Continuously-variable transmission box in Honda MTB

"Van Bagnol" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

Did anyone see the latest issue of _Mountain Bike Action_
featuring Honda's mountain bike and CVT drivetrain? Any
comments?

Van
--
Van Bagnol / v b a g n o l at earthlink dot net / c r l at
bagnol dot com ...enjoys - Theatre / Windsurfing /
Skydiving / Mountain Biking ...feels - "Parang lumalakad
ako sa loob ng paniginip" ...thinks - "An Error is Not a
Mistake ... Unless You Refuse to Correct

It"

looks heavier than a regular drivetrain

Michael

Michael Paul said:

"Van Bagnol" <[email hidden]> wrote in message news:van-
[email hidden]...

Quoted message said:

Did anyone see the latest issue of _Mountain Bike Action_
featuring Honda's mountain bike and CVT drivetrain? Any
comments?

looks heavier than a regular drivetrain

Michael

Downhill rigs looking more and more like motorcross every
year.... sure does look heavy.

A few car manufacturers have made models with CVT boxes over
the years, i think DAF was the first, but they were riddled
with problems, related to belt slippage and the requirement
for very frequent maintainance and such things. I think i
read that Audi have made a CVT system which eliminates belts
so maybe things are improving, Even so, i suspect that Honda
bike wouldn't be good for much more than race runs, wouldn't
go for long without maintenance i bet.

Did anyone read about the technicalities of the Honda
box? Is it belt/roller or some sort of expanding sprocket
and chain?

--
Mark

On Wed, 12 May 2004 17:08:24 +0100, "Mark \(UK\)"

may have said:

Michael Paul said:

"Van Bagnol" <[email hidden]> wrote in message news:van-
[email hidden]...

Quoted message said:

Did anyone see the latest issue of _Mountain Bike
Action_ featuring Honda's mountain bike and CVT
drivetrain? Any comments?

looks heavier than a regular drivetrain

Michael

A few car manufacturers have made models with CVT boxes
over the years, i think DAF was the first, but they were
riddled with problems, related to belt slippage and the
requirement for very frequent maintainance and such things.
I think i read that Audi have made a CVT system which
eliminates belts so maybe things are improving,

If Audi's making it, don't expect it to be worth owning.
They've had to go over to a 100,000-mile drivetrain warranty
just to get people to buy their cars in the US, and their
resale value on out-of-warranty units still isn't as high
proportionately as most other makes. The only car that
depreciates faster, in my experience, is Daewoo...and that's
because GM took Daewoo off the North American market.

Quoted message said:

Even so, i suspect that Honda bike wouldn't be good for
much more than race runs, wouldn't go for long without
maintenance i bet.

Honda probably figures that there's a market for wierd and
unusual tech. I suspect that they will not sell many.

Quoted message said:

Did anyone read about the technicalities of the Honda
box? Is it belt/roller or some sort of expanding sprocket
and chain?

Only the former works in practice; variable-diameter pulleys
drive a heavy belt. Sliding-cone-drive setups have been
tried in the lab, and they always cause some fool at Popular
Mechanics to write it up as The Next Really Great Thing That
Will Be In Every Car In A Few Years. Oddly enough, they
never make it to market. CVTs of the belt type are common in
ATVs and LPCs (light personnel carriers; a glorified term
for "golf cart"😉 and are regarded and durable and reliable
in most applications there. I don't know how Honda has
adapted the concept to the relatively low velocities of a
bicycle, but apparently they must have done so.

Here's a picture of the bike:

world.honda.com2030203.htmlOpen ↗

--
My email address is antispammed; pull WEEDS if replying via
e-mail. Typoes are not a bug, they're a feature. Words
processed in a facility that contains nuts.

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

Quoted message said:

On Wed, 12 May 2004 17:08:24 +0100, "Mark \(UK\)"

may have said:

Michael Paul said:

"Van Bagnol" <[email hidden]> wrote in message news:van-
[email hidden]...
> Did anyone see the latest issue of _Mountain Bike
> Action_ featuring Honda's mountain bike and CVT
> drivetrain? Any comments?
>
looks heavier than a regular drivetrain

Quoted message said:

Even so, i suspect that Honda bike wouldn't be good for
much more than race runs, wouldn't go for long without
maintenance i bet.

Honda probably figures that there's a market for wierd and
unusual tech. I suspect that they will not sell many.

Honda sometimes like to be the Sony of the vehicle market.

Quoted message said:

Quoted message said:

Did anyone read about the technicalities of the Honda
box? Is it belt/roller or some sort of expanding sprocket
and chain?

