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Sander Orvik Humborstad

My first fall. Black Ice.

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Today i had my first fall. I was on my way to work. To get there i have to go over a "mountain". i have not been riding for 2 months and it is pretty cold in Norway at the moment. On my way up the first hill i decided to pull out my phone and connect it to wheellog to follow the temperature/speed of the wheel. While looking at the phone and preparing to turn on to a side road -  SWOOP - the wheel disappeared beneath my body. Within a milisecond i was laying flat out on the asphalt. My wrist and kneeguard took a beating, and i smacked my helmet to the ground aswell. I did not wear elbow protection, which i now regret ^^.  I am pretty sure that if i didnt wear any armor, i would have been injured. The only damage is a little pain in my elbow and some cosmetic damages on my armor and jacket. 

Lessons to take away from this: DO NOT RIDE IN THE WINTER! Although the temperature was 3-5 celcius, there roads were icy. There are also alot of leaves on the ground, which are slippery as fuck. I realize now how completely wrong i was to believe that i could run off the fall, or jump off the wheel if anything happened. My focus was at the cellphone when the fall happened, but there was no time to think about anything. Pure reaction. Hands forward trying to dampen the fall. Yet, my entire body hit the floor. from toe to stomach to head. 

Be carefull in the winter lads! Its slippery and dangerous. Also, wear protection at all times :)

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Leaves are evil even with two wheels.

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I've ridden in winter at down to -20C for 3 years now.

It's near 0 degrees it gets very dangerous. Below 0 it's fine, just go slow and drop the tire pressure. Still beats walking.

I ride around in a big city. Most of the time the roads are cleared from snow/ice but in the morning when I go to work it's always a gamble. I always take the wheel when going out but that first step on the ground checking the grip will always determine if I take the bus a part of the way.

Edited by alcatraz

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It's pretty useful to acquire the skill to stay upright when the wheel disappears under the body. I can attest that this is possible and can be learned. This turns a faceplant at low speed into a quite uneventful walk off and at medium speed into a run off. Even at higher speed one gets to do at least one or two steps before the tumble and (almost) inevitable fall.

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Maybe leave the cellphone operating while riding to warmer times. ;) The first near fall I ever had was when trying to catch the phone that my tumbly wrist support hands dropped. The fast reach attempt of course made the wheel go wild and I was skidding left and right on the dirt for a few seconds. But me and the Lhotz survived!

My first contact with black ice was much nicer than your’s though. I went for a morning ride with a 16S exactly 2 years ago, and didn’t worry since it was +4•C. After 10km I skidded a bit on pavement in a slow tight corner. I stepped off to confirm, and almost slipped since the ground was covered with black ice everywhere!

I freaked out about how close I must’ve been to crashing, since I’d ridden like in the summer, 35km/h whenever possible. I was so stunned that I didn’t even realize to warn when a bicyclist came to the same slippery spot. And fell. :facepalm: Luckily he just jumped back on and rode off.

I’m hopeful that the soft knobby C-186 tire on my MSX will give me just enough traction to ride through the winter and stay upright.

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1 hour ago, mrelwood said:

freaked out about how close I must’ve been to crashing, since I’d ridden like in the summer, 35km/h whenever possible. I was so stunned that I didn’t even realize to warn when a bicyclist came to the same slippery spot. And fell. :facepalm: Luckily he just jumped back on and rode off.

I'm puzzled by the rather docile behavior of wheels on ice, that is, there is considerably more grip with an EUC than with a bicycle, or for that matter shoes.

It might be the repurposed tires are grippier than normal bicycle tires, I guess. EUC tires are weirdly grippy on ice. Leaves will still crash you, but that's not different than being on a bicycle.

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Yeah with that much weight on such a small contact patch you get more grip. You know like how buses can drive faster than cars in winter. They slide around less.

Staying upright is definitely the key. It lets you slide around a little bit without issues but more importantly this prepares you for the feeling of when it's about to happen which is useful when you're going a little faster.

Don't get me wrong, I'm riding maybe 10-15km/h sometimes because the roads are dangerous but when you come to a clear sanded/salted stretch of road you can basically ride normally.

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3 hours ago, LanghamP said:

I'm puzzled by the rather docile behavior of wheels on ice, that is, there is considerably more grip with an EUC than with a bicycle, or for that matter shoes.

Me too. My first thought is to consider the single small contact patch as the reason. The pressure should be a good bit higher per a square inch than on a bicycle or especially on foot.

Second thought is about the free floating behaviour while steering. We don’t and can’t force the tire to turn against it’s natural trajectory, we just take a position where the wheel will steer and turn naturally. On a bicycle we turn the handlebar forcefully, hinged to and taking support from the bike’s frame.

I wonder if riding a bike without hands would cause less slippage when cornering on ice. It could mimic the behaviour of an EUC a bit in that sense.

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4 hours ago, alcatraz said:

that much weight on such a small contact patch you get more grip

This.  But when it finally lets go, it's really gone, lol.

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29 minutes ago, xorbe said:

This.  But when it finally lets go, it's really gone, lol.

Very true. When a bicycle loses grip, it usually loses it at the front tire only. The frame is still relatively upright, and the somewhat tractiony rear wheel slows down the fall by a lot. When an EUC starts to slip, you already hit the ground with your inner foot, with nothing at all to slow down your fall.

