Do you use an fairing or partial fairing on your ebike, emoped or BSM?

General Discussion about electric bicycles.
Post Reply
User avatar
Cowardlyduck   1.21 GW

1.21 GW
Posts: 3903
Joined: Jun 26 2011 8:41pm
Location: Australia

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by Cowardlyduck » Jan 16 2022 5:11am

donn wrote:
Jan 15 2022 11:30pm
Do you think you're losing a lot in the conversion, or is the panel just not putting out much more than 15W?
Both! Hard to say as I've never hooked it up to a proper MPPT to verify, but I suspect my DC-DC is only 80% efficient at best. The panel is '40W' by Chinese standards, so really probably only 35W. I also have a long run of wire through the frame to where it connects to the battery and it's only 18AWG so again, not the best between all those things.
That being said, in optimal conditions it can charge around 100Wh+ per day. Considering the battery is only ~700Wh (was 850Wh, but 400 cycles and 5+ years of heavy use has degraded it), and the bike can manage 12Wh/km, that's around 8.3km additional range per day. If the battery were completely flat it could full charge back up from solar in about a week under optimal conditions. I've never tested that though.

Anyway, the point of this thread is the aero...and I gotta say, while I wasn't expecting it, the benefits of the aero this panel gives on this bike when riding are fantastic. It prevents my body acting like a wind sock, it helps keep my hands warmer in winter, and it deflects the rain (which I usually try and avoid) away from my displays and torso.

I have had a few other panels on in the past with a 15W being my first try, then 30W, and now for the last 3 years or so this 40W. If I need to replace this one I might try a 50W which is slightly longer. The challenge then becomes fitting it so that I don't kick it with my feet, and low enough to see over.

I have also considered getting two panels and mounting them into a V shape. Unsure how that kind of setup would fair though...I am not gentle on things!

Cheers

ebike4healthandfitness   10 kW

10 kW
Posts: 553
Joined: May 19 2012 10:20pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 16 2022 7:22am

Two aerodynamic fairings I found for Sur-ron in a article detailing the street legal EU moped version of Sur-ron (shown in 4th picture. Notice head light, turn signal indicators, side mirrors, etc)

https://evnerds.com/electric-vehicles/e ... in-europe/
Attachments
LIGHT-BEE-SPORT-VERSION-758x435.jpg
LIGHT-BEE-SPORT-VERSION-758x435.jpg (39.36 KiB) Viewed 335 times
light-bee-kits-758x388.jpg
light-bee-kits-758x388.jpg (21.6 KiB) Viewed 335 times
light-bee-old-school-cafe-racer-758x460.jpg
light-bee-old-school-cafe-racer-758x460.jpg (44.69 KiB) Viewed 335 times
SUR-RON-C.jpg
SUR-RON-C.jpg (262.16 KiB) Viewed 335 times

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 16 2022 7:37am

SafeDiscDancing wrote:
Jan 15 2022 6:49pm
SafeDiscDancing wrote:
Jan 14 2022 5:39pm
What initiates lean?

That's the core question.

When you wrap your head around that and realize the center of mass stays relatively constant and the tire initiates rotation then it makes sense.

Basically... in simplified terms... the mass is being twisted by a lever which has the tire contact patch as it's terminal point.

The higher the center of mass the MORE leverage and also the rate of rotational change is slower.
I noticed this was SKIPPED entirely... no one saw the reality of this.

Lean demands rotation.

Rotation is determined by the length of the lever arm.

On a bicycle the force is the tire contact patch and the center of mass determines the length of the lever arm.

This should be really basic stuff.

Image

Image
We've beaten that half to death in an other thread (the 'pegs vs pedals). :)
You are right - higher CG is more *stable*, but not necessarily *more rideable*.

