Shimano Octalink road BB future



>>> Ben C napisa (a):
>>>> What's wrong with 12 & 11?


>> Adam Kadlubek wrote:
>>> Simply put - a jump between 12 and 11 is so huge, that 11 is usable
>>> just for spinning downhill, which makes me not bother with it in the
>>> first place.


> jim beam wrote:
>> no, that's not it. there are mechanical meshing issues with # < 13.
>> it'll work, but it's fugly.


Chalo wrote:
> Yes, there is an efficiency and wear penalty for 11t and 12t
> sprockets. There is for 13t sprockets too, for that matter; it just
> seems like a good place to draw the line for diminishing returns.
>
> I use 11-34 freewheels and cassettes for almost all my derailleur
> bikes now. The range they offer makes it easy for me to settle for a
> single ring, which in turn makes it easy to use a strong and cost-
> effective 3-piece BMX crank. I can keep low gears for hill climbing
> and load carrying without unduly truncating top speed. But I've
> switched to 11-34 even on my bikes with front changers. The benefits
> there are a smaller big ring (e.g. 49t) and deeper overlap between
> ranges. For the relative infrequency and modest power levels with
> which I use the small sprocket, I'm not too concerned about excessive
> losses and wear.
>
> Note that BMX/freestyle bikes are increasingly equipped with 9 tooth
> rear drivers on their single-speed cassette hubs. 25/9 is the typical
> gear combination. I recently saw an 8 tooth driver for the first
> time. You can get a 9 tooth driver made from 7075 aluminum! I
> imagine that this fad will pass before too long, but in the meantime,
> manufacturers are going to make a bundle on replacement drivers (which
> are specific to the hub and cost a lot more than freewheels).


Yeah, I wonder why the popular Profile Racing 9t integrated driver is
Ti? - they sure don't last all that long! A steel piece that small just
couldn't be much extra weight. But then again I don't ride them myself...
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971
 
In article <[email protected]>,
"Tom Nakashima" <[email protected]> wrote:

> "Michael Press" <[email protected]> wrote in message
> news:[email protected]...
> > In article
> > <[email protected]>,
> > Doug Taylor <[email protected]> wrote:
> >
> >> Tell you what, though. In my prime I was a few light years below Cat
> >> 2, and have to ponder whether my choice of an 11 is too much gear in
> >> light of Mike's experience. One drawback with the 11-28 cassette,
> >> even a 10 speed, is the number of 2 tooth jumps in the block and the
> >> absence of a 16. Opting for a 12-27 could solve that problem.

> >
> > That's a slippery slope.
> > Soon you will be running a 13-23.
> >
> > --
> > Michael Press
> >
> > Also running a 46-50 and 14-32 seven speed.

>
> Campagnolo Centaur Compact Crank 50/46
> Shimano ultegra 9sp (with downtube shifters)
> Cassette: 11-23 Racing Wheel (30% of the time)
> Cassette: 12-25 Training Wheel (70% of the time)


Tom, I remember reading that you installed a compact
crank recently and liked it. Did you write such a message?

--
Michael Press
 
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>
>>> from an engineers viewpoint, any cog less than 13 is ugly. compacts
>>> ensure you use 12 & 11 regularly - cringe.

>>
>> I'm an engineer. I have 11's on all my bikes.

>
> like that's a logical connection?
>
> and i see little to support this "engineer" claim.


You wouldn't.

> after all, you also
> confuse plasticity with elasticity - that's a pretty fundamental error
> for a real engineer to make.


Repetition doesn't make truth.

> unless you were deliberately bullshitting
> of course...


Your all-purpose answer.

Where did you get your "engineers[sic] viewpoint"?
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>
>>>> from an engineers viewpoint, any cog less than 13 is ugly. compacts
>>>> ensure you use 12 & 11 regularly - cringe.
>>>
>>> I'm an engineer. I have 11's on all my bikes.

>>
>> like that's a logical connection?
>>
>> and i see little to support this "engineer" claim.

>
> You wouldn't.
>
>> after all, you also confuse plasticity with elasticity - that's a
>> pretty fundamental error for a real engineer to make.

>
> Repetition doesn't make truth.


er, /who/ cited plasticity as a comparison with elasticity? denial
doesn't repair ignorance.

>
>> unless you were deliberately bullshitting of course...

>
> Your all-purpose answer.


only when it's observed to be the case. when you don't ********, you'll
never catch me calling you on it! duh.


