A human traveling on a bicycle at low to medium speeds of around 16–24 km/h (10–15 mph) uses only the power required to walk. Air drag, which is proportional to the square of speed, requires dramatically higher power outputs as speeds increase. If the rider is sitting upright, the rider's body creates about 75% of the total drag of the bicycle/rider combination. Drag can be reduced by seating the rider in a more aerodynamically streamlined position. Drag can also be reduced by covering the bicycle with an aerodynamic fairing. The fastest recorded unpaced speed on a flat surface is 144.18 km/h (89.59 mph)[41]
The last 8 months we've been wrapping up some long duration testing of Statorade across different hub motor lines and performing experiments confirming its long term stability. These results have us pumped to introduce this motor cooling solution beyond DIY'ers and into wider markets. As an example, have a look at the video we below showing the effect this has on a small direct drive folding bike motor.
The other is our first foray into the larger 45mm wide motor series, similar to those sold by MXUS, QS, Leafbike etc. as 3KW or 5kW hubs. We got these made up to properly fit either a standard 135mm dropout with a single speed freewheel, or a 150mm dropout with a 7-8 speed freewheel and some spacers. As expected from Grin they are sealed, include a 10K thermistor for temperature sensing, and have a disk hole injection port for Statorade, and are hubsink compatible. Check out the performance on our simulator both with and without statorade. Unlike so many other direct drive motors, both of these have the proper alignment for disk rotor position and room for disk calipers without shimming things out.
Controllers for brushed motors: Brushed motors are also used in e-bikes but are becoming less common due to their intrinsic lower efficiency. Controllers for brushed motors however are much simpler and cheaper due to the fact they don't require hall sensor feedback and are typically designed to be open-loop controllers. Some controllers can handle multiple voltages.
One of the items we demonstrated at the show is the new GMAC motor series. This is a powerful clutchless geared hub motor developed over the past 2 years in partnership with MAC motors, using a custom axle with an integrated splined torque arm. Imagine a MAC motor with perfect frame fit for modern bicycles, zero torque transmission on the dropouts, and phenomenal regenerative braking control.

To be honest, this bike is really designed for city commuters or kids riding around the suburbs. The fact that it’s foldable will let you carry it on the bus, on the train or even on the plane. It’s just not designed for heavy riding, long distances or tough terrains. If you want something sleek and fabulous at a fraction of the cost of most other e-bikes, this baby’s for you.


The batteries are the most important parts of the bike, because (if you don't do any pedaling) they contain all the power that will drive you along. Typical electric bike batteries make about 350–500 W of power (that's about 35–50 volts and 10 amps), which is about a quarter as much as you need to drive an electric toaster. In theory, you could use any kind of battery on a bicycle. In practice, however, you want to use something that stores lots of power without being too heavy—or you'll be using half your power just moving the battery along! That tends to rule out heavy lead-acid batteries like the ones that start cars, though some electric bikes do use them. Lightweight lithium-ion batteries, similar to those used in laptop computers, mobile (cellular) phones, and MP3 players, are now the most popular choice, though they're more expensive than older rechargeable battery technologies such as nickel-cadmium ("nicad"). Typical batteries will give your bicycle a range of 10–40 miles between charges (depending on the terrain) and a top speed of 10–20 mph (which is about the maximum most countries allow for these vehicles by law). You can extend the range by pedaling or free-wheeling some of the time.

Rad Power’s lineup of 2019 bikes start at $1,699 (there’s also a Cyber Monday special on their 2018 models), proving that electric bikes don’t have to be over $2,000 to have the amenities and quality you need for daily commuting. Of course, that’s still a steep price for some. But as prices keep dropping in the e-bike industry, affordability breeds better access, and this might be the key that our cities—and their traffic—so desperately need.
In the 1890s, electric bicycles were documented within various U.S. patents. For example, on 31 December 1895, Ogden Bolton Jr. was granted U.S. Patent 552,271 for a battery-powered bicycle with "6-pole brush-and-commutator direct current (DC) hub motor mounted in the rear wheel". There were no gears and the motor could draw up to 100 amperes (A) from a 10-volt battery.[5]
The first mechanically-propelled, two-wheeled vehicle may have been built by Kirkpatrick MacMillan, a Scottish blacksmith, in 1839, although the claim is often disputed.[20] He is also associated with the first recorded instance of a cycling traffic offense, when a Glasgow newspaper in 1842 reported an accident in which an anonymous "gentleman from Dumfries-shire... bestride a velocipede... of ingenious design" knocked over a little girl in Glasgow and was fined five shillings.[21]

In general, U.S. and European cycle manufacturers used to assemble cycles from their own frames and components made by other companies, although very large companies (such as Raleigh) used to make almost every part of a bicycle (including bottom brackets, axles, etc.) In recent years, those bicycle makers have greatly changed their methods of production. Now, almost none of them produce their own frames.
There are dozens of good 25Km/h pedelecs. Our advice is to go the nearest good e-bike store and get it from there, because e-bikes may need good support. Only if you like servicing a bike yourself is buying from the Internet a good option. As of Spring 2013, a good benchmark to compare with is the Austrian KTM Amparo also called KTM Severo 8M or the German Kalkhoff Impuls or Agattu series. It has a reliable Panasonic middle motor and a good battery. If you want a more sexy design, try the SMART from the urban car maker of the same name.
The safety bicycle gave women unprecedented mobility, contributing to their emancipation in Western nations. As bicycles became safer and cheaper, more women had access to the personal freedom that bicycles embodied, and so the bicycle came to symbolize the New Woman of the late 19th century, especially in Britain and the United States.[8][73] The bicycle craze in the 1890s also led to a movement for so-called rational dress, which helped liberate women from corsets and ankle-length skirts and other restrictive garments, substituting the then-shocking bloomers.[8]
The $3,099 MSRP is a bit daunting if you've not shopped for high-end bikes before, but it compares favorably with, say, Trek's electric bike lineup. That said, you can get a solid urban/commuter bike without a motor for well under $1,000. You can even score an e-bike for under a grand, but you'll likely be looking at a battery range of less than 40 miles, along with lower-quality components.
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