They updated their whole line recently. Don't expect anything like that anytime soon.

I really don't understand the obsession with a 10t cog. Especially for triathlon where people obsess over individual Watts, because little rings are a drivetrain efficiency nightmare!
Using a 10t cog will cost you as much as moving from a great front wheel to fairly average one.

I'd rather get the extra overall range from bigger chainrings and putting that extra cassette ring at the other end.
In a TT, if I'm using anything smaller than 13t for more than very short periods, then I conclude that I used a chainring that wasn't big enough.

Excitement around the introduction of 12 speed, I understand (although I'm not particularly fussed personally). It'll be a big boost to the 1x crowd, and I certainly wouldn't turn down a little extra tightness at the upper end of my 11-28 cassette if it was offered.

Where have you seen how many watts it costs? And it costs as much as switching wheels compared to what baseline? An 11t? If an 11t is fine, I just don't expect the 10t to be that much worse. Seems like an arbitrary line that people draw because they are used to seeing 11t.

And as you mentioned, top gear isn't something you spend much time in anyway and the additional drive train losses are unlikely to be noticeable at those high speeds when you are pushing a lot of air.

Edit: also, I'm not seeing an obsession with 10t, but rather having a 12th gear. I would personally prefer 11-34 with most of them closely spaced and the last two for bailout.

Re: data - Very little explicitly on 10t, but lots of data out there showing that smaller rings cause more drivetrain friction. For example:
https://ride.diamondback.com/friction-profiles-1x-drivetrains
Look at the increase in friction on a 53-13 vs 53-12 vs 53-11. That line can fairly easily be extrapolated to a 53-10.
My comments re: it being comparable to different quality wheels is based around Watt differences I've seen in charts such as contained in the above.

Re: 11t being an arbitrary line of what's ok - That's not the case and I stated as much in my first comment.
I tend to aim to not really use the 12t or 11t currently. Optimum chainline & efficiency will be on the 15t or similar.

Thanks for the link. Based on that, the difference between 53-11 and 53-13 is 1W. The difference between 53-11 and 53-15 (largest difference) is about 1.7W. That combines articulation and deflection losses.

I think my wheels are worth more than 1.7W. Also, the linear friction increase going from 53-11 to 53-14 would suggest that 53-10 will only add another 0.5-0.7W, which I (or anyone else) wouldn't notice when I'm flying down hill for a few minutes in top gear.

Unless I'm missing something, you're worried about just ~1W here which isn't the case for me. That article makes me feel better about 10t, though I'd still rather just get a bigger cog on the other end of the cassette so I don't have to change freehubs.

There's a reason the pros are putting dinner plates on their cranksets and riding in the 15t-14t-13t in the back. There has been a lot of talk about the increased efficiency of using the larger rear cogs and keeping the chain in-line. A 10t sounds ridiculous, and even with a compact 50t chainring, 90rpm gets you near 35mph. There are so many absurdities buried in only pedaling 90rpm at 35mph they should speak for themselves. No one, not Fabian Cancellara, needs a 10t on the flats, ever.

Take it to extreme.. why not an 8t? 7t? When you want to get the lug nuts off your car wheel to change a flat, try doing it with a wrist-sized pocket wrench.

The main point isn't necessarily that the inefficiency is huge. It's that it's totally pointless and avoidable.
2W is the same type of difference between going from an 80mm front wheel to a 60mm of the same brand. People obsess over these choices all the time.

I'll say it slowly: "If you need more top end speed, go bigger at the front."
There's a reason you see all the switched on pro triathletes on 54-56 chainrings even on flat courses, and it's not because they're pedalling along at 40mph

Don't have any idea on release, but two blokes around here have them. That is all I know. They didn't answer any questions about it. There have been two iterations floating around for 6 months or so.

Of course there is a place for 8-9-10t cogs. You are thinking of this with a 53, 54, 55 front chainring. Instead, these are intended to allow a 46-47-48 front ring instead. That limits the need for 36-38-40t rear cogs when you go toward 1x.

Smaller gears will be more aero front and rear, and lighter.

I hope you're in my age group

Saying it slowly doesn't make it true. Pros ride 20% faster than I do but a 56 chain ring is only 8% bigger than my 52. So they aren't riding big chainrings for their speeds. They're riding in smaller in the rear than I do. I'm in the 16t at my average speed. A pro doing 26 mph with a 56 chain ring at 85-90 rpm would be in the 14-15t.

And as I said, I agree and would also rather go big up front and bigger in the rear but for practical reasons.


This is funny because the article you linked agrees with him. The aero benefit of eliminating the FD is larger than the small "pointless" inefficiency of a smaller cog/chain ring combination.

I’m not worried. I see but a few bikes at most when I make it to transition

Slow swimmer, huh?

(Sorry, I had to)

---

I talk a lot - Give it a listen: http://www.fasttalklabs.com/category/fast-talk
I also give Training Advice via http://www.ForeverEndurance.com

The above poster has eschewed traditional employment and is currently undertaking the ill-conceived task of launching his own hardgoods company. Statements are not made on behalf of nor reflective of anything in any manner... unless they're good, then they count.
http://www.AGNCYINNOVATION.com

To answer the original question . . . 12s Di2 coming soon? Probably coming, but Shimano has tended to take its time responding to SRAM products. I would say it's very likely Shimano will have 12s within 3 to 5 years. It's not as if this is a world-shattering technology without which Shimano will lose a lot of market share. There are other products for which people are clamoring -- 12s isn't one of them.

My bigger hope is that Shimano 1x road cranks and sub-compact cranks will be coming very soon. These products have been available from Shimano's competitors for some time and they have resulted in some Frankenstein'd drivetrains for up to four years. It's past time that Shimano address crankset options for road and gravel. There is proven demand. People are employing work-arounds to get what they want. Shimano has been losing sales in this market. C'mon, Shimano. You've made the best 2x cranks for several generations. Now branch out with the market!

I agree with this