What causes wobbles? (Split from: “Inmotion V13 Speculation”)

[novazeus]

i never said i didn't ride at all, just infrequently. after the z10 went dead, i lost interest. the 18s was still fine up until the fire. the s2 was too, but the shit tire on it made me not want to ride it. btw, maybe because i use to inline skate every night 20 miles, my legs were so strong, maybe that's why i didn't get oscillations. oscillations i define differently from wobbles, but i guess they are the same. the v13 definitely has a tendency to want to oscillate more on braking and why i have to concentrate more on my foot pressure. i think from yesterday's riding of only 30 miles because Bob was being a brat, the smoother i transition from acceleration to braking, the less the wheel wants to oscillate. u can see on the yoga mat where the wheel touches my upper calf muscle in a lean or oscillation. the more evenly i apply weight to my heels, the less the oscillations are. on my short half a km road, i'm starting and stopping 150 times in a session. lots of analyzing. all alone, no distractions, just practicing different techniques. an occasional emergency braking for cows, sandhill cranes, snakes, raccoons, squirrels, donkeys, etc. glad my inline skating braking instincts kick in. pretty much the same way u brake on racing inline skates.

i'm a land developer among other things. my property is worth in excess of $100mil. my interest in euc's isn't for fun, for pleasure, for exercise, to get away from the wife, my interest is strictly financial.

a little lesson for u non land developers. and this is local in nature just like real estate is local in nature. i have no clue how they do shit in finland.

land is only worth what the govt will let u build on it. it is called entitlements. 

now my land being next to 14 lanes of interstate, and next to the interchange, and next to the hottest retail area in the country, ie tiger woods just opened his pop stroke next door, and my property is adjacent that property because we sold it to that developer in 1988. 

so, back to entitlements. highest and best use for my property is multifamily/apts. mf developers like to build 300 unit/doors/keys complexes. 4 story and up. the govt requires certain things from the developers in exchange for granting u permission to build ur mf development. here in pasco county, one acre of park for every 100 units. idk what the parking space requirement is presently, i haven't looked lately. for instance, it might be 2 spaces per apt. if i can convince my county, because of the safe, walkable non vehicular paths i plan to build, so the 3000 apts here don't need an extra car, i might only have to dedicate 1.5 parking spaces per apt. at a million an acre and up, that's alot more money. so i've been studying personal electric vehicles since i first saw i think an airwheel this guy with a sailboat had when i was staying at las olas marina on my boat in 2015. never saw it up close, but i'm guessing it was the two tire type of electric transport. 

i've been studying euc's because of their compact size and also been studying the personalities of euc riders, to see if it could make me more money. strictly financial for me. 

the number one development in the usa for years has been the villages about 50 miles north of me, and the big part of why i think the retirees love it so much, is because they can use golf carts. golf carts take up almost as much room as cars, so not a big parking lot saver. 

this is why i focus on safety, point a to point b. not an enthusiast, not a jumper, not a hobbyist. it's good to know there's so many old timers like me that are attracted to riding them. hopefully they'll figure out the battery/fire problem and i'll be able to eliminate parking spaces. the old wheels i had weren't near as sophisticated as my new ones, and i hope china keeps improving them. one of my attorneys saw a couple in pinellas county where he lives a month ago. there's a guy frank ellis that has a v13 and getting a s22 that lives over in "new york richey". i call it that because so many new yorkers live over there. he posts videos on youtube using the network of trails over there. 

at the end of this month i'm meeting a developer from california that use to be the biggest apartment developer on the planet, they own the la chargers football team. billionaires. we might become partners in developing my land. it's ag spanos. 

the market is softer now thanks to our president, but land was selling for $50k a door. so 300 units is $15 mil for about ten acres. seems like alot, but a penthouse in nyc use to sell for $25mil. i could probably buy the 4 6 ranch in texas, 110 thousand acres for $25 mil. the three rules of real estate. location, location, location.

his point man who i've already met and walked the first apt site with is from california as well, and owns an electric bike, and knew exactly what an euc is, so he gets it. 

