shock absorbers - waste energy?

[Matt O'Toole]

R15757 wrote:

> Jobst Brandt wrote in part:
>
> << Active suspension is less lossy than passive suspension with shock absorption. >>
>
> As a rider of fully rigid mtbs I fully, rigidly agree with you.
>
> << F1 race cars are making use of this method for good reason. >>

Good point, Jobst.

> F1 cars also make use of grooved rubber on dry pavement. What gives?

They don't "make use" of it. Grooves were required by the FIA in an effort to slow the cars down,
and make them more equal.

Matt O.

 

[Benjamin Lewis]

David Reuteler wrote:

> Benjamin Lewis <[email protected]> wrote:
>> Urk -- no way, read the books.
>
> we forget how read book USA. may b u meen this?
>
> http://www.audio-book.ws/books/catch-22.php http://tinyurl.com/2fmuf

What, no pictures? Forget it.

--
Benjamin Lewis

"Love is a snowmobile racing across the tundra and then suddenly it flips over, pinning you
underneath. At night, the ice weasels come." --Matt Groening

 

[Carl Fogel]

Rick Onanian <[email protected]> wrote in message news:<[email protected]>...
> On 6 Feb 2004 15:20:42 -0800, [email protected] (Carl Fogel) wrote:
> >My only practical experience is a rigid touring bike banging over four speed humps (eight-foot
> >wide humps, not bumps) at 20-30 mph daily on the
>
> Speed humps are smooth and are just small hills. You climb them and then descend them. They do not
> force the bike in a complete vertical direction.
>
> >I pull up a bit and unweight a little as I hit them, mimicking suspension, but have yet to see
> >any noticeable change in speed--the effect must
>
> There will be no more effect than doing the same when the grade changes as you crest a hill.
>
> <snip horney wife and oblivious idiot with wrong priorities>
> >. . . And all week long he chortled with repressed delight at the officers'club. Speculation grew
> > rampant among his closest friends.
> >
> >"I wonder what that Shithead is up to," Lieutenant Engle said.
> >
> >--Catch-22, Chapter Eight
>
> I have this book. In fact, I can see it from where I'm sitting. It was suggested by a friend a
> long time ago; I bought it in a hurry on my way out to vacation, then a brief evaluation told me
> it wasn't a book I'd have bought normally. I didn't read it.
>
> Maybe I should.

Dear Rick,

At 20 mph and more, there seems to be a considerable and violent elevation hitting the front side of
these wide speed humps and a distinct bump down the other.

Who cares about bicycles? Let's talk lit.

If you read "Catch-22," don't despair at the bewildering apparent chaos of the flash-forwards, flash-
backs, and flash-sideways that Heller used. The whole point is that it's supposed to be chaos, with
whole chapters named for characters who do not appear in them. That's how Heller saw the war.

It helps to realize that no matter where Heller's jumbled writing starts out, it always leads back
to the same central incident that changed Yossarian from someone who was brave enough to go around
twice to bomb the target into someone who's now brave enough not to go over it even once.

This central incident, the turning point for Yossarian, is the mission over Avignon, where Snowden
died in the back of the bomber and revealed a secret.

Every time Heller's tangled mess (you can't call it a plot) returns to Snowden dying in the back of
the plane, we learn a little more about how Snowden died. Technically, Heller is just a confused
chronology to delay the turning point of the plot far past the middle of the story, which is where
it normally comes in chronological plots.

(In Shakespeare's 5-act tragedies, the main character screws up big-time in act 3--the turning point--
and dooms himself. Heller just puts the turning point scene off by not telling things in order,
saving it until nearly the end of the book. This may add suspense, but it's contrived and
confusing.)

"Catch-22" is worth reading, but it's a novel by someone who flew combat missions and couldn't make
death moving. If you're not careful, you may not notice that almost everyone dies--which, like the
chaos, was Heller's point about how he saw the war.

The trouble is that while Heller's point may be good, the deaths of characters who are little more
than a rank, a last name, and a comic tic are not moving. They're characters, not people. Heller
couldn't bring himself to kill anyone who turned into a person in the book.