Also, talking of 'longer levers' - the level is not just from the ground, but from the spot where lean actually initiated (front contact patch) and the 'anchoring point' - rear wheel contact patch.
What I've found by experimenting with different steering arrangements is that any sort of *spring* in steering system is BAD, very bad. Slop is actually quite tolerable! You can have a lot of slop and simply not notice it, and friction on form of hydraulic damping at least is actually advantageous.
But when there is a lot of spring in your system - the bicycle gets from 'perfectly rideable' to completely undrideable... and same applies to controlling the leaning/balacing!

Which brings me to the my point - recumbents, especially those with long wheelbases, needs *VERY* stiff frames torsionally and laterally. A 'diamond frame bike' has this by default, even if you make it from thin, flexible tubing - though if you go way too far handling still suffer - and it's wheelbase is much shorter.

Electrom uses a huge box for a frame, it must be *extremely* stiff, so is steering - if he used bowden cables with housings that introduce spring into a system, the steering would be much worse and maybe even completely unrideable.

I would be the last person to deny that recumbents no not have issues with control - but I think of this as a challenge, not just a 'turnoff'... because for me 'the lounging chair' aspect is very attractive - my goal is ultradistances, I know all too well how 600 km on a bike in 36 hours feels like in the end...

ebike4healthandfitness   10 kW

10 kW
Posts: 553
Joined: May 19 2012 10:20pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 16 2022 7:46am

BalorNG wrote:
Jan 16 2022 7:37am
SafeDiscDancing wrote:
Jan 15 2022 6:49pm
SafeDiscDancing wrote:
Jan 14 2022 5:39pm
What initiates lean?

That's the core question.

When you wrap your head around that and realize the center of mass stays relatively constant and the tire initiates rotation then it makes sense.

Basically... in simplified terms... the mass is being twisted by a lever which has the tire contact patch as it's terminal point.

The higher the center of mass the MORE leverage and also the rate of rotational change is slower.
I noticed this was SKIPPED entirely... no one saw the reality of this.

Lean demands rotation.

Rotation is determined by the length of the lever arm.

On a bicycle the force is the tire contact patch and the center of mass determines the length of the lever arm.

This should be really basic stuff.

Image

Image
We've beaten that half to death in an other thread (the 'pegs vs pedals). :)
You are right - higher CG is more *stable*, but not necessarily *more rideable*.

Also, talking of 'longer levers' - the level is not just from the ground, but from the spot where lean actually initiated (front contact patch) and the 'anchoring point' - rear wheel contact patch.
What I've found by experimenting with different steering arrangements is that any sort of *spring* in steering system is BAD, very bad. Slop is actually quite tolerable! You can have a lot of slop and simply not notice it, and friction on form of hydraulic damping at least is actually advantageous.
But when there is a lot of spring in your system - the bicycle gets from 'perfectly rideable' to completely undrideable... and same applies to controlling the leaning/balacing!

Which brings me to the my point - recumbents, especially those with long wheelbases, needs *VERY* stiff frames torsionally and laterally. A 'diamond frame bike' has this by default, even if you make it from thin, flexible tubing - though if you go way too far handling still suffer - and it's wheelbase is much shorter.

Electrom uses a huge box for a frame, it must be *extremely* stiff, so is steering - if he used bowden cables with housings that introduce spring into a system, the steering would be much worse and maybe even completely unrideable.

I would be the last person to deny that recumbents no not have issues with control - but I think of this as a challenge, not just a 'turnoff'... because for me 'the lounging chair' aspect is very attractive - my goal is ultradistances, I know all too well how 600 km on a bike in 36 hours feels like in the end...
Higher center of gravity is not more stable.

Perhaps more maneuverable, but not more stable.

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 16 2022 8:30am

Lol. Ok, it seems you can hardly expect instant progress...
Anyway, fairing and control are intrinsically linked - because you cannot have effective fairings w/o compromising the other on a singletrack vehicle (in fact even trucks sometimes get blown sideways due to huge lateral area - but this has to do with *pneumatic* trail effects)

A bike you want to install fairings on must have *excess* of control, so to speak, to make up for sudden perturbations to balance and even steering.
This is why I think that 'upright bike fairings' might make much more sense actually - because you have much worse aero to beging with (hence even a poor fairing will have noticeable effect) and 'excess of control' that recumbent form-factor does lack.

