Recumbent moped.

Pilip said:

The only way out of the situation is to change the tire to another manufacturer and see what happens.

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Perhaps, but not necessarily true. The battery's low vertical position (in addition to its mass of course), can cause the symptoms you described. Simply put, it's too low. Do you need that much Ah capacity? Can you try a smaller, lower capacity battery (or maybe splitting your larger single into two separate batteries)?

I also noticed the steering geometry - I see very little fork offset. Given the slack headtube angle + minimal fork offset, you'll end up with too much positive trail. This will certainly exacerbate the 'heavy steering'.... especially at slower speeds.

Papa said:

Perhaps, but not necessarily true. The battery's low vertical position (in addition to its mass of course), can cause the symptoms you described. Simply put, it's too low. Do you need that much Ah capacity? Can you try a smaller, lower capacity battery (or maybe splitting your larger single into two separate batteries)?

I also noticed the steering geometry - I see very little fork offset. Given the slack headtube angle + minimal fork offset, you'll end up with too much positive trail. This will certainly exacerbate the 'heavy steering'.... especially at slower speeds.

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When I started building this recumbent, there was no war yet and I dreamed of using it to go to the Carpathians to visit the graves of my ancestors, a distance of about 1200 km one way.
Therefore, the battery was originally intended and purchased back in 2019; it should be 72V 180Ah.
So the battery that is now installed is only a third of a full battery.

I drove for a couple more days and am gradually starting to get used to this control; the fact that the control is a little damper is a plus at high speed.
Today I collected some statistics on battery consumption, this is important to me, because the goal of building a recumbent was to gain aerodynamics.
That is, if you drive at a fairly high speed (for this type of transport), then the battery consumption should be less than on a regular electric scooter with a vertical landing, which also has a large battery (10 kWh).
So, the battery consumption on a recumbent is really noticeably less, driving on the same route on a vertical scooter and at a speed of approximately 60-80 km/h required a battery consumption of 44-46 watt-hours/km, on a recumbent 34 watt-hours/km.
But just in case, I'll check again to know for sure.
Namely, I will check the setting of the bicycle speedometer, although I adjusted it along the circumference of the wheel on which the magnet and Hall sensor are installed. The maximum speed limited by the bicycle speedometer is 99.9 km/h.

I am attaching two videos that I posted on YouTube and several photos.

Pilip said:

And so... the feeling is that the wheel has a life of its own, purely speculatively it looks like the fork is very loose or the wheel axle is unscrewed , although in fact everything will stand very rigidly and powerfully, a fork from a pit bike, an axle 15 mm thick, a steering tube on thrust bearings.

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Our recumbent tandem once became very hard to balance. The steering seemed very heavy. Everything seemed normal when I shook the forks, looking for play in the headset, or turned the forks, looking for binding, with us off the bike. It turned out one of the bearing cups had cracked, and would bind on the bearings with our weight applied.

Papa said:

Given the slack headtube angle + minimal fork offset, you'll end up with too much positive trail. This will certainly exacerbate the 'heavy steering'.... especially at slower speeds.

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Absolutely.

Color me impressed !
Your creation looks to be functioning quite well !
Bravo !

Warren said:

Absolutely.

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I also took this into account and thought about it.
But this frame is from a Suzuki motorcycle from the late 80s, it had a two-cylinder engine and a tank of gasoline, its maximum speed was 200 km/h. and I don’t think that the developers made a mistake with the angle of the steering column, everything is fine with it.
I installed (remade) new bearings from a pit bike, they are roller and cone, that is, they are more powerful than those that were in the Suzuki (ball).
I think that the reason for this feeling of steering behavior is the motorcycle tire, although it is thin for a motorcycle (2.5 inches), it is still much thicker than a bicycle one. Therefore, the contact patch between the tire and asphalt is too large for the center of gravity shifted forward on the recumbent.

Papa said:

The battery's low vertical position (in addition to its mass of course), can cause the symptoms you described. Simply put, it's too low.

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I don't believe this for a second. I understand that is conventional motorcycle theory. I have over 60k miles on two recumbent electric assist bikes. Both have heavier than usual batteries mounted low below the seat. Both handle beautifully. My 71 pound Linear's battery weighs 25 pounds. My 131 pound recumbent cargo bike's battery weighs 58 pounds! That recumbent cargo bike is ridden no-hands, in cruise control mode, 80% of the time.