You might enjoy Leon Uris's straightforward first novel, "Battle Cry," far more. Uris wrote about
people rather than cardboard stereotypes, so a simple list of names at the end is far more moving
than anything Heller ever wrote.

Hmmm . . . better re-read both now.

Carl Fogel

 

[Carl Fogel]

Rick Onanian <[email protected]> wrote in message news:<[email protected]>...
> On 6 Feb 2004 15:20:42 -0800, [email protected] (Carl Fogel) wrote:
> >My only practical experience is a rigid touring bike banging over four speed humps (eight-foot
> >wide humps, not bumps) at 20-30 mph daily on the
>
> Speed humps are smooth and are just small hills. You climb them and then descend them. They do not
> force the bike in a complete vertical direction.
>
> >I pull up a bit and unweight a little as I hit them, mimicking suspension, but have yet to see
> >any noticeable change in speed--the effect must
>
> There will be no more effect than doing the same when the grade changes as you crest a hill.
>
> <snip horney wife and oblivious idiot with wrong priorities>
> >. . . And all week long he chortled with repressed delight at the officers'club. Speculation grew
> > rampant among his closest friends.
> >
> >"I wonder what that Shithead is up to," Lieutenant Engle said.
> >
> >--Catch-22, Chapter Eight
>
> I have this book. In fact, I can see it from where I'm sitting. It was suggested by a friend a
> long time ago; I bought it in a hurry on my way out to vacation, then a brief evaluation told me
> it wasn't a book I'd have bought normally. I didn't read it.
>
> Maybe I should.

Dear Rick,

At 20 mph and more, there seems to be a considerable and violent elevation hitting the front side of
these wide speed humps and a distinct bump down the other.

Who cares about bicycles? Let's talk lit.

If you read "Catch-22," don't despair at the bewildering apparent chaos of the flash-forwards, flash-
backs, and flash-sideways that Heller used. The whole point is that it's supposed to be chaos, with
whole chapters named for characters who do not appear in them. That's how Heller saw the war.

It helps to realize that no matter where Heller's jumbled writing starts out, it always leads back
to the same central incident that changed Yossarian from someone who was brave enough to go around
twice to bomb the target into someone who's now brave enough not to go over it even once.

This central incident, the turning point for Yossarian, is the mission over Avignon, where Snowden
died in the back of the bomber and revealed a secret.

Every time Heller's tangled mess (you can't call it a plot) returns to Snowden dying in the back of
the plane, we learn a little more about how Snowden died. Technically, Heller is just a confused
chronology to delay the turning point of the plot far past the middle of the story, which is where
it normally comes in chronological plots.

(In Shakespeare's 5-act tragedies, the main character screws up big-time in act 3--the turning point--
and dooms himself. Heller just puts the turning point scene off by not telling things in order,
saving it until nearly the end of the book. This may add suspense, but it's contrived and
confusing.)

"Catch-22" is worth reading, but it's a novel by someone who flew combat missions and couldn't make
death moving. If you're not careful, you may not notice that almost everyone dies--which, like the
chaos, was Heller's point about how he saw the war.

The trouble is that while Heller's point may be good, the deaths of characters who are little more
than a rank, a last name, and a comic tic are not moving. They're characters, not people. Heller
couldn't bring himself to kill anyone who turned into a person in the book.

You might enjoy Leon Uris's straightforward first novel, "Battle Cry," far more. Uris wrote about
people rather than cardboard stereotypes, so a simple list of names at the end is far more moving
than anything Heller ever wrote.

Hmmm . . . better re-read both now.

Carl Fogel

 

[Tom Sherman]

Mark Hickey wrote:

> Werehatrack <[email protected]> wrote: ...
>>If the damping was sufficiently effective (which it seldom is), there would be little suspension
>>motion from pedalling. The more motion, the more loss. Damping reduces motion, and loss; below a
>>certain point, it could be ignored. I doubt that any OE shock on an under-$800 bike has damping
>>that even reduces the motion to any appreciable extent. (None that I've tried would qualify, in
>>any event.)
>
>
> It's not a matter of spending money - it's a matter of physics. A shock has to react to changing
> dynamics,. whether they're terrain-induced or pedaling induced....

