Who-hoo!

[Tony B]

I was just giving my Cannondale a bit of TLC and happened to notice the
max speed on the cycle computer has got up to 63.7 kmh!!!

Wonder when that was?

Of course it's about now I remember the speeds the really fast riders
get to, hmm...

http://www.speed101.com/now/fastest_0127_1.htm

now that's fast!

bfn,

T

[PhilD]

On Sep 4, 1:59 pm, Tony B > wrote:
> I was just giving my Cannondale a bit of TLC and happened to notice the
> max speed on the cycle computer has got up to 63.7 kmh!!!
>
> Wonder when that was?
>
> Of course it's about now I remember the speeds the really fast riders
> get to, hmm...
>
> http://www.speed101.com/now/fastest_0127_1.htm
>
> now that's fast!
>
> bfn,
>
> T

My Cateye Velo 5 has registered over 190mph, but I think that was
caused by interference from something passing. Would be nice to claim
that, but...

Imagine sustaining that and overtaking a Eurostar or whatever!

PhilD

--
<><

[Dave Larrington]

In ,
Tony B > tweaked the Babbage-Engine to tell
us:
> I was just giving my Cannondale a bit of TLC and happened to notice
> the max speed on the cycle computer has got up to 63.7 kmh!!!
>
> Wonder when that was?
>
> Of course it's about now I remember the speeds the really fast riders
> get to, hmm...
>
> http://www.speed101.com/now/fastest_0127_1.htm
>
> now that's fast!

And out of date...

http://www.wisil.recumbents.com/wisil/whpsc2007/speedchallenge-2007.htm

--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk>
Kinder surprise! What's the surprise? Your children are now dead.

[Membrane]

Tony B > wrote:

>I was just giving my Cannondale a bit of TLC and happened to notice the
>max speed on the cycle computer has got up to 63.7 kmh!!!

<yeahbut> for it to be recognized by the u.r.c. committee you need to
have done it twice in opposite directions within a certain time frame.

--
Membrane

[elyob]

On 4 Sep, 13:59, Tony B > wrote:
> I was just giving my Cannondale a bit of TLC and happened to notice the
> max speed on the cycle computer has got up to 63.7 kmh!!!
>
> Wonder when that was?
>
> Of course it's about now I remember the speeds the really fast riders
> get to, hmm...
>
> http://www.speed101.com/now/fastest_0127_1.htm
>
> now that's fast!
>
> bfn,
>
> T

Really? I hit nearly that every single day ... I did that on the
single speed on Sunday.

My record is 87kph on a MTB ... Always wanted to return to Ditchling
Beacon with a geared up road bike ... am sure I'd break 110kph ..

Now that'd be fast ...

[Pete]

elyob wrote:
> On 4 Sep, 13:59, Tony B > wrote:
>> I was just giving my Cannondale a bit of TLC and happened to notice the
>> max speed on the cycle computer has got up to 63.7 kmh!!!
>>
>> Wonder when that was?
>>
>> Of course it's about now I remember the speeds the really fast riders
>> get to, hmm...
>>
>> http://www.speed101.com/now/fastest_0127_1.htm
>>
>> now that's fast!
>>
>> bfn,
>>
>> T
>
> Really? I hit nearly that every single day ... I did that on the
> single speed on Sunday.
>
> My record is 87kph on a MTB ... Always wanted to return to Ditchling
> Beacon with a geared up road bike ... am sure I'd break 110kph ..
>
> Now that'd be fast ...
>

My best speed ever was on a mountain bike - 79kph. I only managed 75
down Ditchling. I think the extra weight of a fully loaded touring MTB
made more difference than the better aero of the road bike.

Good luck!

Pete

[burtthebike]

"Tony B" > wrote in message
...
>I was just giving my Cannondale a bit of TLC and happened to notice the max
>speed on the cycle computer has got up to 63.7 kmh!!!
>
> Wonder when that was?

Dunno, but it reminds me of the lovely Helms cartoon, the one where the
smiling cyclist is setting out, and his wife is explaining to the neighbour
that "he's been a happy man since I reprogrammed his computer by 10%"

[Daniel Barlow]

Membrane wrote:
> <yeahbut> for it to be recognized by the u.r.c. committee you need to
> have done it twice in opposite directions within a certain time frame.