>
> Where did you get your "engineers[sic] viewpoint"?


you mean where do i get my opinion of people that call themselves
"engineers"? watching them make stupid-ass mistakes, and then let their
ego prevent them learning that which would prevent them from making the
same mistakes in the future, that's where.
 
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:


>>> after all, you also confuse plasticity with elasticity - that's a
>>> pretty fundamental error for a real engineer to make.

>>
>> Repetition doesn't make truth.

>
> er, /who/ cited plasticity as a comparison with elasticity?


I dunno, I didn't.


>>> unless you were deliberately bullshitting of course...

>>
>> Your all-purpose answer.

>
> only when it's observed to be the case. when you don't ********, you'll
> never catch me calling you on it! duh.


I live for that day.


>> Where did you get your "engineers[sic] viewpoint"?

>
> you mean where do i get my opinion of people that call themselves
> "engineers"? watching them make stupid-ass mistakes, and then let their
> ego prevent them learning that which would prevent them from making the
> same mistakes in the future, that's where.


That's all? I thought from the depth of your bitterness they beat you up
and took you lunch money too.

Now, which engineer told you an 11 tooth sprocket was ugly?
 
On Thu, 13 Sep 2007 23:53:07 -0700, "Mike Jacoubowsky"
<[email protected]> wrote:

>For what it's worth, I ride a 50/34 with a 12-27 rear. I *love* that setup.
>Gives me gears for everything I need, including Sonora Pass. Sonora Pass was
>actually the driving force to my move to compact. It was either that or a
>triple, as I just don't have the raw horsepower I used to. The compact
>allowed use of everything I already have, with the exception of needing a
>new crank. A few years down the road, don't be surprised if you see me with
>a triple. But for now, I can handle what comes my way with my current setup.


That's what I run as well. I am an Ergo 10 person. My hubs are
ShimaNO. I use 12/27 x 9sp and a current 10sp rear derailleur and it
shifts aOK. That's my all around bike, a Soma Smoothine with small
rack and 700x28 tires. On another bike, Colnago Ti/CF, I run 12/27 x
10sp but I shift it with an 8sp Record rear derailleur. And the 3rd
bike, Cannondale CAAD 9, Campy all around with a made up 12/29. Made
up with 1st 4 cogs from 12/29 and 17-19, 21-3/26-29. It's actually
better than the Shimano 12/27s. On worn cassettes, the 12/13/14/15
are usually ok. The 17,19,21 are usually the cogs that wear first.
An IRD 12/28 works ok for Campy too.

If you are already running a Campy Middle cage rear derailleur, you
can also run 12/32. You can do it with a standard cage by changing
out the 10 sp derailleur pulley with an 8sp pulley, which has a
smaller diameter. Most often, but not always, you need to add a link,
1" of chain.

PS: I have a 48/36/26 Sugino Crank on the bench ready to go for the
Soma and I'd consider running 11/25. Why shouldn't I have any gear I
want for anyplace I go?
 
On Fri, 14 Sep 2007 08:37:17 -0400, Doug Taylor
<[email protected]> wrote:

>Why the 11 is prevalent among compact users is that they ride with
>friends who have still have the 53:12 as a high gear. So there are
>instances when the compact geared rider is trying to keep pace with
>the standard geared riders (downhill), and finds that 50:12 is too
>fast and tiring to spin.


I've had little trouble with a compact and a 12 w/o an 11. I've
rarely lost contact with some fast pacelines. I do have to spin it up
but not much. The times I've missed an 11 is when drafting a tandem
on a downgrade and they are spinning and not coasting. Downgrade, by
myself, I'm scared to spin up the 50/11 anyway.

A good friend and a former 10 year, European pro, claims that going up
the hill quickly is the glory and coming down fast is crazy. You
only need to go down fast when keeping up with a pack of riders so
that you are in contact when they get to the flat or uphill grade.
The thrills of descending quickly are overcome by touching down on the
pavement of going off road a couple of times.
 
On Sun, 16 Sep 2007 13:38:29 GMT, Paul Kopit <[email protected]> wrote:

> Made
>up with 1st 4 cogs from 12/29 and 17-19, 21-3/26-29.


Correction, 1st 4 cogs from a 12/25.
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:

>
>>>> after all, you also confuse plasticity with elasticity - that's a
>>>> pretty fundamental error for a real engineer to make.
>>>
>>> Repetition doesn't make truth.