yeah, not an tree hugger per se, because i gotta burn gas to charge my wheels because solar is bullshit. looks good on paper but in real life doesn't perform well. 

did u watch jon purcell's video? i've probably watched thousands of euc riders video since i've become interested in saving parking spaces. 

yeah, i ride alot, but studying the riding characteristics is about all i do, and not falling and getting hurt. that's not an option for me. hopefully Bob will let me do 40 miles tonight. he's inside with me now in the ac. i think he's jealous of the v13. breaks my heart to see him gazing at me from our compound. but i gotta do it. plus i think it's beneficial for the bone cancer in my right hip. being sedentary i think helps the cancer grow. 9 years now i've extended my life when the experts with advanced medical degrees said i was untreatable and only offered hospice as medical treatment. so yeah, i challenge authority and experts and make my own decisions. u would think covid would have taught humans something, but nope, too hopelessly brainwashed!

Edited April 8, 2023 by novazeus

[soulson]

Yesterday and today I experimented with antisymmetric braking and I am happy to report that it reduced the severity of brake wobbles for me. It did not eliminate them completely, but did make them much more manageable and less frightening. I will continue to practice.

Another thing that seemed to help with both acceleration and braking is not relying completely on pads, but balancing the force from the heel and ball of my foot on the pedal with the force from my lower leg on the pad. This is the first wheel I've ridden with pads, and it seems I may have been overdependent on them for the first two weeks.

[redsnapper]

imo the most effective wobble suppressant is assymetric weight distribution (as @mrelwood says ) via stong triangular brace:

This pic was for mounting dismounting but same concept applies at speed. U can easily apply very subtle pressure on one side to dampen wobbles. However i hv noticed that in some cases the dampening effect (accross all mentioned techniques) can be much less effective; this suggests to me that there may be some deeper physics at play (regarding angular momentum, roll amplitude/oscillation period/frequency, resonance etc. ) which can hv significant effect on how wobbles start, increase, and diminish. I tested dealing with speed wobbles this morn and was surprised by the lack of consistent dampening effect when applying techniques to apparently similar wobble conditions. Chaotic motion?

Edited April 8, 2023 by redsnapper

[sbb]

A couple data points I've not seen specifically mentioned - we have some minor hills and various pavement types around here, so I was inclined to experiment after a few "oh shit" moments.

1.  I can cause wobbles just by how forward or back my feet are on the pedals.

If my toes are well over the front of the pedals, acceleration and hill climbs will be very stable. However, merely trying to descend a mild grade will be untenable due to wobbles over a few mph. Not braking. Just holding speed.  Braking wobble will be much worse, the more forward on the pedals I am. Accelerating immediately resolves the wobble.

If my heels are well over the rear of the pedals, it makes simple acceleration and hill climbs untenable due to wobble.  Hard braking and descending even the steepest hills, however, is wonderfully stable.

This'll hopefully help with some insight as to a staggered stance being helpful for so many, and why others may find it better to shift their feet fore/aft as needs arise.

 

2. Road texture and profile. Town roads, here, are paved with oil and stone (for those not familiar, a truck will spray a layer of hot tar-oil along the surface,  and a second truck will lay a 1" bed of crush on top of it.)  Over the course of the year, the result becomes quite solid, but the road can develop mild depressions where the car tires generally run. Basically, a shallow pair of half-pipes. Hardly unique.  THAT SAID, if the surface is newer (aggressive traction), I'll tend to get wobbles when in the concave areas. The wobbles tend to go away when riding the crown. If the surface is loose (a strip of fresh oil and loose stone was just laid to patch the road), texture wobbles will cease immediately, and return when back on the high grip surface.  Likewise if the road surface is worn and more smooth, the concave areas will tend to promote wobbles, less.

Higher tire pressure had a large impact on concave sections and flat sections promoting wobbles, for me. Lower pressure reduced it. I don't recall that pressure really mattered when riding the crown.

Roads paved with asphalt generally don't promote wobbles for me, regardless of condition.  Even if milled, prior to repaving.