Only the former works in practice; variable-diameter
pulleys drive a heavy belt. Sliding-cone-drive setups have
been tried in the lab, and they always cause some fool at
Popular Mechanics to write it up as The Next Really Great
Thing That Will Be In Every Car In A Few Years. Oddly
enough, they never make it to market. CVTs of the belt
type are common in ATVs and LPCs (light personnel
carriers; a glorified term for "golf cart"😉 and are
regarded and durable and reliable in most applications
there. I don't know how Honda has adapted the concept to
the relatively low velocities of a bicycle, but apparently
they must have done so.

Last time we had the belt-drive-for-bikes discussion in
here, there was a general consensus that it couldn't be done
at all. Not reliably anyway.
--
Mark South Citizen of the World, Denizen of the Net <<Tiens!
Ce poulet a une grenade!

On Wed, 12 May 2004 22:00:02 +0200, "Mark South"

may have said:

Last time we had the belt-drive-for-bikes discussion in
here, there was a general consensus that it couldn't be
done at all. Not reliably anyway.

I'd have argued that myself if it wasn't for the fact that
it appears that Honda may have come up with a kluge that at
least permits the bike to move forward. How well it works
is, of course unanswered, and I am skeptical about that
subject. Even if they have made it work reasonably
acceptably, though, I don't see it displacing the der setup
anytime soon, since I can't see any way for it to be as
efficient...and the limiting factor in bike performance is
the powerplant, so drivetrain losses just aren't going to be
tolerable to a lot of folks.

The photo of the Honda bicycle shows a unit that bears more
than a passing resemblance to a motorcycle. I doubt that
this is mere coincidence. OTOH, as far as I can see, Honda
doesn't have any marketing channels set up to get this to
the places where it might sell if it really is a worthwhile
piece of tech. In my opinion, that fact is a big hint that
this is a showcase item with no mass production planned. Honda-
branded bikes are sold at K-Mart, however as far as I know
those are strictly pasted-on-label units rather than a
product that actually emerged from Honda's plants. A bike
with a CVT would not be a logical thing to market through
KMart unless it was going to be *really* cheap.

--
My email address is antispammed; pull WEEDS if replying via
e-mail. Typoes are not a bug, they're a feature. Words
processed in a facility that contains nuts.

On Wed, 12 May 2004 22:00:02 +0200, "Mark South"

may have said:

Last time we had the belt-drive-for-bikes discussion in
here, there was a general consensus that it couldn't be
done at all. Not reliably anyway.

I'd have argued that myself if it wasn't for the fact that
it appears that Honda may have come up with a kluge that at
least permits the bike to move forward. How well it works
is, of course unanswered, and I am skeptical about that
subject. Even if they have made it work reasonably
acceptably, though, I don't see it displacing the der setup
anytime soon, since I can't see any way for it to be as
efficient...and the limiting factor in bike performance is
the powerplant, so drivetrain losses just aren't going to be
tolerable to a lot of folks.

The photo of the Honda bicycle shows a unit that bears more
than a passing resemblance to a motorcycle. I doubt that
this is mere coincidence. OTOH, as far as I can see, Honda
doesn't have any marketing channels set up to get this to
the places where it might sell if it really is a worthwhile
piece of tech. In my opinion, that fact is a big hint that
this is a showcase item with no mass production planned. Honda-
branded bikes are sold at K-Mart, however as far as I know
those are strictly pasted-on-label units rather than a
product that actually emerged from Honda's plants. A bike
with a CVT would not be a logical thing to market through
KMart unless it was going to be *really* cheap.

--
My email address is antispammed; pull WEEDS if replying via
e-mail. Typoes are not a bug, they're a feature. Words
processed in a facility that contains nuts.

"Mark South" <[email hidden]> wrote

Quoted message said:

Last time we had the belt-drive-for-bikes discussion in
here, there was a general consensus that it couldn't be
done at all. Not reliably anyway.

Belts can be done, but only if you include a Rohloff
SpeedHub. And maybe a Mountain Drive BB.

rohloff.derohloff.deOpen ↗ schlumpf.chmd engl.htmOpen ↗

pete

Werehatrack said:

Even if they have made it work reasonably acceptably,
though, I don't see it displacing the der setup anytime
soon, since I can't see any way for it to be as
efficient...and the limiting factor in bike performance is
the powerplant, so drivetrain losses just aren't going to
be tolerable to a lot of folks.

