1x11 for road? Ultimate WW wet dream?

[Tenlegs]

One chainring. Huge sprockets. Disc brakes. SRAM seem to really enjoy making road bikes look like sh1te.

^Mountain bikes with drop bars

[btompkins0112]

One chainring. Huge sprockets. Disc brakes. SRAM seem to really enjoy making road bikes look like sh1te.

Amen.....complete nonsense imho.

[mattjevans]

One chainring. Huge sprockets. Disc brakes. SRAM seem to really enjoy making road bikes look like sh1te.

^Mountain bikes with drop bars

After all, it would be dreadful if cycling was fun

[kgt]

IMHO sram's 1x11 tries to solve an issue that does not exist. I guess there is a percentage of the market that will support it though.

[Tenlegs]

Great fun for the weekend/leisure/hybrid market, not Weightweenie or performance though is it?
Cross chaining was and is a bad thing - increased wear,friction and noise even when cassettes were narrower than 9/10/11 speed,
now SRAM are positively encouraging it

[mattjevans]

Point is there is no more cross chaining with a properly set up 1x11 than in a 2x setup - centred chainring means 5-6 cogs is max cross-chain

[LeDuke]

Point is there is no more cross chaining with a properly set up 1x11 than in a 2x setup - centred chainring means 5-6 cogs is max cross-chain

You know, it's like people forget that XX1/XO1/X1 and XTR 1x11 even exist.

And that they drastically outperform anything (2x or 3x) to come before them. I get better chain life out of XX1 than I did with XX, and XT before that.

[djconnel]

This seems an almost religious topic. Lots of "it won't work for all of MY rides because I like climbing xx% grades at high rpm and therefore it's junk" comments. But nothing works for everyone, and the guy I talked to who uses it loves it, and he's been racing since the 1980's. And it DOES save weight -- just not much with that boat anchor rear derailleur.

The cross-chain thing is an issue because the biggest gears will have more of it than they would in a 2x11, and the smallest gears will have more of it than they would in a 2x11. Additionally you'll be in a smaller cog on the big gears and that increases drivetrain loss. But we're talking on order 0.25 watts or so.

[mattjevans]

But there will be less cross chaining compared to a 2x setup in the middle 4-5 cogs

[djconnel]

Yes, but if you shift perfectly to avoid cross-chaining, which likely involves a lot of front shifts, then you can do better with 2x than 1x. My guess is most of us don't to this anyway. It would be interesting to take data recorded in a FIT file from Di2 and determine what the average cross-chaining was fo a typical rider.

Something like this:

[djconnel]

Chainring spacing is 9 mm on SRAM 10-speed crank (according to my rough measurement) while cog spacing is 3.74 mm on 11-speed SRAM/Shimano cogs (from what I've read). So the chainrings are at positions 4.8 and 7.2 with cogs at positions 1-11.

So I took DCRainmaker's gear choices and calculated an average lateral chain deflection of 2.6 cog positions. It turns out all his gears would have fit nicely with a 44 tooth chainring and the same 11-25 cassette. So I calculated which cog would have been the closest match for each gear with the 44 tooth cassette. Then I calculated an average cross-chaining of only 1.4 cogs. This is because he spent the vast majority of his time in gears which can be covered by the middle 5 cogs (14-15-16-17-18).

So in this example you're correct: less cross-chaining overall with the 1x front. But it's just one example.

[bm0p700f]

The thing is 1x11 for road bikes could be done now without buying a new groupset. Light weight square taper cranks and bb's exist so you can get the perfect chainline. Then gut the left hand shifter of the gear gubbins and job done. Hardly anyone does it so i am not convinced it will be a big seller as roadies are more resistant to new ideas than mtb riders.

[eliflap-scalpel]

i am riding a 9-38 cassette with ten speeds.

44T oval ring narrow wide teeth at front.

today's ride https://www.strava.com/activities/292990999

[djconnel]

Traditional problem with 1x systems has been chain tossing. It's even discussed in Eddy B's book from the late 1980's. It's the wide-narrow system which supposedly addresses this. But additionally the clutch derailleur is supposed to help. Although at least one guy here posted his hack to a Red derailleur to get it to handle wider range. So maybe the clutch isn't so important. That would be good because it's a brick.

[mattjevans]

Looking at it another way - there are 14-15 distinct gears in a 2x11 system, 8-9 of which will involve cross chaining >3 cogs (all of the middle gears)

In a 1x system, 5-6 out of 11 gears will require cross-chaining >3 cogs (the extreme high and extreme low gears)

So overall drivetrain friction efficiency will depend on gears used in any given scenario. I don't think it's at all clear cut one way or another