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10 hours ago, alcatraz said:

Yeah with that much weight on such a small contact patch you get more grip.

Unless the surface is changed through the pressure in one way or the other, the grip remains the same for any contact patch size, because grip is proportional to the pressure and to the patch size. Pressure times patch size is a constant for any given vehicle.

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I don't know how to explain it then but an euc has better grip than one would imagine riding bicycles.

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You get more grip if the rubber conforms to the irregularities of the road surface as then its not just friction that is providing grip. I wonder if the self-balancing system contributes to grip in some way? This would need testing to answer.

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32 minutes ago, alcatraz said:

I don't know how to explain it then but an euc has better grip than one would imagine riding bicycles.

What do you mean by imagine riding bicycles?

I rode bicycles for +50000km and EUCs for about 15000km and I can't exactly confirm the "better grip" claim. Grip also depends way too much on the specific combination of tire and surface. I found my goto tires for bicycles quite a bit less edgy on ice than walking. But then that probably also depends way too much on the specific shoes, I guess, ...

In some situations I find an advantage in the "motorized front wheel" of an EUC, as the motor can actively push the sliding wheel back under the rider which does not happen on a bicycle. On the other hand, a motorized front wheel can certainly also induce slip if too much torque is applied.

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8 minutes ago, Nic said:

You get more grip if the rubber conforms to the irregularities of the road surface as then its not just friction that is providing grip.

Indeed, that looks like describing the mechanism how spikes work.

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As soon as you step off the euc it starts sliding around like crazy. As soon as you get on it, it cuts through whatever is underneath and "digs into" the surface.

If I lower the tire pressure to get the same contact patch size as with my body weight on it, it will still only improve slightly but be nowhere near as stable.

So weight in relation to tire size is key.

I'm not refuting your points. I'm just trying to clear up what I was saying.

Edited by alcatraz

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Your experiment is describing vehicles of different weight and same power. Sure, with the same force you can spin out the tire more easily on the lighter vehicle. But the lighter vehicle also needs less force to get the same acceleration and less traction to run in the same curve with the same speed or in any other situation. The traction it needs and the traction it has are both proportional to its weight, which is kind-of a nice situation to be in.

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54 minutes ago, Mono said:

What do you mean by imagine riding bicycles?

Wheels seem to slide little (on ice), and when they do they quickly regrip. In contrast my bicycles slide a lot, and sometimes they regrip slowly and other times quickly.

I do find it very interesting that EUCs often leave a wet trail along ice. Since EUC have one wheel that is half the size of a normal bicycle wheel, I estimate the ground pressure on that EUC patch is about four times greater than a bicycle...enough to melt the ice. Does that give grip? I dunno. It's notable that we are way exceeding the max weight allowable printed on the sidewalk of these tires.

Still...that wet trail on ice. It gives me pause. I don't know of other vehicles that do that.

Edited by LanghamP

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8 hours ago, Mono said:

Unless the surface is changed through the pressure in one way or the other, the grip remains the same for any contact patch size, because grip is proportional to the pressure and to the patch size. Pressure times patch size is a constant for any given vehicle.

And both surfaces do change.  Nothing is perfectly rigid.  Theoretical engineering vs reality.

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2 hours ago, LanghamP said:

I estimate the ground pressure on that EUC patch is about four times greater than a bicycle...enough to melt the ice. Does that give grip?

Well, the water film between ice and device is the hallmark for being able to glide. That's one reason why very cold ice doesn't glide well if at all. That's one reason why ice skates have such a small surface, AFAIK, to generated the water film. So the answer should be a resounding no.

Edited by Mono

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On 10/28/2019 at 2:58 AM, Sander Orvik Humborstad said:

Lessons to take away from this: DO NOT RIDE IN THE WINTER! 

Sorry, but this is nonsense. Many of us ride in the winter. 

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WRT to the grip discussion, my ACM2 definitely had more winter grip than many bicycles; there is one particular hill that at times has been covered in pristine ice; most cyclists have to walk up it, I've always been able to ride up. Few things are sweeter than riding past cyclists walking their bikes due to icy weather conditions. NB. I have had my share of falls though, so it does happen.

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3 hours ago, alcatraz said:

As soon as you step off the euc it starts sliding around like crazy.

This is why I wear studs on my shoes/boots; very difficult to dismount your wheel without falling when you cruise in to a stop on a pure ice surface if your boots don't have some traction when you step off. 

Edited by winterwheel

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31 minutes ago, xorbe said:

Nothing is perfectly rigid.  Theoretical engineering vs reality.

Damn, I really thought rubber was perfectly rigid, at least in theory :eff01bbbfc: :D

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4 hours ago, Mono said:

Well, the water film between ice and device is the hallmark for being able to glide. That's one reason why very cold ice doesn't glide well if at all. That's one reason why ice skates have such a small surface, AFAIK, to generated the water film. So the answer should be a resounding no.

Doh, that right. Obvious when I think about how wet ice on wet ice behaves, or how ice skates work down to a certain temperature, but not lower.

Probably the EUC tire grips despite the wet trail, not because of it.

I'm not afraid of ice as much as I'm afraid of wet leaves. Wet leaves are horrible on an EUC, in the fall (hehe, pun) I scan for them so much that it takes the fun out of riding.

Has anyone not fallen from wet leaves? Crash rate must surely be almost 100%.

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