Kartbuilding Blog: Regular Tips & Information on Building Karts
GoingKarting.co.uk: This website offers great tips and advice to help you get the most out of go-karting. There is some good general knowledge on karting, with all types of karts (pedal to petrol etc.) been covered for both young and old. It also has information on setting up a karting meeting.
Worth a look.
Tony Kart produces high quality racing kart chassis. A catalogue of their kart chassis can be found on their website. A particular chassis model, a Tony Kart Extreme ’97, was modelled using SolidWorks, and is available for download. Below is an overview of the chassis, in isometric and in a plan view.
This chassis is modelled perfectly in SolidWorks, with each member as an individual part and fully in-context. With the complete assembly and part files, it would be very easy to create 2d drawings of the chassis. The chassis is full size, so no scaling would have to be carried out.
Perhaps in the future the author will complete a fully dimensioned chassis using SolidWorks. Please contact the author if you have any queries etc. regarding this.
The SolidWorks assembly file can be downloaded from its original location here, along with some other CAD drawings also. A backup local copy of the SolidWorks chassis is also available.
In case you don’t have a copy of SolidWorks to open and measure the components, the eDrawings viewer can be used to open the chassis, measure each component, and create a section view through the chassis. The chassis opened in eDrawings can be seen below:
Download the Tony Kart Chassis ’97 eDrawing
Note: the eDrawings download of the chassis contains a self executable viewer application.
Hopefully the detailed professional chassis design will give you ideas on how to design and create your own chassis. An idea of the size of the chassis design can also be obtained using the eDrawing. Best of Luck!
If you have any queries or comments, please email them to the author at: 
Edit: A few people emailed me asking for the above Tony Kart in AutoCAD DWG Forma: PDF Format of Tony Kart | DWG Format of Tony Kart (in a Zip File) | STEP Format (in a Zip File)
The following website (http://www.vintagekarts.com/karts.htm) has some excellent photos and articles on old vintage go-karts. These karts were made using the basic necessities, and still achieved high speeds with excellent cornering and handling. Several ideas can be taken from these vintage karts where there were “no frills” to building gokarts. Ideas which can be combed from the gallery of photos include:
View more photos here: http://www.vintagekarts.com/gallery.htm
There are also some excellent in-depth articles about the history of karting, right up to the current day! Some of the topics discussed include:
Hopefully this website will provide further insight and details as to how simple engine powered gokarts were and can be made. If you would like your karting website reviewed and mentioned here, or if you have any comments on this or any other article, please contact the author by email at
The following well produced video shows the stages involved in making a Go-Kart using the Dirt Devil kart plans. The stages shown in the video below are:
A lot of parts were taken from a quad and an other working go-kart! The suspension seems to work very well, however the camber angle on the front wheels seems too much. The front wheels are splayed out sidewards. Perhaps this is the suspension, but ideally this would need to be readjusted. Read more on camber angles here.
The CIA (Commission Internationale de Karting) is the specialised Karting commission of the FIA, the governing body of world Motor Sport. The CIA oversees Karting safety in conjunction with the FIA and with a Research Group exclusively dedicated to Karting.
The CIA publish Technical Regulations for Karting, which includes detailed Drawings and specifications. In their most recent publication (2007), detailed drawings showing measurements and designs for Kart chassis are included.
The drawing above shows actual sizes (metric also!!) of Karts and provide an excellent guide to building a Kart complete to regulation!! Many people, including myself develop free kart plans, and overlook the wealth of information and diagrams offered by Karting Authorities such as the CIA.
Original Reference Hyperlink to CIA’s 2007 Technical Regulations
Saved local copy of the CIA_2007_Technical_Kart_Regulations
Some more Drawings from the above Technical Regulations can be seen below:
There are three different factors when deciding on the Steering Geometry for Go-Karts. Those are:
This article covers the above three factors in relation to Go-Karts with no suspension, and outlines typical angles and geometry which should be used. The information for this article is taken from “The NatSKA Guide to Karts and Karting” and is currently available on ebay! The off-road kart plans, and racing kart plans on this website, take into account these steering geometry angles and match the values in the above Guide.
The (1) Stub-Axle, (2) n shaped Yoke, (3) King-Pin Post make up the essential parts of the steering.
The King-Pin Post is attached/welded to the chassis.
The n shaped Yoke pivots/hinges on the King-Pin Post.
The Stub-Axle is attached to the n shaped Yoke.
These three parts are welded/attached at various angles to make steering easier on a kart. The practical side/making of these parts are not discussed here, and instead just the theoretical setup.