Too bad I'm too spoiled with recumbent form-factor comfort and too busy with other thing to experiment with that, maybe eventually.

ebike4healthandfitness   10 kW

10 kW
Posts: 553
Joined: May 19 2012 10:20pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 16 2022 8:49am

BalorNG wrote:
Jan 16 2022 8:30am

A bike you want to install fairings on must have *excess* of control, so to speak, to make up for sudden perturbations to balance and even steering.
This is why I think that 'upright bike fairings' might make much more sense actually - because you have much worse aero to beging with (hence even a poor fairing will have noticeable effect) and 'excess of control' that recumbent form-factor does lack.
And yet Electrom handles so well.

See, it's not the low center of gravity that is hurting you....it's the way that recumbent you ride is designed and made. This is why you have mistakenly been thinking low center of gravity hurts stability.

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 16 2022 9:58am

ebike4healthandfitness wrote:
Jan 16 2022 7:46am
Higher center of gravity is not more stable.

Perhaps more maneuverable, but not more stable.
:bigthumb: BINGO !!!

Yes. Remember the meaning of "better handling" (at least as I understand the meaning) is something like:

"Can react quickly to unexpected obstacles and gives feedback to the rider when traction is faltering."

We define a better handling bicycle as having the ability to rapidly change course and react to unexpected circumstances.

The word "handling" means essentially the ability to manipulate something to cause some change. The root is "hand".

-----------------

Being able to sense the traction is a huge deal in things like motorcycle road racing which is where real handling matters because they need to actually get around a racetrack. There is no room for bullshit.

A higher center of mass allows more leverage to more forcefully create necessary lean angles and nobody leans as hard and as deep as the motorcycle road racers.

What we have with most streamlined bicycles (like those that race up in Nevada) is racing on a long straight line.

No curves. No handling required. Completely straight line performance.

Image

But the limitation of higher center of mass is acceleration and braking as shown above.

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 17 2022 12:15am

SafeDiscDancing wrote:
Jan 16 2022 9:58am
ebike4healthandfitness wrote:
Jan 16 2022 7:46am
Higher center of gravity is not more stable.

Perhaps more maneuverable, but not more stable.
:bigthumb: BINGO !!!

Yes. Remember the meaning of "better handling" (at least as I understand the meaning) is something like:

"Can react quickly to unexpected obstacles and gives feedback to the rider when traction is faltering."

We define a better handling bicycle as having the ability to rapidly change course and react to unexpected circumstances.

The word "handling" means essentially the ability to manipulate something to cause some change. The root is "hand".

-----------------

Being able to sense the traction is a huge deal in things like motorcycle road racing which is where real handling matters because they need to actually get around a racetrack. There is no room for bullshit.

A higher center of mass allows more leverage to more forcefully create necessary lean angles and nobody leans as hard and as deep as the motorcycle road racers.

What we have with most streamlined bicycles (like those that race up in Nevada) is racing on a long straight line.

No curves. No handling required. Completely straight line performance.

Image

But the limitation of higher center of mass is acceleration and braking as shown above.

Lol. Is this contagious or what? Which is easier to swign - a shortsword or a hammer, even if they have same overall mass, huh?

Please read this and understand ALL the implications:
https://www.motorcyclespecs.co.za/model ... pho_ii.htm

calab   100 kW

100 kW
Posts: 1186
Joined: Dec 11 2013 1:00am

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by calab » Jan 17 2022 2:32am

What about brake feel, cable disk vs hydraulic fluid disk 8)
SafeDiscDancing wrote:
Jan 16 2022 9:58am
Image

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 17 2022 10:03am

BalorNG wrote:
Jan 17 2022 12:15am
Please read this and understand ALL the implications:
https://www.motorcyclespecs.co.za/model ... pho_ii.htm
Two wheel steering huh?

