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I’ve come across 2x12 and 3x11 triple cranksets. Can these systems necessarily provide more range than 2x11 and 3x10 @ > 700%?

Edit: My question is really what can practically be accomplished, with factors such as derailleur cage length and derailleur capacity. Do all such related factors of practicality mean each of these systems have the same range limit? If not, then what are the practical range limits?

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    Rather than exploring capacity limits would it make more sense to determine your need and then seek an appropriate solution?
    – David D
    Dec 27, 2021 at 15:10
  • Not answering your question, but throw a Sturmey Archer 3 speed cassette hub into the mix and you'll have 33% overdrive and 25% reduction on top of whatever your derailleurs can manage. I'm not sure what the smallest sprocket is on those though.
    – bertie
    Jan 2 at 16:41
  • Could you clarify what about my answer doesn't meet your needs? If you stick a 3x crank on a wide-range cassette, you get the combined ranges of the crankset and the cassette, and if you're careful not to cross-chain onto big-big or small-small combinations, you don't have to add extra capacity (and you actually decrease the capacity requirements.)
    – RLH
    Jan 2 at 18:49
  • @RLH, it's a good answer, but I'm still looking for a comparison. You're saying it can't be absolutely determined, because one could always set up a drivetrain with a higher range if they were trusted not to cross-chain. I don't exactly know if bike shops really do that. But for sake of comparison, say this is a bike for ordinary people, you wouldn't. I think this would be a better way to compare than figuring out different ways and how far you can go before a rider might get annoyed by their cross-chain limitations.
    – BBaysinger
    Jan 2 at 19:19
  • @David D, I did explore what my needs are, and I need the most range possible.
    – BBaysinger
    Jan 2 at 19:27

5 Answers 5

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Cage length doesn't directly dictate overall gear range, but under some safety constraints can dictate the overall gear range.

First, instead of "cage length", it's best to talk about "derailleur capacity", which correlates to cage length, but also includes factors such as placement of the derailleur relative to the rear axle and the size of the pulley wheels.

To see why, we can start with a 1x (single chain ring) system. In this case, the derailleur capacity tells us how how different the largest and smallest cogs on the cassette can be.

If we go to a 2x or 3x system, the capacity tells us the maximum range in (chainring teeth + cog teeth) we can access without making the chain too tight or too loose.

For a given cassette, the capacity thus determines the maximum difference between the chainring sizes that can be accommodated, and thus the maximum gear range if the system is required to function in all gear combinations.

If the rider can be trusted not to cross-chain the system into a big-big or small-small configuration, however, the range can be expanded so that capacity dictates the difference between [smallest chainring + smallest cog allowed with that chainring] and [largest chainring plus largest cog allowed in that chainring].

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    +1, this answer i think is close to what the op is asking about, but it still conflates cage length with total capacity. total capacity is a product of cage length and pulley size. cage length by itself is never the whole story. Dec 27, 2021 at 2:58
  • @NathanKnutson Good point. Edited.
    – RLH
    Dec 27, 2021 at 3:22
  • Good answer, much more meaningful than mine lol. Last paragraph: don’t you mean two 1x systems? Eg gears 1-6 are handled by the small chainring and gears 7-12 are by the large chainring.
    – MaplePanda
    Dec 27, 2021 at 3:40
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    @MaplePanda I was thinking 3x systems; I've made a more clear statement.
    – RLH
    Dec 27, 2021 at 3:52
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It’s difficult

What really limits you is derailleur capacity. Take for example a Shimano SLX rear derailleur with long cage (RD-M7000-10-SGS). It has 43 teeth of capacity. Let’s pair it with a crankset which has 36 and 22t chainrings. The crankset ”eats up” 36t-22t=14t of our capacity. So we have 43t-14t=29t of capacity remaining. There are no 10–39 cassettes, but a 10–40 would probably work fine.

The resulting gear range is 654%.

You could achieve >700% gear range by ignoring manufacturer limits. For example you could install a 10–50 cassette for 818% gear range. The chain with such a setup would either be too short in the big/big combination (very bad) or too long in the small/small gear combination (kind of bad).

Edit: Just noticed that the Shimano SLX rear derailleur only allows 11t small sprocket and 36t big sprocket. The other rear derailleurs only have 41t capacity which would reduce your gear range further.

Edit2: I should probably also add that the lowest speed with the above mentioned gear ratio is around 5.5km/h (at 75 rpm cadence) and the highest speed is 55km/h (at 110rpm cadence). That’s actually not that unrealistic or undesirable.

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Let's see what I can come up with here.

  • Cassette: There are 9–52t cassettes available on the market, such as this one from KCNC.
  • Crankset: Shimano makes the FC-M8000-3, which is a 3×11 crankset. 12s cranksets only come in either 1× or 2×, so they have less range than this 11s crankset. It is generally acceptable to mix and match 11s and 12s stuff.

Now for the math:

  • Lowest gear: 22–52, which is a ratio of 0.423
  • Highest gear: 40–9, which is a ratio of 4.444

Therefore, using this setup gives you 1051% range!

Note that at the lowest gear, pedaling at 80rpm would only propel you at 4.7km/h. In this gear, pedaling from a standstill would also yield around 200ft∙lb (~270Nm) of torque at the rear hub even for my 140 pound body weight, so the bike would probably not enjoy this treatment.

