Possibly stupid question

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

Quoted message said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?

Some/some.

Quoted message said:

Is it noticably easier to maintain a given speed in similar conditions on
the
flat than on a similarly constructed solo bike?

What about accelerating and hills.

Flat, yes, faster. Downhill, lots faster. Uphill, splot (well, for us
anyway!) - but see later. Accelerating - well, we don't do out of the saddle
sprints, so probably slower.

Quoted message said:

Physics says they should all be better/easier on a tandem, but how
notcable is
it (or are there other factors I haven't thought about that negate the
advantages)?

People often observe that tandems are slow uphills. What's actually
happening is the aero advantage they enjoy has suddenly gone, and they're
exposing the fact that the riders weren't very strong in the first place
(that's us).

Apart from downhills, we're faster than my wife, but slower than me, and the
difference is most pronounced on the uphills.

Mostly it's infinitely better than the two of us on solos - we both put in
the work we can, and just ride along - no having to wait around/work hard to
catch up, which can be tedious/frustrating respectively.

cheers,
clive

Jensen said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?

Is it noticably easier to maintain a given speed in similar conditions on the
flat than on a similarly constructed solo bike?

What about accelerating and hills.

Physics says they should all be better/easier on a tandem, but how notcable is
it (or are there other factors I haven't thought about that negate the
advantages)?

a lot depends how similar the two of you are for cadence as to how
easy they accelerate or climb hills.

I can ride a lot faster with my daughter than with my wife, mainly
because she has a higher cadence, closer to what I like to spin at

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

Quoted message said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?

One disadvantage of a tandem, is, if the front rider has a 'gas'
problem!(:-)

Alan

In article <[email hidden]>, Alan Holmes
says...

Quoted message said:

One disadvantage of a tandem, is, if the front rider has a 'gas'
problem!(:-)

Alan

Thanks for yet another worthwhile contribution that increases the sum of
human knowledge.

Jensen said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?

Is it noticably easier to maintain a given speed in similar conditions on the
flat than on a similarly constructed solo bike?

What about accelerating and hills.

Physics says they should all be better/easier on a tandem, but how notcable is
it (or are there other factors I haven't thought about that negate the
advantages)?

Well....
I had a look at the records on
http://www.cyclingtimetrials.org.uk/index.asp
to see if I could say anything sensible.
The current 25 mile records are:
Solo Chris Boardman 45:57 (1993)
Tandem Zak Carr & Glenn Taylor 45:03 (2003)

In order to catch up with them Chris would have needed to produce 6%
more power. You might get a better idea if you looked at club records
where you can compare the same riders on solo and tandem.
(for instance http://www.apibikes.com/team/frames.htm )

--
Roger Thorpe

My email address is spamtrapped. You can work it out!

Quoting Jensen <[email hidden]>:

Quoted message said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?
Is it noticably easier to maintain a given speed in similar conditions on the
flat than on a similarly constructed solo bike?
What about accelerating and hills.
Physics says they should all be better/easier on a tandem,

Physics says nothing of the kind. Accelerating; twice the power, twice the
weight. Hills; twice the power, twice the weight. In particular, a
tandem's slower on a hill than the stronger rider would be solo -
something which is more noticeable because you've been rocketing around on
the flat.

They are significantly faster and/or easier on the flat - and downhill
they go like rockets. Although you are fighting air resistance in both
cases, it's much more noticeable downhill because a) gravity, unlike
riders, doesn't feel the desire to ease off a bit when you're already
going faster than a solo and b) the power output from gravity is itself
proportional to speed.
--
David Damerell <[email hidden]> flcl?
Today is Leicesterday, January.

David Damerell said:

Quoting Jensen <[email hidden]>:

Quoted message said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?
Is it noticably easier to maintain a given speed in similar conditions on the
flat than on a similarly constructed solo bike?
What about accelerating and hills.
Physics says they should all be better/easier on a tandem,

Physics says nothing of the kind.

Sorry, you are wrong.

Quoted message said:

Quoted message said:

Accelerating; twice the power, twice the

weight.

WRONG. Yopu forgot the weight of the bike which will, for the same construction
technique be lighter than two solos.

Quoted message said:

Hills; twice the power, twice the weight.