Well... it does sound cool and maybe one day... but in the practical world today we aren't doing it.

--------------------------

Nothing undermines the core physics which says the center of mass is rotated by a force vector which is the contact patch.

Actual rotation is at the center of mass or as close as possible. (Trail has the effect of modifying this)

So... the higher up you put the center of mass the more traction can determine rotation just based on leverage.

Image

A bicycle does NOT behave like a Weebles toy :warn:

-------------------------

https://en.m.wikipedia.org/wiki/Countersteering

Wilbur Wright explained countersteering this way:

"I have asked dozens of bicycle riders how they turn to the left. I have never found a single person who stated all the facts correctly when first asked. They almost invariably said that to turn to the left, they turned the handlebar to the left and as a result made a turn to the left. But on further questioning them, some would agree that they first turned the handlebar a little to the right, and then as the machine inclined to the left, they turned the handlebar to the left and as a result made the circle, inclining inward."

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 17 2022 10:35am

Image

The idea that Weebles Wobble was tried once long ago.

Notice how this Honda prototype race bike had moved the lightweight components (exhaust pipes) up high and then shifted the heavy gas tank down low to shift the center of mass LOWER thinking it would improve things.

From what I heard someone tried a bike like that at Laguna Seca decades ago and when they crested the hill at the end of the front straight it literally took off and the guy crashed hard.

Absolute fail. :flame:

So everyone since then moved the weight up and forward.

In MotoGP a very active new area is the Aerodynamics of "winglets" for downforce and also a "ride height" adjustment to LOWER the bike for the straights. After the acceleration is accomplished they let the suspension spring UPWARDS so they can turn.

This means this is being discussed and developed by billion dollar companies wanting to win races.

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 17 2022 3:18pm

SafeDiscDancing wrote:
Jan 17 2022 10:03am
BalorNG wrote:
Jan 17 2022 12:15am
Please read this and understand ALL the implications:
https://www.motorcyclespecs.co.za/model ... pho_ii.htm
Two wheel steering huh?

Well... it does sound cool and maybe one day... but in the practical world today we aren't doing it.

--------------------------

Nothing undermines the core physics which says the center of mass is rotated by a force vector which is the contact patch.
Indeed it is.
SafeDiscDancing wrote:
Jan 17 2022 10:03am
Actual rotation is at the center of mass or as close as possible. (Trail has the effect of modifying this)
Now where is THAT came from? And what trail has to do with anything? It just does not follow.
SafeDiscDancing wrote:
Jan 17 2022 10:03am
So... the higher up you put the center of mass the more traction can determine rotation just based on leverage.
This is the other way around actually.

SafeDiscDancing wrote:
Jan 17 2022 10:03am
-------------------------

https://en.m.wikipedia.org/wiki/Countersteering

Wilbur Wright explained countersteering this way:

"I have asked dozens of bicycle riders how they turn to the left. I have never found a single person who stated all the facts correctly when first asked. They almost invariably said that to turn to the left, they turned the handlebar to the left and as a result made a turn to the left. But on further questioning them, some would agree that they first turned the handlebar a little to the right, and then as the machine inclined to the left, they turned the handlebar to the left and as a result made the circle, inclining inward."
And what countersteering has to do with that? Yes, you have to 'prelean' into direction of the *turn* on a singletrack HPV - otherwise resulting centrifugal force will inevitably topple you outside of the turn, but it has nothing to do with height of CG and it's effects on stability.

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 17 2022 3:22pm

SafeDiscDancing wrote:
Jan 17 2022 10:35am


In MotoGP a very active new area is the Aerodynamics of "winglets" for downforce and also a "ride height" adjustment to LOWER the bike for the straights. After the acceleration is accomplished they let the suspension spring UPWARDS so they can turn.

This means this is being discussed and developed by billion dollar companies wanting to win races.
Nobody denies that lower CG means better stability in acceleration and deceleration. It is the fact that higher the CG means the bike gets more resistant both to intended and unintended lateral perturbation and falls down slower - hence - more stable, less manoeuvrable. Simple, really.

