Sustaining higher speed

Peter Cole said:

Quoted message said:

For the Shimano derailleur, they seem to find 87% to 97%
efficiencies from 80 to 200 watts, trending toward 92%. I
think that efficiencies are supposed to climb with power, as
shown in one table where the Shimano efficiency rises to
90.6% at 54 watts to 97.2% at 370 watts for one gear. To be
honest, I'm not even certain which combination this gear 25
was, but the text indicates that the lowest efficiency was
with the 12-tooth cog, down around 91%.

The "lowest efficiency" was for a 32-12 combination. Hardly a realistic
choice. If 32-12 was 90%, and 44-12 was 93%, what do you think 53-12
might be? Why these guys only measured MTB cranks, I don't know. Of
course, all these efficiencies are "uncorrected", so add 2-2.5%.

Bottom line, if you're a reasonably strong recreational rider going
hard on the flats, ~90% of your power will be going to wind drag.
That's all you need to know.

http://www.sheldonbrown.com/rinard/aero/

Dear Peter,

Your repeated use of that's-all-you-need-to-know suggests an
interesting attitude for a technical newsgroup.

Cheers,

Carl Fogel

David Damerell said:

Quoting Leo Lichtman <[email hidden]>:

Quoted message said:

I ride occasionally with a friend on a recumbent--I have never been tempted
to change places with him. The bike is very long, so maneuverability is
poor. The bike is so long that he had to have his car carrier modified. If
the group decided to head down a trail, he'd be out of luck, due to the long
wheelbase.

Lots of people ride down trails on tandems, so I don't think wheelbase is
the sole issue here.

Dear David,

I'm intrigued--any links to pictures or accounts of
trail-riding tandems? Possibly people mean different things
by paths--are these rough rocks-and-roots dirt hiking
trails, or very smooth bicycle paths?

I know of sidecar motorcycle trials, but an inline tandem
sounds unlikely to work on a rough trail, particularly if
ground clearance becomes a problem, there's any need to loft
the front wheel, or there are hiking-trail hairpin turns.

(Today seems to be March 30th, not the April of your
signature.)

Curiously,

Carl Fogel

Quoted message said:

Dear Peter,

Your repeated use of that's-all-you-need-to-know suggests an
interesting attitude for a technical newsgroup.

Sorry, after your posts I find myself compulsively driven to pithiness.

I take it you have no objection to the substance of my claims, only the
style?

Quoted message said:

David Damerell said:

Quoting Leo Lichtman <[email hidden]>:

Quoted message said:

I ride occasionally with a friend on a recumbent--I have never been
tempted to change places with him. The bike is very long, so
maneuverability is poor. The bike is so long that he had to have
his car carrier modified. If the group decided to head down a
trail, he'd be out of luck, due to the long wheelbase.

Lots of people ride down trails on tandems, so I don't think
wheelbase is the sole issue here.

Dear David,

I'm intrigued--any links to pictures or accounts of
trail-riding tandems? Possibly people mean different things
by paths--are these rough rocks-and-roots dirt hiking
trails, or very smooth bicycle paths?

http://www.rtrmag.com/issueTwo/Ventana.jpg

for a tiny picture, and the website for Ventana's DS tandem:

http://www.ventanausa.com/frame_elconquistador.html
--
Phil, Squid-in-Training

Peter Cole said:

Quoted message said:

Dear Peter,

Your repeated use of that's-all-you-need-to-know suggests an
interesting attitude for a technical newsgroup.

Sorry, after your posts I find myself compulsively driven to pithiness.

I take it you have no objection to the substance of my claims, only the
style?

Dear Pete,

You take it wrong.

Pithily,

Carl Fogel

Squid-in-Training said:

Quoted message said:

David Damerell said:

Quoting Leo Lichtman <[email hidden]>:
> I ride occasionally with a friend on a recumbent--I have never been
> tempted to change places with him. The bike is very long, so
> maneuverability is poor. The bike is so long that he had to have
> his car carrier modified. If the group decided to head down a
> trail, he'd be out of luck, due to the long wheelbase.

Lots of people ride down trails on tandems, so I don't think
wheelbase is the sole issue here.

Dear David,

I'm intrigued--any links to pictures or accounts of
trail-riding tandems? Possibly people mean different things
by paths--are these rough rocks-and-roots dirt hiking
trails, or very smooth bicycle paths?

http://www.rtrmag.com/issueTwo/Ventana.jpg

for a tiny picture, and the website for Ventana's DS tandem:

http://www.ventanausa.com/frame_elconquistador.html

Dear Phil,

Interesting! It plainly has rear suspension. I'm guessing
that there's front suspension, too, but the site seems oddly
silent about what connects the front wheel to the frame.

The picture is frustratingly tiny, as you mention, but it
looks kinda-sorta like a fairly smooth trail, the kind that
a baby carriage could roll along. I'm not sure, but it looks
as if the front fork is telescopic, thicker on the bottom
than on the top.

Unfortunately, the wheelbase doesn't look as if it would do
well in my neck of the woods--a 52-inch wheelbase trials
machine with plenty of turning angle is hard-pressed on the
hairpins and scrapes the skid-plate dropping into them, so
the extra 20 inches of wheelbase on this MTB tandem would
likely be a problem.

