so stay out of your 11 cog, your 12, your 13...

[thwart]

From the comments after Jan Heine's blog post, about 'marginal gains':

[bikinchris]

I always thought the 11 tooth cog was kinda dumb from a durability standpoint. The 11 tooth cog wears out before the chain if used a lot. Really. Not so much the 12 and certainly not the 13.
In other words, compact drivetrains are not efficient. That has been known for a long time.

[bicycletricycle]

Efficiency goes down as the cog gets smaller. Each link has to pivot more when it leaves the cog under tension. I think the book Bicycle Science covers this with some data.

[OtayBW]

Mmkay. So say goodbye to 11-13, and say hello to a 56 ring? Might as well kiss your compact and lower gearing buh-bye...;)

[Seramount]

in an entire year, if I had a dollar for every minute I spend in 11T, I could get a latte'...

[Jaybee]

Looking forward to the inevitable 56t 1x drivetrain with a 14-60 cassette.

[unterhausen]

14 teeth is considered the limit to efficient power transmission. Go look in the mcmaster carr catalog for a toothed pulley or sprocket with less than 14 teeth. I have never seen one. Cyclists used to be obsessed with efficiency, that's why the smallest cog you could get was 14 for many decades.

[rnhood]

I never had any issues with the 11, and will continue to run them since I run a compact. No, they are not as efficient, but I don't spend a lot of time in it. Only when its a fast paceline pushing beyond 30mph do I need it. I've tried the 12 several times and gave up on it. Having said this, it's probably time that I move to the mid compact setup then I can run the 12. The wide range cassettes from Shimano now have all the bases covered with regards to terrain.

[CunegoFan]

in an entire year, if I had a dollar for every minute I spend in 11T, I could get a latte'...

Unfortunately 1x MTB makes an 11 necessary if you ride to a trail head. If 11 is dumb then what are the 10 and 9 that are available on MTB cassettes?

[gdw]

I ride my MTB to and from the trails and easily put several hundred miles on the 11 tooth cog annually. It might be slightly less efficient but I've never had one wear out before the other cogs.

[Clean39T]

Mmkay. So say goodbye to 11-13, and say hello to a 56 ring? Might as well kiss your compact and lower gearing buh-bye...;)

52/42 w a 14/42 cassette -- :eek:

With ceramic speed OSPW of course - cuz if the eleven tooth is bad on the cassette, it must be twice as bad in the derailleur...

[bikinchris]

14 teeth is considered the limit to efficient power transmission. Go look in the mcmaster carr catalog for a toothed pulley or sprocket with less than 14 teeth. I have never seen one. Cyclists used to be obsessed with efficiency, that's why the smallest cog you could get was 14 for many decades.

Not to mention that when running a freewheel, a 13 was the smallest cog ANYONE could put on there. The less expensive freewheels only had room for a 14 tooth.

But on the track, we preferred using a 14 or 15 tooth cog for the above mentioned reasons.

[SoCalSteve]

in an entire year, if I had a dollar for every minute I spend in 11T, I could get a latte'...

I could get some free water...I run a 12-28 on all my bikes...:)

[Black Dog]

Unfortunately 1x MTB makes an 11 necessary if you ride to a trail head. If 11 is dumb then what are the 10 and 9 that are available on MTB cassettes?

Dumber and dumberer? ;)

[thunderworks]

I'm old and slow . . . but for me, a 14 X 28 11speed cassette with a compact crank offers plenty of gearing. The high gear is around 96 gear inches, which I spin out at around 28mph . . . but I'm happy to coast and enjoy the scenery above that speed anyway. I can't ride 28mph on the flats unless there is a significant tailwind, and going downhill I love to just look around and enjoy.

[dddd]

Frictional losses as a percentage of power transmission actually go down with increased chain tension, especially when cross-chained.
So this at least partially offsets the increased losses at the aft end of the drivetrain where an 11t cog resides.
But I imagine that the only slightly smaller 50t chainring that works with an 11t cog is doing only a little to increase the chain tension in terms of efficiency.

What is needed is quantitative data, just as one needs data to compare efficiency/losses with different tire pressures over rough road surfaces, or when comparing wind-drag benefits/losses of different wheels.