Honda haven't published drivetrain losses for the CVT box,
but I imagine it would operate something like a seamless
Sturmey Archer hub. You'd always be pedalling at the right
cadence which is going to help efficiency, the transmission
can be protected from [censored] and dirt, and you're not dragging
the chain through funny angles and idler gears on a
derailleur. Might actually be more efficient. It looks as if
there's still a chain doing the actual drive from the cranks
to the back wheel. That said, they're racing it as a DH
bike, so pedalling might not be *that* important.

Werehatrack said:

Even if they have made it work reasonably acceptably,
though, I don't see it displacing the der setup anytime
soon, since I can't see any way for it to be as
efficient...and the limiting factor in bike performance is
the powerplant, so drivetrain losses just aren't going to
be tolerable to a lot of folks.

Honda haven't published drivetrain losses for the CVT box,
but I imagine it would operate something like a seamless
Sturmey Archer hub. You'd always be pedalling at the right
cadence which is going to help efficiency, the transmission
can be protected from [censored] and dirt, and you're not dragging
the chain through funny angles and idler gears on a
derailleur. Might actually be more efficient. It looks as if
there's still a chain doing the actual drive from the cranks
to the back wheel. That said, they're racing it as a DH
bike, so pedalling might not be *that* important.

In article <[email hidden]>,

Mark \(UK\) said:

A few car manufacturers have made models with CVT boxes
over the years, i think DAF was the first, but they were
riddled with problems, related to belt slippage and the
requirement for very frequent maintainance and such
things. I think i read that Audi have made a CVT system
which eliminates belts so maybe things are improving, Even
so, i suspect that Honda bike wouldn't be good for much
more than race runs, wouldn't go for long without
maintenance i bet.

Did anyone read about the technicalities of the Honda
box? Is it belt/roller or some sort of expanding sprocket
and chain?

It appears to be a variable-geometry reciprocating ratchet.
It uses no belts or chains, except for the drive chain from
the transmission box to the rear wheel (as in a single-
speed). It does have gears, though.

The basic mechanical transmission is this: Step up pedal
gearing to 11:1 or thereabouts; convert circular motion to
reciprocating; use the reciprocating motion to drive a
ratchet; ratchet converts motion back to circular; circular
chainring pulls chain; chain turns cog at rear hub. The
variable transmission is in the geometry by which the
reciprocating arm engages the pawls. Gear range is about
3:1, the same as an 11-33 tooth cassette. One key feature is
a scalloped or hypocycloid gear that smooths the
reciprocating stroke back into steady circular motion.

Frictional losses are minimized by the liberal use of needle
bearings, and weight is minimized by encasing the tranny in
a carbon-fiber shell with an aluminum "skeleton" for load-
bearing. (The entire mech is bathed in transmission fluid.)
The article admits that weight and transmission efficiency
don't match conventional derailleurs, but points out the
advantage of CVT available at all times, even when under
load, and that the mechanism is sealed from the elements,
reducing chainsuck. Also the fixed front-rear cog sizes
allow for rear suspension travel without pedal feedback.

I only thumbed through the article at the magazine stand but
that's what I remember.

Van
--
Van Bagnol / v b a g n o l at earthlink dot net / c r l at
bagnol dot com ...enjoys - Theatre / Windsurfing / Skydiving
/ Mountain Biking ...feels - "Parang lumalakad ako sa loob
ng paniginip" ...thinks - "An Error is Not a Mistake ...
Unless You Refuse to Correct It"

In article <[email hidden]>,

Mark \(UK\) said:

A few car manufacturers have made models with CVT boxes
over the years, i think DAF was the first, but they were
riddled with problems, related to belt slippage and the
requirement for very frequent maintainance and such
things. I think i read that Audi have made a CVT system
which eliminates belts so maybe things are improving, Even
so, i suspect that Honda bike wouldn't be good for much
more than race runs, wouldn't go for long without
maintenance i bet.

Did anyone read about the technicalities of the Honda
box? Is it belt/roller or some sort of expanding sprocket
and chain?

It appears to be a variable-geometry reciprocating ratchet.
It uses no belts or chains, except for the drive chain from
the transmission box to the rear wheel (as in a single-
speed). It does have gears, though.

The basic mechanical transmission is this: Step up pedal
gearing to 11:1 or thereabouts; convert circular motion to
reciprocating; use the reciprocating motion to drive a
ratchet; ratchet converts motion back to circular; circular
chainring pulls chain; chain turns cog at rear hub. The
variable transmission is in the geometry by which the
reciprocating arm engages the pawls. Gear range is about
3:1, the same as an 11-33 tooth cassette. One key feature is
a scalloped or hypocycloid gear that smooths the
reciprocating stroke back into steady circular motion.

