CVT interest

Per Simon Brooke:

Quoted message said:

and mountain bike racers might well tolerate a small
efficiency deficit if it was compensated by a significant increase in
reliability.

For whatever it's worth, an MTB racer that checked out my Rohloff-equipped FS
said that the extra two pounds would cost him races.
--
PeteCresswell

Simon Brooke said:

If someone came up with a CVT design which was as efficient as a
derailleur, which was no heavier than a derailleur, and which was
reasonably reliable, and which the UCI didn't immediately ban, racing
cyclists would buy it in droves.

Your list? I think you left out "and tossed in a free pony."

On Tue, 06 Jun 2006 11:17:10 +0100, Simon Brooke
<[email hidden]> wrote:

[snip]

Quoted message said:

Jobst's objections with regard to the step-up ratio are an irrelevance,
since the step-up can be handled in the final drive chain.

[snip]

Dear Simon,

It may be worth pointing out that normal-transmission motorcycles tend
to reverse the final chain-drive gearing found in the bicycle world.
(I don't know what CVT motorcycles use.)

That is, bicycles tend to run a big front and small rear sprocket, a
53-52-50-42-39-30 front and an 11-32 rear.

Motorcycles tend to run the reverse of that, with a tiny front
countershaft sprocket and a huge rear sprocket.

At 20-25 mph, my touring bike is usually running 53 x 11, while my
ancient trials machine is running 14 x 52 (much higher chain speed).

This sort of difference might complicate adapting motorcycle CVT to
bicycle CVT.

There are other reasons why motorcycles use real transmissions instead
of the bizarre derailleurs found only on bicycles. High RPM engines
and chain speeds require much heavier chains and gears than low RPM
bicycles with low chain speeds.

(When I was 12, I learned to ride on a Honda Trail 90, whose 4-speed
automatic no-clutch transmission sat in a fuzzy no-man's land between
CVT and a normal transmission, with a small lever under one foot peg
to throw the beast's gears into low range, like a jeep or a front 39
tooth derailleur. It was clumsy, but it worked.)

Cheers,

Carl Fogel

On Tue, 06 Jun 2006 08:11:01 -0400, "(PeteCresswell)" <[email hidden]>

Quoted message said:

Per Simon Brooke:

Quoted message said:

and mountain bike racers might well tolerate a small
efficiency deficit if it was compensated by a significant increase in
reliability.

For whatever it's worth, an MTB racer that checked out my Rohloff-equipped FS
said that the extra two pounds would cost him races.

Dear Pete,

It might, but . . .

Plug in MTB, 250 watts, and 5 miles on this calculator:

http://www.kreuzotter.de/english/espeed.htm

Make the imaginary rider do 15 miles--5 at 7% climb, 5 at 7% descent,
and 5 at level.

Then add 2 pounds to his bike and do it again.

default +2
weight lbs
5 miles 7% grade 37:02.2 37:30.0
5 miles 0% grade 15:27.8 15:27.8
5 miles -7% grade 8:52.5 8:51.0
------- --------- ------- -------
15 miles loop 61:22.5 61:48.8

Less than 30 seconds per hour, probably important to a racer, probably
an invisible 0.7% difference to anyone else

How often do we hear an MTB racer moaning that he needed to lose two
pounds to win a race?

Cheers,

Carl Fogel

Simon Brooke said:

in message <[email hidden]>, Tom

Kunich (') said:

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

in message <[email hidden]>, Ryan

And an opposed-cone system is a variant of belt drive. I just wish I
could find some efficiency figures for it, but thus far I can't.

It's my guess that the SIZE of an opposed cone belt drive is simply out
of scale.

Opposed cone systems as used in motor scooters are very small indeed. The
'dernies' used to pace velodrome cyclists use them, so they can clearly
transfer the power to pull a cyclist up to race speed. Size isn't
inherently a problem. The potential problems are ability to transfer
sufficient torque with reasonable belt life, and overall efficiency.