Or be Alan Holmes



-dan

[Jim Higson[_2_]]

Pete wrote:

> elyob wrote:
>> On 4 Sep, 13:59, Tony B > wrote:
>>> I was just giving my Cannondale a bit of TLC and happened to notice the
>>> max speed on the cycle computer has got up to 63.7 kmh!!!
>>>
>>> Wonder when that was?
>>>
>>> Of course it's about now I remember the speeds the really fast riders
>>> get to, hmm...
>>>
>>> http://www.speed101.com/now/fastest_0127_1.htm
>>>
>>> now that's fast!
>>>
>>> bfn,
>>>
>>> T
>>
>> Really? I hit nearly that every single day ... I did that on the
>> single speed on Sunday.
>>
>> My record is 87kph on a MTB ... Always wanted to return to Ditchling
>> Beacon with a geared up road bike ... am sure I'd break 110kph ..
>>
>> Now that'd be fast ...
>>
>
> My best speed ever was on a mountain bike - 79kph. I only managed 75
> down Ditchling. I think the extra weight of a fully loaded touring MTB
> made more difference than the better aero of the road bike.

I'm not sure if you're saying the extra weight helped or hindered you. In
any case, unless I'm missing something, I don't think it would make any
difference[1], but the aero drag of luggage would probably slow you down
quite a bit.

[1] Heavy things fall at the same speed as lighter things:
http://www.jimloy.com/physics/galileo.htm

[Clive George]

"Jim Higson" > wrote in message
...

> I'm not sure if you're saying the extra weight helped or hindered you. In
> any case, unless I'm missing something, I don't think it would make any
> difference[1], but the aero drag of luggage would probably slow you down
> quite a bit.
>
> [1] Heavy things fall at the same speed as lighter things:
> http://www.jimloy.com/physics/galileo.htm

Where I ride a bike, I normally find this thing called "air". It's quite
useful in some ways, since my body is designed to use it as a source of
oxygen to keep me alive. In other ways it's a bit tedious, air resistance
being the thing I spend most of my riding energy on.

The thing is, due to the presence of this "air", it is no longer true to say
that heavy things fall at the same speed as lighter things. Trivial example
: coin, feather.

Who will descend faster - a rider with empty bottles on the bike, or one
with lead-filled bottles on the bike? Obviously the extra weight won't make
any difference[1] - or would it?

cheers,
clive

[Dan Gregory]

Clive George wrote:

> Who will descend faster - a rider with empty bottles on the bike, or one
> with lead-filled bottles on the bike? Obviously the extra weight won't
> make any difference[1] - or would it?
Jean Robic thought so; see 1953 in this article
http://observer.guardian.co.uk/osm/story/0,,966185,00.html

[PhilD]

On Sep 5, 12:32 pm, "Clive George" > wrote:
> > [1] Heavy things fall at the same speed as lighter things:
> >http://www.jimloy.com/physics/galileo.htm
>
> The thing is, due to the presence of this "air", it is no longer true to say
> that heavy things fall at the same speed as lighter things. Trivial example
> : coin, feather.
>


Force = mass * accelleration, or f=ma

a is constant (gravity), m you can change.

The faster you go, the greater the force you need to overcome (air
resistance mainly, but some other resistances as well). Therefore,
for pelting downhill, all other things being equal, you+bike needs to
be heavier to achieve higher speeds.

PhilD

--
<><

[BigRab]

On 5 Sep, 15:55, PhilD > wrote:
> On Sep 5, 12:32 pm, "Clive George" > wrote:
>
> > > [1] Heavy things fall at the same speed as lighter things:
> > >http://www.jimloy.com/physics/galileo.htm
>
> > The thing is, due to the presence of this "air", it is no longer true to say
> > that heavy things fall at the same speed as lighter things. Trivial example
> > : coin, feather.
>
> Force = mass * accelleration, or f=ma
>
> a is constant (gravity), m you can change.
>
> The faster you go, the greater the force you need to overcome (air
> resistance mainly, but some other resistances as well). Therefore,
> for pelting downhill, all other things being equal, you+bike needs to
> be heavier to achieve higher speeds.
>
> PhilD
>
> --
> <><

Yeahbut......