>>
>> er, /who/ cited plasticity as a comparison with elasticity?

>
> I dunno, I didn't.


er, so who, when being asked about elasticity wrote:
"25% for 6061." on 08/20/2007 @ 11:09 AM?

clue: initials - p.c.


>
>
>>>> unless you were deliberately bullshitting of course...
>>>
>>> Your all-purpose answer.

>>
>> only when it's observed to be the case. when you don't ********,
>> you'll never catch me calling you on it! duh.

>
> I live for that day.


apparently not since you just can't resist bullshitting - see above.


>
>
>>> Where did you get your "engineers[sic] viewpoint"?

>>
>> you mean where do i get my opinion of people that call themselves
>> "engineers"? watching them make stupid-ass mistakes, and then let
>> their ego prevent them learning that which would prevent them from
>> making the same mistakes in the future, that's where.

>
> That's all? I thought from the depth of your bitterness they beat you up
> and took you lunch money too.


eh? so which way do you want it? one minute i'm the bully, now i'm the
bullied? make up your mind!


>
> Now, which engineer told you an 11 tooth sprocket was ugly?



something i learned in school. here, read this since you didn't have
that opportunity yourself.

http://www.renold.com/nmsruntime/saveasdialog.asp?lID=611&sID=860
 
On Sun, 16 Sep 2007 13:46:47 GMT, Paul Kopit <[email protected]> wrote:

>On Fri, 14 Sep 2007 08:37:17 -0400, Doug Taylor
><[email protected]> wrote:
>
>>Why the 11 is prevalent among compact users is that they ride with
>>friends who have still have the 53:12 as a high gear. So there are
>>instances when the compact geared rider is trying to keep pace with
>>the standard geared riders (downhill), and finds that 50:12 is too
>>fast and tiring to spin.

>
>I've had little trouble with a compact and a 12 w/o an 11. I've
>rarely lost contact with some fast pacelines. I do have to spin it up
>but not much. The times I've missed an 11 is when drafting a tandem
>on a downgrade and they are spinning and not coasting. Downgrade, by
>myself, I'm scared to spin up the 50/11 anyway.


The 12 might be a good choice, and it might not depending on the rider
and the circumstances. I'm no former Cat 2, but my personal
experience was that I too often found myself spinning overly hard and
fast for personal comfort @ 50:12 in various situations when hammering
(or trying to) with the animals. Of course if I'm by myself or doing
long slow distance, then absolutely it is a wasted gear.

Be that as it may, my point was simply to explain to the OP why
cassettes starting with an 11 are prevalent among compact users. There
are enough of those riders now "everybody" except Shimano offers
"wide" cassettes (starting with an 11 and ending with 25,26,27, or 28)
for 9 and 10 speed. That was not the case 4 years ago when I first
switched to compact. Then, if you wanted a wide range cassette, you
could cob together individual cogs, or buy a "High and Wide" from
Harris Cyclery if you had 9 speed. IRD, a company which uniquely
"promoted" the resurgence of compacts in the last few years, was the
first I could find that actually sold "compact friendly" wide
cassettes for 9 and 10 speed 3 years ago, and because of that I remain
loyal to IRD and buy all my chains and cassettes from their on line
shop.

Healthy variety of cassettes, and the 10 speed chain is great because
it has a "snap-link" which works like a SRAM 9 speed power link
(symmetrical as opposed to Wipperman connex).

http://store.interlocracing.com/
 
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:
>>>> jim beam wrote:
>>>>> Peter Cole wrote:
>>>>>> jim beam wrote:

>>
>>>>> after all, you also confuse plasticity with elasticity - that's a
>>>>> pretty fundamental error for a real engineer to make.
>>>>
>>>> Repetition doesn't make truth.
>>>
>>> er, /who/ cited plasticity as a comparison with elasticity?

>>
>> I dunno, I didn't.

>
> er, so who, when being asked about elasticity wrote:
> "25% for 6061." on 08/20/2007 @ 11:09 AM?
>
> clue: initials - p.c.


From that post:

">> I think part of the confusion is over the distinction between force
>> and energy. Carbon fibers have high specific strength. Carbon fibers
>> also elongate very little before fracture (~0.8 - 1.4%).


> which compares with __%'s for a steel/ti/al alloys? you know, materials
> that have dislocations and therefore yield well below their theoretical
> strength?