But it does look as if it would do nicely on gentler trails
or paths, which may be what David had in mind. I was hoping
to see tandems doing amazing things, but may have to settle
for less.

Thanks for the link,

Carl Fogel

Quoted message said:

Squid-in-Training said:

Quoted message said:

On 29 Mar 2005 17:49:20 +0100 (BST), David Damerell
<[email hidden]> wrote:

> Quoting Leo Lichtman <[email hidden]>:
>> I ride occasionally with a friend on a recumbent--I have never
>> been tempted to change places with him. The bike is very long, so
>> maneuverability is poor. The bike is so long that he had to have
>> his car carrier modified. If the group decided to head down a
>> trail, he'd be out of luck, due to the long wheelbase.
>
> Lots of people ride down trails on tandems, so I don't think
> wheelbase is the sole issue here.

Dear David,

I'm intrigued--any links to pictures or accounts of
trail-riding tandems? Possibly people mean different things
by paths--are these rough rocks-and-roots dirt hiking
trails, or very smooth bicycle paths?

http://www.rtrmag.com/issueTwo/Ventana.jpg

for a tiny picture, and the website for Ventana's DS tandem:

http://www.ventanausa.com/frame_elconquistador.html

Dear Phil,

Interesting! It plainly has rear suspension. I'm guessing
that there's front suspension, too, but the site seems oddly
silent about what connects the front wheel to the frame.

The picture is frustratingly tiny, as you mention, but it
looks kinda-sorta like a fairly smooth trail, the kind that
a baby carriage could roll along. I'm not sure, but it looks
as if the front fork is telescopic, thicker on the bottom
than on the top.

Unfortunately, the wheelbase doesn't look as if it would do
well in my neck of the woods--a 52-inch wheelbase trials
machine with plenty of turning angle is hard-pressed on the
hairpins and scrapes the skid-plate dropping into them, so
the extra 20 inches of wheelbase on this MTB tandem would
likely be a problem.

But it does look as if it would do nicely on gentler trails
or paths, which may be what David had in mind. I was hoping
to see tandems doing amazing things, but may have to settle
for less.

Dear Carl,

I know an avid cycling couple (hubby & wife) that has tandem road /and/
mountain bikes, the latter of which has been ridden on some pretty rugged
terrain.

I've also seen all-male tandemists (?) on very technical trails, which is
quite something to behold. (Only thing comparable are those absolutely
crazy unicyclists, who simply defy logic and common sense. HTH do they do
that?!?) Haven't seen a two-/woman/ mtb yet AFAIR, but you never know
what's around that next switchback. (Which, ironically, they'd have a very
tough time negotiating.)

Too lazy to read thread to see if this is even germane, Bill "not seen it
all...yet" S.

S o r n i said:

I know an avid cycling couple (hubby & wife) that has tandem road

/and/

Quoted message said:

mountain bikes, the latter of which has been ridden on some pretty

rugged

Quoted message said:

terrain.

I've also seen all-male tandemists (?) on very technical trails,

which is

Quoted message said:

quite something to behold. (Only thing comparable are those

absolutely

Quoted message said:

crazy unicyclists, who simply defy logic and common sense. HTH do

they do

Quoted message said:

that?!?) Haven't seen a two-/woman/ mtb yet AFAIR, but you never

know

Quoted message said:

what's around that next switchback. (Which, ironically, they'd have

a very

Quoted message said:

tough time negotiating.)

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I think
the ideal trail tandem would be articulated like that, with 3 wheels. I
wish there was an adult-sized trailer-bike. These days, I frequently
pull a single-wheeled trailer with my MTB. It works very much the same
way, except for the occasional getting stuck between rocks & launching
me into/over the bar.

S o r n i said:

I know an avid cycling couple (hubby & wife) that has tandem road

/and/

Quoted message said:

mountain bikes, the latter of which has been ridden on some pretty

rugged

Quoted message said:

terrain.

I've also seen all-male tandemists (?) on very technical trails,

which is

Quoted message said:

quite something to behold. (Only thing comparable are those

absolutely

Quoted message said:

crazy unicyclists, who simply defy logic and common sense. HTH do

they do

Quoted message said:

that?!?) Haven't seen a two-/woman/ mtb yet AFAIR, but you never

know

Quoted message said:

what's around that next switchback. (Which, ironically, they'd have

a very

Quoted message said:

tough time negotiating.)

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I think
the ideal trail tandem would be articulated like that, with 3 wheels. I
wish there was an adult-sized trailer-bike. These days, I frequently
pull a single-wheeled trailer with my MTB. It works very much the same
way, except for the occasional getting stuck between rocks & launching
me into/over the bar.

Quoting Peter Cole <[email hidden]>:

Quoted message said:

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I think
the ideal trail tandem would be articulated like that, with 3 wheels.

Presumably with 2 independent drivetrains also? That would permit the use
of conventional cranks, as a useful sideeffect.
--
David Damerell <[email hidden]> Kill the tomato!
Today is First Mania, April.

