N = 1, I wouldn't do it. Even living in the midwest, there are enough hilly rides and races that I do which require multiple chainrings. So far this year, I have done rides/races and used every bit of 53/38 and 11-28, and I'm doing a ride next weekend that will be best with 52/36 and 11-32. I don't want the huge gear jumps of an 11-36 or super-wide 10-42 (or whatever the new SRAM 1x11 MTB stuff is) for road. If I was a big CX racer, I would think about doing it, mostly because the overall speed range on a CX course tends to be much narrower than road riding, and FDs can get mucked up with mud. And it's one less cable to replace.

Clearly 1x systems will work for some folks in road applications (such as folks racing/training exclusively in Texas or Florida, and are on the fitter end of the spectrum), but I don't see it being an overall 'plus' for the lion's share of the market, given all of the considerations/factors involved. Even with two-chainring systems, a lot of people complain about missing a 16t cog (or whatever their cog of choice is) - taking away rings in favor of larger cassettes only makes the problem worse.

LOL NO worries, I know what the data says and I know what I rode. I missed the podium by a minute and analyzed the crap out of that race :) And there are no hills in Knoxville that require you to go below 60RPM :)

I think there are some courses (Welland for one) where a single chainring 46t with 11x32 would suffice but dropping 3-4 teeth per shift is far too much for me on a hilly course.

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Rodney
TrainingPeaks | Altra Running | RAD Roller
http://www.goinglong.ca

That is what I'm using, a 55T, and I'd quite like to increase to 58T. How many teeth does yours have? I suspect the problem of dropping the chain increases significantly with each extra tooth.

I've done Welland. It's the 'Florida of the north' kind of flat course. I don't think I ever 'had' to get out of my aerobars, let alone shift down from my 50T chainring. It would be a good course for a single chainring set up. ... Speaking of that (and to get this back on topic), I just finished a winter 'project bike' and currently have it set up with a single ring up front. The bike is fun to ride! As it relates to Welland: My buddy took one look and said, "Can I use this at Welland?!" (he's doing the bike portion of a relay).

It's a 90's beam bike that was made in Germany. I originally built it up without a FD, but the chain skipped off in my first ride and I realized that I had to come up with some kind of a chain guide solution. So, I have it set up with a DA 7900 front derailleur as a chain guide. I chose this FD because it's designed to be wide enough that you don't have to do any trim adjustment (that... and I already had one). Of course, I can always add front shifting back on if need be.







(re 11-32 cassette)
Keep in mind that just because you've got an 11-32 cassette doesn't mean that you're dropping 3-4 teeth per shift. It's mostly 2 teeth between shifts, except at the easy end. Having said that, I tend to prefer a 50T chainring as it keeps me in the lower end (11-17t) of my cassette with only 1 tooth between shifts. Heck, on a flat TT out here, I just use a straight-block 12-23 and never run out of gears.

Yeah I pre-rode Welland last week and rode aero 99% of the time (outside of some corners and to stretch on "the downhill") and might have used 3-4 different gears :) I bet you could ride a good bike split on a properly geared single speed!

I do like the build you posted, I always love seeing beam bikes. Now that is something that should catch on more!

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Rodney
TrainingPeaks | Altra Running | RAD Roller
http://www.goinglong.ca

Very odd - normal 10 speed chain and cassette? It's just that you're the first person I've come across who has been able to use one without anything to keep the chain on and hasn't had it come off occasionally, so I'd like to know what is different about your setup.

I completely understand your perspective. There defintiely is a compromise going to a 46T Chainring and wide ratio 11/36 Cassette, but for me in an area with super hilly terrain that requires constant shifting loosing the front derailluer and the big cadence swing from 50T to 34T on a compact double is worth it.

For perspective I did some math last night for a 700c Wheel:

52/11 gearing @ 110 cadence = 40.40 mph (so you are really hauling ass!)
52/11 gearing @ 100 cadence = 36.73 mph
46/11 gearing @ 110 cadence = 35.72 mph (I don't spend much time pedaling faster than this)
46/11 gearing @ 100 cadence = 32.48 mph

For the Terrain around Bloomington, IN I'm typically either going sub 20mph uphill (sometimes as low as 4mph - Boltinghouse Hill is killer!) or coasting 40mph+ downhill (50mph down Boltinghouse for example) so the perfect shifting with wider gaps works well.
I'll be using Single Chainring in Ironman Muncie 70.3 in July (I've done this race 17 times) so we'll see how it goes - that course is gentle rollers so tighter spacing is good, but not big enough deal for me to convert my Titanflex back to double. Easier to just put my Red 11/28 cassette on the bike for that race (which I may just do)

Peace!

If I had small feet I would go through the trouble of getting 11 speed, and building a small q factor single ring setup.

But as it is my feet would just hit the chain stays.

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Kat Hunter reports on the San Dimas Stage Race from inside the GC winning team
Aeroweenie.com -Compendium of Aero Data and Knowledge
Freelance sports & outdoors writer Kathryn Hunter

Sure are a lot of PRO Mountainbikers winning races today with the new dedicated Single Chainring SRAM XX1 system on super rugged terrain... I suspect your comment is out of date and was pre- Wide/Narrow chainring design which has taller teeth and altering width of teeth to lock the chain on the chainring.

I'm sure we'll soon see lots of cyclocross races won on SRAM's new CX1 single chainring system.