25% for 6061. You can look up the others yourself. E-series glass is
4-5%, BTW (>3x CF, as I said). "

Obviously I said "elongation before fracture"

Next point?



>
>
>>
>>
>>>>> unless you were deliberately bullshitting of course...
>>>>
>>>> Your all-purpose answer.
>>>
>>> only when it's observed to be the case. when you don't ********,
>>> you'll never catch me calling you on it! duh.

>>
>> I live for that day.

>
> apparently not since you just can't resist bullshitting - see above.
>


You can't read, and as a result have been posting this petulant proof of
my "********" for weeks now. Grow up.


>>
>>
>>>> Where did you get your "engineers[sic] viewpoint"?
>>>
>>> you mean where do i get my opinion of people that call themselves
>>> "engineers"? watching them make stupid-ass mistakes, and then let
>>> their ego prevent them learning that which would prevent them from
>>> making the same mistakes in the future, that's where.

>>
>> That's all? I thought from the depth of your bitterness they beat you
>> up and took you lunch money too.

>
> eh? so which way do you want it? one minute i'm the bully, now i'm the
> bullied? make up your mind!


Oh, you're a bully all right. As usual though you turn things around so
that you're the abused one. Right.


>
>
>>
>> Now, which engineer told you an 11 tooth sprocket was ugly?

>
>
> something i learned in school. here, read this since you didn't have
> that opportunity yourself.
>
> http://www.renold.com/nmsruntime/saveasdialog.asp?lID=611&sID=860
>


Was there anything specific that I'm supposed to read, or do you expect
me to wade through all 29 pages and guess? Unlike you, I'm not a mind
reader. If you have a point just make it or stop wasting my time.
 
> PS: I have a 48/36/26 Sugino Crank on the bench ready to go for the
> Soma and I'd consider running 11/25. Why shouldn't I have any gear I
> want for anyplace I go?


Indeed, why not? Some of the guys I ride with make fun of me for running a
12-27 10-spd block on rides where I don't need anything like a 27. They are
of the opinion that perhaps in the winter you use the lower gears, but
in-season, unless you've got something really gnarly on the itinerary, you
run a 12-25 or even an 11-23.

As if. As if it's going to make a difference having gears just a tiny bit
closer, at the expense of one cassette that does it all? I've got far better
excuses than the lack of that perfect gear for why I get dropped when
climbing! :>)

I'll even admit that I don't even look to see if any of my gearing options
include the legendary "16" tooth that many seem to not be able to live
without. Heck, I don't even know what happens when you go from 39/53 to
34/50 w/regards the need for that "16" back there. Guess I'll have to turn
in the keys to the shop now... and since I'm dumb enough to admit this in a
usenet post, I'll never be able to run away from it either.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com


"Paul Kopit" <[email protected]> wrote in message
news:[email protected]...
> On Thu, 13 Sep 2007 23:53:07 -0700, "Mike Jacoubowsky"
> <[email protected]> wrote:
>
>>For what it's worth, I ride a 50/34 with a 12-27 rear. I *love* that
>>setup.
>>Gives me gears for everything I need, including Sonora Pass. Sonora Pass
>>was
>>actually the driving force to my move to compact. It was either that or a
>>triple, as I just don't have the raw horsepower I used to. The compact
>>allowed use of everything I already have, with the exception of needing a
>>new crank. A few years down the road, don't be surprised if you see me
>>with
>>a triple. But for now, I can handle what comes my way with my current
>>setup.

>
> That's what I run as well. I am an Ergo 10 person. My hubs are
> ShimaNO. I use 12/27 x 9sp and a current 10sp rear derailleur and it
> shifts aOK. That's my all around bike, a Soma Smoothine with small
> rack and 700x28 tires. On another bike, Colnago Ti/CF, I run 12/27 x
> 10sp but I shift it with an 8sp Record rear derailleur. And the 3rd
> bike, Cannondale CAAD 9, Campy all around with a made up 12/29. Made
> up with 1st 4 cogs from 12/29 and 17-19, 21-3/26-29. It's actually
> better than the Shimano 12/27s. On worn cassettes, the 12/13/14/15
> are usually ok. The 17,19,21 are usually the cogs that wear first.
> An IRD 12/28 works ok for Campy too.
>
> If you are already running a Campy Middle cage rear derailleur, you
> can also run 12/32. You can do it with a standard cage by changing
> out the 10 sp derailleur pulley with an 8sp pulley, which has a
> smaller diameter. Most often, but not always, you need to add a link,
> 1" of chain.
>
> PS: I have a 48/36/26 Sugino Crank on the bench ready to go for the
> Soma and I'd consider running 11/25. Why shouldn't I have any gear I
> want for anyplace I go?
 