Baptism:

I came up with a name for my device, let it be UNICORN. I made mudguards and equipped it with identification electric tools, installed a headlight (25 watts), turn signals and a brake light, as well as a powerful, horn-like sound signal (I really liked it).

I continue to learn how to ride lying down:

Hi Philip, Your bike reminds me of one of my earlier Electrom builds. In the end, I went to a long wheelbase layout as I found a short wheelbase where the front wheel is behind the rider's feet was too unstable at high speed. I also found that the weight of 60kg of batteries (I was using lead-Acid at the time) was too heavy for proper safety.

Will your battery packs be removable so that you can just use one or two for shorter trips?


Electrom V2 - 2007


current Electrom Long-wheelbase frame.

Pilip said:

I don’t think that the developers made a mistake with the angle of the steering column, everything is fine with it.

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It is not in the steering angle but in the type of front fork (not designed for this frame) you used. That has much different triple clamp geometry and combined with the front axle forward position gives a much different trail length.

Nice project though so good luck improving and enjoying it!

I'm very curious on your other bike's front suspension set up with the leading axle and non telescopic design. How did you like it and did you like the smoothness of the travel without the friction that normal telescopic has? How come you didn't choose this type of suspension on the front for your new recumbent ?

marka-ee said:

I'm very curious on your other bike's front suspension set up with the leading axle and non telescopic design. How did you like it and did you like the smoothness of the travel without the friction that normal telescopic has? How come you didn't choose this type of suspension on the front for your new recumbent ?

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Hi, I live in an area where there are bad roads on my favorite route and since the tires of the wheels must be well inflated with air (at least 3 bars) to save battery, that is, they must have a good roll, then the entire shock absorber load falls on the shock absorbers themselves.
For this reason, I chose a lever fork for that config
A. Lenherr - R. Weber. The leverage in it is 1: 4.
Of course, you are right to move the shock absorber from its place much easier with the help of a lever, therefore such a fork easily works out small irregularities, and to reduce the unsprung weight of the wheel, I installed a 26-inch bicycle wheel with a double tire there, but with a hub from a light motorcycle and 2.8 mm spokes.
This fork has proven itself well since 2019 (5 years, how quickly time flies). You ask why I didn't install the same fork on a recumbent moped, well firstly the parts for this fork cost me a lot (milled work on a CNC machine, secondly on a recumbent moped the body weight is shifted to the front axle, so a powerful fork with a thick axle (15 mm) was chosen, well the shock absorbers due to the decent load mass do a good job, they cushion well.

tigcross said:

Hi Philip, Your bike reminds me of one of my earlier Electrom builds. In the end, I went to a long wheelbase layout as I found a short wheelbase where the front wheel is behind the rider's feet was too unstable at high speed. I also found that the weight of 60kg of batteries (I was using lead-Acid at the time) was too heavy for proper safety.

Will your battery packs be removable so that you can just use one or two for shorter trips?

View attachment 359134
Electrom V2 - 2007

View attachment 359135
current Electrom Long-wheelbase frame.

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Super, you did it very beautifully!
I didn't experiment with the frame length, but did it on what I already had, you know, I decided that it was easier to change my riding skills than the frame, and as a result, I learned to ride quite well on a reclining couch.
Yes, there are another 40 kg of batteries for the complete set in addition to the 20 that are already in the frame, they will be removable, each of their 3 batteries is provided with independent control electronics and will be connected in parallel.

In general, I'm glad that another sofa lover has been discovered.
I looked at your previous device, it has a backrest for a sitting person, but not a reclining one, why am I focusing on this? Because good aerodynamics on such devices are obtained when the air envelops the body, but does not rest against it, so even if we sit low, but at the same time our body is like a brick for the wind, the aerodynamics are still bad.
After all, we make such sofas not for the sake of relaxing on them, but to save battery.
I posted above the battery capacity consumption at decent speeds, this is 70-80 km / h on average, the consumption on the sofa is 30-32 watt.h / km. But on a seated moped, the same route and at such speeds consumes 44-46 watt.h / km, the difference is noticeable.

About "instability at high speed", everything is exactly the opposite, starting from 60 km/h the sofa just acquires excellent stability, where the excessive steering damper from the friction of the tire on the asphalt at low speeds becomes a plus at high speed, the sofa holds the course direction perfectly. This was literally a revelation for me.

And yes, it also takes corners very well with a decent load on the front wheel.

SlowCo said:

It is not in the steering angle but in the type of front fork (not designed for this frame) you used. That has much different triple clamp geometry and combined with the front axle forward position gives a much different trail length.