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    Isn’t this limited by derailleur cage length?
    – BBaysinger
    Dec 27, 2021 at 1:00
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    @BBaysinger Probably, but we are talking about theoretical stuff here for the most part...don't let those pesky details get in the way. I don't think the massive derailleurs capable of handling 9–52 would have too much trouble with a few more chainrings regardless.
    – MaplePanda
    Dec 27, 2021 at 1:11
  • 40-22 + 52-9 = 61t required rear derailleur capacity which is a lot. For example the Shimano RD-M9120-SGS only has 41t
    – Michael
    Dec 27, 2021 at 8:48
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    Your bike will enjoy the treatment just fine. The force/torque on the rear wheel is limited by your weight and the frame geometry. For typical bikes and riders, the bike will just lift the front wheel off the road long before the rear wheel itself gets into trouble. Dec 27, 2021 at 15:25
  • @Michael Answer was written before the update about derailleur capacity when it was purely a tongue in cheek question about MORE RANGE. Considering market trends, 61t capacity is not sounding too ridiculous.
    – MaplePanda
    Dec 27, 2021 at 23:35
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No, not necessarily. It would be technically possible to have a super wide range 2x11 or 3x10 drivetrain, but at the cost of wide steps between gears.

As cassettes have gained more and more sprockets, they have offered more drivetrain options, allowing for either a moderately wide range with close jumps between gears, or a very wide range with moderate jumps between gears (for example, Microshift offers a 12-46 8-speed cassette, but the jumps are big).

So the number of available ratios is a soft limit in the sense that wide jumps between gears are undesirable, and a harder limit in the sense that it's difficult to move the chain up big jumps, but this wouldn't technically prevent you from having a very wide range with relatively few gears.

A hard limit is derailleur cage length. At some point, the derailleur would need to wrap up so much chain (and hang underneath a big enough sprocket) that the cage would be at risk of dragging on the ground.

Another range limit is the jumps between gears in front. Front derailleurs are fairly crude devices, and don't shift well with steep jumps between gears—if you make a bad shift under heavy load, you can break the derailleur. Current state of the art is 14t 16t steps between chainrings, although that has been cheated with some success. And the rear derailleur's chain wrap comes into play here as well.

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    I’ve never understood why big jumps are a problem for anyone but racers. I ride fixed also, so know you can do a lot of one gear. Five total gears on a 700% range wouldn’t bother me in the least. Climbing, descending, all.
    – BBaysinger
    Dec 27, 2021 at 0:59
  • It is a technical problem with shifting big gaps as much as a practical problem for the rider. The larger the difference between two cogs/sprockets, the harder that shift becomes. Modern wide-range cassettes also have a higher number of speeds, the chain doesn't have to jump further than older systems. There are some wide-range low-speed cassettes like the Microshift Acolyte 12-46 8-speed, but bigger gaps than this probably doesn't work well. Note if you want a system with wide range and lower number of speeds, a triple crankset is still the way to do that. Or just always shift two clicks. Dec 27, 2021 at 3:35
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    @BBaysinger As someone who does a lot of road biking on an 8-speed 11-32 gravel bike I totally understand it because large steps are really annoying. When you find a pleasant cadence you are forced to change it with every slooe change because you cannot find the right gear. Also, it is not rare to see a need for a gear change, change a gear and find out that that you need to return back, because the other gear is worse. This concerns touring as much as it concerns racing. You cannot really compare it to fixed gears, that is completely different way of riding. Very few ride 100k trips fixed. Dec 27, 2021 at 8:48
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    @BBaysinger: If you want to ride at a certain power output and cadence you need fine gear steps. It’s a problem for anyone who wants to do serious training. If I want to do intervals at 300W at 100rpm but only have gears for 270W or 320W it sucks.
    – Michael
    Dec 27, 2021 at 8:50
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    @BBaysinger: Try riding at a certain power (or even speed). With >10% gear steps it can get quite difficult since you have to compensate by adjusting your cadence ±10% up or down (i.e. ride at ~100rpm or ~80rpm when you’d rather do 90rpm).
    – Michael
    Dec 27, 2021 at 13:56
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I came across one combination that allows a 700% range, within reasonable specs deviations of commercially available parts: 36/26 chainrings and a 9/46 cassette (detailed in this question) — it could work in either 11 or 12 speed. But it's not what I did in practice: the implication of such combination would require to use components that only exist from one manufacturer (cassette and rear hub), which I don't like given the current supply situation.

With this combination, the way to circumvent the limit of the derailleur capacity is to "go smaller". On the upper range, having a cassette with 9 teeth sprocket allows you to keep a ratio of 4 with 36 teeth chainring. And the 26 teeth chainring gives you a ratio of 0.57, which is similar to a 30 teeth chainring with a 51 teeth sprocket on the cassette. The benefit of going smaller is that the effects of 1 tooth difference are more significant than with "larger" components. For example, using a 38/28 cassette gives you a 693% range.

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  • I don’t think “…components that only exist from one manufacturer…” is true. The XD freehub body is an open standard made by many manufacturers. Yes, only e13 makes the 9-46 cassette, but 10-46 is available from many more.
    – MaplePanda
    Jan 1 at 10:24
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    @MaplePanda it's true, no need to rely on one manufacturer if you want to have a "working configuration". In my case, the upper ratio of 4 is important, and the e*13 cassette is the only option, with the chainrings/cranksets that are commonly available. Without that requirement, an easiest solution is just to use the standard Shimano groupset (Shimano being the exception to the rule of only one manufacturer).
    – Renaud
    Jan 1 at 15:39

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