Ignorant question: Why is a 2x10 considered better than, say, a 3x8 (or even a 3x7) in the first place? Is it weight? Aerodynamics? Ease of use? Herd mentality?
I run a 2x10 and I am very happy with it. Just curious.
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Is it weight?
Aerodynamics?
Ease of use?
Herd mentality?
Yes.
Ignorant question: Why is a 2x10 considered better than, say, a 3x8 (or even a 3x7) in the first place? Is it weight? Aerodynamics? Ease of use? Herd mentality?
I run a 2x10 and I am very happy with it. Just curious.
Mostly herd mentality. We wrote about it a while back (among other things) in this article:
http://www.slowtwitch.com/Tech/Optimized_to_Train_2806.html
Somewhat tongue-in-cheek, but there are some serious points in there. The biggest ‘plus’ is potential weight savings. The biggest downside is that you lose gear range. If you’re in a flat area, that’s no big deal… but if you’re riding in Leadville - different story. The 2x10 systems are not any easier to use and don’t inherently shift faster/better (in fact, the wider range cassettes shift slower). Oh, and I guess the other upside is potential for narrow q-factor (if you’re in to that sort of thing), but that option does not fit on every frame.
I personally did not / do not like the 2x10 systems. I found myself shifting the front rings a lot. A 32 or 33t middle ring on a triple is a very nice sweet spot for mixed terrain… I normally leave it there for 75% of riding and then dip in to the granny or big ring as needed. With the double, I was always kinda-sorta between rings and shifting around a lot.
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
I’ve never understood the argument against redundant gears. It gets mentioned a lot. In my opinion - redundant gears are good. It means you have a tighter spaced cassette and have to shift the front less.
IMO, I’d rather stay with 3x9 or 3x10 - OR go to a 1x11. I just think that front ring around 32-34ish teeth is key. That plus a 10-42 cassette would be a cool race set up on a course w/o too much super steep stuff (up OR down).
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Good.
But what about SHIFTING?
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
I’m just happy to hear that it simplifies shitting. I’ve grown weary of how complicated a process that can be on the bike.
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Good.
But what about SHIFTING?
There is no inherent shift quality difference in 2x vs 3x. Shift quality has to do with the quality and manufacture of the rings, chain, FD, cassette, etc. You can have a crappy or nice 2x setup… and a crappy or nice 3x setup. I find that most problems with either 2x or 3x go away when nice stuff is used and it’s installed/maintained properly.
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Good.
But what about SHIFTING?
There is no inherent shift quality difference in 2x vs 3x. Shift quality has to do with the quality and manufacture of the rings, chain, FD, cassette, etc. You can have a crappy or nice 2x setup… and a crappy or nice 3x setup. I find that most problems with either 2x or 3x go away when nice stuff is used and it’s installed/maintained properly.
I was just making fun of your typo 
Seriously, I do appreciate the feedback. Your reward for taking time out of your day? A smart@$$ reply from the OP. Such is life.
no typo, 2x makes everything in life easier.
should have also asked are we taking road or mtb?
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Good.
But what about SHIFTING?
There is no inherent shift quality difference in 2x vs 3x. Shift quality has to do with the quality and manufacture of the rings, chain, FD, cassette, etc. You can have a crappy or nice 2x setup… and a crappy or nice 3x setup. I find that most problems with either 2x or 3x go away when nice stuff is used and it’s installed/maintained properly.
I was just making fun of your typo
Seriously, I do appreciate the feedback. Your reward for taking time out of your day? A smart@$$ reply from the OP. Such is life.
Waka waka! Sorry, I missed that one.
no typo, 2x makes everything in life easier.
should have also asked are we taking road or mtb?
Tri, actually, but as that is all I have ever ridden competitively, (again, out of ignorance) I don’t know why it matters.
What were you thinking?
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Good.
But what about SHIFTING?
There is no inherent shift quality difference in 2x vs 3x. Shift quality has to do with the quality and manufacture of the rings, chain, FD, cassette, etc. You can have a crappy or nice 2x setup… and a crappy or nice 3x setup. I find that most problems with either 2x or 3x go away when nice stuff is used and it’s installed/maintained properly.
See I’m not so sure necessarily. I know shifting in and out of the inner ring on my mountain bike absolutely SUCKS, and I attribute that primarily to the fact that it’s a different BCD. Since I upgraded to SLX it’s a heck of a lot better than the Alivio crap I had, but my road, TT, and CX doubles are a lot smoother, and they range from Tiagra compact on CX, 105 compact on road, and Ultegra standard on my TT
shitting is simplified and ideally you wind up with fewer redundant gears.
2x10 also looks cooler than any 3x set-up.
Good.
But what about SHIFTING?