Ain't the way it's done Simon. You use a fixed gear that drives one
cone inside of the rear hub. You press in the steel outer cone into the
hub. You then need a friction-ball mechanism to transfer the inner
power to the outer hub and a mechanism that will infinitely move the
balls in and out along the cones.

The problem is STILL that there isn't enough space to make the cones of
sufficient size for balls of sufficient size to maintain frictional
coupling to work with any efficacy.

For the uninformed - originally computers were all mechanical and I was
a computer engineer. Electronics is gooooooooooooood.

Quoted message said:

Jobst's objections with regard to the step-up ratio are an irrelevance,
since the step-up can be handled in the final drive chain. His
objections with regard to torque transfer are not an irrelevance and may
genuinely be a killer for the idea, since, as he rightly points out,
motor scooter engines rev two orders of magnitude higher than racing
cyclists. But I'd still like to see figures rather than assertions.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; ... exposing the violence incoherent in the system...

in message <[email hidden]>, Tom

Kunich (') said:

Simon Brooke said:

in message <[email hidden]>, Tom

Kunich (') said:

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...
> in message <[email hidden]>, Ryan
>
> And an opposed-cone system is a variant of belt drive. I just wish
> I could find some efficiency figures for it, but thus far I can't.

It's my guess that the SIZE of an opposed cone belt drive is simply
out of scale.

Opposed cone systems as used in motor scooters are very small indeed.
The 'dernies' used to pace velodrome cyclists use them, so they can
clearly transfer the power to pull a cyclist up to race speed. Size
isn't inherently a problem. The potential problems are ability to
transfer sufficient torque with reasonable belt life, and overall
efficiency.

Ain't the way it's done Simon. You use a fixed gear that drives one
cone inside of the rear hub. You press in the steel outer cone into the
hub. You then need a friction-ball mechanism to transfer the inner
power to the outer hub and a mechanism that will infinitely move the
balls in and out along the cones.

That's one way of doing it. It isn't the only way of doing it and, as you
so cogently point out, for bicycle applications it isn't the right way
of doing it.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; When your hammer is C++, everything begins to look like a thumb.

in message <[email hidden]>,

(') said:

On Tue, 06 Jun 2006 11:17:10 +0100, Simon Brooke
<[email hidden]> wrote:

[snip]

Quoted message said:

Jobst's objections with regard to the step-up ratio are an irrelevance,
since the step-up can be handled in the final drive chain.

[snip]

It may be worth pointing out that normal-transmission motorcycles tend
to reverse the final chain-drive gearing found in the bicycle world.
(I don't know what CVT motorcycles use.)

[snip]

Quoted message said:

This sort of difference might complicate adapting motorcycle CVT to
bicycle CVT.

Oh, certainly. I wouldn't advocate doing that. I'm merely making the
observation that motorcycle CVT transmits similar (indeed, up to
substantially more) power in a very reasonably sized package. It's true
that it does so at higher RPM with lower torque, and this may mean that
in the bicycle application you can't get enough 'grip' between cone and
belt, or that belt tension sufficient to get enough grip causes too much
loss or premature belt failure.

Whatever you do to change bicycle transmissions in the future will not
come as something 'bolted on' to existing transmission systems, but as a
radical redesign probably of the bottom bracket area. All other things
being equal it would make sense to move delicate transmission components
into the centre of the bike where they do not contribute to unsprung
weight and are relatively protected from accidental damage. Mind you,
that's not an argument about CVT, rather it's one about transmission
design generally.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

The Conservative Party is now dead. The corpse may still be
twitching, but resurrection is not an option - unless Satan
chucks them out of Hell as too objectionable even for him.

Per [email hidden]:

Quoted message said:

Less than 30 seconds per hour, probably important to a racer, probably
an invisible 0.7% difference to anyone else

Definitely invisible to Yours Truly... but I'm about as far toward the other end
of the Barney-Racer spectrum as one can get.

Quoted message said:

How often do we hear an MTB racer moaning that he needed to lose two
pounds to win a race?

