What We Would Ride
The best all-around 20" bike we've tested. Rugged and nimble for moderate single-track riding, yet comfortable enough for street riding.
Seat Height: 21.6" - 27.6"
Weight: 17.5 lb.
Frame Material: Aluminum Alloy
Tire Size: 20" - geared
Brake Type: Mini V
Geared Bike Type: Street/Light Trail
Gain Ratio: 2.3/6.7
Available Online: Yes
Buying your child’s first 20″ bike is akin to buying them their first car. Somewhere between reading about shifters, geometry, and gear-ratios you think, how did they get this old? With gentle rides in the park gone for good, speed, power, and performance are now top on your list as should be the WOOM4.
An amazing all-around 20″ bike, the WOOM4 is well equipped to handle long paved rides to mild dirt trails. Lightweight with a low-center-of-gravity, the WOOM4 provides an easy and comfortable transition for kids moving up from their 16″ bikes. With 8-speeds for a wide range of gears and grip shifters for shifting newbies, the WOOM4 is an excellent choice for kids needed a top-notch all-around bike.
The WOOM4 is more than your basic neighborhood bike. Capable of comfortably executing everything from 15+ mile paved bike rides to beginning single-track mountain bike trails, the WOOM4 is an amazing all-around bike for the average child rider. Throughout our tests, we found both beginning and more aggressive riders to be comfortable on the bike. The lightweight build (16.9 lb.), low-rise handlebars and low center of gravity frame create a comfortable and familiar ride for beginning riders while the responsive brakes, a slightly more aggressive position and a wide range of gears easily brought a smile to our aggressive rider’s faces.
WOOM4 Works Great for Various Types of Riders
At 21.6″ the WOOM4 has one of the lowest minimum seat heights for a 20″ bike. Maxing out at 27.6″, the WOOM4 is a good fit for kids aged 5 to 8. A child inseam, however, is king when fitting a bike. Experienced riders on 20″ should have the seat height set to 2″ to 3″ ABOVE their inseam to allow for proper leg extension while pedaling. A bike is generally a good fit for an experienced if they can only touch the ground with their tippy toes while on the bike seat. As a result, the WOOM4 is ideal for experienced riders with an inseam ranging from 18″ to 24″ (regardless of age). The standover height of the bike wasn’t an issue for any of our riders.
WOOM4 Ridden by 5 and 6-year-olds
We tested out the WOOM4 is a 5, 6 and 8 year old and found them all to be a good fit on the bike. Our very tall 6-year-old tester with an 23″ inseam and our 8-year-old tester with a 24″ inseam fit on the WOOM4 but it offered little, if any, room for growth.
Frame & Geometry
Designed specifically for kids (not just “small adults”) the WOOM4 frame is built narrower and shorter than the average 20″ bike. To properly fit under a child’s body, WOOM frames are built with smaller, narrower components to prevent kids from having to splay their legs out while pedaling. The “width” of the bike (the distance between the inside of the pedals) is known as the q-factor in the bike world. The q-factor width is equal to the distance kids must spread their feet to pedal. A bike with a lower q-factor provides more proficient pedaling as kids are able to extend more effort in pushing directly down on a pedal.
Narrow Q-factor on WOOM4
Where the pedals are attached the frame of the bike is also plays a significant role in a child’s ability to balance and maneuver a bike. Pedals are attached to crank arms, which are attached to the bottom bracket of the bike frame. The lower the bottom bracket of a bike, the lower a child can sit in relation to the bike tires and the lower the overall center-of-gravity of the bike will be. The lower bottom bracket also creates more distance between the seat and the pedals, which provides more space for kids to properly extend their legs and to get more power out of every pedal stroke. Compared to low and mid-range 20″ bikes, the WOOM4 has a much lower bottom bracket and shorter crank arms which provides more space for proper leg extension when pedaling. The bottom bracket height of a bike can’t be change as it is part of the bike’s frame.
Bottom Bracket Height and Proper Leg Extension on the WOOM4
Fork & Tires
In addition to being lightweight and nimble, the WOOM4’s tires and fork help it excel in various conditions. The aluminum fork offers some dampening, but does not have a shock. While shocks can be extremely helpful for kids hitting the single-track or the pump track, for the majority of kids, it is more advantageous to skip the shock to help save on weight. In fact, most shocks on kids bikes are pretty worthless and act as merely eye candy. For those high-adventure kids looking for a front suspension bike, many big names bike brands have released light-weight 20″ with front suspension.
WOOM4 Tires and Rims
Whether on paved or packed dirt trails, the WOOM4’s 1.5″ wide tires Kenda Small Block tires help provided plenty of traction for dirt, yet thin enough to prevent an significant increase in rolling resistance caused by thicker tires. Wrapped around WOOM’s super lightweight Soopa-Doopa-Hoops aluminum rims, the WOOM4’s wheel’s are well-prepared for a variety of surfaces.
Gearing and Shifting (Gain Ratio)
The WOOM4 has 8 gears ranging from a 2.3 to a 6.7 gain ratio. With a wide range of gears, the WOOM4 is ready to tackle hills as well as easily gain speed on flat rides. With one chain ring in the back and a cassette of eight cogs in the rear, shifting is done via grip shift on the right hand. Twisting up shifts to a higher gear while twisting down shifts to a lower gear. For riders just getting acquainted with gears on a bike, we have found grip shifters to be the easiest and most intuitive to use. For more advanced riders riding more aggressively on mountain bike trails, trigger shifters are generally better.
The WOOM4 is comparable to several other higher-end bikes, including the Islabikes BEINN 20″, Prevelo Alpha Three and the Cleary Owl. While each bike has it’s specific strength, the WOOM4 is our top pick for all-around riding. Compared the Islabikes BEINN 20″, the WOOM4 has a wider gearing range and slightly wider tires for all-terrain riding. Islabikes’ rims are also only compatible with Presta valve tubes, which can be challenging to find. The Prevelo Alpha has trigger shifters and a more aggressive body position best suited for ambitious riders. Lastly, the Clearly Owl is a single-speed which limits its use.
The WOOM4 is the best all-around 20″ bike we have tested. Rugged and nimble enough for moderate single-track riding, yet comfortable enough for street riding, the WOOM4 is the perfect bike to take your all-terrain rider.
By: Natalie Martins
Last Updated: January 30, 2017
FTC Disclosure: No monetary compensation was provided for this review. For many, but not all reviews, products are provided by the manufacturer or distributor to help facilitate the review. All opinions and images are that of Two Wheeling Tots LLC and should not be used or replicated in any way. The majority of, but not all, links provided are affiliate links. Two Wheeling Tots LLC is an affiliate of Amazon.com and WOOM US.