woom 4 Review

From the neighborhood to basic dirt trails, the woom 4 20 inch bike is a great all-around bike that can tackle it all. With a lightweight frame and a low center-of-gravity for easy balancing and maneuvering, the woom 4 provides a 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 woom 4 is an excellent choice for kids who need a top-notch all-around 20 inch bike. In our review, we put the woom 4 to the test with several 6 and 7 year-olds to see how it compares with other top brands.

boy riding the woom 4 20 inch pedal bike

woom 4 Bike Overview

RATING: Exceptional


BEST FOR: Beginning to intermediate riders riding a wide range of terrains and distances – from longer paved trails to basic single-track.

SEAT HEIGHT: 22.1″ – 28″


WEIGHT: 17.9 lb. (with included kickstand and pedals)

GEARS: 8-speed


GAIN RATIO: 2.3/5.9


  • Low minimum seat height for a 20″ bike allows kids to ride at a younger age
  • Wide range of gears (8-speed) suitable for long paved rides to basic trail riding
  • Low center-of-gravity geometry for easier balance and better maneuverability
  • Easy-to-use grip shifters with ergonimc grips to ease wrist strain
  • Variety of colors available


  • Headset not robust enough for really aggressive riders

woom 4 Video Review

Want to see the woom 4 in action? Check out the video below to learn why we love the woom 4 and learn how it compares in size to the larger woom 5. The woom 4 shown in this video is not the most current 2021 model, but all the information provided about the woom 4 is still acurrate.

woom 4 Bike Review – Results of our Test Rides

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 woom 4.

 young girl riding woom 4 in her driveway


While the woom 4 is great for riding around the neighborhood, is it soooo much more than your basic neighborhood bike.  We tested out the woom 4 with five different riders (ages 5 to 8) with various levels of ability and they all gave the woom 4 an enthusiastic thumbs up!

young boy riding woom 4 on a mountain trail

Our team of little testers demonstrated that the woom 4 excels on different terrains for many different types of riders. From young riders who are a little hesitant to move up to a 20″ bike,  to confident trail riders and aggressive riders ready to tackle every curb, jump or dirt mound they see, you really can’t go wrong with the woom.

Its lightweight build (17.9 lb.), adjustable height handlebars (more about that below), and low center of gravity frame work in unison to create a comfortable, confidence-building ride that kids love. About the only thing we wouldn’t recommend the woom 4 for is aggressive mountain bike riding!

Young boy riding a red woom 4 bike in a parking lot

What size child fits on the woom 4?

At 22.1″ the woom 4 has one of the lowest minimum seat heights for a 20″ bike. With the seat height maxing out at 28″, the woom 4 is generally a good fit for kids ages 5 to 8 (or kids 45″ to 51″ in height).  Shorter kids under 45″ would be a better fit on the 16 inch woom 3, while the 24 inch woom 5 provides more room for growth for kids taller than 49″.

A child’s inseam, however, is truly king when it comes to making sure you’re buying the right size bike.  In order to allow for proper leverage on the pedals, an experienced rider should only be able to touch the ground with their tip toes while sitting on the bike seat. 

The seat height should be set to 2″ to 3″ ABOVE their inseam to allow for proper leg extension while pedaling.  As a result, the woom 4 is ideal for experienced riders with an inseam ranging from 19″ to 26″ (regardless of age). 

Our primary 6-year-old tester was just over 46.5″ tall with a 21″ inseam and was a great fit on the woom 4.  To ensure an accurate fit, we used woom’s height and growth chart, which compares your child’s height to the model of woom bike that best fits them.  A thick vinyl sticker that easily mounts to the wall, it removes any doubt as to which woom bike would be best for your child.

46. 5″ tall 6-year-old on woom 4

young boy riding a purple woom bikes 4

Frame & Geometry of the woom 4

Designed specifically for kids (not just “small adults”), the woom 4 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.

Differences in Q-factor

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 efficient pedaling as kids are able to focus more of their physical effort on pushing directly down on the pedal.   As shown below with our 6-year-old tester, the woom 4 is narrower than typical 20″ bikes, making it more efficient and easier to pedal.

Narrow Q-factor on woom 4

image showing the difference in the q factor of the woom 4 versus a novara 20 inch

Lower Bottom Bracket

Where the pedals are attached to the frame of the bike 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.

Low Bottom Bracket Height on the woom 4

image showing the bottom bracket height on a purple woom 4 bike

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. .

Adjustable Handlebar Stem

A unique feature found on woom’s geared bikes is their adjustable handlebar stem. The stem allows parents to easily raise the height of the handlebars on the bike about an inch or so as the child grows in height. Raising the bars helps kids remain much for comfortable on the bike, especially as they get taller and need to seat height raised.

How it Works

The stem (the black part that connects the white headset to the black handlebars) is comprised of two metal pieces that are shaped like number 8’s.  One side of the 8 is attached to the round portion of the headset while the other side is threaded through the handlebars.

When raised, the black “8s” rotate to point upwards instead of back towards the rider. This rotation raises the handlebars about an inch max but can be fixed in place at any point in-between.

image showing the adjustable stem height on a woom bike

Raising the handlebars is quick and easy. Simply loosen the two Allen bolts that hold the stem and pull up or down on the handlebars.  Once the handlebars are at the desired height, rotate the handlebars to ensure the grips, brakes, and shifter are correctly positioned. The front of the handlebars has a “horizontal” marking on it to make sure they are correctly positioned. When the handlebars are in place, retighten the bolts.

image showing the allen bolts on the adjustable stem as well as the horizontal marker on the front on the woom's handlebars

What it Does

Raising and lowering the handlebars can significantly alter a child’s position on a bike.  Out of the box the handlebars are set to the middle position, which all of our testers preferred. 

