K'Nex Serpent Spiral Roller Coaster CoasterReviewRatingChart_KNX_SrpntSpirl.jpg

Flagship of the fully motorized K’NEX® Thrill Ride product category, the aptly named Serpent’s Spiral Coaster is a great ride in every respect. Continuing in the K’NEX® tradition of “Serpent” named roller coaster products this latest entry not only embodies everything we have come to expect from this quality Pennsylvania, USA based manufacturer but also features the following upgrades from previous K’NEX® coaster models:

  1. A more compact “suitcase” style carrying case with handle.
  2. A clear plastic sorting tray which made organizing and selecting the many different lengths and types of parts far simpler than in the past. DO NOT throw away!
  3. The roller coaster train cars themselves have been greatly improved. The bodies are center articulated which, along with improved wheel design, makes for high speeds, low friction, and smooth travel over bending and twisting track configurations.

The instruction manual is accurate and easy to follow with no apparent inaccuracies or omissions and includes plans for three different roller coaster designs. The 1082 parts included with this set are of very high quality and the many different colors make part identification simple and result in a beautiful finished project. Don’t feel daunted by the minimum of eight hours required to assemble the larger 5’ 3” full size tower version of the included roller coaster designs. If the instructions are followed carefully the process is smooth, a whole lot of fun, and rewarding at the finish line. Everything goes together exactly as it should, fit and finish is exceptional and it will work as advertised.

knexssc_knex-serpentsspiral-serpent2.jpgOne signature feature of the K’NEX® Thrill Ride series is their clever use of pulleys, gears, chains, and drive shafts to comprise the various mechanisms. This trend certainly continues with the Serpent’s Spiral roller coaster.  The over ten feet of plastic chain, which must be assembled link by link and represents the only real repetitive activity in this model, works like a charm and should be completely safe even for smaller children.

The motor does require two AA batteries which are not provided by K’NEX®. Of course, if you purchase this product from our site, we DO include the batteries at no additional charge!

The only tool required is a small Phillips screwdriver for opening and closing the battery case on the motor.

Performance Test

image-knex-serpenttest.jpg.jpgThough coming up with a test to evaluate and compare the overall performance of several model roller coaster construction sets, all of which employ vastly disparate engineering philosophies to achieve their own unique appeals, is too complex for our purposes, there is a simple and fun test which can be performed.

Real world steel roller coaster trains are extremely efficient and retain a very high percentage of the energy which they accumulate upon descent. Limited only by the height and slope of the lift hill, the degree of energy retention or “efficiency” is responsible for the incredible speed and breathtaking loops, twists and turns demanded by today’s roller coaster riding (and modeling) enthusiasts. All model roller coasters are also, to varying degrees, limited by the height of their lift hill. With this in mind, the “efficiency” of the model coaster trains will also contribute to the type, complexity, and length of the model coaster circuits which can be built.

Testing what we call the “inline efficiency” of the various coaster trains can provide some indication of just how well, and accurately, they do their job. To perform this simple test, we built (or you can build) a track with identical descending and ascending slopes. (See image above) By starting the train from a fixed point on the down slope and measuring how far it makes it toward the same point on the upslope we can determine how much energy is lost and, therefore, the inline efficiency of the train. In this case, the Serpent’s Spiral achieved an admirable rating of 78% which represents a dramatic increase in performance from previous K’NEX® coaster models. This is a fun test and one which you can certainly perform at home or in the classroom.

This basic test measures only inline performance and there are many other factors which contribute to how well a model coaster train will perform. For example, the Coaster Dynamix® Scorpion train is the only one tested which has wheels on the sides of the rails, as well as above and below, which will certainly provide superior performance around curves. Our intent is simply to suggest a testing benchmark common to all manufacturers. (The layout in the picture above is not a fully functioning roller coaster and was built only to perform this test.)


The fun doesn’t need to end with just the three roller coaster designs featured in the manual. The clever track segment design and flexible structural engineering inherent in the K’NEX® parts palette certainly lend themselves toward creation of one’s own custom roller coaster designs. As the name implies, the Serpent’s Spiral roller coaster as presented is based on a vertical tower with the track spiraling down from top to bottom. It is, however, certainly possible to build awesome, more conventional, horizontal roller coaster designs as well. One of the smaller designs included in the manual gives you a simple introduction to this concept and provides an inkling of the creative possibilities offered by the K’NEX® system.

We provide links to other K’NEX® roller coaster enthusiast’s sites for examples of custom designs and encourage you to visit these sites for inspiration and ideas. Of course, we also encourage you to turn your creativity loose and to share your own designs with our community of model roller coaster enthusiasts through submission to our site. Warning: You may find that just one Serpent’s Spiral roller coaster set is not enough!

Due to some fairly small parts this terrific construction toy is rated for kids nine and above though, with adult supervision, could certainly be an appropriate family activity involving younger children as well. 

We are interested in hearing about building experiences with this model and would like to share your impressions with other visitors to our site.

*Categories are rated on a scale of from one to ten where applicable and reflect only the opinions and experiences of our staff. We provide these ratings only as a guideline to aid you in your product choices. Your building experience may vary.