However, it is possible to design a suspension that does not exhibit "pogo" while pedaling.

Example: <http://www.ihpva.org/incoming/2002/Dragonflyer/df5.jpg>,
<http://www.ihpva.org/incoming/2002/Dragonflyer/df8.jpg>,
<http://www.ihpva.org/incoming/2002/Dragonflyer/df9.jpg>.

Note that the jackshaft that the step-up gears are mounted on is concentric with the
suspension pivot.

Tom Sherman - Quad Cities

 

[Kinky Cowboy]

On 07 Feb 2004 05:24:24 GMT, [email protected] (R15757) wrote:

>Jobst Brandt wrote in part:
>
><< Active suspension is less lossy than passive suspension with shock absorption. >>
>
>As a rider of fully rigid mtbs I fully, rigidly agree with you.
>
><< F1 race cars are making use of this method for good reason. >>
>
>F1 cars also make use of grooved rubber on dry pavement. What gives?
>
>Robert

1: Active suspension is not "less lossy"; it requires quite a lot of energy to power the pumps etc.
It's more accurate than springs and dampers, if done right, but it's there to trade some power
for more traction.

2: F1 cars don't use active suspension any more, the rules were changed to ban it years ago

3: F1 cars use grooved tyres because the rules demand it, rules designed to reduce the speed of the
cars for safety reasons.

Kinky Cowboy*

*Batteries not included May contain traces of nuts Your milage may vary

 

[David Reuteler]

Benjamin Lewis <[email protected]> wrote:
: What, no pictures? Forget it.

well, that's exactly why i watched the movie. but it wasn't nearly as good as the audiobook. bit
more concise, tho.
--
david reuteler [email protected]

 

[Jobst Brandt]

Robert who? writes:

>> Active suspension is less lossy than passive suspension with shock absorption.

> As a rider of fully rigid MTB's I fully, rigidly agree with you.

>> F1 race cars are making use of this method for good reason.

> F1 cars also make use of grooved rubber on dry pavement. What gives?

This was a stupid way of slowing the cars down in corners. The FIA didn't face the challenge to
reduce engine size, fearing the doting auto public would no longer come to watch. In contrast I
propose 4-cylinder, 1000cc, un-supercharged gasoline powered car. That change would get rid of most
aerodynamic devices, the need for grooved tires, smaller tires, and bring a whole range of useful
engine developments.

Bernie Eccelston is so worried about the future of the 'sport' he is thinking of pulling out of
Europe entirely. The cars are running more like slot cars, with unreal accelerations in straights
and curves, in contrast to realistic cars. There is essentially no passing anymore, unless there is
a major error or mechanical failure. Dull, dull, dull.

Jobst Brandt [email protected]

 

[meb]

Originally posted by Tom Sherman
Mark Hickey wrote:

> Werehatrack <[email protected]> wrote: ...
>>If the damping was sufficiently effective (which it seldom is), there would be little suspension
>>motion from pedalling. The more motion, the more loss. Damping reduces motion, and loss; below a
>>certain point, it could be ignored. I doubt that any OE shock on an under-$800 bike has damping
>>that even reduces the motion to any appreciable extent. (None that I've tried would qualify, in
>>any event.)
>
>
> It's not a matter of spending money - it's a matter of physics. A shock has to react to changing
> dynamics,. whether they're terrain-induced or pedaling induced....

However, it is possible to design a suspension that does not exhibit "pogo" while pedaling.

Example: <[url]http://www.ihpva.org/incoming/2002/Dragonflyer/df5.jpg>[/url],
<[url]http://www.ihpva.org/incoming/2002/Dragonflyer/df8.jpg>[/url],
<[url]http://www.ihpva.org/incoming/2002/Dragonflyer/df9.jpg>[/url].

Note that the jackshaft that the step-up gears are mounted on is concentric with the
suspension pivot.

Tom Sherman - Quad Cities

That Dragonflyer design should still have a small amount of pedal induced pogoing. Placing the jackshaft concntric with the pivot axis is a good compromise between construction simplicity and pogoing reduction.