Quoting Peter Cole <[email hidden]>:

Quoted message said:

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I think
the ideal trail tandem would be articulated like that, with 3 wheels.

Presumably with 2 independent drivetrains also? That would permit the use
of conventional cranks, as a useful sideeffect.
--
David Damerell <[email hidden]> Kill the tomato!
Today is First Mania, April.

Tom Sherman said:

I will annoy some by pointing out that a bicycle with a properly
designed hard shell fairing can propelled at 40+ MPH for hours at a time
by a reasonably strong rider. There have been several riders who have
exceeded 50 miles in one hour.

I think Messrs Cipollini and Cunego would also claim to achieve 40mph,
albeit only over 100 metres after being towed there by their
long-suffering team-mates.

Tom Sherman said:

I will annoy some by pointing out that a bicycle with a properly
designed hard shell fairing can propelled at 40+ MPH for hours at a time
by a reasonably strong rider. There have been several riders who have
exceeded 50 miles in one hour.

I think Messrs Cipollini and Cunego would also claim to achieve 40mph,
albeit only over 100 metres after being towed there by their
long-suffering team-mates.

David Damerell said:

Quoting Peter Cole <[email hidden]>:

Quoted message said:

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I

think

Quoted message said:

Quoted message said:

the ideal trail tandem would be articulated like that, with 3

wheels.

Quoted message said:

Presumably with 2 independent drivetrains also? That would permit the

use

Quoted message said:

of conventional cranks, as a useful sideeffect.

Yes, as with the trailer-bike. There are 2 off-road advantages to this:
removing the pedal strike problem with synchronized cranks, and twice
the uphill traction.

David Damerell said:

Quoting Peter Cole <[email hidden]>:

Quoted message said:

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I

think

Quoted message said:

Quoted message said:

the ideal trail tandem would be articulated like that, with 3

wheels.

Quoted message said:

Presumably with 2 independent drivetrains also? That would permit the

use

Quoted message said:

of conventional cranks, as a useful sideeffect.

Yes, as with the trailer-bike. There are 2 off-road advantages to this:
removing the pedal strike problem with synchronized cranks, and twice
the uphill traction.

Peter Cole said:

David Damerell said:

Quoting Peter Cole <[email hidden]>:

Quoted message said:

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I

think

Quoted message said:

Quoted message said:

the ideal trail tandem would be articulated like that, with 3

wheels.

Quoted message said:

Presumably with 2 independent drivetrains also? That would permit the

use

Quoted message said:

of conventional cranks, as a useful sideeffect.

Yes, as with the trailer-bike. There are 2 off-road advantages to this:
removing the pedal strike problem with synchronized cranks, and twice
the uphill traction.

Dear Peter,

The articulated 3-wheel tandem sounds as if it would have
even more advantages--it would help on ground clearance and
allow lofting the front wheel in a normal fashion.

Any chance of pictures of the kind of trail sections that
you have in mind?

Carl Fogel

Peter Cole said:

David Damerell said:

Quoting Peter Cole <[email hidden]>:

Quoted message said:

I pulled my daughter for several years on some very technical trails
around here using a trailer bike (until she was about 90 lb). I

think

Quoted message said:

Quoted message said:

the ideal trail tandem would be articulated like that, with 3

wheels.

Quoted message said:

Presumably with 2 independent drivetrains also? That would permit the

use

Quoted message said:

of conventional cranks, as a useful sideeffect.

Yes, as with the trailer-bike. There are 2 off-road advantages to this:
removing the pedal strike problem with synchronized cranks, and twice
the uphill traction.

Dear Peter,

The articulated 3-wheel tandem sounds as if it would have
even more advantages--it would help on ground clearance and
allow lofting the front wheel in a normal fashion.

Any chance of pictures of the kind of trail sections that
you have in mind?

Carl Fogel

Zog The Undeniable said:

Tom Sherman said:

I will annoy some by pointing out that a bicycle with a properly
designed hard shell fairing can propelled at 40+ MPH for hours at a
time by a reasonably strong rider. There have been several riders who
have exceeded 50 miles in one hour.

I think Messrs Cipollini and Cunego would also claim to achieve 40mph,
albeit only over 100 metres after being towed there by their
long-suffering team-mates.

How many seconds can a (cycling) sprinter maintain anaerobic power?

--
Tom Sherman - Earth (Downstate Illinois, North of Forgottonia)

Zog The Undeniable said:

Tom Sherman said:

I will annoy some by pointing out that a bicycle with a properly
designed hard shell fairing can propelled at 40+ MPH for hours at a
time by a reasonably strong rider. There have been several riders who
have exceeded 50 miles in one hour.

I think Messrs Cipollini and Cunego would also claim to achieve 40mph,
albeit only over 100 metres after being towed there by their
long-suffering team-mates.

How many seconds can a (cycling) sprinter maintain anaerobic power?

--
Tom Sherman - Earth (Downstate Illinois, North of Forgottonia)

Tom Sherman said:

How many seconds can a (cycling) sprinter maintain anaerobic power?

Whether you're a sprinter or not, there's only about a dozen seconds worth
of glycogen in your body.