“A wide selection of options adds to the Flex's versatility, which is what a utility bike is all about.”
- Versatility - A true utility bike
- Mature design - No big gotchas
- Adaptable - Adjusts for rider comfort
- Full, reasonably priced accessory line
- Safety certified and Class 2 compliant
- The price is a bit high
- Android Flyer app is not available
- Only moderate power and torque
The Radio Flyer Flex e-bike is an exceedingly well-thought-out utility bike that can meet the needs of many riders. Like Goldilocks assessing the chair sizes of a family of bears, prospective buyers may find the Flex is “just right.”
The Flex’s success is due to its size, frame style, easy operation, ample safety features, and wide range of accessories.
The Flex is an excellent choice if you’re looking for an e-bike for frequent short trips.
Radio Flyer founder Antonio Pasin, Jr. sold the first Radio Flyer red wagon in 1922. Robert Pasin, the founder’s grandson, is the current CWO (Chief Wagon Officer). Like the iconic wagon, the Flex is designed as a versatile family kid and cargo hauler that’s fun and easy to ride.
Radio Flyer Flex e-bike: Purpose and best use
Radio Flyer describes the Flex as “the ultimate utility e-bike,” which accurately describes its highest and best use. However, you won’t buy the Flex for off-road or dirt riding because it lacks the proper tires and front or rear suspension to soften the impact of bumps, jumps, or other surface irregularities.
The Flex isn’t a great commuter e-bike, partly because its speed is limited to 20 mph and partly because its 67- to 68-pound weight without options is more than most people will enjoy lifting or carrying regularly on stairs or curbs. My test bike, with a full complement of accessories, weighed 86.2 pounds on my digital scale.
Don’t confuse the Flex with a cargo bike like the Pedego Cargo or the Rad Wagon 5. Those bikes are highly capable but long and heavy, built for carrying multiple children and heavier cargo loads. The Flex is shorter and lighter than a cargo bike. Its maximum cargo capacity is 100 pounds plus the rider, limited to 80 pounds on the standard rear rack.
Rear wheel side covers prevent tiny passenger feet from getting caught in the spokes.
The Flex is an excellent choice if you’re looking for an e-bike for frequent short trips around town, running errands, transporting a child to a friend’s house, or just having fun in the neighborhood. The wide selection of options for carrying a (small) passenger, packages, or groceries adds to the Flex’s versatility, which is what a utility bike is all about.
Radio Flyer Flex e-bike: By the numbers
Radio Flyer equips the Class 2 Flex e-bike with a 500-watt Flight Speed rear hub motor. Class 2 bikes are allowed motors up to 750 watts, so the “Flight Speed” name is a bit ambitious. The motor produces 53 Newton meters of torque, which is relatively moderate, especially for a bike that will likely carry close to its maximum 330 pounds capacity for rider and cargo.
The 48-volt 9.6-amp-hour battery, which fits vertically behind the seat down post, stores 458 watt-hours of power, explaining its modest 20- to 40-mile range. You can access battery power with five levels of pedal assistance or a thumb throttle by the left-side hand grip, but you cannot exceed 20 mph using battery power solely. Because of the Flex’s weight and gearing, I doubt it will be possible to exceed 20 mph on level ground by pedaling without battery assistance.
The top speed complies with Class 2 regulations, but the range estimate will vary widely depending on multiple factors, including speed, rate of acceleration, weight, terrain, temperature, and more. I don’t test range because it is widely variable, but if you’re hoping for close to the 40-mile max, stick to a low pedal assistance mode and speeds of 15 mph or less. The 20-mile range could be a stretch if you use the throttle generously.
| Electric motor power | 500 watts |
| Torque | 53 Newton meters |
| Battery power | 48 volts x 9.6 Amp hours = 458 watt-hours |
| Top speed (PAS) | 20 mph |
| Top speed (throttle) | 20 mph |
| Range | 20 – 40+ miles (depending on many factors) |
| Charging time 0-100% | 4.5 to 5 hours |
Radio Flyer Flex e-bike: Comfort and convenience
The Flex is modestly sized, but it’s not a small e-bike. Available in two frame sizes, S/M fits riders from 5 feet to 6 feet tall, and M/L is rated for riders 5 feet, 5 inches to 6 feet, 5 inches. Both sizes are limited to riders who weigh 220 pounds or less. That allows 100 pounds of cargo, a maximum of 80 pounds supported by the rear rack.