I'm not one for riding in the rain, but I'd be curious if wobbles become more, or less likely when various road surfaces road are wet. Especially as the rain brings oil and grease drippings to the surface in the center of each lane.

All of that said, the foot placement (above) will dramatically produce wobbles regardless of surface, asphalt or not. I don't recall wobbles on gravel or dirt, other than from foot placement causes.

Cheers,

 

Edited April 13, 2023 by sbb

[novazeus]

3 hours ago, sbb said:

This'll hopefully help with some insight as to a staggered stance being helpful for so many, and why others may find it better to shift their feet fore/aft as needs arise.

yes, this is why i finally settled on van's waffle soled loafers. sockless. 

when i start my ride, i carefully place both feet on the foot pads exactly where i want them. the yoga mat arrached to the bottom of the foot pads slightly extending beyond the edges gives me a clear outline of where my loafer is oriented on the foot pad. the waffle soles and vicious grip tape(how the v13 is set up) is great adhesion. the loafer doesn't move much at all, maybe just a hair after miles of riding. it finds where it wants to be. but my naked foot inside the loafer is free to squirm around for balancing. on the v13 for instance, the base of my toes is about even with the front edge of the foot pads. i can literally almost grab the front edge of the foot pads with my toes. i'd prefer the setup i have on the s22 where i moved the footpads forward and down, where the entire shoe is supported by the footpad. trying to find aftermarket footpads with a forward bias for it. 

just moving my feet inside my loafers a mm forward or rearward, kinda like a surfer on a surfboard, but much smaller increments. i ride a wheel, the same way a surfer rides a surfboard, but instead of moving inches or feet on the surface of the waxed board, my feet move mm's inside my loafers that don't shift much at all, if any. and i think ur exactly correct. forward bias controls the wheel nicely but on braking i might move my feet inside my loafers rearward. my feet can move left and right too. my legs if going straight, probably aren't touching the wheel, but if the wheel wants to lean against a leg momentarily for whatever reason, so be it, i'm just riding on the footplates, like i'd ride my surfboard, making small balancing movements. and free to move my legs from my ankles up, however they need to be. why i hate pads, and can deal with spiked pedals but much prefer just good grip tape like vicious grip tape. 

kuji rolls rides like this in this video on the s18, whether he realizes it or not. his legs are free to move wherever they need to be. my feet are generally on the outside edge of the pedals so my legs have plenty of clearance from the shell of the wheel. i prefer a flat side like mt s22 and v13 just covered in a 3/8" or 1/2" inch yoga mat, whatever is cheap on amazon. i velcro them on too. comfort, dampening for oscillations, lean points and if i do layover or drop the wheel, a total non-issue. this is why i also don't wear my expensive hard leatt knee brace protection. to wide and uncomfortable for me. i lose the feel when the wheel decides to rest on one or the other. 

as far as oscillations go, road surface imperfections, wind, trying to carry a 35 gallon garbage bage full of garbage to my dumpster(dawn champion has a video of her with massive wobbles trying to carry a huge stuffed animal in the wind), anything in ur hands that can catch wind, a big stiff envelope, a small box, i've never used one, but a long selfie stick might screw with ur balance, the huge bill like on mine and kuji's helmet, not necessarily causing wobbles but affecting ur balance. it's been very windy here lately, 15-25 mph with higher gusts. loose fitting apparel kind really screw u up in the wind. braking with the wind pushing against ur back, all very challenging, especially high up on the "challenger" so aptly named. even the large surface of the v13 can almost twist in these high gusts, but no different than riding a surfboard on the waves. so freedom of movement is necessary. clinching the wheel with ur legs when oscillations happen is when they turn into full blown deadly wobbles. just letting the wheel bounce between ur legs, with the damping effect of the yoga mat, is what prevents the oscillations from going full wobble. i just let the wheel correct itself without interference from me, and it always has. so far. never had wobbles yet. oscillations yes, all the time, nbd. it's part of riding. some wheels like to oscillate more than others depending on the conditions. terrain, wind, speed, braking, etc. i'm just riding on top of it balancing. moving around like a surfer does on a surf board. or i suppose like a skateboarder does, however i never skateboarded. i have surfed though. 

anyway, that's been my experience and i hope i didn't jinx myself and get death wobbles today when i ride.

