Are 12-21 cassettes simply stupid ??

I was reading (I think) Frank Berto's "The Dancing Chain" book last
weekend, and it mentioned some efficiency research that Berto did with
3-speed hubs, 7-speed hubs, and regular derailleur bikes. If I
remember correctly, drivetrain energy loss was about 3-5% for
derailleurs, and 5-7% for internally geared hubs.

More interesting than this was a statement that the highest losses on
derailleur bikes came from 13-tooth cogs. The results implied that
using a 13-tooth cog was tantamount to using a Sturmey Archer 3-speed
hub. And Berto asserted that this is why 14-28 rear clusters are so
popular on road bikes of the 1970's and 1980's.

Has anything changed?

Are 13-tooth (and 12-tooth (and 11-tooth)) cogs only 90-92% efficient?

- Don Gillies
San Diego, CA

Hi.

I think que question is... do u have power enough to move or carry the
load that a 12 and 11 teeth cog has??? racers nowadays are stronger than
in the past... second bikes are more eficient too u know... I dont think
a 12 - 21 cog is an stupid combination, the question is, are u gonna use
the 12 teeth cog??? An sprinter maybe will.. but a regular human being
as the fat guy who started doing pedaling a few years ago every weekend
and have a lot of money it wont need the 12t cog ever, even he doesnt
even need 14, 15 and 13.. but how the bike has them so he will use them
anyways...

U can do thousands of thousands of test about eficiency but at the end
all depends of the racer or rider, his style of riding, his cadence...
his power... experience and other factors that for the fat guy i was
talking about before it doesnt really matter because he has no freaking
idea what he is doing... so... in my experience... if u are strong enough
and do u feel comfortable carring heavy loads such an 11t cog... go
ahead... use it hehehe...

Btw in my case, one of my set of wheels has an 11t cog and havent put
that ever, maybe downhill but not in a flat... I did racing for 20 years
almost and darn... 11? i rather be like lance and ride light... is more
eficient ride using light loads than using heavy loads (old school riding
style)... but well... is only the opinion of an old skool rider

G. luck and sorry for my bad english...





(Donald Gillies) wrote in news:dgf1t4$92m$1
@cascade.cs.ubc.ca:

I was reading (I think) Frank Berto's "The Dancing Chain" book last
weekend, and it mentioned some efficiency research that Berto did with
3-speed hubs, 7-speed hubs, and regular derailleur bikes. If I
remember correctly, drivetrain energy loss was about 3-5% for
derailleurs, and 5-7% for internally geared hubs.

More interesting than this was a statement that the highest losses on
derailleur bikes came from 13-tooth cogs. The results implied that
using a 13-tooth cog was tantamount to using a Sturmey Archer 3-speed
hub. And Berto asserted that this is why 14-28 rear clusters are so
popular on road bikes of the 1970's and 1980's.

Has anything changed?

Are 13-tooth (and 12-tooth (and 11-tooth)) cogs only 90-92% efficient?

- Don Gillies
San Diego, CA

noname wrote:
Hi.

I think que question is... do u have power enough to move or carry the
load that a 12 and 11 teeth cog has??? racers nowadays are stronger than
in the past... second bikes are more eficient too u know... I dont think
a 12 - 21 cog is an stupid combination, the question is, are u gonna use
the 12 teeth cog??? An sprinter maybe will.. but a regular human being
as the fat guy who started doing pedaling a few years ago every weekend
and have a lot of money it wont need the 12t cog ever, even he doesnt
even need 14, 15 and 13.. but how the bike has them so he will use them
anyways...

So where does a compact crankset fit into all this? Also, does this
present an argument for 12 speed wide range clusters so that you can
use larger rear cogs and stay off the small front ring? Small
differences can be decisive in competition.

I know that about 30 years ago I was advised to use the big ring when
there was a choice because it was more efficient.

Actually, straight blocks are very, very useful in certain situations.
If you ride in fast groups and don't want sudden changes, straight
blocks are great. I especially like them with triples. You get climbing
gears and close ratios in fast pacelines. I am not a racer, but the
group that I ride with regularly does 24 to 26 miles/hour. Sometimes
they go above 30 on flats. I am a slow pedaler, and the 12 teeth come
on handy. I can keep up with a 13, but the 12 helps a lot. I have an 8
speed that has a 12, 14, 15, 16, 17, 19, 21, 26. The front has a 34-52.
I usually ride on the 52 and mostly between the 14 and the 17. The 12
is for very fast efforts, and down hills. The 19 and 21 are for
climbing tough hills, and the 26 is for emergencies. I also have
another bike with a 12-23 9 speed and a triple front.

