Power loss decreases as a percentage of total power with higher chain tension on the drive span, it doesn't actually reduce.
Any extra tension on the non drive span is lost power.
What it means is that drive losses due to chain tension will be lower with smaller chainrings and smaller rear cogs as there is more chain tension, but you loose more by wrapping the chain around smaller cogs so you get back less than you gain, hence bigger chainwheels and cogs running at lower tension are the best option.
You are also increasing losses with the quite severe cross angling of the chain in a 1X setup, why you would choose this for a TT bike I will never understand unless you are gear illiterate and cannot manage to work normal gears properly.

Do you have any data for the lower tension and bigger cogs.

Using a 1x setup is if great benefit to me, as it allows me to run a narrow Q

Anyway I want to know if anyone has actually tested it.
1-3w I can live with. 3+ not so much

Not yet. But Jason Smith has indicated he intends to. I'd be shocked if it was 3w+ based on my own experience on it.

I'm working with Jason on a piece on the frictional losses. it's not nearly as bad as what you might think, for some (perhaps) surprising reasons. Based on the data that I have from Jason, the losses are not significantly different from a standard 2X set up, though there are some counterintuitive things to do to ensure this. Running a BIGGER front chainring is a part of this. I.e., people who want to run a 10T with a smaller front chainring are actually going in the wrong direction from a frictional losses perspective.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

define significantly. some folks go to great length for 0.5w and if you give it up going 1x, the aero better make up for it

Thanks Jordan, I think you're right about less than 3w.
I've been running a 54 and setting up with a nice chainline to the 21/25/28

That may be if you just take the inside chainring off. However, if you set it up correctly with the single chainring in dead-center, you will have a better chainline in the cogs you use most (say 13,14,15) than you would with a 2X setup.

The potential q-factor difference is significant -- 2cm or more. People get all worked about a tiny 1mm protrusion from a brake or a tire. Your legs are two big cylinders of air-churning meat. I would not dismiss the possible benefits of bringing them in 2cm closer.

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My latest book: "Out of the Melting Pot, Into the Fire" is on sale on Amazon and at other online and local booksellers

2.5cm for me, and a shed load of watts!

Excuse my ignorance, but how does a 1x allow you to narrow your q-factor by 2.5cm?

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Because I can now use old style super narrow track cranks, this wouldn't be possible on most modern carbon frames due to clearance issues

Ah, gotcha. Do you have any examples of cranks like this? I'm tempted to explore this.

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Old dura ace, but you need a threaded bb as it runs square taper

No problem with the square taper, but aren't track cranksets normally 144bcd? Are there NW rings in this for 144? I can't recall seeing any.

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Custom ring from fibrelyte U.K.

Ballparking the figures, it's a wash in low gearing - because you must run a larger rear cog to get an equivalent which reduces friction by enough to offset the less optimal chainline. At higher gear, because of a very slightly worse chainline, it peaks out at about 0.5w, though it's dependent on what front ring you use. If you basically stick with the same size front ring - say 52 or 54 with a wider range cassette in the back - as opposed to going to a more compact, that minimizes the losses to less than 1w.

These calculations are strictly a function of chainline, and do not include whatever additional losses *MAY* be incurred by a clutch RD. Though worth noting that clutch RDs come standard with 12T - as opposed to 11T - jockey wheels, which could help offset losses by virtue of the pulleys being larger. Right now, this is still a question mark.

The XSync narrow-wide chainrings do not appear to add any measurable friction to the system.

The aero savings are heavily dependent on the bike, but it can be a significant multiple of that (can be 5w+) based on various tests.

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"Non est ad astra mollis e terris via." - Seneca | rappstar.com | FB - Rappstar Racing | IG - @jordanrapp

On the MTB side, this is the draw to an Eagle drivetrain. When you have a 50T bailout gear, most can move to a bigger front ring.

TriByran wrote:

Custom ring from fibrelyte U.K.

Really cool, but not strictly necessary. There are several companies that make 144BCD rings in road pitch (3/32).

http://www.velodromeshop.net/track-chainrings/ta-specialites-3/32-track-chainrings/
https://www.amazon.com/Shimano-DuraAce-Track-chainring-144BCD/dp/B003UWDD6S
https://www.universalcycles.com/shopping/product_details.php?id=52000


Here's my 150mm Campy with a 3/32 ring:




Campy Track BBs are dirt cheap now. ~$60. I will be selling either this crankset or a 165 in a month, when I decide which length to go with. The 165 is cheap (maybe ~190). The one above is so rare, it's probably around $600.

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My latest book: "Out of the Melting Pot, Into the Fire" is on sale on Amazon and at other online and local booksellers

Nice, you geeked out on that setup! Thanks for the info.

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You have no idea!!!

Love to geek out!