E4 Mid-drive Kit Photos

Sun EZ-tandem with E4 mid drive

This EZ-1-SX tandem has been used extensively in the wet Northwestern USA, with motor system holding up well as those put on trikes in caustic environments such as Padre Island off the Texas coast. We get pictures that cease to amaze us how well these motors work after the bikes appear near beaten to Hell!

(One dealer told me the trike was near beyond repair, though the motor system simply needed the double-freewheel unit cleaned and lubed.)

To all our customers! PLEASE do preventative maintenance to avoid the inevitable destruction rust, sand, salt, and other havoc caused by mother nature's reminder we are here on this planet for a very short period!

Swedish Velomobile with E4 drive

E4 motors run through the gears in parallel to your muscle power, allowing you to decide how much (or little) you wish to contribute.

When pedaling there's no motor drag. If the motor is running, the double freewheel feature prevents crank arms from turning unless you want to pedal.

Europeans take their bikes and trikes seriously! We would build a shell around them too if it meant riding for more than a couple of Summer months!

This customer was quite happy with the E4 power and standard size lead acid battery included in the kit!

EZ Sport (influenced by EZ Racer's Gold Rush)

This customer made his own motor and battery mount such that it's totally concealed. (Unfortunately, some folks feel like they've got to hide the electric system when as many e-bikes as regular bikes are now sold in Europe, Japan, and China. The rear tail adds aerodynamics.

Why mid-drive motors over wheel motors??

E4 motor kits excel over hub motors, direct chain to the axle motors, and the old "tire-scrubber motors". This is because every motor has an "efficiency sweet spot" for high torque (start-up or hill climbing) or lower torque cruising at high speed. The sweet spot motor speed is able to be attained by a gear ratio. A bike's gears, like a car's transmission provides these necessary gear ratios. Direct drive motors (including hub type...) are stuck in a specific gear ratio. They may have a 7 speed cluster attached for the rider's muscle power gearing, but the motor itself is confined to one gear ratio that's supposed to cover both high and low torque applications.

Guess what! A single gear ratio for the motor doesn't cover all bases very well...start-up, hills, and cruising needs are all not met unless the motor is overkill large! Massive 750-1000W hub motors are being installed on bikes to meet these needs. Even so, a larger motor is much heavier and requires more battery capacity, adding even more weight! Smaller, lighter geared hub motors provide better up and go, but require higher amperage from the battery for more power when it's needed. High amps mean low efficiency, poor range, and often overworking the battery so it doesn't last long.

Though lead acid batteries can handle high amps, they're more expensive to replace than a few years ago as the price of lead went though the roof along with Gold, Silver, Copper, etc. Lithium batteries...well high amps will kill this more fragile chemistry unless you've got a super duper battery management system and have sized your batteries so they'll handle the high current draw. Though 3C ratings are commonly reported, the rating is likely to be for a mere 30 seconds before the cells break down. $1000 lithium batteries is what most of these high powered hub motors require, and Chinese battery track records aren't what we call stellar!

A surprisingly simple installation on a popular BikeE, using the large main frame tube to conceal the wires.

Good job! (Note the "universal mount" adapted for this specific frame)

Often hub motors neither provide enough power nor enough speed since the rider easily pedals faster than the top motor speed. If you're pedaling fast the motor and battery become dead weight unless they're assisting!

Hub motor fanatics will say, add another battery for higher voltage to achieve the higher speed! We say, if you must break the law we don't want to know. The Owner's Manual of our kit states not to gear the powerful, light-weight E4 motor so it goes beyond legal power assisted speed. Doing so could cause grave problems if you were to ever get hit and try to collect damages.

Understeer EZ3-USX with E4

Another cycle adapted using our "universal mount", with the aid of hose clamps fitting odd sized circular tubing. No need for drilling into the frame, thereby voiding the bike manufacturer's warranty.

An extended range battery was used for this trike, for 40-50 mile runs along the Florida coast and orange groves!

4 wheel quad, using 2, EZ1-SX

There are times a heavier, inefficient motor system is the last thing you want to add to a cycle. This 4 wheeler is one of many made for those with a less able partner (or handicapped child). The bikes weigh twice that of a single bike...then there's the extra passenger weight!