Andres

One aspect of this that is often overlooked is the effect of chain
tension on efficiency... ie increasing the chain tension improves the
chain efficiency... and smaller gears have higher tension (at the same
riding speed and power output) than larger ones. It is true that a 15
tooth sprocket is more efficient than an 11, provided that the power
input and front ring size is the same in both cases; unfortunately that
isn't the right comparison to make. If we want to travel at a
particular speed with a particular cadence, then we have to change the
front ring size by the same proportion... and the chain tension will
change by the same amount. A 53/15 is the same gear ratio as a 39/11.
This is the kind of comparison that needs to be made. Spicer's testing:
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf
showed that chain tension is actually more important than spocket
size... though he failed to note this in his conclusions. But Walton
noticed, and published the results he
http://www.ihpva.org/HParchive/PDF/hp51-2001.pdf
When you compare the effect of sprocket size while keeping riding speed
and power output constant, the smaller sprockets are most efficient...
especially at lower power outputs. At higher power the results
converge.

So... I wouldn't worry about losing efficiency with the small
sprockets.

Some of the other interesting conclusions from Spicer's testing:

1) Cross-chaining has a negligible effect on efficiency.
2) Lubrication doesn't matter (in the lab at least).
3) Friction can account for only a few percent of the overall losses.

That last one is especially noteworthy... If friction doesn't account
for the losses, then what does? Vibration?

Look...

Basically all that stuff about compact cranks and stuff is not gibrish or a
marketing strategy but look... for example... 52x16 is almost the same than
50x15 right?... but 50x15 is a little bit more anyways... u earn a few
inches... result u can go faster right? thats the idea behind compact
crankset plus less weight... but u have to be stronger because u are using
smaller cogs, u need to put more torque to your pedaling... the one that
commands on how light or heavy the load when pedaling is, are the cogs!!!
the wheelchain is only a mere detail in here... if u want more rush at the
end of the sprint use and smaller wheelchain but u have to keep up with the
other guys so u have to put an smaller cog anyways... a bigger wheelchain
will give u more stability when pedaling, thats why is easier to do cadence
and the guys told that it was more eficient.. but again it depends of the
situation.

The guys told u to use the big ring because it was more efficient right?
well.. it depends... I remember bernard hinault won a few races in the
final sprint using 53X16... nothing more than that.. in this case it was
more efficient for him to use something ligter... other guys in that same
sprint were using 53x14 or 13... so who was more eficient at that moment? u
got the idea?... What u'll use it depends of u, the situation, and physical
conditions u r in that specific moment... for example.. i left racing for a
long time and i came back riding a few months ago.. i still have my high
cadence.. and when i go riding behind triathletes or people that i can see
has millions of more miles than me in their bodies.. I use lower gears...
im not strong enough yet... they are stonger than me but im faster and
getting stronger everyday... so who is being more eficient in that case?...
I can go happy after them using smaller loads even do changes in the
cadence w/o any problem.... I was able to move 53x14 at 100/20+ rpm in the
4x100km in the panamerican games of 1990... so basically because a test
shows u that is more eficient use some or something else... doesnt mean it
will be at that moment u know...

Usually this is something triathletes and weekend riders cant realize...
(im not being mean only im letting u know guys a reality that ive learn in
serious racing)... Im talking about the fact that after 2 hours or 3 hours
of racing doesnt matter if u have the best bike on the market or u are
using a brand of shoes because the institute of super speed on bikes told u
so... After 2 or 3 hours nothing matters... U'll be tired... maybe u'll get
a 3rd punch of oxygen... whatever... but to win that freaking race it will
depends of U, and only U. Do u think Lance care about the bike? well at his
level maybe but the guy is a god of cycling... even using a wheel chair
with pedals he will be eficient, or will find the way to be more eficient
than the other racers...

U states that.. "present an argument for 12 speed wide range clusters so
that you can use larger rear cogs and stay off the small front ring?"...
all of that it depends... with compact crank sets u use smaller clusters...
but if that is ok with u... depends of u only... for example i rather like
42x16 than 39x15... but now the configurations are with 39 not with 42... u
can go faster with 39x15 than with 42x16... but all depends of u again...
by the other side... an smaller set of sprokets means less weight.. thats
cool... but if u are tired doesnt matter, right?... Ive seen people
putting lighter clinchers on their bikes because it will give them more
speed????? doesnt matter in long term... another example... tubulars.. a
280/250 grams tubular is more eficient than a 200 grams clincher... and I
bet u wont get a flat with the tubbies... there are a lot of myths... and
believes that when u are racing are thing of the past because u have no
time to think or to react.. or u keep up with the guys or u dont..
period...

With the compact cranksets i have no idea how long they will stay in the
market and i really have no idea if I will use them in the future... but
what i know is that Im very comfortable the way my bike is set up now... I
rather be using confident components than use light stuff because is only
light... (I use 300 grams tubulars, and no clincher will compare to them
ever, real racers can agree for sure)

Doesnt matter if u have the best stuff in the world... or if u are using
compact cracnks or the best frame in the world... sooner or later u have to
make a choice about whats the best for U... not what the market or the book
says... example.. i know a guy that likes to go the mountains using only
the big chainwheel... no kidding, he cant use the small one for some reason
and the guy is not handicap, he was one of the best racers i ever known...
so all it depends... in this case, for him the stupidity was more
eficient... my advice... give a try... if u get use to the new things
great.. if not.. come back to the old stuff or what it makes best results
for ya... u are the one that can say if something is afficient or not, if
it works fine 4 u doesnt mean i have to set up everything the same way...

