BillMckraken
New Member
I've done some figuring on power requirements and wheel speeds for these bikes. I believe quite a few on here have already done some of these figures, but I thought it may be helpful to list these for everyone. For me, still deciding on what to get, it was nice to get a "feel" for the power necessary as well as its' exponential nature.
Okay so these are all figured on a standard MTB frame 26" with no fancy handlebars (lol). Total weight used was 260lbs (190lbs rider / 70lbs bike). I believe this is a decent "rough" weight to go with, of course if total load was higher; power would go up as well. The efficiency of the drivetrain was figured at 85%, I believe this is conservative and only includes drive system not motor/ engine efficiency (e.g. shown watts = req'd Engine SHAFT power). Elevation was figured at 650ft.
Two additional key notes:
This is the power required to maintain X speed, not acceleration or coasting power.
Power was also figured using either 5mph head wind (low speed) or a 1% incline (higher speed). A rough average of those two powers is whats shown. The reason is that in "real world" conditions you will always have some kind of wind / grade attempting to reach these max speeds.
1Hp = appx. 745w
Speed - Power - RPM
10mph - 150w - 129rpm
12mph - 200w - 155rpm
15mph - 250w - 194rpm
20mph - 470w - 259rpm
25mph - 750w - 323rpm
28mph - 950w - 362rpm
30mph -1100w- 388rpm
32mph -1300w- 414rpm
34mph -1500w- 440rpm
36mph -1725w- 466rpm
38mph -1950w- 491rpm
40mph -2250w- 517rpm
45mph -3100w- 582rpm
50mph -4000w- 647rpm
52mph -5000w- 685rpm
figured I'd show the magic 50mph mark, heh. The power requirements above mid 30s gets to be fairly high. From these figures I did compare those to, what I could find for, actual speeds.
200w electric stand up scooter @12mph
300w electric stand up scooter @18mph
Stock 2-stroke HT China 66cc @ appx 34-36mph
(I believe this is average top speed on these?)
Interesting to note then, stock engine outputs 1.5-1.7Kw; not rated 2Kw.
Fully modded HT china 66cc or gp460 etc. @45mph
(I believe this is about the max anyone has officially gone?)
So here it would seem people have squeezed just over 4hp out of these, nice!
So then to hit the magic mark of 50mph requires a minimum of 6hp. Don't think that's easily possible in the 50cc bracket.
Hope this will help some of the builders out there!
thanks
Okay so these are all figured on a standard MTB frame 26" with no fancy handlebars (lol). Total weight used was 260lbs (190lbs rider / 70lbs bike). I believe this is a decent "rough" weight to go with, of course if total load was higher; power would go up as well. The efficiency of the drivetrain was figured at 85%, I believe this is conservative and only includes drive system not motor/ engine efficiency (e.g. shown watts = req'd Engine SHAFT power). Elevation was figured at 650ft.
Two additional key notes:
This is the power required to maintain X speed, not acceleration or coasting power.
Power was also figured using either 5mph head wind (low speed) or a 1% incline (higher speed). A rough average of those two powers is whats shown. The reason is that in "real world" conditions you will always have some kind of wind / grade attempting to reach these max speeds.
1Hp = appx. 745w
Speed - Power - RPM
10mph - 150w - 129rpm
12mph - 200w - 155rpm
15mph - 250w - 194rpm
20mph - 470w - 259rpm
25mph - 750w - 323rpm
28mph - 950w - 362rpm
30mph -1100w- 388rpm
32mph -1300w- 414rpm
34mph -1500w- 440rpm
36mph -1725w- 466rpm
38mph -1950w- 491rpm
40mph -2250w- 517rpm
45mph -3100w- 582rpm
50mph -4000w- 647rpm
52mph -5000w- 685rpm
figured I'd show the magic 50mph mark, heh. The power requirements above mid 30s gets to be fairly high. From these figures I did compare those to, what I could find for, actual speeds.
200w electric stand up scooter @12mph
300w electric stand up scooter @18mph
Stock 2-stroke HT China 66cc @ appx 34-36mph
(I believe this is average top speed on these?)
Interesting to note then, stock engine outputs 1.5-1.7Kw; not rated 2Kw.
Fully modded HT china 66cc or gp460 etc. @45mph
(I believe this is about the max anyone has officially gone?)
So here it would seem people have squeezed just over 4hp out of these, nice!
So then to hit the magic mark of 50mph requires a minimum of 6hp. Don't think that's easily possible in the 50cc bracket.
Hope this will help some of the builders out there!
thanks