This is the inclination of the King Pin whose top leans in a backwards direction towards the rear of the kart. This is the most important factor governing how the kart will handle. This is however, interrelated with the other angles. In the case of the King Pin inclination, the greater the angle, the greater the “jacking effect” on the chassis, and the greater the oversteer the kart will develop. If there is too little, the kart will tend to understeer. The greater the angle, the heavier the steering and tendency to self-center. In practice, many people settle for angles between 20 and 25 degrees.
This is the inclination inwards at the top of the king pin towards the center of the kart, and it is aimed at counter-acting the jacking effect of the castor: at the same time it helps to produce a stronger joint, which will be able to withstand higher shearing forces. Generally this angle is between 10 degrees and 12 degrees, and to allow the wheels to stand flat on the floor, is offset by a similar angle on the stub axle.
This refers to the placement of the steering arms (when viewed from above), in relation to the chassis, and the rear axle. Ideally, lines projected through the center of the King Pins, and through the bolts holding the track rods, should meet at the center point of the rear axle. The effect of this is that the inside wheel always describes a smaller radius arc than the other wheel, when the kart is being turned – this is most especially important at low speeds, and on tight corners. The length of the steering arm, in relation to the spade/drop arm, effects the “speed” of the steering reaction. A long steering arm causes slow but very light steering, whereas a short arm causes quick steering but requires greater effort.
Correct Placement/Arrangement of n shaped Yoke
As can be seen from the following image, there are two possible arrangements of the n shaped Yoke. It can be attached to the chassis, or it can be attached to the stub axle (recommended). It is recommended that you attach the “King Pin Post” to the chassis, and that the n shaped yoke is attached to the front stub axle. This will make it easier if you are installing brakes on the front wheels. It also provides for greater clearance for the steering arm.
The problem with installing the n shaped Yoke on the chassis, is that when attempting to achieve “full steering lock” the steering arm hits off the n shaped Yoke. This was found on a previous kart and a notch had to be removed from the steering arm to allow for extra steering lock.
Conclusion
There does be a lot of debates regarding the ideal steering setup for karts, and especially when deciding on the actual angles to use for King Pin Inclination (KPI), Camber Angles and Castor Angles. All these angles are interrelated and allow for a Go-Kart with no suspension and a solid live rear axle to steer smoothly. If you have any comments, questions or queries about this article, feel free to email me:
EDIT: There is also an excellent article cover some of the above, and also toe-in and toe-out on Racing Cars (Formula 1 etc.) http://www.ozebiz.com.au/racetech/theory/align.html
EDIT: Another excellent article with interactive Flash Diagrams http://www.bcot1.com/karting/ (local)
PopularMechanics is well established magazine, and has an excellent website where there are two very good articles under the theme of kartbuilding:
This article describes how a Rotax Go-Kart with a 34hp two-stroke engine of a mere 125cc! can achieve 100mph!! Including the driver, the total weight of the kart comes to only 300 pounds (or 136kg), with dual disc brakes on the rear axle, and disc brakes on each front wheels.
The Go-Kart has an amazing transmission. It has a 2 speed direct drivetrain which is chainless and shifts electronically via two large paddles mounted onto the steering wheel. There is an electric starter which can also move the kart in reverse!!
Overall its an excellent article with some very informative and detailed photos, and well worth a look. If you don’t have the $8000 money to buy it, you might at least get some good ideas! The article again is located at: http://www.popularmechanics.com/outdoors/adventures/1278136.html
Although this article was written in 2000, it contains some up-to-date details and information on the transmission and capability of an ATV (All Terrain Vehicle). Details on the “Hondamatic” transmission providing engine braking are included, along with Limited Slip Differential are included! This article is definitely for the off-road enthusiast.
There are no exact details on the engine specs or the costs. There is also a hayes owners workshop manual available for this ATV. Perhaps some of the technology could be taken off one of these ATVs and transplanted into a Off-Road Kart.
The article again is located at:
http://www.popularmechanics.com/outdoors/adventures/1277601.html
Recently, a person emailed me (kartbuilding[at]gmail.com) asking about the “factor of safety” (FoS) required when undertaking calculations to design and make a go-kart. The “factor of safety” is the maximum force and stress a kart can possibly undergo, multiplied by a suitable factor/multiplier. Ideally if the maximum force and stress a kart can endure is calculated, then this factor gets multiplied by the factor of safety.
Having a FoS of 1, means that a Go-Kart is not “overengineered”, and nothing extraordinary will occur. It is when the “extraordinary” or unthinkable happens, that the FoS comes into effect.
Quantifying the FoS for a Go-Kart is not an easy task! It certainly cannot be applied to the entire Go-Kart, but parts of it, e.g. the chassis, transmission, brakes, etc. The same FoS cannot be applied to the chassis in every Go-Kart. The purpose and category of Go-Kart must be firstly determined. I.E. is it a racing kart and in what category of racing kart? Once the category and type of Go-Kart is determined, then a FoS can be obtained.