On Sep 16, 11:28 pm, "Mike Jacoubowsky" <[email protected]> wrote:
> > PS: I have a 48/36/26 Sugino Crank on the bench ready to go for the
> > Soma and I'd consider running 11/25. Why shouldn't I have any gear I
> > want for anyplace I go?

>
> Indeed, why not? Some of the guys I ride with make fun of me for running a
> 12-27 10-spd block on rides where I don't need anything like a 27. They are
> of the opinion that perhaps in the winter you use the lower gears, but
> in-season, unless you've got something really gnarly on the itinerary, you
> run a 12-25 or even an 11-23.
>
> As if. As if it's going to make a difference having gears just a tiny bit
> closer, at the expense of one cassette that does it all? I've got far better
> excuses than the lack of that perfect gear for why I get dropped when
> climbing! :>)
>
> I'll even admit that I don't even look to see if any of my gearing options
> include the legendary "16" tooth that many seem to not be able to live
> without. Heck, I don't even know what happens when you go from 39/53 to
> 34/50 w/regards the need for that "16" back there. Guess I'll have to turn
> in the keys to the shop now... and since I'm dumb enough to admit this in a
> usenet post, I'll never be able to run away from it either.
>
> --Mike-- Chain Reaction Bicycleswww.ChainReactionBicycles.com
>
> "Paul Kopit" <[email protected]> wrote in message
>
> news:[email protected]...
>
> > On Thu, 13 Sep 2007 23:53:07 -0700, "Mike Jacoubowsky"
> > <[email protected]> wrote:

>
> >>For what it's worth, I ride a 50/34 with a 12-27 rear. I *love* that
> >>setup.
> >>Gives me gears for everything I need, including Sonora Pass. Sonora Pass
> >>was
> >>actually the driving force to my move to compact. It was either that or a
> >>triple, as I just don't have the raw horsepower I used to. The compact
> >>allowed use of everything I already have, with the exception of needing a
> >>new crank. A few years down the road, don't be surprised if you see me
> >>with
> >>a triple. But for now, I can handle what comes my way with my current
> >>setup.

>
> > That's what I run as well. I am an Ergo 10 person. My hubs are
> > ShimaNO. I use 12/27 x 9sp and a current 10sp rear derailleur and it
> > shifts aOK. That's my all around bike, a Soma Smoothine with small
> > rack and 700x28 tires. On another bike, Colnago Ti/CF, I run 12/27 x
> > 10sp but I shift it with an 8sp Record rear derailleur. And the 3rd
> > bike, Cannondale CAAD 9, Campy all around with a made up 12/29. Made
> > up with 1st 4 cogs from 12/29 and 17-19, 21-3/26-29. It's actually
> > better than the Shimano 12/27s. On worn cassettes, the 12/13/14/15
> > are usually ok. The 17,19,21 are usually the cogs that wear first.
> > An IRD 12/28 works ok for Campy too.

>
> > If you are already running a Campy Middle cage rear derailleur, you
> > can also run 12/32. You can do it with a standard cage by changing
> > out the 10 sp derailleur pulley with an 8sp pulley, which has a
> > smaller diameter. Most often, but not always, you need to add a link,
> > 1" of chain.

>
> > PS: I have a 48/36/26 Sugino Crank on the bench ready to go for the
> > Soma and I'd consider running 11/25. Why shouldn't I have any gear I
> > want for anyplace I go?


You can always tell your friends that you have gaps between gears to
make your ride more challenging and get a better workout.

Andres
 
In article <[email protected]>,
Peter Cole <[email protected]> wrote:

> jim beam wrote:
>
> > from an engineers viewpoint, any cog less than 13 is ugly. compacts
> > ensure you use 12 & 11 regularly - cringe.

>
> I'm an engineer. I have 11's on all my bikes.


Ever hear of chordal action? That's one good reason not to use 11 tooth
sprockets.
 