My guess is that most serious racers don't have two pounds of non-muscle to
lose.
--
PeteCresswell

On Tue, 06 Jun 2006 18:38:03 -0400, "(PeteCresswell)" <[email hidden]>

Quoted message said:

Per [email hidden]:

Quoted message said:

Less than 30 seconds per hour, probably important to a racer, probably
an invisible 0.7% difference to anyone else

Definitely invisible to Yours Truly... but I'm about as far toward the other end
of the Barney-Racer spectrum as one can get.

Quoted message said:

How often do we hear an MTB racer moaning that he needed to lose two
pounds to win a race?

My guess is that most serious racers don't have two pounds of non-muscle to
lose.

Dear Pete,

If they haven't got 2 pounds of non-muscle to lose, then they're at
less than 2% non-essential body fat, which is unlikely. These sites,
for example estimate body fat for cycling athletes at 5% to 15%, or
7.5 to 22.5 lbs for a 150-lb rider:

http://www.brianmac.demon.co.uk/fatcent.htm

http://www.sport-fitness-advisor.com/bodyfatpercentage.html

This one estimate "essential" fat at 2-4%:

http://www.healthchecksystems.com/bodyfat.htm

(Personally, I take more extensive precautions against a hard winter.)

In any case, the much-maligned extra-2-lb Rohloff (I know you like
yours, so don't misunderstand me) might more than make up for its
Lilliputian obesity by eliminating much of the fuss and trouble in MTB
racing of missed shifts and cross-chaining decisions.

Like you, however, I doubt that MTB racers will shift in the Rohloff's
direction, much less a mythical CVT.

Cheers,

Carl Fogel

Per [email hidden]:

Quoted message said:

(Personally, I take more extensive precautions against a hard winter.)

I've been trying to lose 10 lbs for over fifteen years. Last time I checked,
I'd gained about nine...
--
PeteCresswell

On Tue, 06 Jun 2006 19:22:27 -0400, "(PeteCresswell)" <[email hidden]>

Quoted message said:

Per [email hidden]:

Quoted message said:

(Personally, I take more extensive precautions against a hard winter.)

I've been trying to lose 10 lbs for over fifteen years. Last time I checked,
I'd gained about nine...

Dear Pete,

Your body is merely testifying against predictions of global warming.

Cheers,

Carl Fogel

"Simon Brooke" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

in message <[email hidden]>, Tom

Kunich (') said:

Ain't the way it's done Simon. You use a fixed gear that drives one
cone inside of the rear hub. You press in the steel outer cone into the
hub. You then need a friction-ball mechanism to transfer the inner
power to the outer hub and a mechanism that will infinitely move the
balls in and out along the cones.

That's one way of doing it. It isn't the only way of doing it and, as you
so cogently point out, for bicycle applications it isn't the right way
of doing it.

The problem is that it is the most practical system and it is limited by the
materials possible to use. The main problem is that the torque transmission
necessary is too high for small systems without positive engagement. That
pretty much requires toothed wheels and chains.

We have had 140 years of development of the bicycle and the highest rate of
development was in the early 1900's. I suspect that people who believe
there's a better way have never even BEGUN to look into the patents that
were issued by the tens of thousands on bicycle mechanisms.

We are today riding the finest developments of the finest minds. Hell, even
Jobst has added SOMETHING to bicycling engineering by formalizing wheel
theory.

There is always the possibility that someone will come up with something new
that's a step forward but the chances of that are so small as to be
practically nil.

In article <[email hidden]>,

Quoted message said:

On Tue, 06 Jun 2006 18:38:03 -0400, "(PeteCresswell)" <[email hidden]>

Quoted message said:

Per [email hidden]:

Quoted message said:

Less than 30 seconds per hour, probably important to a racer, probably
an invisible 0.7% difference to anyone else

Definitely invisible to Yours Truly... but I'm about as far toward the other
end
of the Barney-Racer spectrum as one can get.

Quoted message said:

How often do we hear an MTB racer moaning that he needed to lose two
pounds to win a race?

My guess is that most serious racers don't have two pounds of non-muscle to
lose.