NatSKA (The National Association for School and Youth Group Karting) governs the sport and activity of karting in schools throughout the United Kingdom. The association holds race meetings run under strict regulations of its governing body (Motor Sports Association), and periodically publishes a Handbook and Regulations. The most recent Handbook and Regulations (2007) outlines the various “classes” of karts, and range from Class 1 (50cc Single Ratio Open) to Class 16 (Honda C70, C90 and C90 Cub Gearbox). Specific specifications (including safety) are outlined for areas of the kart. The following is an edited exerpt from the NatSKA Kart Regulations on chassis design:
The chassis in general shall be of safe, sound and adequately strong construction and shall not include any components of a temporary nature. Specifically, the wheel base is to be a minimum of 101cm and maximum of 127cm. The maximum length of the kart, including bodywork shall not exceed 210cm. No kart is to weigh more than 100kg without the driver.
I highly recommend that the NatSKA handbook and regulations are read and followed, especially if other people are driving and racing your Go-Kart. At the very least, excellent safety guidelines are outlined.
If you are designing your own Kart on a CAD system etc. some software will allow you to carry out “Stress Analysis” of components. Some examples of CAD software packages are: Solidworks and Cosmos, Pro-Engineer and Pro-Mechanica. These software packages will allow you to carry out simulation of kart components, allowing you to place particular loads throughout, and calculate a FoS automatically! If you are heavily involved in design and analysis of karts, this CAD software will speed things up, and provide a wealth of information.
As an example of the amount of information and the ease at which CAD software can calculate the FOS, a stress test was carried out on a Front Stub Axle from a Go-Kart, as can be seen in the image on the left. The entire CAD HTML Stress Analysis is also available. The plans for this “Front Stub Axle” are contained in the Complete Set of Racing Kart Plans.
This test, taking a total of 10 minutes to model and analyse, found that, if a loading of 50 kilograms were placed onto the steering arm, that the resulting Factor of Safety would be 1.466. Therefore, this Front Stub axle is slightly overdesigned. An in-depth knowledge of the individual forces involved in a Go-Kart would be required for an entire Stress Analysis.
In doing some research on Factor of Safety for Go-Karts, I came across an “Amusements Devices Act” which makes specific references to Go-Karts and the required Factor of Safety! Although the act (legally binding), has been superseded by a later document, the numbers and references are interesting to see. Part IV of the above act, pertains specifically to Kart Design! An excerpt of its legal requirements are:
Various universities are taking part in “Formula Student” lots of readily available information about building advanced racing Cars is available. Two excellent reports on designing formula racing cars can be found here and here. The latter document has a section on “Factor of Safety Development”.
The materials used, and the forces involved make the calculations for FOS quite difficult. CAD software makes things much easier, allowing you to select the materials from a drop-down menu, and allowing you to apply forces wherever you require. CAD software will also allow you to change material thicknesses to achieve an optimum FOS, and weight balance.
Using your common sense, and reinforcing areas which would potentially fail in a collision will go a long way in having a robust Go-Kart.
If you have any queries or questions, drop me an email or leave a comment below.
For a long time, the transmission and drive webpage on the kartbuilding.net website has been lying idle, and unfinished. This article covers one of the unfinished articles, “One single gear, using a centrifugal clutch, and chain drive.”.
The Centrifugal clutch is one of the most popular and simple methods of transmitting power from the engine to the rear wheels in a go-kart/go-cart. This type of clutch is fully automatic, and works depending on the speed (revs) of the engine. If the engine is turning over very slowly, then the centrifugal clutch is disengaged, and the kart comes to a stop. If the engine speeds up (increase Revs Per Minute rpm) then the automatic clutch will engage, and the kart will move forward.
These types of clutches can get very technical, in terms of power and speed ratings. There are numerous types of clutches available, with various “inner bore diameters”, “horsepower ratings”, “RPM engage\disengagement ratings”, “sprocket & chain sizes”. It is advisable to find out the essential information for your engine, if you are going to buy one of these centrifugal clutches. The small sprocket which comes attached to the “Bell Housing” needs to match the pitch and width of your large rear sprocket on the rear axle of the go-kart.
The best places to get/buy these types of clutches are: your local karting arena, ebay, www.northerntool.com, www.cometkartsales.com. Don’t go and buy the first Centrifugal clutch you see. Shop around for a cheap quote. Also – try and get a typical and well known clutch (especially of you are buying a brand new one), as the “friction shoes” tend to wear quite quickly depending on your gear ratio. Comet type centrifugal clutches are the most well known brand.
