commuter p0rn

flyingdutch said:

checkout mah cuzzin's new wheels:

Noice!

flyingdutch said:

Biomega shaft driven bike

Neat. I think that'd be just the thing for recumbents, where the
chain gets too long and floppy, and weight doesn't matter.

--
Home page: http://members.westnet.com.au/mvw

flyingdutch said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

Interesting. With drop bars and 700c wheels it is suddenly much more
appealing to me than a flat bar comfort bike with shaft transmission.

Do you know what it is like to ride?

Cheers,

Vince

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

Quoted message said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

--
flyingdutch

As an exercise in low-maintainance commutery goodness, that looks brilliant.

flyingdutch said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

You realise, of course, that shafties don't countersteer, or wheelie.

(Zebee, *SHUSH*)

Bleve said:

flyingdutch said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

You realise, of course, that shafties don't countersteer, or wheelie.

I'm surprised you didn't mention the torque effect when cornering at speed.
A real problem when you're going 'round the bend.

Cheers,

Vince

Bleve said:

You realise, of course, that shafties don't countersteer, or wheelie.

hehe. he's threatening to take it along to glenvale. bwahahahahah.
don't think he used it at Lygon St today...

flyingdutch said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

where'd he get it from..

flyingdutch said:

Bleve said:

You realise, of course, that shafties don't countersteer, or wheelie.

hehe. he's threatening to take it along to glenvale. bwahahahahah.

It would be funny. The losses through gear drive systems are
significant, esp compared to chain drives. It'd be like racing on flat
tyres.

Bleve said:

flyingdutch said:

Bleve said:

You realise, of course, that shafties don't countersteer, or
wheelie.

hehe. he's threatening to take it along to glenvale. bwahahahahah.

It would be funny. The losses through gear drive systems are
significant, esp compared to chain drives. It'd be like racing on
flat tyres.

When I first bought a shaft drive motorcycle various people made the
same claim.

After some years I found an engineering treatise that actually measured
the difference between a shaft and chain drive.

Essentially a chain that is perfectly lubricated and is clean and in
perfect order is just marginally more efficient than a shaft drive.

But, deviation away from "perfect" condition and lubrication drops the
efficency of a chain below that of a shaft drive.

A shaft drive's efficiency essentially does not change....And it
requires little ongoing maintainence and from a lubrication point of
view is a sealed environment.

Where do I buy a shaft drive bicycle?

--

Hi,
Shaft drive looks elegant, and therefore very marketable, so why
haven't shimano/campagnolo produced it?
The discussion here
http://www.gatago.com/rec/bicycles/tech/24617285.htm
may shed some light on this appealing power transmission system.

l

flyingdutch said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

Blue Heeler said:

Bleve said:

flyingdutch said:

Bleve Wrote:
>
> You realise, of course, that shafties don't countersteer, or
> wheelie.
>
>

hehe. he's threatening to take it along to glenvale. bwahahahahah.

It would be funny. The losses through gear drive systems are
significant, esp compared to chain drives. It'd be like racing on
flat tyres.

When I first bought a shaft drive motorcycle various people made the
same claim.

After some years I found an engineering treatise that actually measured
the difference between a shaft and chain drive.

Essentially a chain that is perfectly lubricated and is clean and in
perfect order is just marginally more efficient than a shaft drive.

cite the article, please. My understanding is that bevelled gear
drives have quite significant losses, and that a shaft drive bicycle
has to have two of them. Somewhere in the vicinity of 5-10% or more,
from memory, but it's been a while. Well kept chains (like one tends
to have on a racebike) are rather more efficient.

Blue Heeler said:

Bleve said:

flyingdutch said:

Bleve Wrote:

>You realise, of course, that shafties don't countersteer, or
>wheelie.
>
>

hehe. he's threatening to take it along to glenvale. bwahahahahah.

It would be funny. The losses through gear drive systems are
significant, esp compared to chain drives. It'd be like racing on
flat tyres.

When I first bought a shaft drive motorcycle various people made the
same claim.

After some years I found an engineering treatise that actually measured
the difference between a shaft and chain drive.

Essentially a chain that is perfectly lubricated and is clean and in
perfect order is just marginally more efficient than a shaft drive.

But, deviation away from "perfect" condition and lubrication drops the
efficency of a chain below that of a shaft drive.

A shaft drive's efficiency essentially does not change....And it
requires little ongoing maintainence and from a lubrication point of
view is a sealed environment.

Where do I buy a shaft drive bicycle?

