2015 IZIP E3 Sumo Review


Technical Specs & Ratings



E3 Sumo


Class 3




Hydraulic Disc



417.6 Wh

417.6 Wh

52 lbs / 23.61 kgs


VP Semi-Integrated Ahead

Zoom 3D Forged Aluminum Alloy

TranzX ATB Lowrise

Velo Flat Rubber, Locking

TranzX Alloy with Microadjust


Velo Racing

Wellgo Aluminum Alloy Platform

Hydraulic Disc

Tektro Dorado Hydraulic Disc with 180 mm Front Rotor and 160 mm Rear Rotor, Tektro Dorado Levers with Motor Inhibitors


Video Reviews

Written Reviews

This is the review for the 2015 E3 Sumo, in 2016 an updated model arrived with sturdy thru-axles, an optional $50 boost mode that acts like a throttle and a slightly altered paint job… it also costs a lot less! Check it out in the full review here.

The E3 Sumo is one of the only fat electric bikes I’ve tested that is capable of performing above 20 mph as a US legal “speed pedalec”. It uses an efficient mid-drive motor system by TranzX for climbing and reaching greater speeds and distances efficiently. While I do have a few basic gripes here including the lack of fender, rack and bottle cage bosses as well as the lack of a kickstand (like many fat tire bikes) and an early cutoff in throttle mode at ~6 mph, overall it’s an excellent ebike at an amazing price under $4k. If you like the fat bike style or plan to do trail, sand and snow riding then this is a capable option. The Kenda Juggernaut tires are 4 inches wide and can take 5 to 30 PSI for navigating soft or hard terrain respectively. I love that the bike is available in two frame sizes even though both are high-step, the top tube is angled slightly and the frame is relatively light weight at ~52 lbs but still sturdy thanks to the triangular “diamond” tube configuration. This ebike is made by Currie Technologies, a company that has been a leader in the US electric bike space since 1997 and offers one of the better warranties (lifetime frame, two year drive systems, one year battery) with a vast newtwork of dealers for testing before you buy.

Driving the bike is a 350 watt geared centerdrive from TranzX. It strikes a balance between the more affordable low-end middrives that rely on cadence sensors only and can feel jerky and the more expensive high-end systems with shift detection and rapid drive cutoff. I tested one of the early versions of this TranzX motor in 2013 and wasn’t entirely impressed however, two years later in 2015 (at the time of this review) I found the motor to be quieter, smoother and generally more responsive. It feels very zippy and torquey in throttle mode going from 0 to ~6 mph and is capable of hitting 20 mph if you pedal along. Basically, the throttle is meant to act as an override in lower levels of assist so you can “boost” up short hills without changing assist levels. For that application it works very well and while I’m not sure what the peak output is from TranzX centerdrives, I’d guess it’s upwards of 500 watts which is excellent when combined with a lower gear. The motor itself is small, well positioned (completely replacing the bottom bracket tubing) and fairly responsive. It turns a 38 tooth chainring that includes an aluminum bash guard on the outer edge and a plastic guide on the inner edge (to reduce drops). The control system on the Sumo is measuring your rear wheel speed, pedal cadence and pedal torque to deliver responsive motor output and it feels good but not quite as quick as the Bosch or Impulse system. It also lacks shift detection which means the sprockets and chain take a bit more abuse if you aren’t proactive in how you shift but the chain is extra strong and rust proof to help reduce abrasion.

Powering the Sumo is a 48 volt 8.7 amp hour battery pack reminiscent of other 2015 IZIP models. It’s well positioned on the downtube, keeping weight low and centered, and has some matching stickers to blend in with the frame a bit. I like that it’s designed to lock to the frame with a key for security but that it can be charged on or off (which also makes the bike lighter for transport). Many newer electric bikes run 48 volt systems because electricity is transferred more efficiently at higher voltage and the motor is also able to reach higher torque and power output. The cells inside are light weight, 18650 sized, energy dense Lithium-ion much like you’d find in an electric car. To help them perform best, I recommend storing in a cool dry environment between uses and maintaining a charge level between 20% and 80% so as not to stress the cells. While the pack itself does take up most of the space in the triangular section of the frame (thereby displacing a bottle cage mount) it’s similar to what I see on other models in this price range. The only downside in my mind is that the pack has to be switched on independently of the main display. So basically, you hold the rubber on/off button on the right side of the battery pack for a few seconds and then press the on/off button on the display panel for a second to get the bike rideable. This extra step is just annoying and can actually be confusing if you forget the extra step and then wonder why the display unit won’t come on.

