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mrelwood

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mrelwood last won the day on June 29 2018

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About mrelwood

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  1. mrelwood

    Charge Doctor gone away?

    That is true if the degradation is linear, starting right away. I don’t know if it is though. I agree. The A3 has a 16S4P battery pack, announced to be 520Wh. I was still able to ride for a few kms if I was very careful at any uphills, since the issue was the massive voltage drop under stress. It still charged up to 100% though, so no dead cells.
  2. Just a heads up, that is an overlean to the rest of us. Good luck.
  3. If the wheel doesn’t have the power to accelerate as fast as the rider asks for, it is called an overlean and a face-plant. Not ”unzippyness”.
  4. mrelwood

    Charge Doctor gone away?

    Worth remembering that @Marty Backe rotates between over a dozen wheels, so I’d expect that during the 2 1/2 years none of them have received the amount of charge cycles that many of us mere mortals put on a single wheel in a year. Without battery maintenance an EUC should still get a few hundred charge cycles without notable degradation. With maintenance however the number is multiplied. In turn my 16S, while being the only wheel in use got about two hundred full charge cycles in a year. Despite some battery maintenance, one cell pair died near the end. My Airwheel A3 battery had worn down to unusable levels by about 150 charge cycles without any maintenance.
  5. mrelwood

    New MSX with Pedal defect.

    Is that a 2.5” CST tire you have on there, like in Msuper V3? How does it ride compared to the original 18x3.0”?
  6. We seem to be talking about different things. Perhaps my English hasn’t been precise enough, as you have repeatedly referred to my point as being that a large wheel wouldn’t ”move” unless CoG reaches the front end of the wheel. And here you say ”slower to accelerate”. Neither of which happens, nor did I mean, nor is the point of discussion. ”Step off”? Never said that. And here again, in order ”to move”? No. The point is that for the same rate of acceleration, a larger wheel requires more physical labour/input from the rider. Often worded as larger wheel being less ”zippy” or feeling ”lazy”. That is a fact which every rider knows to be true after the first acceleration on a different size wheel. I was trying to discuss the reason why it is so. I agree, this discussion isn’t taking us anywhere.
  7. Easy enough to try, so I did to make sure. My 16S turns off when tilted past about 45 degrees backwards/forwards while the wheel is running. Didn’t try with the MSX as it’s a bit heavy to be manhandled for me at this very moment. Plenty exposed tire also makes the test slightly more challenging.
  8. @Planemo, I truly wish I was able to explain it better. Hopefully someone will help you get it. One thing missing from all ponderings in this thread up till now is time. Acceleration is not about the amount of force at a frozen moment in time, but the total speed increase of the rider and the wheel. Force is applied, wheel accelerates. Then what? How much does the wheel need to accelerate to achieve the balance it is after? Hold a pen vertically on your fingertip. You need fast movements to keep the balance. Now take a 3 feet long wooden rod and do the same. Much easier, the balance can be kept with much smaller accelerations. Why is that?
  9. Of course not, I’m just trying to help you understand the causality of a bigger radius requiring more weight displacement. Science in English is a bit difficult to explain for me. I hope someone can explain it in a way that opens it up for you. And how is that behaviour different from the current wheels?
  10. If you are wondering about wether the pedals stays level and the rider just tips over because of a lost footing, no, that can’t quite happen on level ground. You might’ve seen extreme accelerations in videos. While the rider’s CoG is well past the front of the pedals, if the rider would start to fall off the front of the pedals, all his weight would be at the very front edge of the pedals. The only way for the wheel to stay level in general is to fight the tilt with acceleration. It wouldn’t stay upright if it would accelerate any less than what is required to catch the rider’s lean. If the wheel doesn’t have the power to accelerate fast enough, it will tilt forwards, pedals and all. This is when and how the crash by an overlean happens. Once the tilt reaches ~45 degrees, the wheel is programmed to turn off the motor. Although, by that time the rider has already fallen or bailed. Sudden obstacles are another matter though. If the wheel hits a pothole, sinks in sand etc, the speed of the wheel is reduced even if the wheel is succesful in staying upright. But there is nothing to slow down the forward leaning rider. The rider is not prepared and the ankles are loose, so the rider doesn’t get his weight on the front edge of the pedals in time. No weight = not enough acceleration, so the rider falls on his face while the wheel stays upright.
  11. Only at a steady speed. The only way to give the input to the wheel is to press the front end of the pedals more than the rear = more weight at the front of the axle than rear = CoG is forward from the axle. Take a canoe vs a boat for an example. Stand on a canoe, and the slightest step sideways tilts the whole system a whole lot. On a rowing boat the same tiny step barely tilts the boat. The bigger the boat, the more you have to step aside from the center line to achieve the same tilt. And it’s the amount of tilt that tells the wheel how fast to accelerate. Or tire width: Take a wheel with a 2” and a 3” wide tires, and tilt them the same amount. The contact point on a wide tire moves further away from the center line than on the narrow one, so the wide one turns more. During riding this means that the wide tired wheel doesn’t need to tilt as much during the same turn. RockyTop made a marvellous illustration and a video about why large wheels require more lean at an uphill. The same physics apply. And it does, of course. But how fast? That’s the reason why large wheels feel lazy, they don’t need to accelerate as fast to balance the system.
  12. In addition to all that’s been said, I think turning at slow speeds on a 18” will benefit a lot more from purposefully tilting the wheel between your legs than on a 14”. The third gear is a good analogy, it will feel lazy to accelerate and brake. But all the power is there, it will just take larger physical movements to command the wheel. Start slowly and try different turnings and accelerations at slow speeds first. The differences will reveal themselves to you right away, and you should be able to adapt quite quickly. Because it is up to the laws of physics, not advancement in tech. On a 14” wheel you can easily reach the front end of the wheel with your center of gravity. Imagine a 100” wheel. You would have to take an actual step forward to get your CoG to where the front end of the wheel is. Moving the magnets to the edge of the rim will not affect the CoG in relation to the wheel diameter. 10”, 14” and 16” wheels each already have the magnets right next to the rim. The same behavior is still present, bigger wheels feel more lazy to accelerate/brake. Edit: Moving the magnets would increase the maximum torque available from the motor. But the 18” isn’t lazy because reaching the maximum torque. It’s because you need to physically move more to get the same offset in CoG in relation to the wheel diameter.
  13. mrelwood

    Riding while under the influence 🙁

    The general opinion is obviously clear, as the forum is filled with sensible and smart people. Physically one of the first things to be affected in a person by alcohol is balance. Needless to ponder further.
  14. mrelwood

    Replacing a bad cell in a battery pack?

    I honestly don’t know, but I would expect the originals to be a good choice even if some other cells might fit the situation even better.
  15. mrelwood

    EUC tire management

    Guys, lube up! Hot water bath may be helpful, but for me a good lube on the rim and tire bead is easier, and makes the outer tire removal and install a breeze. And decreases the stress on tire irons down to about 10%. Without lubing a tire removal is a 2 man job. Lubed? 0.3. Hand dish soap (undiluted) is good for this. For the tire irons, bicycle variety works well as long as the process is well lubed. My current tire irons do have a steel core though.
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