There is a tensile force in the direction of the chainline. Multiply that force vector by the distance of the chain at the entry tooth of the drive cog from the pivot gives you the moment.

If you lowered the jackshaft a couple of inches so the chainline coincided with the pivot axis you would not have a moment about that pivot.

Biopace rings or Rotorcranks would also reduce pogoing since they reduce max torque at traditionally high torque crank positions and increase torque at low torque positions of the crank rotation.

 

[Kinky Cowboy]

On Sat, 07 Feb 2004 19:47:02 GMT, [email protected]
wrote:

>Robert who? writes:
>
>>> Active suspension is less lossy than passive suspension with shock absorption.
>
>> As a rider of fully rigid MTB's I fully, rigidly agree with you.
>
>>> F1 race cars are making use of this method for good reason.
>
>> F1 cars also make use of grooved rubber on dry pavement. What gives?
>
>This was a stupid way of slowing the cars down in corners. The FIA didn't face the challenge to
>reduce engine size, fearing the doting auto public would no longer come to watch. In contrast I
>propose 4-cylinder, 1000cc, un-supercharged gasoline powered car. That change would get rid of most
>aerodynamic devices, the need for grooved tires, smaller tires, and bring a whole range of useful
>engine developments.
>
>Bernie Eccelston is so worried about the future of the 'sport' he is thinking of pulling out of
>Europe entirely. The cars are running more like slot cars, with unreal accelerations in straights
>and curves, in contrast to realistic cars. There is essentially no passing anymore, unless there is
>a major error or mechanical failure. Dull, dull, dull.
>
>Jobst Brandt [email protected]

What F1 needed was more mechanical grip and less downforce, so fat slicks and no wings is the way to
go. Current rules prevent overtaking by ensuring that you lose half your grip as soon as you're
close enough behind the next guy to make a realistic passing move. Jobst's 1000cc formula sounds
like a new use for MotoGP engines, but it's too small, nobody will be interested in 250bhp Grand
Prix cars. Maybe a 2 litre with no more than 8 cylinders is realistic with today's engine
technology, allowing for the fact that F1 rules already prohibit a lot of exotic materials for
engine internals on the basis of safety and cost, that should take us back to 500bhp cars, which
will probably be able to hit close to 200mph with the reduced drag implied by smaller or non-
existent wings. That's about where we were at the introduction of the Cosworth DFY motor in 1983

Kinky Cowboy*

*Batteries not included May contain traces of nuts Your milage may vary

 

[Kinky Cowboy]

On 07 Feb 2004 22:33:09 GMT, [email protected] (R15757) wrote:

>Jobst Brandt wrote:
>
><< This was a stupid way of slowing the cars down in corners. The FIA didn't face the challenge to
>reduce engine size, fearing the doting auto public would no longer come to watch. In contrast I
>propose 4-cylinder, 1000cc, un-supercharged gasoline powered car. That change would get rid of most
>aerodynamic devices, the need for grooved tires, smaller tires, and bring a whole range of useful
>engine developments.
>
>Bernie Eccelston is so worried about the future of the 'sport' he is thinking of pulling out of
>Europe entirely. The cars are running more like slot cars, with unreal accelerations in straights
>and curves, in contrast to realistic cars. There is essentially no passing anymore, unless there is
>a major error or mechanical failure. Dull, dull, dull.
> >>
>
>
>It seems to me that the biggest problem with modern F1 racing is not engine size but the traction
>control computers that let the teams dial in precise amounts of tire slip and let drivers make
>perfect accelerations out of every turn. In the past, you could count on drivers spinning while
>accerating too hard.
>
>Robert

Except that they don't actually have traction control anymore, or at least none that the FIA
scrutineers can find going through the engine management code line by line. Somebody needs to post
the current F1 regs if we're going down this path. My DNS isn't resolving fia.com at the moment, or
I'd give y'all the link, but I think it's something like http://www.fia.com/regle/REG_TEC/F1/F1-Reglements-techniques-2003-
a.pdf

Kinky Cowboy*

*Batteries not included May contain traces of nuts Your milage may vary

 