Once the Sumo electric bike is actually switched on and ready to go, the display panel does a quick eight second countdown. I like how large the LCD readout is and that it’s mounted front and center just above the stem (with two plastic legs for extra strength). this display can swivel forward and back to help reduce glare if it’s sunny out but it’s not removable which means it could take more wear from the sun, rain or fellow pedestrians at bike racks. Near the left grip you’ve got a rubberized control pad with four unique buttons (up, down, display and power). There are four levels of assist in here and the throttle can be used to override any of them at full power (up to 20 mph) at any time if you’re pedaling. To hit that 28 mph top speed you’ll need to be in level four and using one of the higher gears. I found that the TranzX motor spins at a limited range of speeds but offers more power at those speeds and what this means is the lower gears will only go so fast, even in the highest drive mode. This works alright and just requires that you shift through one of the 10 speeds using the trigger shifters near the right grip. There is a zero mode where the throttle and pedal assist are inactive and to get to this you need to hold the display button for a couple of seconds while in assist level one. The display also has built in backlighting which can be activated by holding up for a couple of seconds (there is also a day/night light sensor built into the display for automatic lighting). All things considered, the display and control pad are great for a mid-level ebike like this. They are much improved over the 2014 Currie systems and offer lots of great feedback about your ride including an odometer and range estimator that automatically approximates how far you can go with the remaining battery power depending on which level of assist you’re in.

I feel that the IZIP E3 Sumo has found a sweet spot between performance and value and addressed one of the biggest hurdles that fat e-bikes face which is having enough power to actually move the large wheels through soft terrain. The TranzX drive system has improved significantly in recent years (or maybe I’ve just become more used to it) and while there’s still room for improvement, it definitely gets the job done at above average levels. I like that they went with cut out wheels to reduce weight and add a bit more cushion and that they upgraded the brakes to hydraulic but included motor inhibitors on the brake levers. The upgraded Wellgo pedals are nice and stiff but depending on your foot size the wider Wellgo MG-1 Magnesium Pedals might be worth considering, I like the locking grips and the quick release wheelset is super convenient for transport and maintenance. It’s a solid fat bike that is very capable of off-road riding.


  • Capable of reaching higher top speeds with rigorous pedaling in the highest assist level, one of the only fat electric bikes I’ve tried that is a speed pedelec
  • Excellent weight distribution with the mid-frame battery pack and centerdrive motor, this improves balance and handling, especially on trails or in the sand and snow
  • Mid-drive motor leverages the 10 speed cassette for improved efficiency and range, great for moving the larger wheels and tires here
  • Cut-out rims reduce wheel weight which makes starting and steering easier, they also provide increased cushion because the tube is more flexible than the tires and it can stretch through the cutout holes
  • Throttle adds power dynamically (up to 20 mph) when pedaling, great for overcoming small hills with a little boost when using a lower level of assist, you can completely shut off pedal assist by holding the power button for a couple of seconds while the bike is on and in assist level 1
  • New 2015 display panel can swivel to reduce glare and is attached at two points for improved strength, also backlit for use in dark environments
  • Front and rear quick release wheels makes the bike easier to transport in your car (especially given the larger 26″ x 4″ tires), this also makes fixing flats easier while you’re out on the trail
  • Removable battery reduces overall weight of the bike when transporting on cars racks and makes charging easier if you store the frame in your garage (keep the battery at neutral temperatures and charged after each ride)
  • Available in two sizes for improved fit, both are “diamond” high-step frames which provides greater stiffness and strength than step-thru
  • Nice component upgrades including the SRAM X7 derailleur, locking grips and oversized aluminum alloy pedals
  • Hydraulic disc brakes operate without requiring much effort so you can keep a strong hold on the handlebars and avoid fatigue when braking, they are smooth and provide quick stopping power
  • Remote button pad on left bar is well sealed against water, blends in with the bar and is easy to reach while riding – intuitive menus make operating the bike while riding easy
  • Solid warranty from Currie Technologies, available to see and test ride at many shops across the United States and get serviced ongoing


  • The throttle can only reach ~6 mph if you’re not pedaling along, it cuts out abruptly and leaves me wishing it could hit 20 mph on its own without pedaling along
  • No water bottle cage mounting points, you’ll have to use a Camelbak or get a saddle rail adapter to add a a cage separately, no rear rack mounts (consider a beam rack) or fender mounts and no kickstand
  • Display panel is not removable, when using the bike to commute to work or park in town this exposes it to more wear through weather and possible tampering
  • Value drive system with larger front ring and simpler control sensors than higher end systems like Bosch or Impulse, the motor doesn’t kick in or stop as quickly and it also can’t sense when you’re shifting gears
  • The battery pack has a rubber on/off switch as well as the main control pad so you have to press “on” two times to get the display to activate which takes a bit more energy and time than… not a huge deal, might reduce tampering

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