Frictional losses are minimized by the liberal use of needle
bearings, and weight is minimized by encasing the tranny in
a carbon-fiber shell with an aluminum "skeleton" for load-
bearing. (The entire mech is bathed in transmission fluid.)
The article admits that weight and transmission efficiency
don't match conventional derailleurs, but points out the
advantage of CVT available at all times, even when under
load, and that the mechanism is sealed from the elements,
reducing chainsuck. Also the fixed front-rear cog sizes
allow for rear suspension travel without pedal feedback.

I only thumbed through the article at the magazine stand but
that's what I remember.

Van
--
Van Bagnol / v b a g n o l at earthlink dot net / c r l at
bagnol dot com ...enjoys - Theatre / Windsurfing / Skydiving
/ Mountain Biking ...feels - "Parang lumalakad ako sa loob
ng paniginip" ...thinks - "An Error is Not a Mistake ...
Unless You Refuse to Correct It"

Shawn Curry said:

Looks fat and inefficient (I should know). Hopeless
concept as an XC bike. Chain drive is just too efficient.

You miss the point. It was not an exercise intended to
result in a better bicycle, it was an exercise intended to
result in better motor company engineers.

That said, derailleur systems are primitive, unreliable,
inelegant junk that owe their existence to the fact that
they are cheap as dirt to manufacture. If Brand S had
invested the kind of engineering resources in, say, internal
gear hubs that they have sunk into prolonging the heyday of
derailleur systems, we'd already have better options
available.

Any motor vehicle drivetrain, for example, that did as
thorough a job of rapid self-destruction as a bike
derailleur system would go down in legend as a
laughingstock. The fact that most derialleur bikes are toys
or fetish objects rather than regular transportation allows
the continued prevalence of multi-speed transmissions that
self-digest in a few thousand miles and demand constant
maintenance.

Chalo Colina

Chalo said:

Shawn Curry said:

Looks fat and inefficient (I should know). Hopeless
concept as an XC bike. Chain drive is just too efficient.

You miss the point. It was not an exercise intended to
result in a better bicycle, it was an exercise intended to
result in better motor company engineers.

I was stating facts, not making a "point". Nevertheless, I
think you missed the point. It was an exercise to improve
the bottom line, to show off Honda to a crowd that thinks
SUV and Subaru.

Quoted message said:

That said, derailleur systems are primitive, unreliable,
inelegant junk that owe their existence to the fact that
they are cheap as dirt to manufacture. If Brand S had
invested the kind of engineering resources in, say,
internal gear hubs that they have sunk into prolonging the
heyday of derailleur systems, we'd already have better
options available.

Any motor vehicle drivetrain, for example, that did as
thorough a job of rapid self-destruction as a bike
derailleur system would go down in legend as a
laughingstock. The fact that most derialleur bikes are
toys or fetish objects rather than regular transportation
allows the continued prevalence of multi-speed
transmissions that self-digest in a few thousand miles and
demand constant maintenance.

Chalo Colina

I think most consumers and manufacturers look at it
differently. The wildly enthusiastic commuter might ride a
dozen miles each way to work etc. 120 miles a week, 6000
miles/yr (remember, this is a very skewed population on
these NGs). Oil the chain twice a month and replace the
derailleurs, chain, etc twice a year. $300/year (you're not
gonna buy new XTR replacement parts are you?). Big deal. A
VERY efficient car would cost that much in gas alone. If
they're like a lot of us they buy a new bike every few
years. They're super hot ride from three years ago gets
relegated to commuter status. The cost of acquiring the bike
itself only amounts to the lost sale value of the outdated
bike (I'm not considering the Seven Duo crowd here). S/he's
saving big bucks! The market pressure to develop a new
efficient transmission just isn't there. I commuted on a
fixie quite a few years ago-costs even less. :-)

Shawn

Chalo said:

That said, derailleur systems are primitive, unreliable,
inelegant junk that owe their existence to the fact that
they are cheap as dirt to manufacture.

As if price doesn't count. The onus is on other systems to
compete on price-value-performance, _which they have not
done_. That pretty much speaks for itself.

Quoted message said:

If Brand S had invested the kind of engineering resources
in, say, internal gear hubs that they have sunk into
prolonging the heyday of derailleur systems, we'd already
have better options available.

Right. If only _all_ bicycle designers in history had been
as far-sighted and intelligent as you, they could have made
a killing on a superior system that works better and costs
less. There sure are a lot of stupid people "out there."
They just don't know how to act in their own self-interest
and put a superior system on the market... sheesh!

