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Everything posted by Mono

  1. I let them try using a learning belt, no question about it.
  2. Right, and that most of us never had the experience of learning to ride a bicycle as an adult.
  3. As we seem to have negative and positive examples for this business model, the reason of failure cannot be the business model itself.
  4. Right, it is for sure not, very likely the exact opposite. To be fair, the claim was that it is 10 times more likely to fall off of an EUC, which is probably true.
  5. I guess the only point here is that we find it obvious because we have experienced it. However, we seem not dare to make it obvious to someone who doesn't yet own one. I really don't know why I am not fair by wanting to let them know the obvious beforehand. When you have to get a license, you obviously do try before to buy in almost all cases. I know that from personal experience
  6. It's seems pretty easy to see when looking at a few posts in this forum, like: "I thought it was a peace of cake to learn but then I tried..." I see your point that for some buyers it might in the end be better to not have had this information before, but it remains to be a somewhat deliberate misinformation, therefore I called it a false flag. I stand corrected if you tell them why you don't let them try, namely that it would drop sales. In this case I am perfectly with you.
  7. Sure, but I wouldn't say it is detrimental to his sales, as you suggested it were. Even experienced riders trying out stuff might beginners convince that they make a good choice to buy such a thing. I don't like the apparent implication of your point (don't let beginners try out as it is detrimental to sales, apparently for several reasons): you sell a product under a false flag, that is, you leave the buyer in a false belief until they payed.
  8. good point. I never tried Sugru, so I wonder whether this takes it to the next level (the duct taping).
  9. When checking reports, be aware that there is at least three different wheels, V5+, V5F, V5F+. The V5+ has a weaker motor and hence for sure a max speed of less than 30km/h even after a fix, so this shouldn't concern you if you buy an F version. BTW, I have never heard of firmware updates for InMotions, has anyone else?
  10. No, I am not sure and I might be wrong or there might be even different versions of it: I would tend to trust the number from ewheels, they might have a "special edition", but before to make the deal I would probably still ask.
  11. Unless you want the added safety from 16". Personally, I probably will never buy a 14" wheel for general purpose use anymore. The safety advantage might only be small, but it is decisive for me.
  12. @MattJ looks awesome, despite the dirt
  13. There seem to be one or two quite successful shops in Paris allowing people to test ride any wheel they want.
  14. isn't the answer always tape? Tape is one of the true miracles of the 20th century
  15. The V5F has a 288Wh battery. So you are asking for less than 10Wh/km consumption (plus there is always some juice left even in the "empty" battery). Possible: yes. Comfortably: I have my doubts, in particular if you want to go beyond 15km/h, but I also don't have a V5F. Check maybe also this
  16. I am convinced that taking all appropriate measures to prevent falling is even better than wearing good protection, but they are not mutually exclusive. Yet this thread is about how to fall. I lean in favour of the hypothesis that how to fall can make a difference, so I find it interesting to consider. Is it more important than wearing protection? It probably depends on the person. Most people will have a hard time to actually change their falling reflexes effectively. Let alone that we don't quite really know what the good reflexes are. Yet if...
  17. I actually watched the vids and I really like them (I also was training Ju-Jutsu for a year or so, so I have some basic idea of what a roll is supposed to look like, but I also know there are other techniques in case). These guys in the vids are artistic pros, trained for hours and hours and they plan very well ahead in time what they will do. Therefore I couldn't convince myself that a roll is what I should do as an emergency measure. On the other hand like in the first vid after stumbling during a run off, the roll seems a perfectly viable technique.
  18. Thanks @Chriull for the data, I will have a look. That voltage is not available is a pity. Agreed, that is also my (rather limited) experience and that is how it should be. I don't think that works, because there is no inertia or memory in acceleration, it's all stored in the speed (impulse or momentum is speed times mass and the mass doesn't change). If you stop pushing due to lack of power you stop accelerating immediately. Still, when going downhill with tailwind one could imagine to hit cut off speed despite the lack of motor power It would be useful to always make the distinction between insufficient torque and cut off (or cut out), because the first is instantaneously recoverable when the demand is lowered.