THanks


Ps: in europe steel frames are comming back... isnt that great
ps2: sorry for my bad english




wrote in news:1126900804.114243.111660
@g49g2000cwa.googlegroups.com:


noname wrote:
Hi.

I think que question is... do u have power enough to move or carry the
load that a 12 and 11 teeth cog has??? racers nowadays are stronger than
in the past... second bikes are more eficient too u know... I dont think
a 12 - 21 cog is an stupid combination, the question is, are u gonna use
the 12 teeth cog??? An sprinter maybe will.. but a regular human being
as the fat guy who started doing pedaling a few years ago every weekend
and have a lot of money it wont need the 12t cog ever, even he doesnt
even need 14, 15 and 13.. but how the bike has them so he will use them
anyways...

So where does a compact crankset fit into all this? Also, does this
present an argument for 12 speed wide range clusters so that you can
use larger rear cogs and stay off the small front ring? Small
differences can be decisive in competition.

I know that about 30 years ago I was advised to use the big ring when
there was a choice because it was more efficient.

Hi...

12, 14, 15, 16, 17, 19, 21, 26?? nice set... i like it a lot.. hehe

U r just one of the people i was just thinking about in my other replys...
for u 12 works fine... thats cool... so in your case 12 - 21 isnt stupid
hehehe... as i said before it depends of the rider...

thanks...







wrote in news:1126905842.065253.229880
@g43g2000cwa.googlegroups.com:

Actually, straight blocks are very, very useful in certain situations.
If you ride in fast groups and don't want sudden changes, straight
blocks are great. I especially like them with triples. You get climbing
gears and close ratios in fast pacelines. I am not a racer, but the
group that I ride with regularly does 24 to 26 miles/hour. Sometimes
they go above 30 on flats. I am a slow pedaler, and the 12 teeth come
on handy. I can keep up with a 13, but the 12 helps a lot. I have an 8
speed that has a 12, 14, 15, 16, 17, 19, 21, 26. The front has a 34-52.
I usually ride on the 52 and mostly between the 14 and the 17. The 12
is for very fast efforts, and down hills. The 19 and 21 are for
climbing tough hills, and the 26 is for emergencies. I also have
another bike with a 12-23 9 speed and a triple front.

Andres

yeah, lubrication and tension affects too... well im assuming the guys
have a nice and well mantained bike u know... hehehehe...






"Ron Ruff" wrote in news:1126906119.902827.294740
@g44g2000cwa.googlegroups.com:

One aspect of this that is often overlooked is the effect of chain
tension on efficiency... ie increasing the chain tension improves the
chain efficiency... and smaller gears have higher tension (at the same
riding speed and power output) than larger ones. It is true that a 15
tooth sprocket is more efficient than an 11, provided that the power
input and front ring size is the same in both cases; unfortunately that
isn't the right comparison to make. If we want to travel at a
particular speed with a particular cadence, then we have to change the
front ring size by the same proportion... and the chain tension will
change by the same amount. A 53/15 is the same gear ratio as a 39/11.
This is the kind of comparison that needs to be made. Spicer's testing:
http://www.ihpva.org/HParchive/PDF/hp50-2000.pdf
showed that chain tension is actually more important than spocket
size... though he failed to note this in his conclusions. But Walton
noticed, and published the results he
http://www.ihpva.org/HParchive/PDF/hp51-2001.pdf
When you compare the effect of sprocket size while keeping riding speed
and power output constant, the smaller sprockets are most efficient...
especially at lower power outputs. At higher power the results
converge.

So... I wouldn't worry about losing efficiency with the small
sprockets.

Some of the other interesting conclusions from Spicer's testing:

1) Cross-chaining has a negligible effect on efficiency.
2) Lubrication doesn't matter (in the lab at least).
3) Friction can account for only a few percent of the overall losses.

That last one is especially noteworthy... If friction doesn't account
for the losses, then what does? Vibration?

FYI, the Kyle/Berto test is published he
http://www.ihpva.org/HParchive/PDF/hp52-2001.pdf

Donald Gillies wrote:

Are 13-tooth (and 12-tooth (and 11-tooth)) cogs only 90-92% efficient?

Don't know, but who uses those cogs, anyways?

With 42/52 doubles, I like 11-21/23 cassettes because the really useful
cogs (15,17,19) are at the center of the cluster, which makes for good
chainline. Also, it seems like a lot of frames can't accomodate the
smallest cog on a 9 or 10 speed cassette, (chain rubs on seat stay), so
that last cog is just a placeholder. The chain rubs on the crank, too,
when you're way out on the smallest cogs.

-Vee