Dear Pete,

If they haven't got 2 pounds of non-muscle to lose, then they're at
less than 2% non-essential body fat, which is unlikely. These sites,
for example estimate body fat for cycling athletes at 5% to 15%, or
7.5 to 22.5 lbs for a 150-lb rider:

http://www.brianmac.demon.co.uk/fatcent.htm

http://www.sport-fitness-advisor.com/bodyfatpercentage.html

This one estimate "essential" fat at 2-4%:

http://www.healthchecksystems.com/bodyfat.htm

This argument reminds me of a joke in Futurama where Bender the robot
defends the meal he just made: "There was nothing wrong with that food!
The salt level was 10% less than a lethal dose."

Note that "essential" fat is the fat you need or you get sick and die. I
would suggest that most bike racers probably want the same margin of,
er, safety in their body fat as they do in their race frames: let's
guess that weight-conscious racers (climbers, GC hopefuls, and XC
mountain bikers) aim for about double the essential fat level and I bet
you're about right. Below that, you're courting performance limiting
health issues: it's easy to get sick, et cetera. I've been following a
friend's attempts to push his BF to 5%, and while he has hit single
digits (and looks disease-lean at that BF level), 5% has been elusive.

Quoted message said:

In any case, the much-maligned extra-2-lb Rohloff (I know you like
yours, so don't misunderstand me) might more than make up for its
Lilliputian obesity by eliminating much of the fuss and trouble in MTB
racing of missed shifts and cross-chaining decisions.

I don't read a huge number of XC bike race reports, but I can tell you
that few of them comment on drivetrain failures as a problem during
races, even in 24-hour races. Most XC racers have also gone to two front
rings to improve shifting and because, well, they're so good they don't
need a granny gear.

There's also a world of difference between the amount of time the
average pro race bike gets between tune-ups and the amount of time the
average "serious" MTB rider's bike gets between tune-ups. Anybody good
enough to be paid to race XC is going to be racing on a bike that is
constantly maintained. I wouldn't be surprised to hear that they use a
new chain for every race weekend; even GC roadies typically race on
chains changed weekly during grand tours.

Quoted message said:

Like you, however, I doubt that MTB racers will shift in the Rohloff's
direction, much less a mythical CVT.

The pros seriously don't have two pounds to lose from their bodies, and
if you think 30s/hour isn't much, look here:

http://www.cyclingnews.com/mtb.php?id=mtb/2006/jun06/sarre06

I've grabbed the first MTB race with timings from Cycling News.
Admittedly, the winner beat the runner-up by more than your 30s/hour
estimate, but note that every Pro man from 3rd through 8th has less than
a 30s gap to the rider ahead of him. In other words, if any one of those
riders had gained two pounds, they would have probably lost a position,
assuming everything else remained equal.

For non-racers, well, let's just say that 30-pound bikes are quite
popular, so I can see the reasoning behind adding a Rohloff to the mix.

ObCVT: there would certainly be an excellent market for a CVT that was
light, efficient, and practical for bicycles. Please add it to the pile
of desired bike inventions along with mine:

-a reliable 5-pound road bike that costs $100
-crosswind-friendly wheels as aerodynamic as discs
-a 10-pound MTB with 6" of travel at each end and no suspension movement
due to pedaling.
-a bicycle as aerodynamic as the Varna Diablo II, as light as the
Litespeed Ghisallo, and as practical as the Surly Karate Monkey.
-a better water bottle holder
-a Wal-Mart tandem for $99.

Seriously, there's almost no point in asking the question: if the
transmission truly has no takeaways compared to current drivetrains, and
the advantages of a CVT, people will use it. Please do not forget that
price matters.

And while you're at it, we need someone to build a ribbon for a space
elevator. Could you take care of that, too?

--
Ryan Cousineau [email hidden] http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos

in message <[email hidden]>, Ryan

Cousineau (') said:

I don't read a huge number of XC bike race reports, but I can tell you
that few of them comment on drivetrain failures as a problem during
races, even in 24-hour races. Most XC racers have also gone to two
front rings to improve shifting and because, well, they're so good they
don't need a granny gear.