Such hard data always seems to be in short supply when shopping for bike parts.

While I am no fan of compacting the drivetrain, even 35 years ago there were Suntour freewheels that could be built with available 11t cogs.

[thunderworks]

[QUOTE=dddd;2439058
While I am no fan of compacting the drivetrain, even 35 years ago there were Suntour freewheels that could be built with available 11t cogs.[/QUOTE]

You could be right, but I don't think so. I was in the bike business from 1974 through 1994 and to the best of my memory, through most of the 1970's, Suntour cogs were 14 X something. The Ultra series added a sixth, and ultimately a seventh cog, and then a 13 tooth option . . . But I don't remember ever seeing a freewheel that had an eleven tooth cog.

My memory is not the greatest, but that is what I remember.

[oliver1850]

You could be right, but I don't think so. I was in the bike business from 1974 through 1994 and to the best of my memory, through most of the 1970's, Suntour cogs were 14 X something. The Ultra series added a sixth, and ultimately a seventh cog, and then a 13 tooth option . . . But I don't remember ever seeing a freewheel that had an eleven tooth cog.

My memory is not the greatest, but that is what I remember.

11-28 8 speed MTB cassettes are probably the easiest SunTour cassettes to find these days, but I've never seen a freewheel of any brand with an 11 tooth cog. Not sure SunTour made a freewheel with a 12T cog but they are common among other brands.

[Ken Robb]

Unfortunately 1x MTB makes an 11 necessary if you ride to a trail head. If 11 is dumb then what are the 10 and 9 that are available on MTB cassettes?
Marketing? :)

[steelbikerider]

Sun Tour winner 7-speed freewheels had 12 tooth cogs.

[mtechnica]

14 teeth is considered the limit to efficient power transmission. Go look in the mcmaster carr catalog for a toothed pulley or sprocket with less than 14 teeth. I have never seen one. Cyclists used to be obsessed with efficiency, that's why the smallest cog you could get was 14 for many decades.

This is mostly only true for higher RPM, for machine design they don't recommend less than 17t but that at thousands of RPM.

[jambee]

SO is Jan actually proposing that compact cranks are inefficient and that we should all move to bigger rings on the front?

Jan is a member of this forum. Lets hear from the man himself!

[HTupolev]

SO is Jan actually proposing that compact cranks are inefficient and that we should all move to bigger rings on the front?
Actually, Heine tends to argue in favor of a smaller crankset for most riders. A lot of cyclists don't get much utilization out of the top-end on modern road bikes, and spend a lot of time cross-chained, or even ride mostly in the small ring. For such riders, combinations like 46-30 or even down to 42-26 can provide a more 1x-plus-bailout arrangement, where most of the time is spent in the big ring and middle of the cassette.

I mostly agree with him on this. I see recreational cyclists bottoming out their gearing far more often than spinning out, and to considerably larger consequence in both riding opportunity and raw performance. And loads of people complain about being "between chainrings" on 50-34 compacts. Folks sometimes get around the issue by using huge cassettes, but this hurts gear spacing and adds weight.

[wgp]

in an entire year, if I had a dollar for every minute I spend in 11T, I could get a latte'...

Hey, I resemble this remark! Same for me with my 12T (I don't even bother buying cassettes that "go to 11").

[mattsurf]

My favourite cassette is a DA 12-25 on mid compact chainset, Quite happy downhill at 45mph spinning like mad. However, I love the tight ratios

I recently got a Campag 13-29 for my commuter bike, and love this set of ratios as well (running a 53/39 chainset), by the time I spin out, I may as well be free wheeling anyway.

[chiasticon]

If 11 is dumb then what are the 10 and 9 that are available on MTB cassettes?for race starts only.

[marciero]

Frictional losses as a percentage of power transmission actually go down with increased chain tension, especially when cross-chained.
So this at least partially offsets the increased losses at the aft end of the drivetrain where an 11t cog resides...


Chain tension is independent of what cog you are engaging. It depends on force at the pedals, length of crank, and the size of the chainring, decreasing as the latter increases. So for a given pedal force and crank length running a smaller chainring with the 11 will have greater tension than larger chainring with larger cog. I'm thinking this is what you are saying here.

