 or 27 up to 34

You'll also need to install 7 cogs worth of spacers to hold the remaining three in a fixed place on the freehub.

And I politely challenge the "I only want the 11, 22, and 33 cogs" because that would be horrible to ride. There's plenty of times where 11 tooth is too high, but 22 would be way too low-geared. Imagine a slight headwind where 11 tooth would be slow and 22 would be way too fast for comfort.

Of course the extreme version of your idea is a track bike, a single fixed gear at something like 54/12, which leads to a nice pedal cadence at around 50 km/h Great for an enclosed velodrome, but not practical to ride elsewhere.

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  • Actually, singlespeed is quite practical outside velodrome. 49/16 gives me a nice cruising speed at 80-90 rpm and sprint speed to about 60 km/h. Mountains are of course a problem, but my country does not have those. The old Torpedo 3-speeds had 33% steps between gears, and they were very useful and popular for a long time.
    – ojs
    Jan 20, 2016 at 12:19
  • Why would we need any spacers at all? Just make a 3 speed cassette and only use the first 3 positions on the shifter. If 11,22,33 is too radical, imagine a 5 speed instead with something like 11, 15, 19, 25, 33. Remember the question wasn't if it is practical for headwinds. I am asking if it will work. For an old man that doesn't pedal fast (maybe 10 MPH tops), 5 gears (or even 3 gears) should suffice. I didn't say what the single front chainring would be but for those speeds, something small like 28 might be good.
    – David
    Jan 20, 2016 at 12:42
  • You'd need the 3 speed cassette to fit on the freehub body and kept with appropriate spacing so the shifter worked. Aside from that, you don't get loose cogs anymore.
    – Batman
    Jan 20, 2016 at 14:35
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    10 mph does not need a spread of 3:1 and no way your three speed as a kid was 3:1. Shift and have your cadence to from 80 to 40?
    – paparazzo
    Jan 20, 2016 at 16:16
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    The actual gears in Torpedo hubs were roughly 3:4, 1:1, 4:3 or 1.77:1 total spread.
    – ojs
    Jan 20, 2016 at 17:08
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There are a few problems with this idea.

  1. Derailleurs are built with the parallelogram on a slope that approximately follows the slope of the cassettes they're designed to work with, so that the jockey pulley will be correctly positioned relative to the current cog as the derailleur moves through its range. There is no derailleur that is designed for this kind of slope, which incidentally is very non-linear, with a 100% step followed by a 50% step. Using any extant derailleur to try to get the chain to move 11 > 22 and (to a lesser extent) 22 > 33 is going to be very rough indeed, and mostly you're going to be jamming the chain into the side of the adjacent gear, rather than engaging it with the teeth of the adjacent gear. Shifting ramps, mentioned elsewhere, are designed to assist with shifts. There are no gears ramped for this kind of scenario, and indeed, it would probably be impossible to ramp the gears for it.
  2. Hub gears already solve the problem of a small number of widely spaced gears. It's not clear what is to be gained by trying to force derailleur gears to do this too.
  3. As mentioned elsewhere, it's true that early press about cassettes & freehubs touted their potential for mix-and-match gearing, but also as mentioned elsewhere, it turns out that lower gears need to be on multi-gear carriers to avoid chewing up the freehub splines, which is how we wound up with riveted or CNCd setups. Companies can only throw so many resources at developing, manufacturing, and distributing cassette configurations, and are naturally going to gravitate toward the ones that people actually want, not the ones that people hypothetically want. This is not the only reason that freehubs were developed, btw: the main reason, as I recall, was to move the drive-side hub bearings farther outboard, to better support the axle. It also makes swapping gears a lot easier (removing a freewheel could take a lot of muscle).
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not getting much love on this one. I like the idea and thought about it myself. SRAM casettes do seperate so you could ditch of say a ten speed and use spacers on the outsides of your now mini casette. Set your deraileur limits and just ignore those extra indexes. You will retain your range, the only problem may be the jump between gears but I think it will be fine. There was a lot of experiments using 42 teeth range extending cogs on ten speed cassettes that were quite popular before 11 speed came in. I find I'm shifting multiple gears most of the time anyway. Just because the industry wants you to put more and more gears on your bike (13 on the way!) doesn't mean you need them. I wish they would make a wide range 7 speed with heavy duty sprockets and chains that had durability in mind!

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    As mentioned in other answers, the upper jockey wheel will not track the new angle of the gears, so it will be either too far from the smaller gear, or too close to the bigger gear, or both. OP had a penchant for asking interesting-sounding questions but had no intention to progress to practical implementation.
    – Criggie
    Sep 5, 2017 at 4:14

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