1x vs 2x?

[Carlton green]

IMHO 1x mainly suits bike makers, novice riders, commuters, and a subset of MTB riders. For nearly everything else, 2x is better.

Yes, I’d have thought that a pretty succinct assessment and 2 x is what’s fitted to my ‘touring’ bike. Having said that when I was a young man I did many day rides, and at least one B&B tour, on a 1 x; and many decades back (say 1950’s and 60’s) it was common for folk to get by on one chainwheel.

[biker38109]

Go Outdoors have a big sale on at the moment:

https://www.gooutdoors.co.uk/16245347/c ... 9-16245347

That's pretty fantastic - £400 for a bike that retails at £700!
2x9 drivetrain, low gear of about 16.5"

Certainly, I did suddenly think though that I plan to move in the next few weeks, if all goes well, so best to wait until after to purchase anything so may well miss the sale. Plan to keep researching in the meantime.

2x gives a wider range which, for many people, is preferable. Think of it as effectively adding 48, 54 and 62
teeth cogs to the 11 - 42 cassette.

By careful selection, you can get ranges using 1x that equal or exceed what many 2x deliver, just that they usually come with fewer steps in between.

I think I have misunderstood what range means then. I was thinking it means the bigger the range = the more gears, but it seems it rather means what it sounds like (!) the range from high to low and doesn't depend on how many are in between.

By careful selection what kind of chainring would be considered to give a wide range, one in the middle? Not too big and not too small? Then again, it isn't so much overall range as I have mentioned quite a bit, rather really low low gear, and just hard enough on high gear to not 'spin out' too easily on flats.

As a curiosity, would having a tiny, 22 on the front and say this on the back still be usable when in 11 on the back or would it 'spin out' terribly on the flat?

Going back to appealing aesthetics, discussed in other thread, I do like the brash and 'muscly' looking single chainring and dinnerplate setup.

So achieving what a 2x with a 1x would be a fancy.

[Nearholmer]

However, I would note that whatever you do with your 1x, you can turn it into a 2x and have twice as many gears, more range, or w.h.y

Surely at some point, though, you must hit a limit based on feasible derailleur length, so if the 1x you start with has a dinner-plate, the difference between chain-ring sizes has to be so small that there is not much point in having two (unless I suppose you are total cadence obsessive).

What is the practical limit on total difference in chain length that can be “eaten” by a derailleur before, on say a 700c, it starts to be in real peril of hitting the ground (long ones already snag oodles of vegetation off-road)?

[rareposter]

I think I have misunderstood what range means then. I was thinking it means the bigger the range = the more gears, but it seems it rather means what it sounds like (!) the range from high to low and doesn't depend on how many are in between.

Correct. Range is just the difference between the highest and lowest gear. It doesn't have to be huge, it just needs to be suitable for the use.

So the range of gears on a kids bike might only be about 40" between the highest and lowest gears cos the basic use of the bike tends to be flattish terrain, unladen, novice child on board.
The required range on a road bike will be much wider, it needs to be capable of being ridden up and down potentially quite big/steep hills at a reasonable speed.

On a mountain bike, you will need a range that's much more biased towards low end speed (so much lower gears than on a road bike) cos the bike is being ridden more slower and on (potentially) much more extreme terrain.

How MANY gears you have is set by the number of cogs on the back and the number of chainrings on the front.
1 x 11 = 11 gears
2 x 9 = 18 gears (however some in the middle will be duplicate ratios, there's actually only about 12-13 distinct individual gears). Similar to how you can calculate the number 20 by 4x 5 or 2x 10 - two different ways of arriving at the same answer. Gear ratios are a lot like that.

You can - by selection of the chainring(s) and cassette sizes - easily have the same (or larger) range on a 1x as on a 2x so in practice it often makes very little difference. My new MTB (1 x 12) has an almost identical gear range to my old 3 x 10 MTB. A fractionally lower low gear and it's missing a few gear inches off the high end which doesn't matter cos the only time you'd use such a gear is fast on-road descent. So I've got the near enough the same usable range on a 1x as I had on a 3x.

Ultimately, so long as the lowest gear is low enough and the highest gear high enough, it really doesn't matter much how you arrive at it. 1x is easier to use (only the one shifter) but 2x gives a few more gears. It's very much horses for courses. You'll find some people love 1x for the simplicity, some people think it's the work of the devil.

[biker38109]

However, I would note that whatever you do with your 1x, you can turn it into a 2x and have twice as many gears, more range, or w.h.y

Surely at some point, though, you must hit a limit based on feasible derailleur length, so if the 1x you start with has a dinner-plate, the difference between chain-ring sizes has to be so small that there is not much point in having two (unless I suppose you are total cadence obsessive).

What is the practical limit on total difference in chain length that can be “eaten” by a derailleur before, on say a 700c, it starts to be in real peril of hitting the ground (long ones already snag oodles of vegetation off-road)?