  19. Tilt-back is a mechanism to incentivise the rider to slow down. The mechanism is simple: the neutral inclination angle of the shell and hence the pedals is changed from horizontal to negative, tilting the pedals back This gives the rider the incentive to initiate a slow down (see also below). Here I discuss my understanding of the energetic (and a few other) consequences of tilt-back. Remember the feeling to lose the ground under your feet when the tilt-back sets in? Here is why. Simple geometric consideration reveals that if the riders feet stay in contact with the pedals, tilt-back raises the riders front feet and lowers the riders heels. Lowering ones heels feels like losing support and means that the riders body lowers as well if the heels remain grounded. The effect from the centre of mass: most of the work to raise the riders body (or the toes ) is done by muscles, hence the energy comes from the food the rider has digested. (Lifting 102kg by 1cm loss-free needs about 10W=102*9.81*0.01W for one second or 100W for 0.1s thereby adding 2.78mWh=10/60^2Wh=0.0024kcal to the potential energy of the rider). However not only the rider needs to work: when the wheel pushes the rider forward (or backward), straightening up or raising the riders body adds momentarily to the riders perceived weight and hence to the power demand of the wheel. Vice versa, bending the knees or lowering the body gives the wheel a short period of decreased power demand (perceived decreased rider weight). Lowering by 5cm would remove the entire rider weight for 1/10 of a second. This is definitely something one should exploit in any critical situation: the reflex of bending the knees to keep or restore the wheel under the rider is a life saver! I had two or three quite surprising saves from intentionally going rapidly-almost-falling-like deep into the knees. Unfortunately, going deep into the knees is particularly difficult and somewhat physically limited under tilt-back. Yet, soft knees are our suspension. Soft knees get us over bumps and out of potholes. Bending knees is THE invaluable reflex when riding an EUC. But I digress... First summary: when tilt-back sets in, the riders heels lower and (without body posture change) the riders centre of mass lowers and this leads to a small but possibly notable power demand reduction. The effect from the change of tilt angle (here I stand corrected): because changing the tilt angle backwards increases the speed of the motor traveling relative to the shell, changing the angle requires energy. The amount however seems to be rather miniscule. If we travel 20km/h=5.6m/s with an 18" EUC and change the tilt angle from 0º to -10º in 1 second (pretty scary, IMHO), the shell position changes over the wheel circumference by 4cm = 10/360 * 18" * π. Hence, the circumferential rotation speed increases for 1 second by 0.72% = 0.04m/5.6m, i.e. by less than one percent. I am actually not sure what the power demand of this mechanism is (between 0 and 1.4% seems a good guess), but to all I can tell it must be negligible. Tilting the wheel also lowers its centre of mass. Lowering 20kg by 1cm in 1s may deliver 2W for 1s at most. Second summary: all in all, I do not dare to decide whether the effect from titling the wheel saves or demands a very small amount of energy. For the remainder, the simple but conclusive approach is to considered energy conservation: any consumed energy from the battery must be converted into kinetic energy or potential energy or heat. After the tilt angle has changed, from the energy balance perspective nothing is different to the situation before. If the wheel consumes additional energy, it produces more torque. More torque leads to acceleration (hence energy is converted to and conserved as kinetic energy), just as it happens without tilt-back or while the tilt-back sets in. Some people feel that under tilt-back they seem to apply more pressure to the front foot, or equivalently, that the wheel applies more up-pressure. This means that the wheel produces more torque to provide this counter pressure. Torque however invariably leads to acceleration of the wheel (or the wheel and the rider). The other way around, if the wheel does not accelerate, this feeling is a perception due to the uncomfortable foot position but not actually an increased up-pressure. Finally, slowing down the wheel, with or without tilt-back, can be accomplished by initially accelerating the wheel to the front of the rider. Tilt-back is the invitation to do exactly this. In particular, if the rider does not adapt to the changing neutral tilt angle, the wheel accelerates (without the rider and quickly). This acceleration requires some additional power (less than the acceleration of wheel and rider). With the knee-bending trick applied immediately, the additional power to initiate braking can at higher speeds probably be reduced to zero.
  20. Good question indeed. Football pros almost always slide. My hunch is that sometimes may be just not enough time left to initiate a roll, so rolling might only be the best option if you can plan ahead enough in time.
  21. And a third one (for English enable [cc])
  22. There is one useful view point I forgot to mention. When tilt-back is setting in, we can consider a constant angle scenario and a constant pressure scenario. In the constant angle scenario, the rider keeps the pedal horizontal by putting additional pressure to the forefoot. Consequently, the wheel accelerates quickly, because the horizontal angle is now a "push forward" angle (the neutral angle is negative). This is an unstable situation and leads quickly to a bud-plant. In the constant pressure scenario, the rider follows the changing tilt angle of the pedals with the feet while keeping the pressure constant. In this case, speed remains constant and nothing really changes but the angle of the feet and pedals. This is the desired scenario, but if tilt-back sets in quickly and catches the rider by surprise it may be difficult to achieve. I think that most wheels use tilt-back to indicate speed limit, but not to indicate torque limit. The KingSong KS 14C seems to be an exception and there might be others. In case of torque limit, the wheel usually gets rather soft and seems to tilt-forward (when pushed forward). When both happens at the same time it might become very confusing for the rider.
  23. 1.+2.=3, it's fast, fun, and you have soon a replacement board available
  24. Allegedly there are three new Ninebot One wheels which look all the same: A1, S1 and S2. The A1 has 155Wh (one battery) and a 400W motor, the S1 and S2 signify the same wheel and have 310Wh (=2x155Wh) and a 500W motor. That's what I remember to have read, no warranties whatsoever, see also