Oh, and the 'can turn' aspect, again, has nothing to do with height of CG per se, but the fact that you *will* scrape the bodywork and go down if your suspension is fully compressed. Plus, as we already discussed in other thread, the higher the CG - the greater the ability to compensate for 'lifting up' force from fat moto tires, something that you can hardly care about in bike formfactor - you will slide sideway due to lack of traction LONG before you get to corner at close to 2g.

ebike4healthandfitness   10 kW

10 kW
Posts: 553
Joined: May 19 2012 10:20pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by ebike4healthandfitness » Jan 17 2022 3:54pm

BalorNG wrote:
Jan 17 2022 3:22pm
SafeDiscDancing wrote:
Jan 17 2022 10:35am


In MotoGP a very active new area is the Aerodynamics of "winglets" for downforce and also a "ride height" adjustment to LOWER the bike for the straights. After the acceleration is accomplished they let the suspension spring UPWARDS so they can turn.

This means this is being discussed and developed by billion dollar companies wanting to win races.
Nobody denies that lower CG means better stability in acceleration and deceleration. It is the fact that higher the CG means the bike gets more resistant both to intended and unintended lateral perturbation and falls down slower - hence - more stable, less manoeuvrable. Simple, really.
Balor, if center of gravity is raised from some point down low on the bike to somewhere around the level of the gas tank....the bike will be easier to turn because the bike pivots around it's center of mass. It is also going to make the bike easier to turn by a crosswind and thus be less stable.

Maneuverability and stability are inversely related. MotoGP bikes are willing to make this tradeoff though.

Stop trolling my thread.
Last edited by ebike4healthandfitness on Jan 17 2022 3:58pm, edited 1 time in total.

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 17 2022 3:57pm

BalorNG wrote:
Jan 17 2022 3:18pm
SafeDiscDancing wrote:
Jan 17 2022 10:03am
So... the higher up you put the center of mass the more traction can determine rotation just based on leverage.
This is the other way around actually.
Since this is your ERROR we should stick to this and not go down any rabbit holes.

Did you grasp the "Wheebles Wobble" reference?

Image

The mistake you make is not uncommon and even the very best have fallen into it.

But these days the knowledge is better and frankly the $$$ in MotoGP are so huge there is little room for an error like this to still be around.

Reconsider. You goofed. You made a mistake. Ponder deeply. You made the rookie mistake.

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 17 2022 4:20pm

Image

https://en.m.wikipedia.org/wiki/Weeble

Since your (BalorNG) thinking can be described as "Weebles Wobble" let's understand how that idea manifests itself.

From the article:

Weeble is shaped like an egg—in order for the physics principles to work as intended, the shape must have a bottom which is a more or less smooth (unfaceted) hemisphere (to allow the Weeble to roll) and from the central vertical axis the shape must be nearly cylindrically symmetrical (that is, any plane cut through the vertical axis line must produce close to the same profile). Next, the shape must be filled with two basic types of unmixed solids, and the volume of the lighter solid must be greater than that of the heavier solid. Next, the overall shape must have constant positive curvature. Next, the relationship between the heavy solid and the light solid must be such that any orientation of the object off of the vertical axis line must cause the object's centroid to raise and to become offset. Lastly, the object must have only one position in which it can achieve stable mechanical equilibrium.

Combining these characteristics produces a basic Weeble. In theory, it is not possible to have a Weeble with a centroid that is too low to achieve a stable mechanical equilibrium.

--------------------

Can we agree this is your essential position?

Once we get past the definition of the problem then we can systematically move through the thinking to get to the actual answer.

Image

Remember Tron?

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 17 2022 11:36pm

ebike4healthandfitness wrote:
Jan 17 2022 3:54pm

Balor, if center of gravity is raised from some point down low on the bike to somewhere around the level of the gas tank....the bike will be easier to turn because the bike pivots around it's center of mass. It is also going to make the bike easier to turn by a crosswind and thus be less stable.