You are moving up a hill, therefore you have wind resitance. There will be less
of this for two people on a tandem than two solo riders. Barely noticable (I
would imagine, unless it's a very shallow hill), true , but that was the point
of the question.

Quoted message said:

In particular, a
tandem's slower on a hill than the stronger rider would be solo .

Obviously, but you should still get up the hill faster than when cycling as a
pair of solos because in that case it takes as long for the pair to get up the
hill as the slower rider. Of course, that isn't really a matter of physics.

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

Quoted message said:

David Damerell said:

Quoting Jensen <[email hidden]>:

Quoted message said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?
Is it noticably easier to maintain a given speed in similar conditions on
the
flat than on a similarly constructed solo bike?
What about accelerating and hills.
Physics says they should all be better/easier on a tandem,

Physics says nothing of the kind.

Sorry, you are wrong.

Not that wrong. His approximation for accelerating and hills is about
right - as experience shows.

Quoted message said:

Quoted message said:

Quoted message said:

Accelerating; twice the power, twice the

weight.

WRONG. Yopu forgot the weight of the bike which will, for the same
construction
technique be lighter than two solos.

Not really wrong enough to justify the capital letters - the tandem will
need to be built heavier, and anyway it's insignificant compared to the
weight of the riders.

Quoted message said:

Quoted message said:

Hills; twice the power, twice the weight.

You are moving up a hill, therefore you have wind resitance. There will be
less
of this for two people on a tandem than two solo riders. Barely noticable
(I
would imagine, unless it's a very shallow hill), true , but that was the
point
of the question

It's not significant. Unless the point of the question is the exact answer,
it's not worth it - as a general approximation, tandems don't gain going up
hill.

You may wish to consider the tandem-specific losses too - coordination is
quite important, and losses can be had there.

clive

Clive George said:

Flat, yes, faster. Downhill, lots faster. Uphill, splot (well, for us
anyway!) - but see later. Accelerating - well, we don't do out of the
saddle sprints, so probably slower.

And out of the saddle sprints might not even be possible depending on
how well the riders are coordinated.

--
Andrew

Naqerj said:

Clive George said:

Flat, yes, faster. Downhill, lots faster. Uphill, splot (well, for us
anyway!) - but see later. Accelerating - well, we don't do out of the
saddle sprints, so probably slower.

And out of the saddle sprints might not even be possible depending on
how well the riders are coordinated.

I seem to remember seeing a few tandem track sprints on the telly. As I
recall they usually seemed to end with at least two people lying on the
track. Broken chains too?
It's all a bit hazy and seems unlikely to me now. Maybe I dreamt it.

--
Roger Thorpe

My email address is spamtrapped. You can work it out!

Roger Thorpe wrote:

seem to remember seeing a few tandem track sprints on the telly. As I

Quoted message said:

recall they usually seemed to end with at least two people lying on the
track. Broken chains too?
It's all a bit hazy and seems unlikely to me now. Maybe I dreamt it.

replying to myself...

Maybe I didn't dream it.
it definitely happens in the Paralympics
http://users.htcomp.net/gladu/images/page22.html
and this looks like pro event and is frightening.
http://www.ijs.si/~mleskovar/tandem1_2.jpg
and this shows why tandem racing is an acquired taste for the stoker.....
http://www.sudibe.de/fotos/renntandem/paralympics_2000_3.jpg

--
Roger Thorpe

My email address is spamtrapped. You can work it out!

In news:[email hidden],
Roger Thorpe <[email hidden]> tweaked the
Babbage-Engine to tell us:

Quoted message said:

Roger Thorpe wrote:

seem to remember seeing a few tandem track sprints on the telly. As I

Quoted message said:

recall they usually seemed to end with at least two people lying on
the track. Broken chains too?
It's all a bit hazy and seems unlikely to me now. Maybe I dreamt it.

replying to myself...

Maybe I didn't dream it.
it definitely happens in the Paralympics
http://users.htcomp.net/gladu/images/page22.html
and this looks like pro event and is frightening.
http://www.ijs.si/~mleskovar/tandem1_2.jpg
and this shows why tandem racing is an acquired taste for the
stoker.....
http://www.sudibe.de/fotos/renntandem/paralympics_2000_3.jpg

Somewhere in a book, I have a picture of a brace of tandems track-standing
at the top of the banking of a wooden velodrome...