Wait are you saying that if you have a dinner plate on the back the chainring size on the front becomes negligible? How so? Since my whole biking experience smaller on front always leads to lower gearing.

[Nearholmer]

what kind of chainring would be considered to give a wide range

If we are talking about 1x, then it’s the cassette at the back, not the chainring, which gives the range.

So, taking the 10-51 (iirc) Deore cassette on my son’s bike, that has a 510% range, you can put various sizes of chainring at the front, and that will alter the available ratios, but not the range of available ratios.

Continuing with that bike as an instance, it currently has a 30T chainring, so lowest gear of 30/51x29 = 17”, and a top gear of 39/10x29 = 87”. That makes it good for climbing steep, very bumpy stuff, but pretty slow on long, easy sections, which is very typical of off-the-shelf MTBs. He uses mostly as a utility runabout, always in top gear! Annoyingly, again typical of MTBs, because of the way the chain-stays bulge out to accommodate fat tyres, there is next to no space to fit a bigger chainring, it might squeeze 34T I think.

So, you may find that if you absolutely have to have gnarly-looking MTB, you will get caught in this low top-gear trap too, many people are.

[Nearholmer]

Wait are you saying that if you have a dinner plate on the back the chainring size on the front becomes negligible? How so? Since my whole biking experience smaller on front always leads to lower gearing.

No, I’m not saying that, I’m posing a technical question about a limiting condition for Brucey.

[Brucey]

IME no further increases in derailleur size are required; a lot of extant RD designs have sufficient total capacity, but lack largest sprocket capacity. However, if all new, all shimano 11s parts are used, a hanger extender will work just fine, and of course allows larger sprockets to be employed.

[Nearholmer]

^^^

Yes, that last bit I will soon capitalise on, because when the present one wears out, I’m going up from 36 to 42 on the cassette on my main bike.

[pq]

I have 1x on my gravel bike. That's because it's easier to get exactly the gears I want by swapping the chainring (2x is usually much less versatile in that respect), because I don't need high gears off road, and in any case a 68 top is fine for the little bit of road riding I do on it. The chain is more likely to stay on which is nice off road. In fact I've never dropped a chain on this bike. Not bothered about the marginally simpler set-up and modern transmissions run better out of line, so chainline issues aren't that important.

On road, apart from my fixed, all my bikes have 2 or 3x. That's because I use a wider range of gears on road and smaller gaps between them are more important. Chain security is less of an issue too. I can't imagine a situation in which I'd use 1x on road - possibly on a commuter of there were no major changes in speed needed, but in that case I'd be more likely to ride a fixed. If I was buying a modern bike for road duties I'd go for 2x because cassettes now have such a wide range I don't seen the point of the 3rd chainring. Having said that my fast tourer/audax bike has 3x10 which is nice.

So to summarise, off road, 1x can be really good. On road it seems pointless to me.

[Carlton green]

So to summarise, off road, 1x can be really good. On road it seems pointless to me.

If that works for you then all’s good. Will it suit everyone? I doubt it and that’s fine too, well I think so.

My daily ride - on road and off road - uses an SA AW, so just three gears, and I’m very happy with it. For some years my daily ride used a single chainwheel and wide ratio block; I loved its simplicity and ease of care, and I didn’t mind the slight loss of performance over a multi chainwheel arrangement. We’re all different so it should be no surprise that different solutions are adopted and adapted by us .

[Cugel]

The advantage of 2X - it gives you two ranges of (overlapping) gear ratios from the cassette: one for slower terrain and one for faster terrain. 3X is even better for that.

The disadvantage of 1X - the gear ratio jumps are much too great for various kinds of changing terrain, especially on longer stretches of roads but also tracks, where slight changes in incline require slight changes of ratio.

[ed.lazda]

The most sensible way is to divide chainring teeth by sprocket teeth, then multiply by wheel radius divided by crank radius, that way you get a proper dimensionless gear ratio that includes all the relevant variables.

...

Except that it doesn't tell you all you need to know because it excludes the crank length.

(Cue a re-run of the never-ending thread full of people who can't understand why crank length is part of the gear ratio.)

That hadn't occurred to me up until now. I consider myself educated.

[Nearholmer]

I do find it mildly perplexing that the same community which lauds Rohloff, a 1x system with 14 (I think) quite large steps is very sceptical about derailleur 1x systems, overlooking the fact that they now get very close indeed to doing the same thing (in 12 or 13 steps) at lower initial cost (maintenance is another thing altogether!). I do wonder whether the mindset is fixed in the days of far fewer cogs being available across the back (admitting that doing it that way is cheaper at the moment).

[Brucey]

..... modern transmissions run better out of line, so chainline issues aren't that important....

modern, skinny chains do indeed 'run better' when misaligned but the apparently casual assumption that as a consequence we shouldn't worry too much about chainlne is probably not correct. Bad chainlines are usually on a par with chordal losses as a major source of transmission inefficiency, even if there are no obvious signs of complaint from the chain.