Adjusting the seat height to find your most comfortable position is easy. You can also rotate the handlebar by loosening four bolts on the stem. Radio Flyer provides three spacers to place in the handlebar stem cap to change the height. This last adjustment process isn’t hard, but it is a bit complicated. Fortunately, the manual provides a clear explanation with graphics.
| Flex e-bike weight (bike only) | 67 lbs (S/M), 68 lbs (M/L) |
| As tested with options (M/L) | 86.2 lbs |
| Seat height | 31.5″ to 39.5″ (S/M), 34″ to 42″ (M/L) |
| Rider height | 5′ to 6′ (S/M), 5’5″ to 6’5″ (M/L) |
| Bike capacity (rider + cargo) | 330 lbs |
| Rear rack capacity | 80 lbs |
| Maximum rider weight | 220 lbs |
The standard seat is moderately comfortable, especially for relatively short trips. An optional thicker and softer seat is available, but I didn’t request one for the test bike. The lack of a front fork suspension and no rear suspension with a standard seat means you’ll feel the bumps in the road.
Fat tires can help soften an e-bike’s ride by deflating a bit from the maximum inflation rating to get help from sidewall flexing, but the front 24-inch and rear 20-inch tires on the Flex are a moderate 2.4-inch wide, so there is not much help there.
Side covers for the rear wheel are standard, which helps prevent feet, shoelaces, or anything else hanging down from the rear rack from getting caught in the bike’s spokes.
The shifter, throttle, brakes, and bell operating controls are well thought out and easy to use. The control buttons on the display case power the bike, select PAS levels, turn the headlight and taillight on or off, and activate the turn signals.
When the turn signals are blinking, an indicator light appears on the display. Tap the button again to turn them off. However, the Bluetooth-linked Flyer app allows you to specify a blinking duration.
Holding down the minus button on the display case enables walking mode, which powers the bike at about three mph to help you push it. This feature is an especially appreciated convenience when the bike is loaded with cargo, and you’re pushing it up an incline.
The Flex has a center stand instead of a kickstand. Although it requires more effort, it’s extremely helpful when loading passengers or cargo on the rear rack.
The Flex has a center stand instead of a kickstand. Although it requires more effort, it’s extremely helpful when loading passengers or cargo on the rear rack.
Radio Flyer Flex e-bike: Riding impressions
The Flex is pleasant to ride. That may sound like weak praise, but I thought it was fun and easy to ride. However, pleasantness has to be taken into context. I only drove on regular paved streets or lawns, which hardly counts as off-road. Limited to 20 miles per hour, I could avoid potholes in the pavement or tree roots on the lawn, so the lack of suspension didn’t matter.
I angled the handlebars back a bit because I prefer riding upright, which is comfortable. The Flex felt balanced and easy to control in standard form, as in the photo above, or with a full complement of added racks and accessories, as below.
The Flex is a strictly defined Class 2 bike, so the speed is not a problem. Torque, however, is a bit of an issue. We have a very steep, long driveway. I test torque from a standing start at the bottom of the driveway with the throttle only, so it uses battery power only.
Most e-bikes with 750-watt plus motors can gradually move out from a standing start, picking up moderate speed soon. I couldn’t do it with the 500-watt Flex. I had to pedal and push the thumb throttle to ride up my driveway from a standing start. Is this a big deal? Not really. I don’t usually stop at the bottom of the driveway and then start, and the Flex had no issues with it from a rolling start.
If you are stopped at a traffic light or stop sign and must ride up a steep incline, use pedal power assistance with the Flex. Using the throttle alone might not be enough.
The standard Tektro hydraulic disc brakes with 180mm rotors have excellent stopping power. However, if you’re riding with a child or cargo on the rear rack, anticipating and stopping a bit earlier than usual is always a good idea, which is true for all e-bikes.
Our take
The Radio Flyer Flex is an excellent choice for a general-purpose utility e-bike. The Flex is priced at $2,099, which is a bit more than you might expect, but the vast options and upgrades selection is reasonably priced, so overall, the pricing is okay. Radio Flyer has a 30-day free trial period, with return shipping paid for, which is unusual. There are some reasonable use conditions, but this policy is an outstanding way to alleviate concerns.
Other e-bikes to consider are Rad Power Bikes RadRunner 3 Plus and the RadWagon 5. At $2,199, the Radrunner 3 Plus has a higher starting price and weighs 8 pounds more than the Flex, but it has a front suspension and more torque. The Rad Wagon 5 has tons of torque and is a Class 3 e-bike with a 28 mph top speed. However, the Rad Wagon 5 costs $2,399, weighs 18 pounds more and is six to eight inches longer than the Flex, making it significantly larger to move over curbs or around tight spaces.
If you’re shopping for a versatile and undemanding e-bike for a fun and convenient transportation mode, the Radio Flyer Flex is highly recommended.