The bevel driven camshaft Ducatis didn't seem to suffer any ill effects.

Friday

Bleve said:

Blue Heeler said:

Bleve said:

flyingdutch wrote:
> Bleve Wrote:
>> You realise, of course, that shafties don't countersteer, or
>> wheelie.
>>
>>
> hehe. he's threatening to take it along to glenvale. bwahahahahah.
It would be funny. The losses through gear drive systems are
significant, esp compared to chain drives. It'd be like racing on
flat tyres.

When I first bought a shaft drive motorcycle various people made the
same claim.

After some years I found an engineering treatise that actually measured
the difference between a shaft and chain drive.

Essentially a chain that is perfectly lubricated and is clean and in
perfect order is just marginally more efficient than a shaft drive.

cite the article, please. My understanding is that bevelled gear
drives have quite significant losses, and that a shaft drive bicycle
has to have two of them. Somewhere in the vicinity of 5-10% or more,
from memory, but it's been a while. Well kept chains (like one tends
to have on a racebike) are rather more efficient.

My memory is that the total efficiency loss with a shafty is about 5%
(all other things being equal) That the torque effect while significant
is not dangerous (I can confirm that from experience, as can Zebee I
should think) and I cannot see that being a factor in a bicycle) and
that the shaft assembly weighs a significant amount more)

Nothing that would be a really big deal in a motorcycle, and a
interesting way to go in a utility bicycle but on a race bike... the
difference between a waterpipe frame and carbon fibre.

Dave

dave said:

My memory is that the total efficiency loss with a shafty is about 5%

Shaft drive motorcycles often have to have just one bevelled gear (you
can rotate the
engine). They also have lots of power. Bicycles have to have 2
transmissions
or you have to ride the bike sideways (tricky!). Thus, double the
losses, and more weight and complexity. They work, sure, and for a
commuter, they're fine, but for racing, they are a dead loss. Well
maintained chain drive systems are light and very efficient (99-95%
efficiency, according to the data I've seen in 'bicycling science, 3rd
ed'. We train to try and get a few extra watts here and there, not to
then give them away through a heavy and inefficient drivetrain. As
above, as a commuter, who cares about a few watts? But racing?

Quoted message said:

(all other things being equal) That the torque effect while significant
is not dangerous (I can confirm that from experience, as can Zebee I
should think) and I cannot see that being a factor in a bicycle) and
that the shaft assembly weighs a significant amount more)

Nothing that would be a really big deal in a motorcycle, and a
interesting way to go in a utility bicycle but on a race bike... the
difference between a waterpipe frame and carbon fibre.

Bigger than that. A waterpipe frame, on flat ground or a descent, is
really no slower than a uberlight CF wonder, but bust its transmission?

Bleve said:

cite the article, please. My understanding is that bevelled gear
drives have quite significant losses, and that a shaft drive bicycle
has to have two of them. Somewhere in the vicinity of 5-10% or more,
from memory, but it's been a while. Well kept chains (like one tends
to have on a racebike) are rather more efficient.

I can no longer cite the article, after all I've owned shaft drive
motorcycles now since 1978...

But, here's a little logic for you.

You say that you think that the "loss" through a bevel is 5~10%, times
that by two as on my old Yamaha that has a bevel "middle drive box" as
well as a bevel final drive, that would be 10~20%.

OK?

Now the "loss" has to go somewhere and the obvious thing is that it
would be disapated as heat and noise, both of which are really good
ways to sink power "losses".

Ok this far?

The bike had approximately 100hp, actually it really didn't, but lets
pretend for a moment, cause the real value is close and my pretend one
makes for easy maths.

Now given that I could ride the bike all day and neither the first or
second bevel drive housings got too hot to touch and I didn't have to
turn up the walkman to drown out the howling bevel gears (in fact I
couldn't hear them at all). It would seem that 10 to 20hp were not
being disappated as "losses" in the shaft drive.

In fact were it so they would have needed either massive heatsinks or
needed to be water cooled. Ten to twenty horsepower converted to heat,
is a lot of heat, you would notice it.

The reality is that they did not require external cooling. so I think
it is safe to say "MYTH BUSTED" on the 10~20% power loss

OK this far.

Now in the past, I owned a GPZ1100 Kawasaki, a bike with an absurd
amount of horsepower and very few manners. After a good long thrashing
the chain and sprockets would be too hot to touch, so on that
eccelectic measure the chain in that situation was dissapating more
energy than my shaft drive did.