Surely as you increase mass then your acceleration (for a given
force ) will be less?

[Ben C]

On 2007-09-05, BigRab > wrote:
> On 5 Sep, 15:55, PhilD > wrote:
>> On Sep 5, 12:32 pm, "Clive George" > wrote:
>>
>> > > [1] Heavy things fall at the same speed as lighter things:
>> > >http://www.jimloy.com/physics/galileo.htm
>>
>> > The thing is, due to the presence of this "air", it is no longer true to say
>> > that heavy things fall at the same speed as lighter things. Trivial example
>> > : coin, feather.
>>
>> Force = mass * accelleration, or f=ma
>>
>> a is constant (gravity), m you can change.
>>
>> The faster you go, the greater the force you need to overcome (air
>> resistance mainly, but some other resistances as well). Therefore,
>> for pelting downhill, all other things being equal, you+bike needs to
>> be heavier to achieve higher speeds.
>>
>> PhilD
>>
>> --
>> <><
>
> Yeahbut......
>
> Surely as you increase mass then your acceleration (for a given
> force ) will be less?

Yes, but the miracle of gravity is that it automatically applies a
bigger force to something with a bigger mass.

Air resistance on the other hand doesn't. The force it applies depends
on speed (squared, about) and frontal surface area (roughly).

So although gravity on its own results in exactly the same accelerations
on the heavy and the light bikes, air resistance results in a greater
deceleration on the lighter bike (same force, but less mass, so more
deceleration) at a given speed assuming both bikes have about the same
frontal area.

So the heavy bike ends up going faster down hills.

[Martin Dann]

Ben C wrote:
> On 2007-09-05, BigRab > wrote:
>> On 5 Sep, 15:55, PhilD > wrote:
>>> On Sep 5, 12:32 pm, "Clive George" > wrote:
>>>
>>>>> [1] Heavy things fall at the same speed as lighter things:
>>>>> http://www.jimloy.com/physics/galileo.htm
>>>> The thing is, due to the presence of this "air", it is no longer true to say
>>>> that heavy things fall at the same speed as lighter things. Trivial example
>>>> : coin, feather.
>>> Force = mass * accelleration, or f=ma
>>>
>>> a is constant (gravity), m you can change.
>>>
>>> The faster you go, the greater the force you need to overcome (air
>>> resistance mainly, but some other resistances as well). Therefore,
>>> for pelting downhill, all other things being equal, you+bike needs to
>>> be heavier to achieve higher speeds.
>>>
>>> PhilD
>>>
>>> --
>>> <><
>> Yeahbut......
>>
>> Surely as you increase mass then your acceleration (for a given
>> force ) will be less?
>
> Yes, but the miracle of gravity is that it automatically applies a
> bigger force to something with a bigger mass.
>
> Air resistance on the other hand doesn't. The force it applies depends
> on speed (squared, about) and frontal surface area (roughly).
>
> So although gravity on its own results in exactly the same accelerations
> on the heavy and the light bikes, air resistance results in a greater
> deceleration on the lighter bike (same force, but less mass, so more
> deceleration) at a given speed assuming both bikes have about the same
> frontal area.
>
> So the heavy bike ends up going faster down hills.

For a very long hill with a fixed gradient, a heavy bike
will go faster. However a lot of the initial acceleration
will come from the cyclist putting k.e. in with his legs.
E=(1/2)mv^2, so for a fixed energy input, a lighter bike
will go faster.

If you are going down hill, and hit an up hill section, a
heavy cycle will decelerate faster than a light cycle if
both are being pedalled, as lifting up the heavy bike
needs more energy than the light bike.

Martin.

[Clive George]

"Martin Dann" > wrote in message
...

