woom bike sizes

woom numbers run 1 to 6 and map directly to wheel size: 1 is 12 inch, 2 is 14, 3 is 16, 4 is 20, 5 is 24 and 6 is 26. Pick the size whose minimum saddle height is at or just below your child's inseam. If your child sits between two sizes, take the smaller one — the saddle ranges overlap and the smaller bike is rideable from day one.

How to read the chart

Start at the saddle range column, not the age column. The lower figure is the minimum saddle height, which is the lowest the seat will go. If your child's inseam is below that number, they cannot put their feet flat on the ground on that bike at its lowest setting, and the size is wrong no matter what the age band says.

The upper figure tells you how long the bike will last. The GO 3 has 6.1 inches of saddle travel, which is the widest window in the woom range and typically two seasons of growth. The GO 2 has 3.8 inches, which is closer to one.

The two places woom sizing surprises people

The GO 3 starts higher than you expect

A 19 inch minimum saddle on a 16-inch bike is high. A Prevelo Alpha Two, the same wheel size, starts at 16.9 inches. That two-inch gap is roughly a year of growth, and it is why a small five-year-old who fits other 16-inch bikes may still be on a GO 2. Buy the GO 3 on the inseam, not on the fact that your child is five.

The jump from GO 4 to EXPLORE 5 is the biggest in the range

The GO 4 tops out at a 28.7 inch saddle and the EXPLORE 5 starts at 27.2 inches, so the overlap is real but narrow, and the EXPLORE 5 is a different kind of bike: hydraulic disc brakes, eight gears and a trigger shifter instead of the GO 4's seven-speed twist setup. That is a step up in capability as well as size.

Between two sizes? Take the smaller one

woom's ranges overlap deliberately, so plenty of children genuinely fit two consecutive sizes. When that happens, the smaller bike is almost always the better buy. It is lighter, it is easier to control, and your child can ride it on the day it arrives. The larger bike buys you a few extra months at the far end of its life, by which point the bike is too big to be fun and too worn to resell well.

The exception is a child who is clearly mid-growth-spurt and already near the top of the smaller bike's saddle range. In that case the larger size is the sensible call, provided they clear its minimum saddle today.

How woom compares on weight

The reason woom sizing gets searched as much as it does is that the bikes are unusually light for their size, so parents cross-shop them against bikes a size down. A 13 lb 16-inch GO 3 weighs less than many 14-inch bikes and far less than the 21.16 lb big-box 16-inch most children get. The full weight comparison is on why kids bikes are so heavy.

If you are deciding between brands rather than between sizes, the head-to-heads are on woom vs Guardian and woom vs Retrospec, and the general chart that covers every brand is the kids bike size chart.

Matching a woom size to a wheel size you already know

Most parents arrive at woom already knowing roughly what wheel their child is on, because that is how every other brand is sold. The mapping is direct, with one wrinkle: woom's minimum saddle heights tend to sit higher than other brands at the same wheel size, so the equivalent woom is sometimes a number lower than you expect.

That table is worth sitting with for a moment. At 16 inches the woom needs 3.6 more inches of inseam than the Prevelo does. At 24 inches the gap to the Guardian is 4.4 inches. If your child is on the small side for their age, the woom in their wheel size may genuinely not fit yet even though every age chart says it should.

GO or EXPLORE?

woom runs two lines that overlap at 20 inch. The GO line is the road-and-path bike: lighter, rim brakes on the smaller sizes, simpler gearing. The EXPLORE line adds hydraulic disc brakes and wider tires for gravel and light trail use, at a weight penalty of under a pound at 20 inch.

For most families the GO is the right answer, because most kids riding is pavement and the disc brakes are capability the child is not yet using. Choose EXPLORE if the riding genuinely involves loose surfaces, steep descents or wet weather, where the extra braking power is doing real work.

Checking a woom size without owning one

The useful proxy is their current bike. Measure its saddle height from the ground to the top of the saddle at the setting they actually ride, and compare that figure to the woom's minimum saddle height in the chart above. If the woom's minimum is at or just below that figure, it fits today and has room to grow.

If you are starting from nothing, measure the inseam. The method is on how to measure your child's inseam, and the five-step fitting process once the bike arrives is on how to fit a kids bike.

When to move your child up a woom size

Three signals, none of them a birthday. The seatpost is at its minimum-insertion mark and the saddle is still too low. The knees come up towards the handlebars at the top of the pedal stroke. Or the child has started riding with their weight well behind the saddle because the reach has become short.

Any one of those means the frame is finished. Because woom's ranges overlap at the edges, the next size up will usually already fit by the time the current one runs out, which is the practical benefit of staying within one brand as they grow.