It seems that on the grounds of efficiency alone, one can’t possibly justify running a 1x drivetrain. This is specially critical for racing long events, which seems to be the gist of Gravel racing in the US. But even for non racers, efficiency is key in long rides.
Is this data wrong?. How can ppl leave some so many watts on the table? How are the informed ppl in this esteemed forum making this decision?
When was the last time you saw a gravel bike with a 53t chainring?
Well, drop your chain at key points during a couple or events and get it jammed up causing you to have to spend multiple minutes - sometime 10 minutes or more to get it unjammed and you will not care about efficiency. Ask me how I know.
Few off the top of my head…
I simply don’t care. It’s just easier altogether to deal with.
It’s the principle, from the data it follows that, for instance a 50-34 will still be more efficient.
Good point. But isn’t this mostly mitigated with the GRX drivetrain?
I can see the case. There are at least 3 bikes I’m considering that take 45mm and 2x. But the reason that I’m asking is why aren’t there more?
Shit, I don’t know - I’m running 105 on my Diverge 
Clearly your next gravel bike needs a triple chainring 
GRX and Sram Wide both have a claimed limit of 700x45. Can’t find the GRX link at the moment, but there’s this from Sram.
It seems more frames are allowing tires beyond 700x45 so they opt for 1x.
It says 42mm. That sounds about right
Yup…42mm for regular Rival/Force AXS and 45mm for wide with the 43/30 crankset.
1x 36t: 10-42 cassette haven’t met any reason for more gears. I live in Florida but travel to Maine, Arizona and the Carolina’s every year. Lots of steep stuff there….
Maybe I’d need more gearing in Colorado, don’t know but it’s less of headache and less maintenance using a 1x.
I can see high risk of spinning out at 36/10
The difference ranges from nothing to 6 watts in a gear you almost never use versus a gear a gravel bike doesn’t even have.
If you wanna worry about this let’s talk about people using wide ass handlebars and throwing away double digit amounts of watts?
Where I spend most of my time the frictional loss is only about 2.5w according to that graph.
Having had both GRX 2x and now sram 1x, riding my 100km loop, I’m faster on the 1x.~average 30km/h.
I race 2-3times/year, but have to clean my bike many many more, I can get the 1x cleaner much quicker. I will take 2.5w hit for that.
Also I really swapping in the mullet setup-when required.
If I was at the pointy end of winning a race regularly , I would take the 2x….but I’m not so 1x is better for me.
1x rival mechanical came on my bike. On my bike, lauf true grit, it’s a bit of a pain to switch unless I want to switch to electronic and then I’d lose some tire clearance in the back.
If I was fighting for podium and that was important to me I suppose I’d give it more thought.
2x looks bad and I don’t want to think about shifting two different deraileurs 
6 watts for 6h is a lot
Yeah. That conversation is starting.
Good point.
Yes that does happen, I should probably run a 40t+ but haven’t yet. I can spin a pretty high cadence from my bmx years, but yea I need to change that soon.
