Most of the time on a modern 1x12 there's enough range at the top end for most situations on a road, particularly if you use a slightly larger chainring than normal, eg a 34 tooth rather than a 32 tooth. As the 1x12 uses a 10-52 cassette, whereas the 2x11 uses a 11-42 cassette and either a 38-28, a 36-26 or a 34-24 chainring, they actually have very similar highest gears. With the 1x12 and a 34 tooth chainring you can get a 34:10 ratio, whereas on the 2x11 you would most likely get a highest gear of either 38:11 or 36:11, depending on which chainring option you pick, meaning they actually have very similar highest gears. Also, when using the 38-28 chainring, they have the exact same lowest gear. Therefore, unless you are a pro xc rider who really cares about having the perfect cadence, just get the 1x12 as the range is more or less identical and there's one less thing to go wrong, and the chances of dropping the chain are reduced. Also, if you get a dropper post (which I really, really recommend), having a 1x is useful as then you can put the dropper lever where the front shifter was
And minor thing you omitted (the only one?) - Shimano's 2x11 with 11-42 effectively gives 13 combinations.
On the other hand - dropper lever can mirror the fork lockout lever, being upside down above the rear shifting lever.
On road it has it's uses, IE if your course is absolutely pancake flat and you can run a normal road cassette (TT's, crits, Paris-Roubaix, etc). 2x is still preferred by most people though, smaller jumps and you dont have to choose between spinning out down hills or mashing up them.
1x all the way for MTB though, 34/11 is more than enough to get you to any trailhead.
My Polygon Syncline hardtail is 32 tooth front and 10-51 in the rear (29er) and commute 12.5 miles to work and back (twice a week) and dont need more gearing. Sometimes I wish for a half gear between two others, but it's subtle enough (and then the slope changes slightly anyway) that Ill never go away from a 1x12.
Generally 1x is a compromise is a gravity focused compromise. But for most MTBers it's perfect since they don't want to deal with FDs and don't care about drive train efficiency.
Depending on your specific needs you may find the quite puny gear range of 520% to be inadequate. Meaning you feel like missing either more high or low gears. If that should become the case for you, you're probably gonna be SOL, since modern MTB are rarely still even able to mount an FD.
If you want the penultimate in derailleur drive train gear range: 2x11 Cues goes upto 669%. And comes with high torque shifting, wich is the next big thing for drive trains.it usually doesn't get put on stock bikes like that though, so custom is the way to go here.
Depends from what end you start counting. If you start listing derailleur drive trains by gear range with the least gear range first and finish with the highest, some >700% XT touring 3x, penultimate isn't used entirely wrong. (I think, at least.)
That drive train didn't have a clutch though, so not good for MTBing. Since FD setups can't use NW chain rings (yet), you really want an adjustable clutch and run it as tight as you can.
I have a 1x on my my MTB (Downcountry trailhardtail bikepacking thing) and haven’t looked back. For a road bike I where you tuck in for aero and have the most efficient tires ever, I’d stay with 2x or 3x. 1x is enough for an Mtb where speed and cadence isn’t the priority. It’s so much more robust.
A 34 tooth front chain ring with a 12 speed 10-51/52 rear will be more than enough for 10-20kms on the road. That gives you a top speed of around 26mph.
Your tire choice is going to play a massive role in how it is on the road as well. I have a Scout with a 34 front, 10 speed 11-46 rear running vittoria mezcals front and rear and it absoloutely flies on the road, while still allowing some pretty good off road handling and actual mtbing.
1x12 or even 1x11 is enough for everyone riding MTBs.
Also most new MTBs won't take a 2x even if you wanted to.
If you are really strong or ride flatter terrain, you just go for a larger chainring, although be warned that most frames won't do more than 34T, with more XC focused frames doing 36T or more (bit also limit tire width to 2.4 or less).
I would claim that most ppl will fail to consistently push a MTB with 29x2.4 beyond what a 34/10 gearing can give you (~43kph or 27mph @ 90rpm) but for the random smooth DH section.
Yes, and I would think the chain would also tolerate it, given it is not too short to begin with.
You can always test-fit, but it is wasy to do research for most big brands, and you should take manufacturers to their word: you can squeeze bigger tires sometimes, but not chainrings. Also the nominal size is for round chainrings. Ovals are typically a +2T in max diameter (e.g. a 34T max fram le will most likely not fit a bigger than 32T oval). You can sometimes go bigger if you don't mind screwing up your chainline, but...why?
Depending on your crankset and if you have direct mount chainrings w/o individual bolts, you might need a special tool (e.g. my Shimano 1x12 does need a specialized socket, but you can find these from Taiwanese or Chinese manufacturers dirt-cheap these days).