Nice project though so good luck improving and enjoying it!

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Do you mean that the new fork is longer or shorter?
The angle of the fork remained the same, but yes, of course, the original frame was designed for a driver and a passenger and, accordingly, the steering qualities may differ, but a person is such a beast that he can get used to everything.

Papa said:

The battery's low vertical position (in addition to its mass of course), can cause the symptoms you described. Simply put, it's too low.

Click to expand...

Warren said:

don't believe this for a second. I understand that is conventional motorcycle theory. I have over 60k miles on two recumbent electric assist bikes. Both have heavier than usual batteries mounted low below the seat. Both handle beautifully. My 71 pound Linear's battery weighs 25 pounds. My 131 pound recumbent cargo bike's battery weighs 58 pounds! That recumbent cargo bike is ridden no-hands, in cruise control mode, 80% of the time.

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Warren,. Damn few builders have more respect for your many accomplishments than I do, so please don't take what I'm about to say personally.

An important point: Most all single-track-vehicles do NOT "lean" while in motion... they rotate.

The only way to control the single-track-vehicle's balance and navigation, is by predictably manipulating the vehicle's CoG lateral position. We do this by laterally repositioning the tire's contact patch(s) beneath the vehicle's Center of Gravity (CoG).

But there's a catch...

The vehicle's CoG must be sufficiently above the tire's contact patches to work efficiently and predictably. If the vehicle's CoG is too low, it starts interfering with the lateral movements of the contact patches. Much lower still, and you restrict the contact patches to the point of losing both balancing and navigation.

As they say, "Proof is in the pudding".....

Grab your household sweep broom, the one with a 48-54" handle, and position it vertically (bristles up, handle down, in the palm of you hand. Most find it easy to maintain balance while vertical. And with a little practice, you can literally walk throughout your house while still remaining vertical. Why?... because the broom's CoG is closer to the elevated bristles, and a sufficient distance above your hand.

Now reverse the broom 180, handle up and bristles down, resting in the palm of your hand. Not so easy to balance,.. now is it? Why is that?

The broom's bristles (and its CoG) is much too close to the palm (read, contact patch) of your hand. When you attempt to react to the falling handle, all you succeed in doing is pushing the CoG sideways.
.
So. this begs the question.. "Just where should the single-track-vehicle's vertical CoG be ideally located?" Answer...
.... at or near the vehicle's longitudinal roll axis.

Papa said:

The broom's bristles (and its CoG) is much too close to the palm (read, contact patch) of your hand. When you attempt to react to the falling handle, all you succeed in doing is pushing the CoG sideways.
.
So. this begs the question.. "Just where should the single-track-vehicle's vertical CoG be ideally located?" Answer...
.... at or near the vehicle's rotational axis.

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At 58 pounds, my cargo bike battery is only 40% of my 145 pound body mass. All of that body mass is above the battery. Now on a motorcycle, were the battery mass can match or exceed the weight of the rider, or on a lowrider, where the battery has to be as high, or higher than the rider, you will have an issue.

In other words, on a bicycle, the rider is a very significant portion of the total vehicle mass, and is the single largest determinant of the vehicle's vertical CoG.

Papa said:

So. this begs the question.. "Just where should the single-track-vehicle's vertical CoG be ideally located?" Answer...
.... at or near the vehicle's longitudinal roll axis.

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A single track vehicle's longitudinal roll axis is at the contact patch....ground level. Have you ever seen a motorcycle rotate around it's vertical CoG, rotating both tires off the ground?

Warren said:

Have you ever seen a motorcycle rotate around it's vertical CoG, rotating both tires off the ground?

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Affirmative. The initial rotational force was generated by hitting another object (large German Shepard) with the front wheel.
I think our British friends use the term "ass over teakettle".

Warren said:

A single track vehicle's longitudinal roll axis is at the contact patch....ground level.

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Negative Chief,

(I'm currently occupied, so will explain later)

In general, this issue, regarding the center of gravity, has already been discussed on forums where people ride on sofas.
It should be taken into account that the center of gravity in this case is our butt and if our butt is horizontally at the level of the shoulders and head, then we do NOT have the opportunity to maneuver while maintaining the vertical position of the moped.
But this in no way depends on where the battery or the internal combustion engine is located, or rather it depends because the lower the battery, the less inertial masses we need to move left and right while maintaining balance.
An example is the position of the driver in some sports where the driver gets up on his feet (rides standing) to maintain balance and literally stops in motion on a motorcycle.