Updated through August 2026.
The K’NEX Big Air Ball Tower is an unusual Classic K’NEX ball machine. In addition to standard rods, connectors and other Classic parts, it uses a specialised system of large tubes, flexible tubes, clamps, ball-routing parts and an Air Motor.
The Big Air system is particularly interesting because balls are transported through large tubes using airflow, rather than relying only on conventional mechanical ball lifts.
Several product numbers are known for the Big Air Ball Tower, including 63170, 63172 and 63184. Set 63172 was marketed as the Ultimate Big Air Ball Tower. The known versions are closely related, but differences in packaging, graphics and production should only be assigned to a particular version where they can be confirmed.
How the Big Air system works
The Air Motor provides the airflow needed to move the large K’NEX balls through the tube system.
Special parts guide the balls into and out of the tubes, while holders and clamps position the tubes within a structure built largely from standard Classic K’NEX parts.
Other specialised parts, including a chute, trampoline and basket, continue the ball’s route through the model.
Special Big Air Ball Tower parts
| Function | Part number | Part |
|---|---|---|
| Air system | 99075 | Air Motor |
| Straight tube | 99077 | Tube, 25.4 cm |
| Straight tube | 99078 | Tube, 28.5 cm |
| Straight tube | 99079 | Tube, 7.9 cm |
| Flexible connection | 99074 | Flexi Tube, Orange, approx. 9 cm |
| Flexible connection | 99076 | Flexi Tube, Orange, approx. 11 cm |
| Tube mounting | 99069 | Tube Holder, Orange, 3.8 cm |
| Tube mounting | 99070 | Tube Holder, Orange, 6.3 cm |
| Tube mounting | 22511A | Medium Clamp, Black |
| Tube mounting | 22511C | Large Clamp, Black |
| Ball entry | 22561 | Entry Trough |
| Ball routing | 22541 | Chute |
| Ball exit | 99073 | Exit Spout |
| Ball handling | 99071 | Trampoline, Orange |
| Ball handling | 99072 | Basket, Orange |
| Ball | 22526 | K’NEX Ball, approx. 50 mm |
Some of these specialised parts were also used in other K’NEX models. Their appearance on this page therefore indicates their use in the Big Air system, not necessarily that they were exclusive to it.
Straight Tubes
Big Air uses large-diameter straight tubes in several lengths:
| Part number | Length |
|---|---|
| 99079 | 7.9 cm |
| 99077 | 25.4 cm |
| 99078 | 28.5 cm |
Clear tubes are associated with the Big Air system. Other K’NEX tubes were produced in colours including yellow and blue, but similar dimensions alone do not establish that a tube originally belonged to a Big Air Ball Tower.
Translucent plastics can also change appearance with age. Colour should therefore be considered together with length, construction and set context when identifying a loose tube.
Seamed and Seamless Tubes
K’NEX tubes have been found in two visibly different constructions.
Clear Tubes
The Ultimate Big Air Ball Tower 63172/63184 uses three sizes of clear tube. The original parts inventory distinguishes between standard clear tube and “Clear Tube (with groove)”.
| Quantity | Length | Type |
|---|---|---|
| 1 | 3⅛” (7.9 cm) | Clear Tube (with groove) |
| 1 | 10″ (25.4 cm) | Clear Tube |
| 4 | 11⅜” (28.7 cm) | Clear Tube (with groove) |
The groove is a visible longitudinal feature running along the tube. It is therefore an identification characteristic of the tube itself and should not be confused with ageing or discolouration of the clear plastic.
Tube construction and tube colour are separate characteristics.
Flexi Tubes
Two short orange corrugated tubes allow bends in the air path:
| Part number | Length |
|---|---|
| 99074 | approx. 9 cm |
| 99076 | approx. 11 cm |
Their flexible construction allows connections that would be difficult to make with a rigid straight tube.
Tube Holders & Clamps
The large tubes need specialised supports to integrate them with the surrounding Classic K’NEX structure.
Tube Holders
The Ultimate Big Air Ball Tower 63172/63184 includes two different orange Tube Holders:
| Quantity | Part | Size |
|---|---|---|
| 1 | Short Tube Holder | 1½” (3.8 cm) |
| 1 | Tall Tube Holder | 2½” (6.3 cm) |
The two holders differ not only in height but also in their attachment arrangement. They support and position the large-diameter tube system within the surrounding Classic K’NEX structure.
| Part number | Part |
|---|---|
| 99069 | Tube Holder, Orange, 3.8 cm |
| 99070 | Tube Holder, Orange, 6.3 cm |
| 22511A | Medium Clamp, Black |
| 22511C | Large Clamp, Black |
The holders and clamps are therefore an important part of the Big Air system even though the balls do not pass through them.
The Large Clamp is also known from other K’NEX models and should not be regarded as exclusive to Big Air.
Entry, Chute & Exit Spout
Several shaped parts control the transition between different stages of the ball’s route.
22561 Entry Trough guides the ball towards the air-powered section.
22541 Chute provides a shaped route for the moving ball.
99073 Exit Spout provides a transition as the ball leaves part of the tube system.
These unusually shaped parts can be particularly useful when identifying incomplete Big Air sets or loose collections of K’NEX parts.
Trampoline & Basket
Two of the most distinctive Big Air parts are:
| Part number | Part |
|---|---|
| 99071 | Trampoline, Orange |
| 99072 | Basket, Orange |
The Trampoline redirects a moving ball, while the Basket receives or guides a ball during another stage of its route.
Both form part of the specialised ball-handling system.
Air Motor
99075 is the specialised Big Air Ball Tower Air Motor.
Its purpose is to generate airflow for the tube system. It should therefore be distinguished from conventional K’NEX motors whose principal function is to provide rotating mechanical drive.
For other motor and power systems, see K’NEX Motors & Power.
Balls
Big Air uses large K’NEX balls of approximately 50 mm diameter. Part number 22526 is associated with this type of ball.
Balls – check the size
The Big Air Ball Tower uses 50 mm K’NEX balls.
K’NEX also produced smaller balls of approximately 45–46 mm for other sets. These can look very similar, and both sizes may have a two-part construction. The smaller balls should therefore not be confused with the 50 mm Big Air balls.
Important: when identifying a loose ball for the Big Air Ball Tower, check its diameter. A K’NEX ball of approximately 45–46 mm belongs to a different application and is not the correct Big Air size.
The Ultimate Big Air Ball Tower also includes the distinctive clear 50 mm ball containing a figure.
Different colours and versions of approximately 50 mm K’NEX balls are known, and similar balls were also used in other K’NEX ball machines. Diameter or colour alone should therefore not be used to identify a ball as exclusive to Big Air.
The wider range of these balls can be covered separately under Classic K’NEX Balls.
Known Set Numbers
The Big Air Ball Tower is known under several product numbers, including:
| Set number | Name |
|---|---|
| 63170 | Big Air Ball Tower |
| 63172 | Ultimate Big Air Ball Tower |
| 63184 | Big Air Ball Tower |
The Ultimate Big Air Ball Tower 63172 dates from 2004 and contains 1,367 parts.
The known versions are closely related. Differences in packaging, production runs, tube appearance or individual components should not be attributed to a particular set number unless that difference can be established.
Building Instructions
Original building instructions are known for the Big Air Ball Tower.
Where a digital version is available, it can be found through the K’NEXCHANGE Building Instructions index.
Two different graphic pieces are known:
| Identification | Description |
|---|---|
| 63172/63184/11 | Orange Big Air Ball Tower graphic panel |
| 63172/63184/12 | Orange Big Air Ball Tower graphic panel |
K'NEXCHANGE 