Once you have obtained a suitable Centrifugal clutch, and depending on whether it has the correct “inner bore diameter”, fitting will be relatively straight forward. As mentioned earlier, there are 2 pieces/components to the Centrifugal Clutch: the Bell Housing, and the Center Shaft.
The bell housing goes onto the engine shaft first, with its concave bell housing facing outwards. This bell housing spins freely on the engine’s shaft, so make sure to put some grease between the inner bore diameter of the housing and the outer diameter of the engine shaft. Push the bell housing in on the engine shaft as far as possible (until it hits the flange on the engine).
The Center Shaft with its Friction shoes is placed onto the engine next. There should be a “keyway” cut into the inner diameter of the clutch shaft which should align with a keyway in the engine’s shaft. This keyway makes sure that the “Center Shaft” will rotate with the engine. To stop the “Center Shaft” from slipping out off the engine shaft, there is a hole to allow a “grubscrew”. A grubscrew is where a threaded small bolt will screw through the Center shaft and tighten in on the engine shaft. You may or may not receive the rectangular metal “key” with the centrifugal clutch or not. I suggest you visit a lawnmower repair shop or a hardware store to obtain a suitable “key”. Below is a photo of the Centrifugal clutch transmission complete. A plastic chain guard can also be seen. If your engine does not have a keyway, and perhaps has another PTO (power take off) Shaft Type(s) as can be seen here, then you may have to resort to welding the “Center Shaft” to the engine’s output shaft. This should only be done as a last resort.
On Centrifugal Clutches, the small sprocket attached to the “Bell Housing” has typically 10 teeth (although this can vary). As a rough estimate, a gear ratio of 5:1 is needed for a standard/typical go-kart/cart, with a 5hp engine running at 3500 rpm, and with rear wheels of diameter 300mm or 12inches. The speed of the go-kart can be calculated based on this “gear ratio” combined with rpm of the engine and diameter of the rear wheels (Calculate speed of go-kart). A large sprocket with 50 teeth for the rear axle can be difficult to obtain. Ask for this large sprocket at the time you are buying the centrifugal clutch and it will save a lot of looking.
Instead of buying a purpose go-kart centrifugal clutch, it is also possible to get similar centrifugal clutches in “chainsaw engines” and “mopeds/scooters”. Although these types of clutches were not designed specifically for a go-kart it is possible to adapt these to suit a different engine. As can be seen in the photo on the left, a smaller “inner bore diameter” will be found in clutches from chainsaw engines. Also, instead of a small drive sprocket attached, there will be a special star shaped sprocket, which typically drives a cutting chain. A small drive sprocket will instead have to be welded to the “Bell Housing”.
Inside mopeds/scooters there are also centrifugal clutches, however these are slightly different in the fact that they are “wet clutches”, where the “Bell Housing” and “Weighted Center Shaft” run in an oil bath! It might seem impossible at first that a clutch can run in oil, however the oil keeps the clutch cool and free from maintenance. Again similar to the chainsaw type centrifugal clutch, there will have to be adaptations done, as there will be a “Splined” inner bore which will need to be drilled out to suit the engine’s output shaft.
In some mopeds/scooters there are 2 centrifugal clutches each which engages at different rpm of the engine. Therefore when the scooter is going slow and the engine is slow, the first centrifugal clutch engages. This provides a high gear ratio giving extra torque at low speeds. When the moped is moving at an average speed, and the engine turns faster, the second centrifugal clutch with a lower gear ratio kicks in and changes the gear ratio. This setup is very complicated involving a ratchet type free wheel system and is not feasible for use on a kart. It is possible to adapt and use one of these clutches however on a kart.
Having a clutch in a kart allows for great freedom, where the engine can be started and the kart can remain stationary. It also allows the driver to stop the kart without having to turn off the engine. Depending on the weight of the kart, the speed and power of the engine, a centrifugal clutch may not be ideal, but it will work. It is the most effective and simple Single Gear Transmission for a Go-kart. It is referred to as a “Single Gear Transmission” because there is only 1 speed and 1 gear ratio that the kart can go at. As a result of there been only 1 gear ratio, there has to be a hard line drawn between fast take off speed and high end speed.
If you have any comments or queries on this article, feel free to contact the author at: kartbuilding [at] gmail.com
A person attempts to drive a go-kart fast enough in order to make it disappear! The go-kart, ontop of a parking garage in Las Vegas is driven towards three people with fire extinguishers, and as the CO2 is discharged, causing a cloud of smoke, the go-kart vanishes into thin air!
Incase you were fooled in the above video, the go-kart didn’t disappear. The following website shows how a mistake in the camera angle, combined with slow motion playback, reveal the true outcome of the go-kart.