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
Here, take these cheese-shaped stilts. You'll know when to use
them.

Quoting Jensen <[email hidden]>:

Quoted message said:

Quoted message said:

Quoting Jensen <[email hidden]>:

Quoted message said:

I see a lot of people talking about tandems on this group, and I've often
wondered: How much energy do you save/ how much faster can you go?
Is it noticably easier to maintain a given speed in similar conditions on
the flat than on a similarly constructed solo bike?
What about accelerating and hills.
Physics says they should all be better/easier on a tandem,

Physics says nothing of the kind.

Sorry, you are wrong.

If you are unwilling to listen to actual tandem riders, why did you ask?

Quoted message said:

Quoted message said:

Accelerating; twice the power, twice the weight.

WRONG. Yopu forgot the weight of the bike which will, for the same
construction technique be lighter than two solos.

This is a relatively small difference (and, actually, I wouldn't bet -
what with giant keel tube and 48s wheels and drum brake and all - that my
tandem's any lighter than two similar solos); if you want to get into
relatively small differences, you have to consider the inevitable losses
to coordination, longer drivetrain, etc.

So; simple assessment, twice the power, twice the weight. Complex
assessment; you can't tell where the advantage would be, but it's
certainly not wise to assume the tandem will be faster. In particular, hard
acceleration is exactly where the coordination losses are most easily
seen; a single rider simply can get power onto the pedals more quickly and
effectively, can shift gears more effectively, etc.

Quoted message said:

Quoted message said:

Hills; twice the power, twice the weight.

You are moving up a hill, therefore you have wind resitance.

Again; if the hill's a hill, not a gentle incline, this is a small factor
and it's not sensible to consider it without considering all other small
factors.

Quoted message said:

Quoted message said:

In particular, a
tandem's slower on a hill than the stronger rider would be solo .

Obviously, but you should still get up the hill faster than when cycling as a
pair of solos

That is true; my observation is that the stronger rider can feel that
progress is frustratingly slow on hills.
--
David Damerell <[email hidden]> flcl?
Today is Brieday, January.

On Jan 26, 6:19 pm, David Damerell <[email hidden]>

Quoted message said:

Quoting Jensen <[email hidden]>:

Quoted message said:

Quoted message said:

Quoted message said:

Accelerating; twice the power, twice the weight.

WRONG. Yopu forgot the weight of the bike which will, for the same
construction technique be lighter than two solos.This is a relatively small difference (and, actually, I wouldn't bet -

what with giant keel tube and 48s wheels and drum brake and all - that my
tandem's any lighter than two similar solos);

According to Dawes website the Galaxy Twin is 21kg (Aluminium frame)
The Super Galaxy is 13.5kg (631 steel). So that's 6kg difference
between 2 SGs and one Galaxy twin. Rider weights, say 80kg each (light
weight pilot, slightly heavy stoker), so (6/(160+21))x 100 = 3%
increase for the solos. Not a lot.

Tim

In article said:

Quoting Tim Hall <[email hidden]>:

Quoted message said:

On Jan 26, 6:19 pm, David Damerell <[email hidden]>

Quoted message said:

what with giant keel tube and 48s wheels and drum brake and all - that my
tandem's any lighter than two similar solos);

According to Dawes website the Galaxy Twin is 21kg (Aluminium frame)
The Super Galaxy is 13.5kg (631 steel). So that's 6kg difference
between 2 SGs and one Galaxy twin. Rider weights, say 80kg each (light
weight pilot, slightly heavy stoker), so (6/(160+21))x 100 = 3%
increase for the solos. Not a lot.

Not a lot, and you have compared an aluminium-framed tandem with
steel-framed solos. The Galaxy Twin also doesn't have a drum brake in the
spec, but a lighter disc brake - personally, I would not care to do the
sort of loaded touring these bikes have in mind without a drum brake.

For loaded touring you can add a similar load to both, making the
difference even smaller as a percentage of the total weight. Unless
there's some reason why two tourists on a tandem should use more or
heavier kit than the same tourists on two solos.