Peter Cole wrote:
> jim beam wrote:
>> Peter Cole wrote:
>>> jim beam wrote:
>>>> Peter Cole wrote:
>>>>> jim beam wrote:
>>>>>> Peter Cole wrote:
>>>>>>> jim beam wrote:
>>>
>>>>>> after all, you also confuse plasticity with elasticity - that's a
>>>>>> pretty fundamental error for a real engineer to make.
>>>>>
>>>>> Repetition doesn't make truth.
>>>>
>>>> er, /who/ cited plasticity as a comparison with elasticity?
>>>
>>> I dunno, I didn't.

>>
>> er, so who, when being asked about elasticity wrote:
>> "25% for 6061." on 08/20/2007 @ 11:09 AM?
>>
>> clue: initials - p.c.

>
> From that post:
>
> ">> I think part of the confusion is over the distinction between force
> >> and energy. Carbon fibers have high specific strength. Carbon fibers
> >> also elongate very little before fracture (~0.8 - 1.4%).

>
> > which compares with __%'s for a steel/ti/al alloys? you know, materials
> > that have dislocations and therefore yield well below their theoretical
> > strength?

>
> 25% for 6061. You can look up the others yourself. E-series glass is
> 4-5%, BTW (>3x CF, as I said). "
>
> Obviously I said "elongation before fracture"


deliberately fudging context between plastic and elastic!


>
> Next point?


how about not being evasive?


>
>
>
>>
>>
>>>
>>>
>>>>>> unless you were deliberately bullshitting of course...
>>>>>
>>>>> Your all-purpose answer.
>>>>
>>>> only when it's observed to be the case. when you don't ********,
>>>> you'll never catch me calling you on it! duh.
>>>
>>> I live for that day.

>>
>> apparently not since you just can't resist bullshitting - see above.
>>

>
> You can't read, and as a result have been posting this petulant proof of
> my "********" for weeks now. Grow up.


are you getting sore? it's easy to fix - stop evading the truth.


>
>
>>>
>>>
>>>>> Where did you get your "engineers[sic] viewpoint"?
>>>>
>>>> you mean where do i get my opinion of people that call themselves
>>>> "engineers"? watching them make stupid-ass mistakes, and then let
>>>> their ego prevent them learning that which would prevent them from
>>>> making the same mistakes in the future, that's where.
>>>
>>> That's all? I thought from the depth of your bitterness they beat you
>>> up and took you lunch money too.

>>
>> eh? so which way do you want it? one minute i'm the bully, now i'm the
>> bullied? make up your mind!

>
> Oh, you're a bully all right. As usual though you turn things around so
> that you're the abused one. Right.


buddy, those are all your words. i simply asked you whether you were
going to make up your mind.


>
>
>>
>>
>>>
>>> Now, which engineer told you an 11 tooth sprocket was ugly?

>>
>>
>> something i learned in school. here, read this since you didn't have
>> that opportunity yourself.
>>
>> http://www.renold.com/nmsruntime/saveasdialog.asp?lID=611&sID=860
>>

>
> Was there anything specific that I'm supposed to read, or do you expect
> me to wade through all 29 pages and guess? Unlike you, I'm not a mind
> reader. If you have a point just make it or stop wasting my time.


er, go to the section on tooth count?

it's a bit rich to be bleating about wanting to be spoon fed when you're
the guy wanting citations all the time. now you have one. it's easy to
navigate. you take it from here.
 
jim beam wrote:
> Peter Cole wrote:
>> jim beam wrote:
>>> Peter Cole wrote:


>>>> Now, which engineer told you an 11 tooth sprocket was ugly?
>>>
>>>
>>> something i learned in school. here, read this since you didn't have
>>> that opportunity yourself.
>>>
>>> http://www.renold.com/nmsruntime/saveasdialog.asp?lID=611&sID=860
>>>

>>
>> Was there anything specific that I'm supposed to read, or do you
>> expect me to wade through all 29 pages and guess? Unlike you, I'm not
>> a mind reader. If you have a point just make it or stop wasting my time.

>
> er, go to the section on tooth count?


Er, there is no section on "tooth count". Tooth count is discussed in
several places in different contexts. Why are you being so coy?

> it's a bit rich to be bleating about wanting to be spoon fed when you're
> the guy wanting citations all the time. now you have one. it's easy to
> navigate. you take it from here.


Sounds like you're unsure of yourself. I make statements then offer
cites to back them up. You have yet to make a statement, other than 11
tooth sprockets are "ugly" -- which is pretty ambiguous. If you have a
point, make it. Put up or shut up.
 