Now before you jump down my keyboard, there are way to many variables
in that comparison for it to mean anything at all, other than to say
that chain is clearly not "lossless."

I will look again, but I suspect that I've long lost the article, but
if I do still have it, I'll scan and post it somewhere.

--

flyingdutch said:

checkout mah cuzzin's new wheels:

Biomega shaft driven bike
converted to 700c wheels
disc on front, drum brake on back
8spd nexus hub

Shweeeet! 😄

http://www.boroondarabug.org/images/Shaftie_1.jpg
http://www.boroondarabug.org/images/Shaftie_2.jpg

--
flyingdutch

Hey, we bumped into him on the way to the start of ATB when we picked
up two riders who weren't too sure of the way to the Docklands. At
first I only noticed that he had a hub gear on a road bike, which I
thought was unusual. Totally missed the fact that there was no chain!

Blue Heeler said:

Bleve said:

cite the article, please. My understanding is that bevelled gear
drives have quite significant losses, and that a shaft drive bicycle
has to have two of them. Somewhere in the vicinity of 5-10% or more,
from memory, but it's been a while. Well kept chains (like one tends
to have on a racebike) are rather more efficient.

I can no longer cite the article, after all I've owned shaft drive
motorcycles now since 1978...

But, here's a little logic for you.

You say that you think that the "loss" through a bevel is 5~10%, times
that by two as on my old Yamaha that has a bevel "middle drive box" as
well as a bevel final drive, that would be 10~20%.

OK?

Now the "loss" has to go somewhere and the obvious thing is that it
would be disapated as heat and noise, both of which are really good
ways to sink power "losses".

Ok this far?

The bike had approximately 100hp, actually it really didn't, but lets
pretend for a moment, cause the real value is close and my pretend one
makes for easy maths.

Now given that I could ride the bike all day and neither the first or
second bevel drive housings got too hot to touch and I didn't have to
turn up the walkman to drown out the howling bevel gears (in fact I
couldn't hear them at all). It would seem that 10 to 20hp were not
being disappated as "losses" in the shaft drive.

In fact were it so they would have needed either massive heatsinks or
needed to be water cooled. Ten to twenty horsepower converted to heat,
is a lot of heat, you would notice it.

The reality is that they did not require external cooling. so I think
it is safe to say "MYTH BUSTED" on the 10~20% power loss

I'll have to dig up the mech-eng texts on the subject. It won't be
today. I take your mythbuster and suggest 'bad science" 🙂

Interestingly though, this site :
http://www.zakgear.com/Hypoid_worm.html claims 99% efficiency for a
spiral bevel gear, but does then state that these gears are not
suitable for high torque applications. Exactly how much is high-torque
it doesn't make clear.

Quoted message said:

OK this far.

Now in the past, I owned a GPZ1100 Kawasaki, a bike with an absurd
amount of horsepower and very few manners. After a good long thrashing
the chain and sprockets would be too hot to touch, so on that
eccelectic measure the chain in that situation was dissapating more
energy than my shaft drive did.

Now before you jump down my keyboard, there are way to many variables
in that comparison for it to mean anything at all, other than to say
that chain is clearly not "lossless."

I will look again, but I suspect that I've long lost the article, but
if I do still have it, I'll scan and post it somewhere.

I'm not suggesting chains are lossless at all, but that they are less
lossless when maintained correctly than bevelled 90 degree gear drives.
You're forgetting the heatsink of the motorcycle chassis. Metal is a
very good thermal conductor and your GPZ1100 kwaka had both water and
oil coolers. One only needs to look at racing motorcycles to see that
there's very, very few with shaft drives (any?). This is not for
aesthetic reasons. My understanding is that belt drive is the most
efficient, in terms of pure power losses, but that for motorcycles it's
impractical (too wide a belt is needed for high performance motorbikes)
and it's impractical for bicycles because it limits available gearing
to geared hubs or singlespeeds (that limit also applies to shaft drive
bicycles, obviously!)

It's worth looking at the following :

http://en.wikipedia.org/wiki/Shaft-driven_bicycle

I'm sure that for you that's a redundant article, but others may find
it interesting.

Bleve said:

Quoted message said:

The reality is that they did not require external cooling. so I think
it is safe to say "MYTH BUSTED" on the 10~20% power loss

I'll have to dig up the mech-eng texts on the subject. It won't be
today. I take your mythbuster and suggest 'bad science" 🙂

I'll also throw Jobst at you 🙂

http://yarchive.net/bike/shaft_drive.html