A hub motor may work fine for flatter areas, but smaller front wheel hub motors are more prone to difficulty lacing spokes, and keeping the wheel true as it bumps along with added un-sprung weight.

A better solution is the mid-drive of course.

Note: We offer the conversion kit for this quad and the following side-car arrangement...if this is of interest! Hundreds of these have been sold so far, some with a quick release option to disconnect the bikes for single passenger use.

EZ-1 recumbent bike with side car kit

Higher current (Amp) draw by inadequately geared motors means likely overheating the motor also. To make matters worse, hub motors usually don't have controllers that cut power if the motor overheats. The E4 controller includes protective sensors against heat overload, and mounting the motor to a frame adds more protection to transfer heat better than a hub motor connected to front or rear fork. The small connection points at the fork are a very poor heat transfer, and reason why some hub motors try to solve the problem with fins. Open hub motor vents are impossible since the motor must be sealed from the elements.

Should we mention difficulties changing flat tires on hub motor wheels...un-sprung weight in heavy wheels...repairing or replacing the wheel or wheel motor????

Hopefully we've convinced you to opt for a mid-drive system unless it's just too complicated to adapt to your specific bike.

Unknown brand of tad-pole recumbent
Customer indicated he placed the battery up front on the frame member leading to the crank arms. This distributed the weight nicely. Again, our "universal" mount plate was cut and adapted with hose clamps to fit this unique frame.

Who needs a Harley?

This guy knocked this bike out in record time, probably because his son was not about to wait to show off his new set of wheels! A 3 speed rear hub makes the kit all the more special on this chopper. A real looker as the rider shifts into high gear under full power!

Lithium (iron phosphate, "LFP" type) battery available soon for lighter weight...longer lasting power!

After considerable testing, we hope to offer an alternative to lead acid batteries in the coming months. Our first results using Lithium left much to be desired...largely because cells made in China tend not to be as consistent in capacity as they could (and should) be. A top notch BMS (battery management system) is required for lithium cells to not overwork, nor discharge such that they become harmed or too out of balance with the rest.

Even after we're comfortable selling LFP (LiFePO4, Lithium Iron Phosphate), the cost promises to be 3 times that of lead acid, plus the expensive charger. On lighter bikes it might make more sense if the rider needs to carry the battery distances to and from the charging outlet.

Same for trikes, though our experience has been these are normally owned by folks with garages or spaces where they can be kept near an outlet. The added weight of a trike means saving 10 lbs. on a lighter battery is not all that significant. Consider the weight of the rider, cycle, motor system and battery...then drop 10 lbs. Not all that much, and certainly not worth the extra bucks if they don't last the 3-4 times more discharge cycles compared with lead acid (as represented by the manufacturers). Time will tell!...and there's always tomorrow if you don't need to be the first on the block to get the latest and (supposed) greatest!

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Look into commuter bike employer-federal tax credits, "environmental rebates", salary bonuses, and other electric vehicle incentives. As an example, California Air Resources Board offers their employees $100 monthly bonus if they use an e-bike to commute to work. Genentech in South San Francisco offers their employees a bonus for using a motorcycle or bicycle rather than a car to get to work. Many employers are jumping on this "green" band wagon and/or participating in the Federal bike commuter tax incentive worth $20 per month. Though $20 isn't $100, it's $240 per year towards the cost of your bike or e-bike!

Unfortunately, the only significant Federal incentives for electric vehicles are for those that are "freeway legal". This is an American statement, given our love of cars, our allowing the government to subsidize our cars at the expense of other means of transportation (and at the expense of the environment, lives and treasure lost in wars fought for oil required for cars), despite the green-washing by so many politicians! Tesla and Fiskar electric car companies have both received millions in stimulus monies...for cars slated to cost from $90 to $120,000 (and up...)...as though most of us will ever be able to afford such luxuries! Are the wealthy paying higher taxes for these toys, or is it the working class stiff who'll foot the R & D bill, just like he/she foots the cost of Tomahawk missils, Apache helicopters, and other multi-million dollar American Indian "war-path weapons".

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