Maneuverability and stability are inversely related. MotoGP bikes are willing to make this tradeoff though.

Stop trolling my thread.
'The bike pivots around its center of mass' is quite literally nonsense. The bike pivots on the line intersecting contact patches when leaning, and in turns the pivot is the rear wheel unless drifting. You mistake a bike for an aeroplane... what's you next thread - had anyone added wings to your bike? :)
And 'trolling' is what YOU do.

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 17 2022 11:37pm

SafeDiscDancing wrote:
Jan 17 2022 3:57pm
BalorNG wrote:
Jan 17 2022 3:18pm
SafeDiscDancing wrote:
Jan 17 2022 10:03am
So... the higher up you put the center of mass the more traction can determine rotation just based on leverage.
This is the other way around actually.
Since this is your ERROR we should stick to this and not go down any rabbit holes.

Did you grasp the "Wheebles Wobble" reference?

Image

The mistake you make is not uncommon and even the very best have fallen into it.

But these days the knowledge is better and frankly the $$$ in MotoGP are so huge there is little room for an error like this to still be around.

Reconsider. You goofed. You made a mistake. Ponder deeply. You made the rookie mistake.
This thread seems to be a crank magnet, and I'm not talking about cadence sensors...
How about actual *arguments* in favor of your position for a change?

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 17 2022 11:39pm

SafeDiscDancing wrote:
Jan 17 2022 4:20pm
Image

https://en.m.wikipedia.org/wiki/Weeble

Since your (BalorNG) thinking can be described as "Weebles Wobble" let's understand how that idea manifests itself.

From the article:

Weeble is shaped like an egg—in order for the physics principles to work as intended, the shape must have a bottom which is a more or less smooth (unfaceted) hemisphere (to allow the Weeble to roll) and from the central vertical axis the shape must be nearly cylindrically symmetrical (that is, any plane cut through the vertical axis line must produce close to the same profile). Next, the shape must be filled with two basic types of unmixed solids, and the volume of the lighter solid must be greater than that of the heavier solid. Next, the overall shape must have constant positive curvature. Next, the relationship between the heavy solid and the light solid must be such that any orientation of the object off of the vertical axis line must cause the object's centroid to raise and to become offset. Lastly, the object must have only one position in which it can achieve stable mechanical equilibrium.

Combining these characteristics produces a basic Weeble. In theory, it is not possible to have a Weeble with a centroid that is too low to achieve a stable mechanical equilibrium.

--------------------

Can we agree this is your essential position?

Once we get past the definition of the problem then we can systematically move through the thinking to get to the actual answer.

Image

Remember Tron?
No, but we can agree this is a great strawman though.

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 17 2022 11:47pm

BalorNG wrote:
Jan 17 2022 11:39pm
No, but we can agree this is a great strawman though.
I stand by my post as it was solid.

You are 100% in error and seem unwilling to even consider the basis of the error.

But no one PAYS you any money to think right?

I mean it's not like you are building anything that's going to cause harm to others right?

So you continue unchanged and keep believing what you believe.

This happens a lot these days.

User avatar
Chalo   100 GW

100 GW
Posts: 10392
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by Chalo » Jan 18 2022 12:01am

SafeDiscDancing wrote:
Jan 17 2022 11:47pm
BalorNG wrote:
Jan 17 2022 11:39pm
No, but we can agree this is a great strawman though.
I stand by my post as it was solid.

You are 100% in error and seem unwilling to even consider the basis of the error.

But no one PAYS you any money to think right?

I mean it's not like you are building anything that's going to cause harm to others right?

So you continue unchanged and keep believing what you believe.

