0

I have found from experience on my 3x7 MTB that shifting a triple front chainring is useful if you do the following: I tend to use only the first 3 cogs in the smallest chainring so that is 3 very low gears for hills, grass, or just low speed stuff. I can use all 7 cogs in the middle chainring but tend to avoid the largest cog so that is 6 more gears. Then for downhill or just for slow cadence, I can use the 2 smallest cogs on the large chainring so that is 2 more gears. So that is 3+6+2 = 11 usable gears. What is particularly nice about this is the shift sequence (using S,M,L for chainring with S being small (granny), M being middle, and L being largest, and using 1 thru 7 for cogs with 1 being largest diameter cog and 7 being smallest) is (S1, S2, S3, M2, M3, M4, M5, M6, M7, L6, L7), is that there is never a shift to a gear more than 1 cog or chainring away. Going from S3 to M2 for example and also from M7 to L6. So this is basically a poor mans 11 speed bike but it works and fairly well too (from actual riding experience).

So my question is why do people tend to favor a 1x11 as superior to a 3x7 where only 11 of those are used as a described here? Is it because the 1x11 shifts better and with less complexity? How about the joy of doing successful double gear shift simultaneously that is fun. Also with the triple you can get very tall and very short gears without having to resort to very large and very small cogs, both of which cause some problems. Also shifting the 3x7 as I described here should have better chain alignment on average (assuming it has chainrings aligned with cogs 2,4 and 6 and the 1x11 has the single chainring aligned with cog 6).

Some answers here talk about ground clearance. My largest chainring on my triple is 42 which is less teeth than the larger chainring on some doubles.

Also to make my triple chainring shift sequence even easier, the rider can shift only 9 gears this order (L1, L2, L3, M3, M4, M5, M6, M7, H7). A biker can select front chainring sizes such that the shift from L3 to M3 and the shift from M7 to H7 is moderate (10% for example, such as 40 to 44 teeth). If I had an 8 speed freewheel I could get 10 progressive gears which would be good.

  • Primary opinion based? – Hellreaver Jan 25 '16 at 18:47
  • 2
    The 3x7 arrangement gives you more options, especially when you must shift quickly. On a reasonably modern bike all 21 speeds are usable, even if one does tend to "prefer" combos such as you describe. And, on my bike, I will often, to slightly adjust gear ratio, shift up on the ring and down on the cluster or vice-versa, to reach ratios that are not available by just shifting the rear. But the 1x11 does have the advantage of simplicity, if that's your goal. – Daniel R Hicks Jan 25 '16 at 22:24
  • On my triples, I tend to ride in the front ring that suits the terrain. For uphills that is in middle or little, and I might just cross-chain at the back if there's only a slight downhill followed by more uphill. So its similar on a short grade - I might power up it in big/big and accept the mechanical loss. – Criggie May 26 '18 at 2:57
8
  1. Less complexity (less things to go wrong and set-up.)
  2. No chance of shifting front and back gears simultaneously leading to loss of chain tension and resulting in chain drop.
  3. Less weight.
  4. Optional chain guides.
  5. More clearance (in most practical applications)

Furthermore:

3x7 is very old. 1x11 is pretty new. Materials and technologies have evolved significantly since 3x7. Naturally this is not an inherent advantage in the idea of 1x11 but an advantage of real world 1x11 over real world 3x7.

However:

1x11 has worse chain line than a correctly used 2x? or 3x?.

You should generally avoid doing simultaneous gear shifts. Most people who think they are often doing simultaneous shifts really shift the rear, then shift the front a very short time afterwards (or vice versa, though rear then front is far safer).

Performing genuinely simultaneous shifts, especially on real MTB terrain, is asking for serious damage to yourself and your bike.

Finally:

The actual choice is largely personal but is influenced by terrain and riding style.