[oldpotatoe]

Mmkay. So say goodbye to 11-13, and say hello to a 56 ring? Might as well kiss your compact and lower gearing buh-bye...;)


Like most things ‘bike’, ‘efficiency falls way off’, is like ‘aluminum chainring bolts way lighter than steel ones’...For us mere mortals(and Jan), the differences are teeny tiny in this human powered, micro horsepower machine..A lot like tire rolling resistance charts and crank arm stiffness comparisons...most of the differences are lost in the noise of riding a bike. Keep yer 11 and 12t cog, ride yer farging bike...get fit, ride a well fitting bike, ride or race smart, lose the fat...
4 “Fs” of being better on a bike.
Fit-be fit
Fit-good bike fit
Finesse-ride smart
Fat-less=better

[palincss]

Not to mention that when running a freewheel, a 13 was the smallest cog ANYONE could put on there.

Not entirely true. The AM-7 Moulton, introduced in the early 1980s, had a 7 speed freewheel with a 9 tooth smallest sprocket.

[Jan Heine]

I'm just reporting data. If I were a pro racer doing a downhill time trial, I might run a bigger chainring to stay out of the small cogs.

For most riders, the 11-tooth cassettes are a reality, and if you have them on your bike, you might as well use them for those rare occasions when you are sprinting against friends with a tailwind on a slight downhill grade. Most of the time, you'll be on a more efficient cog anyhow.

A subcompact crank gives you many advantages: not just smaller steps between gears (because you can use a closer-range cassette), but also the ability to ride on most terrain without front shifts. We covered that in another blog post: https://janheine.wordpress.com/2018/09/27/why-we-like-custom-gearing/

SO is Jan actually proposing that compact cranks are inefficient and that we should all move to bigger rings on the front?

Jan is a member of this forum. Lets hear from the man himself!

[Road Fan]

Frictional losses as a percentage of power transmission actually go down with increased chain tension, especially when cross-chained.
So this at least partially offsets the increased losses at the aft end of the drivetrain where an 11t cog resides.
But I imagine that the only slightly smaller 50t chainring that works with an 11t cog is doing only a little to increase the chain tension in terms of efficiency.

What is needed is quantitative data, just as one needs data to compare efficiency/losses with different tire pressures over rough road surfaces, or when comparing wind-drag benefits/losses of different wheels.

Such hard data always seems to be in short supply when shopping for bike parts.

While I am no fan of compacting the drivetrain, even 35 years ago there were Suntour freewheels that could be built with available 11t cogs.

Hard data is provided in Bicycling Science by David Wilson. He also gives references for the claims he makes and data he presents, as well as describes how the tests were run. He does not explore your statement about cross-chained gearsets or the tension changing with front chainring size.

Your comments suggest you think data is not available. I'm trying to show that's not true. But I'm not surprised "nobody knows it." Most consumers will not look at Wilson. Most sprocket/cassette/gearing makers will not promote the data that says 11 teeth is less efficient than 14, because "the bicycle" is the world standard in mechanical efficiency, we all ride state-of-the-art machines and most remain at the cutting edge, and of course the newest designs have to be the most efficient, right? We see from this data that that is not the case, but if all high-end bicycles have about the same gearing, 11 teeth is not a disadvantage in terms of competition.

Consider it instead a motivation, increase our wattages another few percent?

[Road Fan]

My favourite cassette is a DA 12-25 on mid compact chainset, Quite happy downhill at 45mph spinning like mad. However, I love the tight ratios

I recently got a Campag 13-29 for my commuter bike, and love this set of ratios as well (running a 53/39 chainset), by the time I spin out, I may as well be free wheeling anyway.

I think 13-29 is pretty nice on 50/34, as well!

[Gummee]

But on the track, we preferred using a 14 or 15 tooth cog for the above mentioned reasons.

Weirdly enough, I liked a 53x16 better than I liked 49x15, but ran 49/50x15 a lot 'to fit in.'

M

[avalonracing]

But of course, these cog sets with the huge lower gears are heavier.

[Mark McM]

Frictional losses as a percentage of power transmission actually go down with increased chain tension, especially when cross-chained.
So this at least partially offsets the increased losses at the aft end of the drivetrain where an 11t cog resides.
But I imagine that the only slightly smaller 50t chainring that works with an 11t cog is doing only a little to increase the chain tension in terms of efficiency.