This happens a lot these days.
It's you who's mistaken. Unlike your Weeble analogy, a rolling bike's point of contact is the part that swings across the surface. Low center of mass impairs both maneuverability and control, because you either end up having to swing a large fraction of the bike's mass across the surface to establish a lean angle (mass concentrated at the high and low extremities), or the period of motion is so quick that it becomes difficult to control (mass concentrated low near the ground).
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

User avatar
SafeDiscDancing   10 kW

10 kW
Posts: 514
Joined: Jan 03 2022 12:01pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by SafeDiscDancing » Jan 18 2022 12:08am

Chalo wrote:
Jan 18 2022 12:01am
...a rolling bike's point of contact is the part that swings across the surface. Low center of mass impairs both maneuverability and control, because you either end up having to swing a large fraction of the bike's mass across the surface to establish a lean angle (mass concentrated at the high and low extremities), or the period of motion is so quick that it becomes difficult to control (mass concentrated low near the ground).
The "root" of the discussion began at:

So... the higher up you put the center of mass the more traction can determine rotation just based on leverage.

That was my position and BalorNG took the opposite position.

----------------

Rotational Inertia is less of an issue with bicycles but can be a huge deal on a motorcycle.

If the weight is spread out then it takes more energy to initiate lean and that rotation can want to keep going so you could literally be fighting the motorcycle if it's heavy and the weight is badly located.

The gas tank is purposely located at very near the center of mass because that way as the fuel goes down your overall handling stays mostly the same.

Imagine the nightmare of a motorcycle with the gas tank on the bottom?

Not only does it shift the weight too low but it would be gradually drifting the center of mass upwards as the fuel is used.

That's why it was funny that a top motorcycle designer... I think it was Irv Kenimoto... made such a blunder. But he quickly switched back. Sometimes designers just try stuff to see what happens which is cool.

Image

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 18 2022 12:25am

SafeDiscDancing wrote:
Jan 18 2022 12:08am
Chalo wrote:
Jan 18 2022 12:01am
...a rolling bike's point of contact is the part that swings across the surface. Low center of mass impairs both maneuverability and control, because you either end up having to swing a large fraction of the bike's mass across the surface to establish a lean angle (mass concentrated at the high and low extremities), or the period of motion is so quick that it becomes difficult to control (mass concentrated low near the ground).
The "root" of the discussion began at:

So... the higher up you put the center of mass the more traction can determine rotation just based on leverage.

That was my position and BalorNG took the opposite position.
Which is exactly the other way around, because the bike is 'swung around' from contact patches, and which is easier to swing - a pensil or a hammer?
Chalo formulated how it works pretty clearly - I just fail to understand how can anyone NOT understand that - you must have some very, very weird notions how bike balancing works.
And indeed Weeble toy has absolutely nothing to do how bike is balanced manually or manifest self-stablility - this is a much more complex phenomena, lock you steering and all 'stability' is out of the window.
There *is* a return to center force manifested when leaning in turns - but it has everything to do with bicycle tires being torus-shaped *springs* that try and return to their original shape when compressed (with some penalty, that's where rolling resistance comes from).

BalorNG   1 kW

1 kW
Posts: 343
Joined: Nov 10 2019 7:22pm

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by BalorNG » Jan 18 2022 12:31am

SafeDiscDancing wrote:
Jan 17 2022 11:47pm
BalorNG wrote:
Jan 17 2022 11:39pm
No, but we can agree this is a great strawman though.
I stand by my post as it was solid.

You are 100% in error and seem unwilling to even consider the basis of the error.

But no one PAYS you any money to think right?

I mean it's not like you are building anything that's going to cause harm to others right?

So you continue unchanged and keep believing what you believe.

This happens a lot these days.
0% arguments, 100% trolling. Good work.

calab   100 kW

100 kW
Posts: 1186
Joined: Dec 11 2013 1:00am

Re: Do you use an fairing or partial fairing on your ebike, emoped or BSM?

Post by calab » Jan 18 2022 12:46am

Argument from authority https://www.dailywire.com/news/watch-be ... nk-berrien
If you want to take issue with the argument I would urge you not to use the argument from authority, which is: somebody has a PhD by their name they know what they’re talking about. That’s a dumb argument.

Post Reply