Larry Dickman wrote:
> In article <[email protected]>,
> Peter Cole <[email protected]> wrote:
>
>> jim beam wrote:
>>
>>> from an engineers viewpoint, any cog less than 13 is ugly. compacts
>>> ensure you use 12 & 11 regularly - cringe.

>> I'm an engineer. I have 11's on all my bikes.

>
> Ever hear of chordal action? That's one good reason not to use 11 tooth
> sprockets.


Sure, I'm familiar with the effect (not the term). Creates a variation
in chain speed.

Using a formula I found (1 - cos (180°/N)), I calculate:

11T - 4%
12T - 3.4%
13T - 2.9%

I'm not going to lose sleep over it.

Smaller sprockets also cause a loss in efficiency due to greater
articulation, I'm not going to lose any sleep over that, either.
 

> And even though I'm more of a grinder than a spinner, and love to sprint, I
> haven't found a need for an 11 back there. The 12 works just fine, for me.
> Besides, it's a taller gear than I used to race with (52x13).
>
> --Mike-- Chain Reaction Bicyclesc


Eddy used a 52/13, Rando types used 46-28 with a 13-26 in back.
The English all raced Sturmey FMs, 4 speed medium ratio.
Either everybody was a lot slower in the old days or people have
gotten a lot stronger, must be the drugs. ;-)

11 & 12 are less efficient than a 13 cog, according to Frank Bertos
tests.
 
On Wed, 19 Sep 2007 12:49:02 -0700, "Scott G." <[email protected]>
wrote:

>
>> And even though I'm more of a grinder than a spinner, and love to sprint, I
>> haven't found a need for an 11 back there. The 12 works just fine, for me.
>> Besides, it's a taller gear than I used to race with (52x13).
>>
>> --Mike-- Chain Reaction Bicyclesc

>
>Eddy used a 52/13, Rando types used 46-28 with a 13-26 in back.
>The English all raced Sturmey FMs, 4 speed medium ratio.
>Either everybody was a lot slower in the old days or people have
>gotten a lot stronger, must be the drugs. ;-)
>
>11 & 12 are less efficient than a 13 cog, according to Frank Bertos
>tests.


Dear Scott,

It's a little more complicated than that.

Briefly, real testing shows little practical difference with
derailleurs when looking at the highest gearing.

Here's Berto's chain efficiency graph for a real Shimano wide range
triple, showing 15 selected gears for 44-32-22 x 12-16-20-26-34. I
added the gear ratios and color:

http://i6.tinypic.com/4kn6wxu.jpg

(It's figure 11 from http://www.ihpva.org/pubs/HP52.pdf, but that
takes forever to load, has no captions, and is hard to figure out. It
was a 9x3 27 speed, but Berto didn't test the rear 14, 18, or 23.)

As you can see, the highest gear (44x12) is the rightmost red data
point, gear number 27.

The rightmost red 44/12 turns out to be right at average efficiency,
not the lowest efficiency.

For chart fiends, note that each rear gear (the five colors) shows the
same pattern of a three-point curve for its combination with the
22-32-44 front rings, with the middle point always lowest for the
middle 32 ring. Just trace any color's 3 data points from left to
right to see what I mean.

One reason for this unexpectedly good performance by the smallest cog
is that the little 11-tooth is paired with the biggest and most
efficient 44-tooth front sprocket.

Another reason is that the chainline for the 44-12 is better than
cross-chaining on many other combinations on the wide triple.

Most of all, at the same bicycle speed, higher gearing means lower
chain speed, which in turn means greater chain tension at the same
power, which is the biggest factor in chain efficiency at these
levels. In the highest gear, 44/12, the chain moves slowly at high
tension and efficiency.

Of course, few riders putting out only 80 to 200 watts care much about
such tiny efficiency changes--and that's what these are, small
differences of less than 10 more watts lost out of 200.

At 200 watts, for example, the best combination is the 44/20, 95.9%
efficient, producing a theoretical 191.8 watts.

At the same 200 watts, the 44/12 is 93.7% efficient, producing a
theoretical 187.4 watts, only 4.4 watts less.

Even that difference of 191.8 watts versus 187.4 watts is deceptive
because in real cycling, human legs put out the 200 watts, not an
electric motor.

At the same bicycle speed of 20 mph, the 44/20 spins frantically at
116 rpm, while the 44/12 cruises along at a gentle 70 rpm. Bending
your knees 60% faster to go the same speed will waste more watts than
the chain efficiency will save.