Yes, drivetrain efficiency goes up with chain tension. But at the same time, drivetrain efficiency goes down to greater degree with chain articulation angle (i.e., how much the links have to bend when the engage/disengage the sprocket, which increases as sprocket size decreases). For the same power and gear ratio, using a smaller chainring and sprocket will result in net loss of efficiency. So a 44x11 will be less efficient than a 48x12, which will in turn be less efficient than a 52x13.

What is needed is quantitative data, just as one needs data to compare efficiency/losses with different tire pressures over rough road surfaces, or when comparing wind-drag benefits/losses of different wheels.

Such hard data always seems to be in short supply when shopping for bike parts..

Its out there, if you look for it. For example, the James Spicer study, published in the IHPVA journal, is widely cited: http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf. Frank Berto published several articles on this when he was the technical editor at Bicycling magazine. More recently, the Jason Smith at the Friction Facts web page has published some test data. Here's an article on a Friction Facts study that confirms that it is most efficient to stay in the big chainring most of the time (because smaller sprockets are less efficient): https://www.bikeradar.com/us/road/gear/article/friction-facts-free-speed-from-proper-shifting-44016/

[benb]

I've always felt intuitively like the compact setup was costing something & was a PITA. These findings just make sense to me.

You're spending more time in those smaller cogs, often having to run a wider range cassette with bigger jumps between the cogs, often feeling like I'm shifting the front derailleur more with the compact because of where the gears fall, and usually feeling like I have to change more gears in the back when I change the front...

I've spent a fair amount of time on compacts because one of my bikes came with it and that bike is a) heavy b) gets used offroad some c) has spent time towing. But it would have been better if it came with a triple I think. Just less fashionable.

[dddd]

Yes, drivetrain efficiency goes up with chain tension. But at the same time, drivetrain efficiency goes down to greater degree with chain articulation angle (i.e., how much the links have to bend when the engage/disengage the sprocket, which increases as sprocket size decreases). For the same power and gear ratio, using a smaller chainring and sprocket will result in net loss of efficiency. So a 44x11 will be less efficient than a 48x12, which will in turn be less efficient than a 52x13.



Its out there, if you look for it. For example, the James Spicer study, published in the IHPVA journal, is widely cited: http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf. Frank Berto published several articles on this when he was the technical editor at Bicycling magazine. More recently, the Jason Smith at the Friction Facts web page has published some test data. Here's an article on a Friction Facts study that confirms that it is most efficient to stay in the big chainring most of the time (because smaller sprockets are less efficient): https://www.bikeradar.com/us/road/gear/article/friction-facts-free-speed-from-proper-shifting-44016/

I can't be sure, but I may have learned some of what I posted from you, on Cyclingforum, many years ago. Many sources of data came forward in those discussions and you were usually at the forefront of the tech discussions.

As for the Suntour 11t freewheel cogs, I have them here, but perhaps they may have been intended for use on ~1990(?) Suntour cassette hubs. Because they fit on a Suntour freewheel (stacked onto a special 13t cog) is why I thought that they were freewheel cogs from the 1980's. They have no modern tooth profiling to them at all. These may have allowed a 7s cassette hub to be expanded to 8s.

Gearing preferences are regional, and here in the foothills I struggle with any top gear short of 52-13t.
And over such generally rolling terrain, 1-tooth cog ratio spacings are often more trouble than they are worth (and definitely more trouble than they are worth when friction-shifting).

[dddd]

With an 11 or 12-xx cassette on the back wheel, a highly-developed modern drivetrain using a 34-42-50t or 36-44-52t crankset would be a combo that I would be enthusiastic to try.
Not having to worry about huge ratio drops off of the big ring would more seamlessly extend the cassette's ratio spread from one ring to the other, and chainline extremes might thus be avoided.
Or, perhaps better yet, an even "tighter" stack of four quicker-shifting chainrings, which could employ yet-narrower spacing, while sharing structure to minimize weight, and which could be part of a shifting sequence that minimizes cross-chain friction. Imagine bike shopping: Will that be 1x or 4x sir?

By now we all know that newer gearing strategies are forever on the horizon.