[Kinky Cowboy]

On Sat, 07 Feb 2004 23:05:13 GMT, Kinky Cowboy <[email protected]>
wrote:

>On 07 Feb 2004 22:33:09 GMT, [email protected] (R15757) wrote:
>
>>Jobst Brandt wrote:
>>
>><< This was a stupid way of slowing the cars down in corners. The FIA didn't face the challenge to
>>reduce engine size, fearing the doting auto public would no longer come to watch. In contrast I
>>propose 4-cylinder, 1000cc, un-supercharged gasoline powered car. That change would get rid of
>>most aerodynamic devices, the need for grooved tires, smaller tires, and bring a whole range of
>>useful engine developments.
>>
>>Bernie Eccelston is so worried about the future of the 'sport' he is thinking of pulling out of
>>Europe entirely. The cars are running more like slot cars, with unreal accelerations in straights
>>and curves, in contrast to realistic cars. There is essentially no passing anymore, unless there
>>is a major error or mechanical failure. Dull, dull, dull.
>> >>
>>
>>
>>It seems to me that the biggest problem with modern F1 racing is not engine size but the traction
>>control computers that let the teams dial in precise amounts of tire slip and let drivers make
>>perfect accelerations out of every turn. In the past, you could count on drivers spinning while
>>accerating too hard.
>>
>>Robert
>
>
>Except that they don't actually have traction control anymore, or at least none that the FIA
>scrutineers can find going through the engine management code line by line. Somebody needs to post
>the current F1 regs if we're going down this path. My DNS isn't resolving fia.com at the moment, or
>I'd give y'all the link, but I think it's something like http://www.fia.com/regle/REG_TEC/F1/F1-Reglements-techniques-2003-
>a.pdf
>
>
>Kinky Cowboy*
>
>*Batteries not included May contain traces of nuts Your milage may vary

Ignore that comment, apparently the buggers do have traction control. I'll kick my brother's ass
tomorrow for leading me up the wrong track on that one. Kinky Cowboy*

*Batteries not included May contain traces of nuts Your milage may vary

 

[Rick Onanian]

On Sat, 07 Feb 2004 03:54:32 GMT, [email protected]
wrote:
>Not necessarily so, because a rider can use active suspension that does not need to dampen the
>motion in a viscous friction manner that absorbs energy in both directions. The rider can travel
>essentially in a level course as the bicycle rolls over a series of rolling undulations about the
>length of the bicycle. Shock absorbers would dump bound and rebound into heat while a rider can
>leave constant pressure on the pedals while standing and allowing the bicycle to go over the bump
>while not changing rider elevation.

This is true, and I must say, I really enjoy riding those sort of bicycle-length rolling
undulations, because it really is fun to be level while the bicycle reciprocates vertically beneath
me. I look forward to those whenever I get the chance to ride them.

However, passive mechanical suspension is much more useful for the constant barrage of small rocks
and sticks and ruts and what not found on trails. It does the smoothing work, leaving your leg
muscles fueled and ready for pedalling.
--
Rick Onanian

 

[Antti Salonen]

Kinky Cowboy <[email protected]> wrote:

> Ignore that comment, apparently the buggers do have traction control. I'll kick my brother's ass
> tomorrow for leading me up the wrong track on that one.

The rules were changed to allow traction control again just last year, I believe. The FIA finally
decided that they couldn't really make sure that nobody was using it, or even define "traction
control" accurately enough in the rules.

I think this is getting completely off-topic.

-as

 

[Kinky Cowboy]

On 7 Feb 2004 23:28:56 GMT, Antti Salonen
<[email protected]> wrote:

>Kinky Cowboy <[email protected]> wrote:
>
>> Ignore that comment, apparently the buggers do have traction control. I'll kick my brother's ass
>> tomorrow for leading me up the wrong track on that one.
>
>The rules were changed to allow traction control again just last year, I believe. The FIA finally
>decided that they couldn't really make sure that nobody was using it, or even define "traction
>control" accurately enough in the rules.
>
>I think this is getting completely off-topic.
>
>-as

Traction control was re-introduced in 2002 when it became obvious that the well funded teams were
cheating by using adaptive engine management to replicate the function of traction control

You should see the other groups I post to if you think this is off topic!