Not too leaned forward, but not too upright, the middle position is upright enough to allow the majority of a child’s weight to rest on the saddle (kids naturally prefer to have their weight centered on their hips), while leaned forward enough to allow the rider to shift their weight through turns and while tackling hills.

Timid or beginning riders, however, may prefer the lowest stem height setting, which positions the rider in the most upright setting.  The more upright positioning is the result of the handlebars being shifted closer to the rider’s body.

how the differences in stem height on the woom 4 alters the geometry of the bike

Adventurous riders may prefer a more aggressive position, which can be created by setting the stem to its highest position. The highest position raises the handlebar by pushing the handlebars away from the child, which extends the child’s reach and creates a more aggressive body position.

woom 4’s Components

Front Fork and Tires

In addition to being a lightweight and nimble bike, the woom 4’s tires and fork help it excel in various riding 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 added weight.

In fact, most shocks on kids’ bikes are pretty worthless and act merely as eye candy. For those high-adventure kids looking for a front suspension bike, many big-name bike brands have released lightweight 20″ bikes with front suspension such as the Prevelo Zulu Three.

Whether on paved or packed dirt trails, the woom 4’s 1.4″ wide Schwalbe Little Joe tires help provide plenty of traction for dirt, yet are thin enough to prevent a significant increase in rolling resistance caused by thicker tires. 

Wrapped around woom’s super lightweight Soopa-Doopa-Hoops aluminum rims, the woom 4’s wheels are well-prepared for a variety of surfaces.  For added visibility bonus, each tire also has a white reflective strip.

Gearing and Shifting (Gain Ratio)

The woom 4 has 8 gears ranging from a 2.3 to a 5.9 gain ratio. With a wide range of gears, the woom 4 is ready to tackle hills as well as easily gain speed on flat rides. With one chainring in the back and a cassette of eight cogs in the rear, shifting is done via a grip shift on the right hand. Twisting upshifts to a higher gear while twisting downshifts to a lower gear.

For riders just getting acquainted with gears on a bike, we’ve 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 lastest 2021 woom 4 comes with ergonomic grips to help ease the strain on the wrist during long rides.

woom 4 SRAM Grip Shifters and Easy Reach Brake Levers

SRAM grip shifters and ergo grips on a geared woom bike

Narrow-Wide Chainring – 2021 update

For fewer hassles with the chain, the woom 4 now comes with a narrow-wide chainring to minimize chain slippage. Narrow wide chainrings alternate the size of the teeth on the ring to match the narrow and then wide links on the chain. This helps keep the chain smoothly rolling along without skipping or missing a link.

More details about the benefits of narrow-wide chainrings is available on the drivetrain portion of our woom 5 review.

narrow-wide chainring on geared woom bikes


Kickstands can be lifesavers for kids’ bikes, but they can also be a pain.  The vast majority of kickstands are mounted right behind the crank arms of the bike.  As a result, if kids don’t remember to put up the kickstand before they pedal, the crank arm of the bike will get jammed in the kickstand.

woom 4’s included kickstand is unique in that it mounts on the rear of the bike, away from the crank arms.  As a result, if a child forgets to put up the kickstand, they can still pedal their bike without a problem.  The kickstand will then bounce up and out of the way whenever it comes into contact with the sidewalk, grass, or anything in its path.

woom’s Kickstand

rear placed kickstand on a woom bike

woom 4 Comparisons

The woom 4 is comparable to several other higher-end bikes, including the Prevelo Alpha Three and the geared Cleary Owl. While each bike has its specific strengths, the woom 4 is our top pick for all-around riding. 

The Prevelo Alpha has trigger shifters and a more aggressive body position best suited for ambitious riders.  The Clearly Owl is lightweight and positions the rider similarly to the woom. However, it only has three speeds and its trigger shifting mechanism was trickier to use compared to the woom’s grip shifter.

WOOM 4 Comparison

FeaturesWOOM 4Prevelo Alpha ThreeCleary Owl (3-sp)
BikeWOOM 4

Prevelo Alpha Three

Cleary Owl - 3 speed

Best ForGreat all-around - best for riders of various mild terrainsIntermediate trail ridersAmbitious neighborhood & light trail riders
Weight17.9 lb.18.9 lb.19.1 lb.
Seat Height22.1" - 28"20.7" - 25.5"21" - 26.4"
Shifters8sp/SRAM Grip8sp/Shimano Trigger 3sp/Trigger
Gain Ratio2.3/5.92.1/6.7

woom 4 Review Bottom Line

The woom 4 is the best all-around 20″ bike we’ve tested. Rugged and nimble enough for moderate single-track riding, yet comfortable enough for street riding, the woom 4 is the perfect, versatile bike to take your all-terrain rider anywhere they want to go.

FTC Disclosure: Affiliate links are included in this review.  No monetary compensation was provided for this review, however, the reviewed product was supplied by the manufacturer or distributor to help facilitate this review. All opinions and images are that of Two Wheeling Tots LLC.  All content and images are copyrighted and should not be used or replicated in any way. View our Terms of Use.

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