Many do ride without a granny ring, certainly; part of the reason for
that is because of shifting problems, and another part of the reason is
to shorten the cage on the rear mech to keep it out of crud. Both of
these issues relate directly to drivetrain failures, because, as I said,
a broken or bent rear derailleur usually means a lost race.

Quoted message said:

There's also a world of difference between the amount of time the
average pro race bike gets between tune-ups and the amount of time the
average "serious" MTB rider's bike gets between tune-ups. Anybody good
enough to be paid to race XC is going to be racing on a bike that is
constantly maintained.

And this, too, is because the bikes (and particularly their
transmissions) are so vulnerable to damage and to wear, to the extent
that it impacts racing performance.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/
"The result is a language that... not even its mother could
love. Like the camel, Common Lisp is a horse designed by
committee. Camels do have their uses."
;; Scott Fahlman, 7 March 1995

in message <[email hidden]>, Tom

Kunich (') said:

We are today riding the finest developments of the finest minds. Hell,
even Jobst has added SOMETHING to bicycling engineering by formalizing
wheel theory.

We are currently riding bicycles which are the shape they are because
every potentially race-winning innovation in the last seventy years has
immediately been banned by the UCI. Our racing bikes are slower than the
HPV people's tourers, and our time trial bikes are considerably less
than half as fast as their Battle Mountain Specials. So the idea that
the modern diamond frame bicycle is the last word in innovation and
development is risible.

Quoted message said:

There is always the possibility that someone will come up with
something new that's a step forward but the chances of that are so
small as to be practically nil.

Innovation is still possible and will still come. How quickly it gets
adopted is a matter of the conservatism of the UCI and of the cycling
sport in general, but in the meantime is you gave the HPV people one
half of, say, Giant's annual research and development budget to
productise the developments they've made at Battle Mountain, you'd see a
practical, lightweight machine probably with front wheel drive and a
monocoque chassis in which you could halve your current time-trial
times. The chances of that are so large it's virtually certain.

The chances that the UCI would accept it /are/ nil, however.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

IMHO, there aren't enough committed Christians, but that's care
in the community for you. -- Ben Evans

In article <[email hidden]>, Peter Cole

() said:

Zero interest. I don't see the need for an infinitely variable
transmission -- we're not diesel engines.

Lots of torque at low rpm, limited rev range? Sounds pretty diesel-
esque to me. Bicycles and heavy lorries both have lots of gears.

--
Dave Larrington - <http://www.legslarry.beerdrinkers.co.uk/>
Do not top-post like a Cretinous Foul-Yob fit only for Stoning.

Simon Brooke said:

Innovation is still possible and will still come. How quickly it gets
adopted is a matter of the conservatism of the UCI and of the cycling
sport in general, but in the meantime is you gave the HPV people one
half of, say, Giant's annual research and development budget to
productise the developments they've made at Battle Mountain, you'd see a
practical, lightweight machine probably with front wheel drive and a
monocoque chassis in which you could halve your current time-trial
times.

I doubt this very much. I follow recumbents a fair bit - ride one
myself as my main recreation bike. The significant increases would be
with a faired bike on a course with relatively few hills and no high
wind factor. Without a fairing, recumbents have problems staying with
the better USCF TT people - a trained TT person is not all that
inefficient into the wind, so at best you may get a small delta, not a
large one.

A practical lightweight machine that can beat the average USCF club
riders by 50% is nonsense. You aren't blowing smoke - you're refusing
to exhale...

Curtis L. Russell
Odenton, MD (USA)
Just someone on two wheels...

in message <[email hidden]>, Curtis L.

Russell (') said:

Simon Brooke said:

Innovation is still possible and will still come. How quickly it gets
adopted is a matter of the conservatism of the UCI and of the cycling
sport in general, but in the meantime is you gave the HPV people one
half of, say, Giant's annual research and development budget to
productise the developments they've made at Battle Mountain, you'd see
a practical, lightweight machine probably with front wheel drive and a
monocoque chassis in which you could halve your current time-trial
times.