Kinky Cowboy*

*Batteries not included May contain traces of nuts Your milage may vary

 

[Rick Onanian]

>On Fri, 06 Feb 2004 05:01:58 +0000, Werehatrack wrote:
>> This is actually the one thing about the suspension fork that has been of some value to me
>> outside of the trails; by causing me to want to stay in the saddle instead of getting up off of
>> it on accelerations,
On Fri, 06 Feb 2004 22:05:40 -0500, "David L. Johnson" <[email protected]> wrote:
>But a suspension fork does not _allow_ anything new. You could have sat and spun before. It does
>prevent you from getting out of the saddle and hammering. Frankly, I like the ability to decide
>which of those I want to do on a given hill.

My mtb has an ultra-cheap, undamped, steel spring RST suspension fork. It's a bit stiff, even under
my 210 pounds, but it takes the edge off some stuff, and gives me a nice springboard for enhancing
my front-end lifts.

It's also got a Thudbuster paralellogram suspension seatpost.

I can choose to sit and spin or stand and [hammer|honk] whenever I please, with no major
power losses.

Meanwhile, the suspension does make it easier to sit, so the choices are now more even, and the
decision to sit or stand can be made without factoring bone-shock as strongly.
--
Rick Onanian

 

[Werehatrack]

On Sat, 07 Feb 2004 03:09:50 -0600, Tom Sherman
<[email protected]> may have said:

>However, it is possible to design a suspension that does not exhibit "pogo" while pedaling.
>
>Example: <http://www.ihpva.org/incoming/2002/Dragonflyer/df5.jpg>,
><http://www.ihpva.org/incoming/2002/Dragonflyer/df8.jpg>,
><http://www.ihpva.org/incoming/2002/Dragonflyer/df9.jpg>.
>
>Note that the jackshaft that the step-up gears are mounted on is concentric with the
>suspension pivot.

Possible, but not by any means commonly the case; that which is not on hand, does not help.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Yes, I have a killfile. If I don't respond to something,
it's also possible that I'm busy.
Words processed in a facility that contains nuts.

 

[Chalo]

[email protected] wrote in message news:<[email protected]>...
> Chalo Colina writes:
>
> >> But - is it true that any shock absorbing mechanism wastes energy that could be used to propel
> >> the bike ahead? It seems that this must be true..
>
> > That is never more true than when the shock absorbing mechanism is the rider.
>
> Not necessarily so, because a rider can use active suspension that does not need to dampen the
> motion in a viscous friction manner that absorbs energy in both directions. The rider can travel
> essentially in a level course as the bicycle rolls over a series of rolling undulations about the
> length of the bicycle.

That requires that the rider be "tracing" the surface irregularities in a manner that not only
requires muscular effort, but also a good deal of eccentric muscle contraction. Eccentric
contractions are much more fatiguing and damaging to muscles than those used to push pedals.

When the surface is bumpy, it's plain that one can go farther, faster, with less exertion if one has
appropriately tuned suspension. When the surface isn't bumpy, then the penalty suspension exacts in
extra weight and pedaling losses may not be worth it.

Even the tiniest, horsepower-challenged 50cc track-racing motorcycles use sophisticated suspension
on both wheels, though they operate exclusively on smooth prepared racetracks. If suspension really
cost speed (compared to not having it) then you'd think that the racers of some such motorbikes
would attempt to do without.

Chalo Colina

 

[Jobst Brandt]

anonymous writes:

>>> F1 cars also make use of grooved rubber on dry pavement. What gives?

>> This was a stupid way of slowing the cars down in corners. The FIA didn't face the challenge to
>> reduce engine size, fearing the doting auto public would no longer come to watch. In contrast I
>> propose 4-cylinder, 1000cc, un-supercharged gasoline powered car. That change would get rid of
>> most aerodynamic devices, the need for grooved tires, smaller tires, and bring a whole range of
>> useful engine developments.