 

[mrelwood]

 

5 hours ago, sbb said:

1.  I can cause wobbles just by how forward or back my feet are on the pedals.

If my toes are well over the front of the pedals, acceleration and hill climbs will be very stable. However, merely trying to descend a mild grade will be untenable due to wobbles over a few mph. Not braking. Just holding speed.  Braking wobble will be much worse, the more forward on the pedals I am. Accelerating immediately resolves the wobble.

If my heels are well over the rear of the pedals, it makes simple acceleration and hill climbs untenable due to wobble.  Hard braking and descending even the steepest hills, however, is wonderfully stable.

Great pointers! These both relate to tense legs causing the wobble. If you stand too far back, you need to stand on your toes (or balls of feet) to accelerate. It’s practically impossible to do with relaxed legs.

Same goes for standing too far front. The only way to brake is to tense your ankles and calves as you lift your forefoot upwards in order not to fall on your back.

 Handling these situations without wobbles definitely requires practice.

 

[Punxatawneyjoe]

I had experienced some wobbles during hard acceleration by standing to far forward on the pedals. I also had some braking wobbles doing the same thing. As soon as i moved my feet back a bit, it helped a ton. The only time i get them now is when my legs start getting tired and can easily nulify them standing back up and relaxing my feet as @mrelwood pointed out. Since my legs are getting more used to the wheel, i almost never get them now. As others have said the wheel is super stable at speed.

[Cerbera]

I have noticed that the move I make to solve my wobbles is remarkably similar to the power squat move I make whilst 'dropping the kids off at the pool' !

Or perhaps giving birth, standing up, though I haven't tried that, so can't speak from experience...

Either way, don't follow through ! 

 

 

 

Edited April 13, 2023 by Cerbera

[Stevebee]

43 minutes ago, Cerbera said:

I have noticed that the move I make to solve my wobbles is remarkably similar to the power squat move I make whilst 'dropping the kids off at the pool' !

Or perhaps giving birth, standing up, though I haven't tried that, so can't speak from experience...

Either way, don't follow through ! 

 

 

 

Images I’m struggling to get out of my mind now - thanks!

[sbb]

5 hours ago, mrelwood said:

These both relate to tense legs causing the wobble. If you stand too far back, you need to stand on your toes (or balls of feet) to accelerate. It’s practically impossible to do with relaxed legs.

True! In addition (the more I think about it) I find that the closer the balls of our feet are to the centerline of the axle, the less leverage we'll have to prevent a wobble when accelerating, and more leverage we'll have to prevent it with our heels, when braking. I'm thinking about it from a yaw perspective.

Take the extreme case of placing the bulk of your weight on just the ball of your big-toes when leaning forward, and put those balls of those toes exactly on the centerline of the axle, snug against the wheel.  That distance from the centerline will be very short. When I think about it from the perspective of the moments that are involved with that distance from the axle centerline, our ability to assert force becomes tiny.  Contrast that with placing the balls of your big toes on the forward outside corners of the pedals, with your feet in a V shape, the leverage to prevent a wobble (unwanted yaw) is comparatively enormous.

As a strategy, keep your weight away from the centerline of the axle, due to the moments involved?

 

Edited April 13, 2023 by sbb

[rcgldr]

8 minutes ago, sbb said:

As a strategy, keep your weight away from the centerline of the axle, due to the moments involved?

This isn't possible, the rider has to exert a torque onto the EUC equal to the torque the motor exerts onto the wheel+tire, otherwise the EUC would be tilting due to an imbalance in torques between rider and motor. In order to generate that torque, the riders center of mass needs to be a fixed offset from the centerline of the pedals, which in hard mode is also the centerline of the axle. In a softer mode, the pedals move a bit back for a forward tilt and vice-versa, but the end result will be a fixed offset from the axle.