>> Yes, but the miracle of gravity is that it automatically applies a
>> bigger force to something with a bigger mass.
>>
>> Air resistance on the other hand doesn't. The force it applies depends
>> on speed (squared, about) and frontal surface area (roughly).
>>
>> So although gravity on its own results in exactly the same accelerations
>> on the heavy and the light bikes, air resistance results in a greater
>> deceleration on the lighter bike (same force, but less mass, so more
>> deceleration) at a given speed assuming both bikes have about the same
>> frontal area.
>>
>> So the heavy bike ends up going faster down hills.
>
> For a very long hill with a fixed gradient, a heavy bike will go faster.
> However a lot of the initial acceleration will come from the cyclist
> putting k.e. in with his legs.
> E=(1/2)mv^2, so for a fixed energy input, a lighter bike will go faster.

Doesn't take that long a hill to reach the steady state, so even assuming
you mean "fixed energy input from the cyclist", rather than taking into
account the PE change, the heavier bike wins fairly soon.

cheers,
clive

[Roger Merriman]

Martin Dann > wrote:

> Ben C wrote:
big snips
> >
> > Yes, but the miracle of gravity is that it automatically applies a
> > bigger force to something with a bigger mass.
> >
> > Air resistance on the other hand doesn't. The force it applies depends
> > on speed (squared, about) and frontal surface area (roughly).
> >
> > So although gravity on its own results in exactly the same accelerations
> > on the heavy and the light bikes, air resistance results in a greater
> > deceleration on the lighter bike (same force, but less mass, so more
> > deceleration) at a given speed assuming both bikes have about the same
> > frontal area.
> >
> > So the heavy bike ends up going faster down hills.
>
> For a very long hill with a fixed gradient, a heavy bike
> will go faster. However a lot of the initial acceleration
> will come from the cyclist putting k.e. in with his legs.
> E=(1/2)mv^2, so for a fixed energy input, a lighter bike
> will go faster.
>
> If you are going down hill, and hit an up hill section, a
> heavy cycle will decelerate faster than a light cycle if
> both are being pedalled, as lifting up the heavy bike
> needs more energy than the light bike.
>
> Martin.

yes i notice that on things like club runs where i'll move up the group
on downhills partly weight and partly wider tires that are less likely
to wash out on gravel etc, but any uphill bits, tend to knock one back.

still it is a club run not a race etc.

roger
--
www.rogermerriman.com

[David Damerell]

Quoting BigRab >:
>On 5 Sep, 15:55, PhilD > wrote:
>>On Sep 5, 12:32 pm, "Clive George" > wrote:
>>>>[1] Heavy things fall at the same speed as lighter things:
>>>>http://www.jimloy.com/physics/galileo.htm
>>>The thing is, due to the presence of this "air", it is no longer true to say
>>>that heavy things fall at the same speed as lighter things. Trivial example
>>for pelting downhill, all other things being equal, you+bike needs to
>>be heavier to achieve higher speeds.
>Surely as you increase mass then your acceleration (for a given
>force ) will be less?

"For a given force" is where you go wrong. What matters is the net force.
If I am at terminal velocity on a given hill, the net force is zero; if I
magically exchange an empty water bottle for a lead-filled one, the air
resistance does not change but the gravitational force does. The net force
is now positive; I accelerate to a higher terminal velocity.

However, generally you aren't increasing mass without changing air
resistance. The square-cube law means heavier riders tend to have a higher
ratio of mass to frontal cross section, so they descend faster. A tandem
has added an extra rider's mass almost entirely in the wind shadow of the
first rider; they descend _much_ faster. But the original question, loaded
or unloaded bike; the panniers are partly in the shadow of the legs,
partly not, probably less dense than a human rider - it's not all that
clear whether they will increase or decrease terminal velocity.
--
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rden:burdened,!cmdassist,msg_window:reversed,!spar kle,horsename:Rumiko,showrace

[Martin Dann]