There is no inherent shift quality difference in 2x vs 3x. Shift quality has to do with the quality and manufacture of the rings, chain, FD, cassette, etc. You can have a crappy or nice 2x setup… and a crappy or nice 3x setup. I find that most problems with either 2x or 3x go away when nice stuff is used and it’s installed/maintained properly.
See I’m not so sure necessarily. I know shifting in and out of the inner ring on my mountain bike absolutely SUCKS, and I attribute that primarily to the fact that it’s a different BCD. Since I upgraded to SLX it’s a heck of a lot better than the Alivio crap I had, but my road, TT, and CX doubles are a lot smoother, and they range from Tiagra compact on CX, 105 compact on road, and Ultegra standard on my TT
There is a TON of stuff that can affect front shifting.
-Derailleur adjustment/placement
-Derailleur brand/model/material/stiffness
-Chain brand, model, wear
-Ring model, size, wear, stiffness
-Crank stiffness
-Frame braze-on mount stiffness, placement, etc
-Difference in ring size
-Frame alignment
-Whether or not the BB was prepped and chainline is correct
…to name a few. Trust me, going from a very low-end double system (or one that’s poorly adjusted, has mis-matched parts, etc) to a high end triple like XTR… well, let’s just say the triple will most definitely shift better. And vice versa with a nice double or crappy triple. You’d really have to control for every single of the above conditions to get a fair comparison. In my experience, most bad front shifting is due to 1) FD adjustment 2) Cheap machined rings 3) Chain brand, 4) Cheap FD. And more recently - 5) Really lightweight and/or misplaced braze-on mounts.
So here’s what I notice on my new 2x10: It’s seems harder to adjust the barrel adjust to make the chain chatter disappear across the range. Yeah, I know I should not expect the chain to be happy while on the big rings front and rear, but I do want it to be happy on the big front/small rear combo. I’m finding the front ring is not happy with the extreme angle to the small rear ring. I guess it’s what people want, but my old 2x9 was definitely quieter in all combinations.
This is a subject I’m pretty interested in as well…
For starters, an incremental change in gear size to your small gear makes a much bigger difference than the same incremental change to the larger gear.
To illustrate this, plug in some chainring and cassette cog sizes into Sheldon Brown’s gear-inch calculator.
53x12=8.9
53x15=7.1
50x15=6.7
50x11=9.2
39x11=7.2
You have to reduce your chainring size by 11 teeth to seem the same magnitude of a difference in gearing change as a swap from a 12t to a 15t cog. Chainrings are larger and heavier than cassette cogs, so it seems to stand to reason that if you wanted to vary the gear range on a bike you would simply modify the cassette while reducing the size of the chainrings. On the surface it seems we could simply reduce the size of the front AND rear gears, thereby reducing weight! Theoretically we could do away with the big ring entirely such that a bike would use only a 39t ring in the front. This should save a good bit of weight over the 50 or 53t standard crankset, right? The problem is that to achieve the high-end gear ratio that most people want (53x12, or 50x11–>~ gain ratio of ~9) with a 39t front chainring you would have to reduce the size of the rear cog to 8 or 9 teeth. 10 teeth is the functional limit on gear sizing due to the difference between the chain entry velocity and ride velocity around the cog–the magnitude of the difference between these two velocities asymptotically approaches a large undesirable number as the number of teeth approaches 10. At 11 teeth the magnitude of the difference is somewhere around 8% IIRC.
Furthermore, the difference between 8 and 9 teeth (in terms of output gearing size) would be the equivalent of shifting by two gears at the hard end of a normal 12-25 cassette, or 3 gears at the easy end of that 12-25 . In other words, you can’t simply reduce the cassette size until you achieve a certain range of gain ratios. So now we’re back to looking at chainring sizes. Swapping from a 53x12 to 50x11 makes tons of sense. For starters, you cut weight on both ends of your drivetrain. Secondly, you gain gear. Thirdly, you gain drivetrain stiffness by reducing the magnitude of front-end components.
Dr. Gearhead or How I Learned to Stop Worrying and Love the Compact.
I currently have a 3x10 (dura ace and FSA) on my road and a 2x10 compact (ultegra) on my tri bike.
The triple is harder to get adjusted properly even though it’s top of the line components. I don’t think the triple shifts as well, but that could just be me.
On the triple, I still seem to lose the big/big and small/small combos, and lose those the middle/small gear too.
With the wider range of cassettes (11-32), I’m looking to swap out the triple for a compact double. I’m ok with losing the big/big and small/small with it since I don’t get those anyway with the triple.
But I thought that with a smaller rear cog, drivetrain efficiency was lost.
Indeed. That phenomenon is due to the extent to which the chain bends to conform to the gear (angle and radius of curvature I think)–this would be bounded at an arc length of maybe 150 or 160 deg regardless of cog size, and the cog radius would be bounded by the free hub size
Wow. Thank you for that very informative response.
I have never heard of Sheldon Brown before. Looking forward to playing with it.