As for leverage, having the shins pointed forwards and contacting the upper pads ahead of the centerline of the pedals provides much more yaw leverage than pedals only. Power pads would also help. As I posted earlier, I wonder if the issue with mild wobbles when braking is due to the shins being more vertical and providing less yaw leverage.

[mrelwood]

3 hours ago, rcgldr said:

This isn't possible, the rider has to exert a torque onto the EUC equal to the torque the motor exerts onto the wheel+tire

They probably meant off center in sideways.

[sbb]

6 hours ago, rcgldr said:

This isn't possible, the rider has to exert a torque onto th

I'm referring to the points of contact, where body weight is applied, being as physically far from the axle centerline as you can make them.  Q.v. the examples given previously, including "staggered", where weight is symmetrically balanced between the obnoxiously forward toes of one foot, with the obnoxiously rearward heel of the other, and minimum direct pressure is applied at the centerline.  Rider inputs (weight) would be applied as far away from that centerline as possible, which means the outside forward corner and outside rearward corner of the pedals. In an unrealistic example to demonstrate the concept, those would be the sole points of contact with the EUC, in a configuration much like the pedals of a bicycle when the pedals made level to each other.

 

6 hours ago, rcgldr said:

braking is due to the shins being more vertical and providing less yaw leverage.

I believe that'll be a significant part of it.  That said, my above experiences with foot placement deliberately did not include any shin contact or leg squeezing - it was strictly foot and weight placement. The resulting wobble tendencies (and lack thereof) were quite significant.

If you get bored the next time you go out, place the toes of both feet an inch or so in front of the centerline (heels off the back of the pedals), almost to the point that you cannot steer when traveling forward - and do some very careful accelerating and braking with no shin contact and you'll see what I mean.  Then apply your shins at various angles - the idea is that, with your toes so far rearward, your shins are the only thing fighting the yaw when the wheel is moving forward. I'm hoping you'll find a sweet spot where you become comfortable with your control over the yaw. Note how far forward the top of your shins are from the axle if you find it.

Then, repeat it in your normal stance - I'm curious if the top of your shins end up contacting the wheel in nearly the same location as the experiment?  Or was it, instead, the angle of the shins that provide the control?  Either result will go a very long way.

Cheers,

 

[rcgldr]

10 hours ago, rcgldr said:

As for leverage, having the shins pointed forwards and contacting the upper pads ahead of the centerline of the pedals provides much more yaw leverage than pedals only. ... I wonder if the issue with mild wobbles when braking is due to the shins being more vertical and providing less yaw leverage.

 

1 hour ago, sbb said:

your normal stance - I'm curious if the top of your shins end up contacting the wheel in nearly the same location as the experiment?

I ride a V8F. I weigh about 187 lbs | 85 kg, so I don't go faster than 18 mph | 30 kph (GPS speed, app shows 19.2 mph) for some margin, and the tire is narrow at 2.125 inches wide, so it's not prone to wobble due to the limited speed and narrow tire.  I've tried shifting my feet forwards and backwards +/- about 1 inch, but it doesn't cause a control issue due to the limited acceleration and braking of the V8F. I have EUC World setup to call out speed, charge, distance, time every 15 seconds as an audio speedometer. I tried moving my feet forwards a bit to reduce calf muscle stretch for comfort, but it didn't help much. I switched to hi-top hiking boots which solved the issue, and I ride with my feet close to centered (the hiking boots are offset forwards, so they are offset forwards on the pedals when my feet are centered: distance from balls of feet and center of heels equal distant from pedal edges).

As for my wondering about shin orientation affecting wobbles, angular momentum of the lower legs could also be a factor. Youtuber Duf (EUC Army) is so bow legged that he can't touch the upper pads, so if only using pedals (no power pads) he lowers tire pressure to avoid wobbles:

https://www.youtube.com/watch?v=pwXgkZcfAmQ&t=67s

He also gets wobbles during braking, again, not an issue with contact with the upper pads, since he doesn't contact them without straining. A link later in the same video:

https://www.youtube.com/watch?v=pwXgkZcfAmQ&t=298s

 

Edited April 14, 2023 by rcgldr