Quick answer: Height decides it, not age. Measure them. Under about 168cm and the K22 is the bike. Over 179cm and only the K47 Pro fits. Between those two numbers both of them fit, and that is the band where the decision is actually interesting. Both are private-land machines, ridden with the landowner's permission.
See the K22 → See the K47 Pro →
If you are not yet sure the bike they have is finished, start with the four checks in our upgrade guide instead. This post picks up from the point where you already know it is time.
Why age stops being useful here
Lower down the range, age is a decent shortcut. A six-year-old is usually a K7 Pro and a nine-year-old is usually a K10 Pro, and the shortcut works because children of that age are mostly a similar size.
Teenagers are not. Fourteen-year-olds arrive at wildly different heights, and two of them standing side by side can need different machines entirely. The box says 14 to 18 for the K22 and the product page says 5'6" to 6'7" for the K47 Pro, and those two statements can both be true of the same birthday.
So get a tape measure out. It takes thirty seconds and it settles the whole thing.
The three bands
Under 168cm (5'6"). The K22. It is the bike designed for this rider and the K47 Pro will not fit them, whatever they tell you. The K22's own range starts at 128cm, so there is a lot of room below them.
168cm to 179cm. Both fit. This is the overlap, and the rest of this article is about it.
Over 179cm (5'10½"). The K47 Pro. At that height they are past the top of the K22's rider height range, and the K47 Pro is the bike sized for them.
Measure to the top of the head, with shoes off, standing against a wall. Then check that figure against the rider height range on each product page before you order — the product page is the authority on sizing, and it settles arguments faster than a spec sheet does.
The two bikes, side by side
| K22 | K47 Pro | |
|---|---|---|
| Rider height | 128–179cm (4'2" to 5'10½") | 167–201cm (5'6" to 6'7") |
| Stated ages | 14–18 | Adults and taller teens — not a children's bike |
| Motor | 2000W (3000W peak) | 72V, 3,000W continuous (5,000W peak) |
| Speed modes | 25 / 35 / 55 km/h | 25 / 45 / 80 km/h |
| Range | Up to 50km | Up to 90km |
| Bike weight | 46kg | 67kg |
| Warranty | 12 months | 12 months |
One figure that is not in the table because only one of the two bikes publishes it: the K22 takes a rider up to 120kg. For most teenagers that means the bike is never outgrown on weight, only on height.
The row that matters most on a first reading is the speed modes, and it is not the one people look at. Both bikes have a bottom gear of 25 km/h. A rider stepping onto either one has the same gentle first hour available to them. The difference is at the other end, and the other end is optional.
Inside the overlap: how to actually choose
Your teenager measures 172cm. Both bikes fit. Here is what separates them.
How much growing is left. A fourteen-year-old at 172cm still has growing to do, and the K22's range runs to 179cm, so there is runway in it yet — for a rider who has not finished growing, that is usually the answer. A seventeen-year-old at 172cm has broadly finished, so you are sizing for today rather than for next summer. Same height, different answer.
Who else is going to ride it. This is the one people forget. The K47 Pro is an adult machine, so if there is a parent in the house who fancies a go, it is a bike for two riders rather than one. The K22 is built around a teenager, and an adult is not its intended rider.
How much bike they can handle. Twenty-one kilograms separates them, and weight is felt most at low speed, on a slope, and when picking the thing up after a fall. A confident rider with three years on a K10 Pro will manage either. A teenager who is new to this will find the lighter bike easier to learn on, and learning on the bike you can pick up yourself is worth more than a top speed you are not using.
What they are riding on. A paddock and a few tracks is K22 territory all day. Big open ground where you want range and a long straight is where the K47 Pro's longer range and its top mode start earning their keep.
What does not change
Neither is road legal, and both are for private land with the landowner's permission. There is no new paperwork to think about because you have moved up a size. Our guide to where you can legally ride covers the ground, and the licence and insurance post sets out what GOV.UK actually says.
Both come with a 12-month warranty and UK-based support from our own UK team. Check the current dispatch position on each product page before you order — at the time of writing the K47 Pro ships from stock and the K22 is on pre-order. The K47 Pro goes out as a two-person delivery with a booked slot, because at 67kg it is not a parcel.
Proper gear matters more at these speeds than it did on a smaller bike, and a teenager's head will usually have outgrown a youth-sized helmet. Our own helmet range is sized for children and will not fit an adult head, so that is one to buy elsewhere.
Frequently asked questions
My 15-year-old is 175cm. Which one? Both fit, so it comes down to the rest of it: whether anybody else will ride it, and how much machine they can handle. At fifteen there is usually some growing still to come, and the K22 is sized and built for exactly this rider. The K47 Pro makes more sense if they are experienced, if they are close to the top of the K22's range already, or if a parent wants to ride it too.
Is the K47 Pro too fast for a teenager? Its bottom mode is 25 km/h, the same as the K22's. A bike is as fast as the mode it is left in, and the modes are yours to set. What matters more is whether they can handle 67kg of machine.
Can they ride the K47 Pro if they are 5'5"? No. The range starts at 5'6" and it is not a figure to stretch. The K22 is the bike.
Will the K22 be outgrown? On height, only by a rider who passes 179cm. On weight it takes a 120kg rider, so for most teenagers it is the bike they keep rather than the next step on a ladder.
Can I ride the K22 myself? It is built and sized for a teenage rider, so it is not the one we would point an adult at. If you want a machine you can both use, that is the K47 Pro.
What do we do with the bike they have outgrown? Our upgrade guide covers handing it down, keeping it a season or stripping it for spares.
Can we ride together? Yes, and it is the best reason to own two. Riding with your kids sets out how to plan a day when the two bikes are not matched.
The bottom line
Measure them first. Under 168cm it is the K22, over 179cm it is the K47 Pro, and in between you are choosing on growing room, on who else wants a ride, and on how much machine they can pick up on their own.
Both are full-size bikes that a teenager grows into rather than out of — the next bike after the one that got them here.
See the K22 → See the K47 Pro →
Specifications correct as at 9 November 2026; check the product pages before you order, as they are the authority on sizing. Kubbi supplies electric bikes and scooters to over 15,000 UK families. Everything ships from our own UK warehouse with a 12-month warranty and UK-based support.