Quoted message said:

Any motor vehicle drivetrain, for example, that did as
thorough a job of rapid self-destruction as a bike
derailleur system would go down in legend as a
laughingstock.

There is nothing inherently wrong in the balance of
tradeoffs of accepting an occasional chain replacement, a
less often cog replacement, a still less often ring
replacement, and less often derailleur replacement. A new
chain is $10, and the time taken to earn the funds to
replace it and the time taken to install are truly quite
small, especially in light of the amount of time the chain
actually gets used.

The onus is on other systems to compete on the balance of
tradeoffs. They haven't, so they just aren't around as much.

Quoted message said:

The fact that most derialleur bikes are toys or fetish
objects rather than regular transportation allows the
continued prevalence of multi-speed transmissions that self-
digest in a few thousand miles and demand constant
maintenance.

Ridiculous. It has nothing to do with "the service mode they
operate within." A chain is a chain and wears out whether
one is racing, sight-seeing, or commuting. The balance of
tradeoffs continues to select the current systems in the
marketplace; drivetrain wear is part of that tradeoff. The
onus is on other the systems to overcome their own
disadvantages and win on the balance of tradeoffs.

Besides, "constant maintenance is untrue." I do nearly
zero maintenance on my drivetrains in between chain
changes. If it squeaks, I'll lube it in < 1 min, otherwise
I just ride. It is like complaining that the car keeps
running out of gas.

On Wed, 12 May 2004 19:18:43 GMT, Werehatrack
<[email hidden]> wrote:

[snip]

Quoted message said:

Here's a picture of the bike:

world.honda.com2030203.htmlOpen ↗

Dear Werehatrack,

What I really like about this is the profile of the Japanese
rider, which gives the five essentials that we bicycling
enthusiasts all want to know:

1) Birthday
2) Place of birth
3) Height
4) Weight
5) Blood type

Is Japanese bicycling fiercer and bloodier than I've been
led to believe? Are battlefield transfusions common? Do
blood type A riders have a secret haemoglobin advantage
over type O?

Carl Fogel

Philip Williamson said:

It reads exactly like a Japanese fighting videogame, like
Tekken, where the characters are identified in just the
same way, including the blood group. I wonder if the
videogame cliche came first, or if it's based on an actual
practice in sports. ? I guess it's good to know.

Horoscope-style prediction based on blood type is a popular
supersition in Japan. It's the equivalent of listing
someone's star sign in Western culture.

I suppose it is marginally less ridiculous in that
blood type is actually a physical property of the
person in question.
--
David Damerell <[email hidden]>
Distortion Field!

Quoted message said:

Oil the chain twice a month and replace the derailleurs,
chain, etc twice a year.

I agree with Chalo here. Can you imagine telling "Suzie SUV"
she has to oil her drivetrain every other week, and would
have to replace her transmission every oil change?

I and almost everyone I know carries a chain tool out of
necessity.

Compared to automobiles and almost all other vehicles,
bicycle drivetrains are [censored].

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

Quoted message said:

On Wed, 12 May 2004 19:18:43 GMT, Werehatrack
<[email hidden]> wrote:

[snip]

Quoted message said:

Here's a picture of the bike:

world.honda.com2030203.htmlOpen ↗

Dear Werehatrack,

What I really like about this is the profile of the
Japanese rider, which gives the five essentials that we
bicycling enthusiasts all want to know:

1) Birthday
2) Place of birth
3) Height
4) Weight
5) Blood type

Is Japanese bicycling fiercer and bloodier than I've been
led to believe? Are battlefield transfusions common? Do
blood type A riders have a secret haemoglobin advantage
over type O?

Carl Fogel

I noticed that too, and it made me laugh. It reads exactly
like a Japanese fighting videogame, like Tekken, where the
characters are identified in just the same way, including
the blood group. I wonder if the videogame cliche came
first, or if it's based on an actual practice in sports. ? I
guess it's good to know.

Philip

John Harlow said:

Quoted message said:

Oil the chain twice a month and replace the derailleurs,
chain, etc twice a year.

I agree with Chalo here. Can you imagine telling "Suzie
SUV" she has to oil her drivetrain every other week, and
would have to replace her transmission every oil change?

When was the last time you heard "Suzie SUV" say "I'm not
going to commute by bike, there's too much maintenance
involved." LOL You may get SS there to commute two miles on
a cruiser now and then. Oil the chain once a year (Biff
Bimmer can handle that).

Quoted message said:

I and almost everyone I know carries a chain tool out of
necessity.

For Commuting?