IES Centaur Review

Ies Centaur Electric Bike Review 2
Ies Centaur Electric Bike
Ies Centaur Rear Dc Motor
Ies Centaur Key And Battery Display
Ies Centaur Headlight And Fender
Ies Centaur Rear Fender
Ies Centaur Electric Bike Review 2
Ies Centaur Electric Bike
Ies Centaur Rear Dc Motor
Ies Centaur Key And Battery Display
Ies Centaur Headlight And Fender
Ies Centaur Rear Fender


  • One of the oldest purpose-built electric bikes I've tested, dating back to 2004
  • Powered by a large and heavy Lead-acid battery pack seated into the top tube, offers decent balance
  • May have to replace battery manually if buying used, IES is no longer in business to offer support
  • Offers front and rear fenders, lights and a suspension fork as well as seat post shock for good comfort

Video Review



IES (International Ecological Systems, Ltd.)




$2,000 USD

Body Position:


Suggested Use:


Electric Bike Class:

Throttle on Demand (Class 2)
Learn more about Ebike classes


United States

Model Year:


Bicycle Details

Total Weight:

88 lbs (39.91 kg)

Geometry Measurements:

Dimensions: 68.9" x 23.62" x 41.34"

Frame Types:


Frame Fork Details:

Basic Suspension

Attachment Points:

Fender Bosses

Gearing Details:

5 Speed 1x5 Shimano

Shifter Details:

Grip Twist on Left Bar


Aluminum Alloy with Rubber Tread


Low Rise

Brake Details:

Mechanical V-Brakes


Oversized Comfort

Seat Post:

Suspension Shock

Wheel Sizes:

26 in (66.04cm)


Plastic Front and Rear Fenders, Double Leg Kickstand, Front and Rear Lights, Bash Guard on Front Ring, Bell on Left Bar


Removable Battery Pack, Keyed Ignition Switch

Electronic Details

Motor Type:

Rear-Mounted Geared Motor
Learn more about Ebike motors

Motor Nominal Output:

190 watts

Battery Voltage:

36 volts (Uses Three 12 Volt Cells)

Battery Chemistry:

Sealed Lead Acid

Estimated Min Range:

25 miles (40 km)

Estimated Max Range:

30 miles (48 km)

Display Type:

LED Console


Brake Indicator, Battery Level, Low Voltage Indicator, Front Light Indicator

Drive Mode:

Twist Throttle

Top Speed:

15 mph (24 kph)

Written Review

The International Ecologic Systems (IES) Centaur electric bike is a classic beauty. It was state of the art in 2004 and featured a purpose built frame with Lead Acid battery pack designed right into the topbar. It features front and rear headlights, a backlight power display, fenders, shocks and a beautiful clean aesthetic that tucks neatly wrapped wires out of sight.

This bike is a rare find and one that unfortunately isn’t very useful these days given the company has gone out of business and there are far lighter, nimbler electric bikes options available. Still, this exotic beast lives up to its namesake. Like the half horse, half man mythical creature for which it is named, the IES Centaur melds human power with electric boost in a beautiful way.

The Centaur is powered by a 190 watt side-mounted direct current motor similar to that of the eZip Trailz. This creates a bit of imbalance in the frame but makes servicing the rear wheel easier. Powering the motor is a 36 volt Lead Acid pack that adds a lot of weight to the bike. While I like the integrated design, it is positioned high up on the frame making it less stable overall. It does however include a built in handle for easy removal and transport.

Integrated directly into the frame, just above the battery pack, is a backlight display that lists battery capacity and headlight status. This was very high-tech for its time and lends to the beautiful design of the bike. The fenders match well and provide great utility along with the integrated lights that run off the same Lead Acid battery powering the bike.

Given that many of today’s electric bikes don’t include computer readouts of battery life or power lights from the core battery, this bike was ahead of its time and well thought out. It even includes a locking system with key for securing the battery. The biggest drawback is the weight and that is due in large part to the Lead Acid battery pack. Given how heavy this bike is, the v-brakes mounted on the front and rear wheels do a good job but lose stopping power and become unsafe if the rims get wet.

This bike was designed to go upwards of 25 miles per charge with a top speed of 15 miles per hour. If you find a used one however, I would imagine it struggling to reach 10 miles because Lead Acid lacks the charge cycle capacity that Lithium polymer batteries now offer. I do know people who have rebuilt the battery however so if you don’t mind the weight and want a fun project in a retro electric bike, this could be a wonderful buy.


  • Beautiful design with integrated battery pack and well organized wires
  • Front and rear fenders keep you clean and dry in wet riding conditions
  • Front and rear lights are powered off the main battery pack
  • Comes in red or silver color schemes
  • Integrated battery capacity display also shows headlight status
  • Front fork shock and seatpost shock smooth out the ride


  • Extremely heavy 88 pound bike including battery pack
  • Lead Acid battery packs don’t last as long as newer Lithium-ion batteries and are much heavier
  • Only offers twist throttle mode, no pedal assist option
  • Front and rear v-brakes work well enough but given the weight of this bike should be kept dry and clean for safe stopping


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