>> Bernie Eccelston is so worried about the future of the 'sport' he is thinking of pulling out of
>> Europe entirely. The cars are running more like slot cars, with unreal accelerations in straights
>> and curves, in contrast to realistic cars. There is essentially no passing anymore, unless there
>> is a major error or mechanical failure. Dull, dull, dull.

> What F1 needed was more mechanical grip and less downforce, so fat slicks and no wings is the way
> to go. Current rules prevent overtaking by ensuring that you lose half your grip as soon as you're
> close enough behind the next guy to make a realistic passing move.

It's not so much a drivers race these days as one of mechanical reliability and pit crews, something
Indianapolis 500 has suffered from for years. I'm glad I saw the days of Stirling Moss and other
great drivers of the past. Moss, on the 1000km Nurburgring race would wave and smile for amateur
photographers in the midst of a drifting turn in an oversteering Porsche on his way to victory.

> Jobst's 1000cc formula sounds like a new use for MotoGP engines, but it's too small, nobody will
> be interested in 250bhp Grand Prix cars.

Don't forget that great racing that went on in the 1500cc F1 days with less power than Motos have
today. It's the competition that counts, not the speed.

> Maybe a 2 litre with no more than 8 cylinders is realistic with today's engine technology,
> allowing for the fact that F1 rules already prohibit a lot of exotic materials for engine
> internals on the basis of safety and cost, that should take us back to 500bhp cars, which will
> probably be able to hit close to 200mph with the reduced drag implied by smaller or non-existent
> wings. That's about where we were at the introduction of the Cosworth DFY motor in 1983

I think the numbers you cite speak for themselves. There are no passing possibilities at 200mph. We
don't need cars that go that fast to have a good race just as we don't need multi-thousand dollar
bicycles made of space age materials to have a good bicycle race although from the hyperbole you
might believe so.

Jobst Brandt [email protected]

 

[Carl Fogel]

[email protected] (Chalo) wrote in message news:<[email protected]>...

[snip]

>
> Even the tiniest, horsepower-challenged 50cc track-racing motorcycles use sophisticated suspension
> on both wheels, though they operate exclusively on smooth prepared racetracks. If suspension
> really cost speed (compared to not having it) then you'd think that the racers of some such
> motorbikes would attempt to do without.
>
> Chalo Colina

Dear Chalo,

I don't know what they race these days, but during the 50cc wars between Honda and Suzuki in the
1960's, the miniature engines went to two cylinders. Both companies had obscene 3-cylinder models
ready, but quit competing when the rules changed and limited the number of cylinders.

These 1960's 50cc engines put out 15 to 17 brake horsepower through up to 14 gears at 18,500 to
22,000 rpm. Their top speeds were routinely listed at 90 to 105 mph--far beyond the current 75 mph
50cc world speed record that neither company cared about.

Here's a Suzuki history page:

http://www.suzukicycles.org/history/history_04-race-1960-1967.shtml

If you browse and search, you'll find top speeds listed from 145 to 170 km/h for three different
50cc models. Typical machines weighed 110 to 130 pounds, with riders weighing around 130 pounds.

Suspension pays off, even at 50-60 mph, because you need to a 110-pound machine's tires on the
asphalt. Cornering and braking matter far more in motorcycle road racing than in bicycling.

Notice, for example, how rarely cornering is even mentioned here on rec.bicycles.tech. Downhill
cornering takes lots of skill, but it just doesn't win normal bicycle races. On the the flats, we
bicyclists tend to pull the inside foot up and coast through, slowing down.

Notice the huge road-style drum brakes in the pictures in the link above. They were needed to handle
the speed and weight of even these light-weight machines. So were the spindly little suspension
units, whose front fork springs were often exposed instead of being internal. The suspension was
still heavy, and its inherent friction robbed power, but the machines needed suspension to keep
their skinny little tires on the ground when cornering, just like their big brothers.

How much speed suspension really costs is still open to question. I don't remember seeing any
figures so far in this thread. But while road-racing bicycles can get by with rigid frames, I'd hate
to try to keep up with those nearly forty-year-old 50 cc suspended machines on any modern rigid
frame 50 cc motorcycle on a tight course.

Carl Fogel