I for example love 1x11 but it is totally impractical for my local area + style:

15degree-20degree climbs and some even steeper descents. Some descents don't really give you much opportunity to pedal, but others do and the 1x11 can't provide a high enough gear. Likewise some climbs are not particularly technical but very steep and I prefer to leisurely spin up them at 110rpm which is simply not going to happen with 1x11 without making the higher gears even more unacceptably low.

EDIT UPDATE: Based on personal experience/partly subjective since going 1x11, you don't ride where I do, how I do, or in the weather I do, so your results will almost certainly vary:

  • With a clutch RD and Narrow Wide chain ring: No chain drop in 3.5k+ km.
  • Less to do when shifting. Not a big deal, but it's nice.
  • Better positioning for my dropper trigger.
  • Can't maintain just the right cadence so easily. This is worth it for me, but can be irritating if I am riding something not very technical. However I've taken to forcing myself to push the harder gear (initially I would drop to the easier gear and border on spinning out), so one can also "look at the positive side" of this feature... but it's certainly a negative.
  • The shifting does actually feel allround better than my old XT 3x10 (with SLX shifters)
  • Surprisingly I am getting more life out of my first chain. (Note: I am rarely in the easiest 2 gears, where the chain line is pretty bad.)
  • I am getting noticeably more wear on my hardest 3 gears, but everything is still running perfectly.
  • More noise in the easiest 2 gears.
  • Less noise everywhere else. (Even without considering the lack of chain slap due to clutch RD)

END EDIT.

  • 1
    Update: I'm 1x11 after all. This is partly to do with 11-46 cassettes becoming common and affordable (also 11-50 sunrace is out and apparently works with GS cages with B screw near max, though not officially.) I've just accepted my lack of upper range (and about half a gear loss of lower range). It is actually improving my overall riding, since beyond a certain speed, my only option is to focus on line choice and pumping more. – Purr Dec 20 '17 at 13:28
  • 1
    Next time you need to change cassette, evaluate the costs of just changing the smallest three cogs. Assuming you stay on top of your chain changes, this could be more economical. – Criggie May 26 '18 at 3:00
  • 1
    I already considered the economy of it, it's about 1/5th to 1/6th of the cost of the 11-50: I sold the 11-46 XT cassette when it was almost brand new, and bought the SunRace MX80 11-50 and the SGS cage plates for the XT RD. I asked about SunRace MX80 compatibility with XT 3 smallest cogs (after selling the 11-46 already haha) and I'll be updating that question/post with the actual real life results of using XT smallest cogs with that cassette when the time comes (hopefully that won't be this year). – Purr May 27 '18 at 4:50
3

This actually describes basically exactly the way my bike is set up. I have 52x42x30 chainrings with a 12-23 cassette. The 30x23 is plenty easy for the hills that I tackle, and the 52x12 is such a hard gear that I rarely ever need to use it. And the spaces between cogs are only 1 or 2 teeth, making the steps between the gears quite small. The reason that most people choose to use double or single chainrings as opposed to triples is exact as you allude to in the question. It's much easier to keep everything in tune. With a single chainring you have no front shifting at all. With a double setup, you have to only adjust the derailleur limit screws to get things set up properly. Getting things set up properly on a triple can be a bit more tricky. I basically have the same range and spacing as many road bikes with an 11 speed cassette.

2

One important advantage of 1x11 gearing is the improved clearance of the front chainring. In technical riding, the largest cog would strike stones as you are riding over them. This happened to me all the time until I removed it (I have 2x10 now).

Another advantage is reduced weight and mechanical complexity - if you have just one front cog, you don't need a front derailleur, and the corresponding shifting mechanism and its cable are not needed.

  • Why don't they have some type of FD shifter that prevents it from going from the smallest to largest chainring (all at once) in a front triple setup? That way you could just twist hard to change the front chainring to the next size and concentrate more on the cog change to get the progressive gear you want. For example, on my cheap Walmart MTB, the middle chainring setting is not even marked (but I can easily mark it with whiteout or similar). I ride mostly on the street and a little on the grass so having a 42T large chainring is not an issue with me. I don't use it as often as the middle. – David Feb 6 '16 at 18:29

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.