laser1 Posted November 12, 2011 Author Report Share Posted November 12, 2011 Im no expert, but unsprung weight would be the 1st thing that comes to my mind. The large mass at the rear of the bike, exposure to the elements, Shock and vibration.... a 2wd configuration might be interesting if you did make one. Quote Link to comment Share on other sites More sharing options...
toofasttim Posted November 12, 2011 Report Share Posted November 12, 2011 Thanks for that Gwhy. I'm curious to know what are the reasons are? Best of balance. Neo High unsprung weight Claudio. It'll handle like a rock. Quote Link to comment Share on other sites More sharing options...
neo Posted November 12, 2011 Report Share Posted November 12, 2011 High unsprung weight. It'll handle like a rock. The weight would be no where near as high as a traditional bike and the battery would most likely be mounted low too. "Handling like a rock" ... I don't think so. There's still a tyre there to provide some "spring" ... but can you imagine the traction on the rear wheel? There are companies working on electric mountain bikes like this. And as far as I know this configuration is working for them. Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
gwhy Posted November 12, 2011 Report Share Posted November 12, 2011 The weight would be no where near as high as a traditional bike and the battery would most likely be mounted low too. "Handling like a rock" ... I don't think so. There's still a tyre there to provide some "spring" ... but can you imagine the traction on the rear wheel? There are companies working on electric mountain bikes like this. And as far as I know this configuration is working for them. Best of balance. Neo Hub motors have been around for over 100years they are very very heavy for what they are ( very old tec ), and do not produce much torque unless its a geared hub but then the gears are normally the weak link in a hub motor, you would be maybe looking at around 10kg of weight in the wheel( cooling is also a problem with high power hub motors), you will also be limited to change the gearing on a hub motor as its all built in, Bicycles are able to get away with it due to the weight, the only real contender hub bike out there is the 'bomber' its a very good mountain bike but would not cut it for any serious off road stuff ( very good for trails but not trials ). I have ridden a high power hub motor setup on a push bike and it just dont feel right because of the big weight that far out from the COG Quote Link to comment Share on other sites More sharing options...
neo Posted November 13, 2011 Report Share Posted November 13, 2011 Hub motors have been around for over 100years they are very very heavy for what they are ( very old tec ), and do not produce much torque unless its a geared hub but then the gears are normally the weak link in a hub motor, you would be maybe looking at around 10kg of weight in the wheel( cooling is also a problem with high power hub motors), you will also be limited to change the gearing on a hub motor as its all built in Interesting but I've read that the latest technology motors on trains are hub motors and offer a much higher torque than traditional motors so maybe time have changed? But in reality I don't really mind. So long as the bike can deliver a real "Punch of Power" and shut off the power (without engine brake) with a leaver on the left hand side of the handle bars Best of balance. Neo Quote Link to comment Share on other sites More sharing options...
90vanman Posted November 16, 2011 Report Share Posted November 16, 2011 (edited) Pots? You can't push 30-40 amps through a pot*. Nah, they'll vary the duty cycle using transistors or FETS. *To be honest I have seen 400A through a "pot" but it was more of a variac than a pot. And it was rather large. Hi, I know that we're talking bigger scale, but I fly electric model aircraft using LiPo batteries,brushless motors,and some very fancy speed controllers.Using this current technology (no pun intended), a very small motor,fitting in the hand, can produce a couple of horsepower. There are downsides however, the LiPo batteries require very careful handling and charging and voltage management to avoid fires. The speed controller will be very expensive in a size to handle the current for this application, but also very efficient. A clutch would be superfluous, but the drive take-up would need working on so as not to break traction under hard acceleration, these drives do not build up like an ICE, full torque is there from nothing. If you have a little time on your hands, research LiPo technology, it's a real eye-opener. PS 400 amps is easily manageable in a small plane, so imagine scaling it up to bike size. Edited November 16, 2011 by 90vanman Quote Link to comment Share on other sites More sharing options...
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