Another way to put it is to imagine where a 22-32-44 would sit on the
chart if we replaced the 12 with an 11 or a 13. The whole curve isn't
likely to move up or down as much as the difference between any other
sets of 3 data points for the rear cog, since they're all for
increases of 4, 6, or 8 teeth on the rear.

Chain efficiency tends to be more theoretical than practical in
ordinary bicycling.

Cheers,

Carl Fogel
 
On Wed, 19 Sep 2007 17:08:13 -0600, [email protected] wrote:

>On Wed, 19 Sep 2007 12:49:02 -0700, "Scott G." <[email protected]>
>wrote:
>
>>
>>> And even though I'm more of a grinder than a spinner, and love to sprint, I
>>> haven't found a need for an 11 back there. The 12 works just fine, for me.
>>> Besides, it's a taller gear than I used to race with (52x13).
>>>
>>> --Mike-- Chain Reaction Bicyclesc

>>
>>Eddy used a 52/13, Rando types used 46-28 with a 13-26 in back.
>>The English all raced Sturmey FMs, 4 speed medium ratio.
>>Either everybody was a lot slower in the old days or people have
>>gotten a lot stronger, must be the drugs. ;-)
>>
>>11 & 12 are less efficient than a 13 cog, according to Frank Bertos
>>tests.

>
>Dear Scott,
>
>It's a little more complicated than that.
>
>Briefly, real testing shows little practical difference with
>derailleurs when looking at the highest gearing.
>
>Here's Berto's chain efficiency graph for a real Shimano wide range
>triple, showing 15 selected gears for 44-32-22 x 12-16-20-26-34. I
>added the gear ratios and color:
>
>http://i6.tinypic.com/4kn6wxu.jpg
>
>(It's figure 11 from http://www.ihpva.org/pubs/HP52.pdf, but that
>takes forever to load, has no captions, and is hard to figure out. It
>was a 9x3 27 speed, but Berto didn't test the rear 14, 18, or 23.)
>
>As you can see, the highest gear (44x12) is the rightmost red data
>point, gear number 27.
>
>The rightmost red 44/12 turns out to be right at average efficiency,
>not the lowest efficiency.
>
>For chart fiends, note that each rear gear (the five colors) shows the
>same pattern of a three-point curve for its combination with the
>22-32-44 front rings, with the middle point always lowest for the
>middle 32 ring. Just trace any color's 3 data points from left to
>right to see what I mean.
>
>One reason for this unexpectedly good performance by the smallest cog
>is that the little 11-tooth is paired with the biggest and most
>efficient 44-tooth front sprocket.
>
>Another reason is that the chainline for the 44-12 is better than
>cross-chaining on many other combinations on the wide triple.
>
>Most of all, at the same bicycle speed, higher gearing means lower
>chain speed, which in turn means greater chain tension at the same
>power, which is the biggest factor in chain efficiency at these
>levels. In the highest gear, 44/12, the chain moves slowly at high
>tension and efficiency.
>
>Of course, few riders putting out only 80 to 200 watts care much about
>such tiny efficiency changes--and that's what these are, small
>differences of less than 10 more watts lost out of 200.
>
>At 200 watts, for example, the best combination is the 44/20, 95.9%
>efficient, producing a theoretical 191.8 watts.
>
>At the same 200 watts, the 44/12 is 93.7% efficient, producing a
>theoretical 187.4 watts, only 4.4 watts less.
>
>Even that difference of 191.8 watts versus 187.4 watts is deceptive
>because in real cycling, human legs put out the 200 watts, not an
>electric motor.
>
>At the same bicycle speed of 20 mph, the 44/20 spins frantically at
>116 rpm, while the 44/12 cruises along at a gentle 70 rpm. Bending
>your knees 60% faster to go the same speed will waste more watts than
>the chain efficiency will save.
>
>Another way to put it is to imagine where a 22-32-44 would sit on the
>chart if we replaced the 12 with an 11 or a 13. The whole curve isn't
>likely to move up or down as much as the difference between any other
>sets of 3 data points for the rear cog, since they're all for
>increases of 4, 6, or 8 teeth on the rear.
>
>Chain efficiency tends to be more theoretical than practical in
>ordinary bicycling.
>
>Cheers,
>
>Carl Fogel


An improved version of the colored and captioned Berto graph:

http://i19.tinypic.com/4zux068.jpg

CF
 

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