Pedal Bike Review

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.

View on WOOM View on Amazon View on Amazon Canada

Product Specifications

MSRP: $450

Recommendation: Exceptional

Seat Height: 21.8" - 27.5"

Weight: 17.5 lb.

Frame Material: Aluminum Alloy

Tire Size: 20" - geared

Brake Type: Mini V

Speed/Shifters: 8/Grip

Suspension: No


Geared Bike Type: Street/Light Trail

Gain Ratio: 2.3/6.7

Wheelbase: 835

Available Online: Yes


WOOM4 seal - updated

**The current WOOM4 weighs 17.5 lb.**

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. The best 20″ bike really depends on where and how your child rides (street, mountain, city or BMX), but we found WOOM’s lightweight, quick and nimble 20″ to the best all-around bike we’ve tested.  With a lower-center of gravity, bottom bracket and handlebar height, the WOOM4 is well equipped to comfortable take your child from sidewalks to basic trails.


Built with lightweight AA-6061 aluminum, WOOM’s frames are lightweights and rigid.  Backed by a solid 5 year, hassle-free warranty, every frame is built to last.  Made of ChroMoly steel, the fork is responsive and offers some dampening.  But wait, it doesn’t 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 addition, 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.


The optimal geometry of a 20″ kids bikes is also quite different than on a 16″, 14″ or 12″ bike. Kids tall enough to advance to a 20″ have generally already mastered balancing, stopping and starting a bike and are ready to progress to a more aggressive, lower center-of gravity, body position.  In addition, on a properly sized bike, they shouldn’t be able to put both of their heels on the ground, as they will likely out-grow the bike too soon. Instead, as long as they can touch the ground with one foot while seated on the saddle, the bike is a good fit.  As a result, kids can properly fit on a bike with a minimum seat height 2″ to 2.5″ greater than their inseam.

In addition to the body position of the rider, the position of the child on the frame makes a great impact on the handling and performance of the bike.  By lowering their bottom bracket, handlebars and shortening the crank arms (the bars that attach the pedal to the frame), a child is able to sit lower on a WOOM bike, thereby decreases the overall center-of-gravity of the rider.  When compared to the standard bottom bracket height found on the mid-range Novara Pixie, the difference is significant.

WOOM4 vs. Novara

Crank Arms

A lower bottom bracket also requires a shorter crank arm (to keep the pedals from hitting the ground when turning the bike), which has additionally benefits to the rider.  A shorter crank arm for kids (for adults there is certainly more science to this), provides a lower up-stroke height (shown below), which allow for a more efficient knee bend angle.  In other words, the less cramped a child’s legs are when riding, the easier and more efficient their pedaling will be.  Even when their saddles are set to the same height, the Novara requires a much tighter knee bend than the WOOM4, making the Novara more difficult to pedal.

WOOM4 angles

WOOM4 crank length


In addition to knee bend angles, the amount of splay a bike requires of a child’s legs is significant.  The greater the splay, the less efficient and more uncomfortable a bike will be to ride.  In order to save money, most kid’s bikes use components designed for the wider hips on an adult. When riding these bikes, kids have to splay their legs to pedal to compensate for their naturally narrower hips.  To provide for a more comfortable ride, WOOM uses components specifically designed for kids bikes, which allows for a narrower Q-factor.  By looking over the top of a bike, the Q-factor, or the distance between the pedals, can be seen.

WOOM4 q factor


The newly updated version of the WOOM4 comes with grip shifters versus trigger shifters.  Trigger shifters are slightly easier for kids to activate, but for most kids, their fingers aren’t long enough to reach the triggers.  Grip shifters take more effort to activate, but are generally easier for kids to use.  The twisting motion can be challenging for kids as they can twist too hard, causing them to tweak their handlebars and crash.  In the end, there isn’t a perfect shifting solution currently on the market for kids, both trigger and grip have their drawbacks.

Gearing (Performance)

Aggressive riders will also enjoy the higher gear-ratio on the WOOM4.  With a larger front cassette, the WOOM4 allowed kids to easily power up and down mild elevation changes.

WOOM4 off road

WOOM4 vs. Isalbikes BEINN 20″ Small

Islabikes and WOOM both make amazing bikes, which utilize the proven long and low geometry (long wheelbase, lower bottom bracket), but which is best? While their bikes are similar, there are several significant differences, which lead our testers to prefer one over the other depending on their skill level and riding conditions.  In general, higher gear-ratio and trigger shifters of the WOOM4 were much preferred by more experienced or aggressive riders, especially on non-paved trails.  The lower gear-ratio and narrower tires were preferred by more timid riders as well as those who ride on mainly paved surfaces, especially for longer distances.

WOOM4 vs. IslaIsla vs. WOOM 2

Additional differences include crank size and rims.  The WOOM4 has slightly longer cranks than the BEINN small with 120mm vs. 114mm.  The BEINN 20″ large, however, has 127mm cranks.  Both bikes also have lightweight rims, but the Islabikes saves a slight amount of weight with 20 spokes, versus WOOM’s 34 (performance is the same). Islabikes rims, however, only take Presta valves, which are MUCH harder to find replacement tubes for than the Schrader valves on the WOOM.  We have yet to find a 20″ or 24″ Presta locally, so ordering backups ahead of time online is essential.

Isla vs. WOOM 20


Lastly, the Islabikes is a pound lighter than the WOOM.  For more riders, the difference in weight was a non-issue.  In fact, when one of 8-year-old testers, who typically rides a big-box store bike, had the chance to ride the WOOM4, he promptly got off of it, held it up above his head and yelled, “THIS BIKE IS SO LIGHT!”.  Like the other features previously mentioned, those testers who often road longer distances on paved surfaces, did prefer the lighter-weight Islabikes.

Isla vs. WOOM 4

Bottom Line

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.

MSRP: $450

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.

  • Anna

    I need help choosing between Woom 4 and Islabike Benin 20 large. My 6 year old daughter is 48 inches tall and has a 21 inch inseam. She has been riding a balance bike and but this will be her first pedal bike, although she can pedal on a tricycle. She is a very hesitant rider and takes a while to learn new skills. I was leaning towards the Benin large because it would last longer but I am worried she could not touch the ground with her feet to stop and have trouble balancing while starting and stopping. At the same time I am worried she may grow out of the Woom 4 a lot sooner. What would you advise would be the best choice for a beginner?