Clive George wrote:
> "Martin Dann" > wrote in message
> ...
>
>>> Yes, but the miracle of gravity is that it automatically applies a
>>> bigger force to something with a bigger mass.
>>>
>>> Air resistance on the other hand doesn't. The force it applies depends
>>> on speed (squared, about) and frontal surface area (roughly).
>>>
>>> So although gravity on its own results in exactly the same accelerations
>>> on the heavy and the light bikes, air resistance results in a greater
>>> deceleration on the lighter bike (same force, but less mass, so more
>>> deceleration) at a given speed assuming both bikes have about the same
>>> frontal area.
>>>
>>> So the heavy bike ends up going faster down hills.
>>
>> For a very long hill with a fixed gradient, a heavy bike will go
>> faster. However a lot of the initial acceleration will come from the
>> cyclist putting k.e. in with his legs.
>> E=(1/2)mv^2, so for a fixed energy input, a lighter bike will go faster.
>
> Doesn't take that long a hill to reach the steady state, so even
> assuming you mean "fixed energy input from the cyclist",

Yes that is what I meant. Have you ever started at the top
of a hill and just freewheeled without any pedalling, it
takes a while to get going. The lighter bike will have a
better initial acceleration, the heavy bike will have
fight wind resistance better, and have a higher terminal
velocity.

rather than
> taking into account the PE change, the heavier bike wins fairly soon.

Where I live I am rarely on hills like that, and when I do
get up to terminal velocity, I normally have to slow down
for traffic lights, bends, cars etc, or I hit another up hill.

[Rob Morley]

In article >, Martin Dann
says...

> Yes that is what I meant. Have you ever started at the top
> of a hill and just freewheeled without any pedalling, it
> takes a while to get going. The lighter bike will have a
> better initial acceleration,

Why?

[David Damerell]

Quoting Martin Dann >:
>Yes that is what I meant. Have you ever started at the top
>of a hill and just freewheeled without any pedalling, it
>takes a while to get going. The lighter bike will have a
>better initial acceleration,

Uh - bunk. The force is proportional to the mass, and so the accelerations
are equal until wind resistance takes over.
--
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rden:burdened,!cmdassist,msg_window:reversed,!spar kle,horsename:Rumiko,showrace

[Alan Braggins]

In article >, David Damerell wrote:
>Quoting Martin Dann >:
>>Yes that is what I meant. Have you ever started at the top
>>of a hill and just freewheeled without any pedalling, it
>>takes a while to get going. The lighter bike will have a
>>better initial acceleration,
>
>Uh - bunk. The force is proportional to the mass, and so the accelerations
>are equal until wind resistance takes over.

I'm fairly sure he means the lighter bike will have a better initial
acceleration _when pedalled_, at the point at which without pedalling
it would take a while to get going. And if you put the same rider(s)
on a more massive bike, their pedalling force will not be proportional to
the mass, so the initial acceleration of the lighter bike will indeed
then be higher.

[David Damerell]

[Supersedes]
Quoting Alan Braggins >:
>In article >, David Damerell wrote:
>>Quoting Martin Dann >:
>>>Yes that is what I meant. Have you ever started at the top
>>>of a hill and just freewheeled without any pedalling, it
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>takes a while to get going. The lighter bike will have a
>>>better initial acceleration,
>>Uh - bunk. The force is proportional to the mass, and so the accelerations
>>are equal until wind resistance takes over.
>I'm fairly sure he means the lighter bike will have a better initial
>acceleration _when pedalled_,

In that case you should reexamine the article replied to.

Or maybe not. I'm sorry; I think it's too incoherent to definitely admit
of either explanation.
--
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rden:burdened,!cmdassist,msg_window:reversed,!spar kle,horsename:Rumiko,showrace

[Alan Braggins]

In article >, David Damerell wrote:
>[Supersedes]
>Quoting Alan Braggins >:
>>In article >, David Damerell wrote:
>>>Quoting Martin Dann >:
>>>>Yes that is what I meant. Have you ever started at the top
>>>>of a hill and just freewheeled without any pedalling, it
> ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>>>takes a while to get going. The lighter bike will have a
>>>>better initial acceleration,
>>>Uh - bunk. The force is proportional to the mass, and so the accelerations
>>>are equal until wind resistance takes over.
>>I'm fairly sure he means the lighter bike will have a better initial
>>acceleration _when pedalled_, at the point at which without pedalling
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>>it would take a while to get going.
^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
>
>In that case you should reexamine the article replied to.
>Or maybe not.

Indeed.