I'm hoping SRAM invents a road version of the SRAM XX1 parts with a 50T chainring - I'll be first in line!

50T with a 10/42 cassette or 10/40 cassette would be awesome for Hilly Terrain (40mph top end and compact gear ratio climbing all without a front derailluer - sign me up!)

Cool Ride! (this from a fellow Beam Bike Lover!)

Here is a pic of the Wide/Narrow Chainring Teeth... look close and you'll see the teeth alternate in width from wide to narrow to wide to narrow which helps lock the chain on. Also see in the second pic the teeth on the dedicated single ring are much taller than a normal chainring. Cool Stuff!

Quick check in now that I have over 100 miles on my Titanflex with single chainring. Reminder - I'm currently running a WolfTooth components 44T wide/narrow chainring with a SRAM XX 11-36 cassette (10spd) and SRAM XX rear derailleur. Bike is functioning perfect. Not a single dropped chain on lots of rough pavement and steep climbs. So NICE not have to deal with a front derailleur! So far so good with the 44T front chainring without needing bigger for more speed - I was thinking I would want to get a 46T SRAM CX-1 chainring when available, but I think I'm happy with the 44T I'm using. I've found I'm able to add pedal torque at 38 mph downhill so I think I'm good with this setup... Hit 50.3 mph (coasting) down Boltinghouse Hill this weekend - ride recap pic below :)

Used my Titanflex with single chainring (44t wide/narrow chainring & SRAM XX 11-36 cassette) in Ironman Muncie 70.3 yesterday. Everything worked flawless for 56 miles at an average pace of 21.17mph. Course was windy with constant gentle rollers - basically 18mph uphill and 24+ downhill. A few sections downhill with a tailwind at 31mph. All in all another great bike course at Ironman Muncie 70.3 (much much better than last years course!).

The wide ratio rear SRAM XX cassette 11-12-14-16-18-21-24-28-32-36 (208 grams) worked well - I thought about using my SRAM Red 11-28 cassette with tighter spacing for the race 11-12-13-14-15-17-19-22-25-28 (158 grams) , but I decided to not mess with it and just go with my hilly terrain cassette since I was not going for a PR in this race.

Next year I'll probably swap out cassettes for the race since the terrain is gentle rollers. I only used 11 thru 18 cogs in the race so I could have saved 50 grams (0.11 lbs) and had tighter spacing for slightly improved efficiency with the 11-28 Red cassette.

Bottom Line - I'm not going back to a front derailleur (and see no need for heavier double derailleur electronic shifting as a result)!!!!!

Yeah I am also into 1x setups and agree that this basically eliminates the biggest advantage of electronic shifting. Wife has Ultegra Di2 10 speed and it really is magical in the front.

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/kj

http://kjmcawesome.tumblr.com/

Anyone seen any efficency data on the wide/narrow chainrings compared to the standard tooth profiles? When I put a Wolf Tooth 32T chain ring on my MTB bike I felt that there was a perceptible increase in friction. Could be just dirt and shiz in the drivetrain though.

I don't think the experiences with a 10t cog (or smaller) on the road have been positive.
-SD

Sweet ride! I love the steel frame with the curved top tube. Do you race it?

I agree Di2 is pretty sweet, but the cost, weight, and complexity are overcome via the simplicity and feather weight of the single chainring solution for me. I am very intrigued by SRAM's forthcoming wireless electronic shifting. That would be sweet with a single ring up front and wireless shifting in the rear, but I doubt it will be compatible with 11-36 cassettes or bigger.

My dream component set would be a road version of SRAM XX1 10-42 11 speed cassette with a single chainring and wireless electronic rear shifting (absolutely no front derailleur!)

Can do that set up mechanical right now. You just need the special driver that accommodates a 10t cog. 11 speed right lever and the naked left brake lever. 46t front narrow/wide chainring and you're good to go!

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/kj

http://kjmcawesome.tumblr.com/

SRAM's 11 speed road shifters (exact actuation) don't play with the XX1 mountain bike rear derailleur (x-actuation) which is necessary to use the 10-42cassette. I've tried using a 42T cog conversion on a shimano 11-36 cassette but the required B-tension adjustment with a regular long cage derailluer is too much for nice shifting in my experience - it works but not great...

The best way you can use SRAM XX1 on a triathlon bike setup is to use the XX1 11 speed grip shifter on the aerobar. Place the grip shift behind your hand on the aerobar so that your hand is in front of the shifter - see pics below. I used this setup with much success in the past with a temporary TRI bike I assembled from spare parts laying around and a cheap Leader frame... I may convert to the SRAM XX1 parts on my Titanflex in the future using the grip shifter on the aerobar, but the current setup is working so well for now I'll stick with it for some time!

Here is my second single chainring bike (I own the Titanflex in above pics too). It's a Giant TCX Advanced 1 Cross bike that I converted to single chainring with a 44T Wolf Tooth Chainring up front and SRAM XX 10 speed 11-36T cassette and Derailleur. Did an epic 43 mile, very hilly gravel road ride today and everything worked flawless! I upgraded the wheels, tires and crank in the conversion too...

Stock Bike (size XL) weighed 19.82 lbs,
Bike as in Pic is 16.91 lbs (not bad for Hydraulic Disc Brakes and Cross Tires!)