4 ms·

Regarding the dangerous speeds that a 2kW motor could propel you to, the full 2kW might only be used when going uphill. At 100% efficiency, 2kW will let a 75kg

by zhyder 14y ago

Regarding the dangerous speeds that a 2kW motor could propel you to, the full 2kW might only be used when going uphill. At 100% efficiency, 2kW will let a 75kg person travel at 10 meters/s [1] (sprinting speed) on a 15% incline. [1] 2000 / (75 * 9.8 * sin (15))

001sky 14y ago
As a cyclist, 15 deg incline is steep. Honestly, steeper than all but rural roads and even then rare. There might be some hills like that in SF. Even in the mountains, graded switchbacks are not nearly that steep, for the most part. Which beings me to who and why would you want to ride down something so steep on a skateboard? I have a hill a mile from my house, thats ~200 vertical feet, and a around a 1/4 mile, its 12 degrees max on my GPS topo. I'm easily 35-45 mph on this, coasting. No hands descent would be NFW. 40 mph on a skateboard and there is a piece of gravel on the road, I'm not sure a Helmet will even help you with the face-plant potential. But other than that, I think for a flat city it may be of interest. Or even a flat-ish area like soma/mission. But Manhattan? Nah. I'd pass. Maybe in the sub-urbs or exurbs? Where its just a long slog down a random road to the store or whatever would be more interesting. There is a lot of sprawl out there. And this would be cooler than a segway =D.
- guelo 14y ago
  SF actually has streets that reach over 30 deg incline.
  - 001sky 14y ago
    Yes, with stop signs =D. And Cable car Tracks. And Cross-traffic. LOL. Bottom line = 30 degrees is sketchy, even ATGATT, on a Motorcyle. ___________ [Edit] Citaton: Just how steep is this? A large avalanche in Montroc, France, in 1999, 300,000 cubic metres of snow slid on a 30° slope, achieving a speed of 100 km/h (60 mph). It killed 12 people in their chalets under 100,000 tons of snow, 5 meters (15 ft) deep. The mayor of Chamonix was convicted of second-degree murder for not evacuating the area, but received a suspended sentence. TL;DR: Avalanche Risk? = Don't skate ! http://en.wikipedia.org/wiki/Avalanche http://en.wikipedia.org/wiki/Avalanche
  - iyulaev 14y ago
    Wrong. 30% grade != 30 deg incline.
    - 001sky 14y ago
      Converter for those interested. http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Grades_degrees.svg/300px-Grades_degrees.svg.png http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Gra...
  - malandrew 14y ago
    37 degrees to be exact. Prentiss between Chapman and Powhatten
    - cocoflunchy 14y ago
      I think you must be mistaken. 37° is steeper than any road you've ever driven. It would be very hard to even walk !
      - malandrew 14y ago
        Ooops, my bad. I didn't know there was a different between grade and degree. http://en.wikipedia.org/wiki/Grade_(slope) http://en.wikipedia.org/wiki/Grade_(slope)
    - kbutler 14y ago
      http://www.datapointed.net/2009/11/the-steeps-of-san-francisco/ http://www.datapointed.net/2009/11/the-steeps-of-san-francis... cites it at 37% grade (37' rise for 100' run, approx 20 degrees).

by zhyder 14y ago

001sky 14y ago

As a cyclist, 15 deg incline is steep. Honestly, steeper than all but rural roads and even then rare. There might be some hills like that in SF. Even in the mountains, graded switchbacks are not nearly that steep, for the most part. Which beings me to who and why would you want to ride down something so steep on a skateboard? I have a hill a mile from my house, thats ~200 vertical feet, and a around a 1/4 mile, its 12 degrees max on my GPS topo. I'm easily 35-45 mph on this, coasting. No hands descent would be NFW. 40 mph on a skateboard and there is a piece of gravel on the road, I'm not sure a Helmet will even help you with the face-plant potential. But other than that, I think for a flat city it may be of interest. Or even a flat-ish area like soma/mission. But Manhattan? Nah. I'd pass. Maybe in the sub-urbs or exurbs? Where its just a long slog down a random road to the store or whatever would be more interesting. There is a lot of sprawl out there. And this would be cooler than a segway =D.

guelo 14y ago
SF actually has streets that reach over 30 deg incline.
- 001sky 14y ago
  Yes, with stop signs =D. And Cable car Tracks. And Cross-traffic. LOL. Bottom line = 30 degrees is sketchy, even ATGATT, on a Motorcyle. ___________ [Edit] Citaton: Just how steep is this? A large avalanche in Montroc, France, in 1999, 300,000 cubic metres of snow slid on a 30° slope, achieving a speed of 100 km/h (60 mph). It killed 12 people in their chalets under 100,000 tons of snow, 5 meters (15 ft) deep. The mayor of Chamonix was convicted of second-degree murder for not evacuating the area, but received a suspended sentence. TL;DR: Avalanche Risk? = Don't skate ! http://en.wikipedia.org/wiki/Avalanche http://en.wikipedia.org/wiki/Avalanche
- iyulaev 14y ago
  Wrong. 30% grade != 30 deg incline.
  - 001sky 14y ago
    Converter for those interested. http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Grades_degrees.svg/300px-Grades_degrees.svg.png http://upload.wikimedia.org/wikipedia/commons/thumb/4/45/Gra...
- malandrew 14y ago
  37 degrees to be exact. Prentiss between Chapman and Powhatten
  - cocoflunchy 14y ago
    I think you must be mistaken. 37° is steeper than any road you've ever driven. It would be very hard to even walk !
    - malandrew 14y ago
      Ooops, my bad. I didn't know there was a different between grade and degree. http://en.wikipedia.org/wiki/Grade_(slope) http://en.wikipedia.org/wiki/Grade_(slope)
  - kbutler 14y ago
    http://www.datapointed.net/2009/11/the-steeps-of-san-francisco/ http://www.datapointed.net/2009/11/the-steeps-of-san-francis... cites it at 37% grade (37' rise for 100' run, approx 20 degrees).