I doubt this very much. I follow recumbents a fair bit - ride one
myself as my main recreation bike. The significant increases would be
with a faired bike on a course with relatively few hills and no high
wind factor. Without a fairing, recumbents have problems staying with
the better USCF TT people - a trained TT person is not all that
inefficient into the wind, so at best you may get a small delta, not a
large one.

A practical lightweight machine that can beat the average USCF club
riders by 50% is nonsense. You aren't blowing smoke - you're refusing
to exhale...

Jan Ullrich, 51Km/h for almost one hour (outdoor road riding, not flat)
Chris Boardman, 56Km in one hour (indoor velodrome)
Sam Whittingham, 84.215km in one hour (outdoor, banked oval track)
Craig MacLean, 65.47Km unpaced 500m flying start (indoor velodrome)
Sam Whittingham, 130.36 Km/h unpaced 200m flying start (outdoor, flat
road)

I grant you 84 isn't twice 56, but 130 is remarkably precisely twice 65.
I also suggest to you that Ullrich and Boardman are probably slightly
better athletes than Whittingham. Those are pretty big deltas.

--
[email hidden] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; better than your average performing pineapple

Ryan Cousineau said:

Let me know when the average recumbent tourer is actually more aero than
a good position on a good DF. There are exceptions, but there are also a
lot of 'bents out there that manage to combine the ponderous handling of
a recumbent with the weight of a heavy recumbent and the aero
performance of a DF.

I really, really like the idea of HPVs, and especially land speed
vehicles. I have to: the Varna Diablo was built less than 100 km from my
house.

(I smell topic drift)

Well, a Tour Easy
(http://home.pacifier.com/~jwills/diane-big.jpg)
makes a pretty good touring bike with a fairing and a body sock:
http://www.crazyguyonabike.com/journal/page/pic/?o=lt&pic_id=48336&v=1a1&size=large
IMO, it's the best *compromise* among the competing demands of comfort,
utility, durability, light weight, and aerodynamics in the recumbent
world. It's not the best in any of those areas, but it's competitive in
most of them. A couple of the guys who did the cross-US tour also do
the local 10-mile time trials on the same bikes.

I would guess that modifying the Varna Diablo for greater streetability
would result in something like the Velox Solium:
http://www.ohpv.org/albums/bm2004/velox/pages/velox3.htm . It was
capable of nearly 60mph at Battle Mountain and was easily ridable at
walking speeds.

Jeff

Simon Brooke said:

I grant you 84 isn't twice 56, but 130 is remarkably precisely twice 65.
I also suggest to you that Ullrich and Boardman are probably slightly
better athletes than Whittingham. Those are pretty big deltas.

And his bike has nothing to do with a practical time trialer. Not even
close. And comparing a time trial on the road with one on the track is
also pretty specious. Whittingham was in a fully enclosed recumbent
that would get in trouble if it came to a stop in the wrong place (as
in, no one to hold it up). The front tire has minimal steering
capability. The tires are too pumped to handle a real bump with the
fairing on. That is not practical.

FWIW, I've seen three sponsored time trial recumbents come loaded for
bear at different time trials on rolling - not hilly - roadways, in
the general area of 40 km. Technically, two of the three met USCF regs
at the time and were generally roadworthy. Not one led even in a split
after one initial downhill on one of the courses (the other two never
led a split period) and one fell over in a turnaround. None, needless
to say, won and none would have been in the top ten overall,which
included national level cat 1s riding 'regular' USCF legal TT bikes
and that spent a lot of time on time trials.

I'm willing to concede that a person that raced recumbents on a
regular basis over 40 km courses could give the cat 1s a run for their
money on a 'practical' course - maybe someday beat them. And if a good
recumbent rider went to a local club TT and it was the right course,
they might be able to set the low time right now. However, you set the
conditions - Giants budget to turn out a practical HPV that would
reduce the TT time by 50%. You are blowing smoke - on a good day.
Nothing you said helps your argument.

Curtis L. Russell
Odenton, MD (USA)
Just someone on two wheels...