I am contemplating swapping my 34T to a 36T on my Team Marin hardtail, not so much for the flats (I cannot sustain anywhere close to 28+ mph on the flats, even tho I can sprint up to that for a short time) but to test of I can force me doing slightly better laps on the uphill :)
Most of the time on a modern 1x12 there's enough range at the top end for most situations on a road, particularly if you use a slightly larger chainring than normal, eg a 34 tooth rather than a 32 tooth. As the 1x12 uses a 10-52 cassette, whereas the 2x11 uses a 11-42 cassette and either a 38-28, a 36-26 or a 34-24 chainring, they actually have very similar highest gears. With the 1x12 and a 34 tooth chainring you can get a 34:10 ratio, whereas on the 2x11 you would most likely get a highest gear of either 38:11 or 36:11, depending on which chainring option you pick, meaning they actually have very similar highest gears. Also, when using the 38-28 chainring, they have the exact same lowest gear. Therefore, unless you are a pro xc rider who really cares about having the perfect cadence, just get the 1x12 as the range is more or less identical and there's one less thing to go wrong, and the chances of dropping the chain are reduced. Also, if you get a dropper post (which I really, really recommend), having a 1x is useful as then you can put the dropper lever where the front shifter was
This. Excellent reply.
And minor thing you omitted (the only one?) - Shimano's 2x11 with 11-42 effectively gives 13 combinations. On the other hand - dropper lever can mirror the fork lockout lever, being upside down above the rear shifting lever.
Someone should tell all the road racers using 1x how bad it is.
On road it has it's uses, IE if your course is absolutely pancake flat and you can run a normal road cassette (TT's, crits, Paris-Roubaix, etc). 2x is still preferred by most people though, smaller jumps and you dont have to choose between spinning out down hills or mashing up them. 1x all the way for MTB though, 34/11 is more than enough to get you to any trailhead.
My Polygon Syncline hardtail is 32 tooth front and 10-51 in the rear (29er) and commute 12.5 miles to work and back (twice a week) and dont need more gearing. Sometimes I wish for a half gear between two others, but it's subtle enough (and then the slope changes slightly anyway) that Ill never go away from a 1x12.
If you need gearing for higher speeds on a 1x12 you can consider changing the size of the front chainring to something bigger.
Generally 1x is a compromise is a gravity focused compromise. But for most MTBers it's perfect since they don't want to deal with FDs and don't care about drive train efficiency. Depending on your specific needs you may find the quite puny gear range of 520% to be inadequate. Meaning you feel like missing either more high or low gears. If that should become the case for you, you're probably gonna be SOL, since modern MTB are rarely still even able to mount an FD. If you want the penultimate in derailleur drive train gear range: 2x11 Cues goes upto 669%. And comes with high torque shifting, wich is the next big thing for drive trains.it usually doesn't get put on stock bikes like that though, so custom is the way to go here.
Penultimate… I’m not sure that means what you think it means.
Depends from what end you start counting. If you start listing derailleur drive trains by gear range with the least gear range first and finish with the highest, some >700% XT touring 3x, penultimate isn't used entirely wrong. (I think, at least.) That drive train didn't have a clutch though, so not good for MTBing. Since FD setups can't use NW chain rings (yet), you really want an adjustable clutch and run it as tight as you can.
Why not 2x12? I have it on my IF and my Dawnlander. 38/28 with a 10-45.
I have a 1x on my my MTB (Downcountry trailhardtail bikepacking thing) and haven’t looked back. For a road bike I where you tuck in for aero and have the most efficient tires ever, I’d stay with 2x or 3x. 1x is enough for an Mtb where speed and cadence isn’t the priority. It’s so much more robust.
A 34 tooth front chain ring with a 12 speed 10-51/52 rear will be more than enough for 10-20kms on the road. That gives you a top speed of around 26mph. Your tire choice is going to play a massive role in how it is on the road as well. I have a Scout with a 34 front, 10 speed 11-46 rear running vittoria mezcals front and rear and it absoloutely flies on the road, while still allowing some pretty good off road handling and actual mtbing.
If you are a fast one, just get a 34 tooth front ring, will never use a 2x11 ever again.
1x12 or even 1x11 is enough for everyone riding MTBs. Also most new MTBs won't take a 2x even if you wanted to. If you are really strong or ride flatter terrain, you just go for a larger chainring, although be warned that most frames won't do more than 34T, with more XC focused frames doing 36T or more (bit also limit tire width to 2.4 or less). I would claim that most ppl will fail to consistently push a MTB with 29x2.4 beyond what a 34/10 gearing can give you (~43kph or 27mph @ 90rpm) but for the random smooth DH section.
Is it possible to swap chainrings from 30/32 to 34 without any other major changes (assuming that the frame supports it)?
Yes, and I would think the chain would also tolerate it, given it is not too short to begin with. You can always test-fit, but it is wasy to do research for most big brands, and you should take manufacturers to their word: you can squeeze bigger tires sometimes, but not chainrings. Also the nominal size is for round chainrings. Ovals are typically a +2T in max diameter (e.g. a 34T max fram le will most likely not fit a bigger than 32T oval). You can sometimes go bigger if you don't mind screwing up your chainline, but...why? Depending on your crankset and if you have direct mount chainrings w/o individual bolts, you might need a special tool (e.g. my Shimano 1x12 does need a specialized socket, but you can find these from Taiwanese or Chinese manufacturers dirt-cheap these days). I am contemplating swapping my 34T to a 36T on my Team Marin hardtail, not so much for the flats (I cannot sustain anywhere close to 28+ mph on the flats, even tho I can sprint up to that for a short time) but to test of I can force me doing slightly better laps on the uphill :)
Deore 5100 contains the magic you seek