Drivable 3D Printed Mario Kart Go-Kart V2.1

This project originated from my fascination with Mario Kart on the Nintendo Switch, and its design prioritizes the feasibility of open-source replication. Please read the text below before commencing this project.

Important: This is an exceptionally large project, requiring a significant time and financial investment to complete the replication!

Preface:

The vehicle in this project is constructed using a framework of carbon fiber tubes and 3D-printed connectors made from engineering-grade filament using FDM technology.

Below are videos of previous vehicles built using the same structure

I. Single-speed road bicycle (PPA-CF components): https://www.bilibili.com/video/BV1Fo15YcEXX

II. VPP-structured mountain bike (ABS-GF components): https://www.bilibili.com/video/BV1WCfbYVEeb

III. Go-Kart V1 based on standard go-kart components (PA6-CF components): https://www.bilibili.com/video/BV1nyEszNES8

The Go-Kart V1 design is now open-source➡️https://makerworld.com/zh/models/1629021-go-kart-v1-1-carbon-fiber-tubes-and-nylon-3d-print#profileId-1720255

Its popularity surpassed my expectations, but frankly, the V1 design did not consider open-source feasibility. For instance, the rear axle assembly, a core component of V1, was highly integrated and lacked precision. I myself had to undergo numerous adjustments, compensating for manufacturing inaccuracies using shims, to complete the vehicle's construction. In the V2 version, therefore, I minimized the use of specialized go-kart components, instead employing readily replicable 3D-printed parts, tubing, and standard components with easily controlled machining tolerances.

The vehicle was initially designed based on a traditional go-kart structure without a rear differential (due to the 10-degree kingpin inclination of the front wheels, the inner rear wheel lifts during turns, releasing power to assist cornering). Furthermore, the H-shaped chassis, constructed from carbon fiber tubes and PA 3D-printed components during the construction of the Go-Kart V1 version, provided excellent shock absorption. I aimed to combine these elements, and during the design phase, I did not foresee any issues.

However, during vehicle testing, I discovered a conflict between these elements. The height difference between the left and right wheels during turns was absorbed by the flexible chassis, preventing the rear wheel from lifting and thus compromising the cornering experience.

This proved troublesome. I attempted to add extra carbon fiber tubes, tie rods, and other devices, simulating their effect on the chassis using Altair Inspire, without significant improvement, until I tried installing a 15mm thick carbon fiber plate horizontally and upright beneath the main chassis beam under the seat. This addition enhanced the chassis stiffness by 880 newton-meters per radian, a result I found highly satisfactory.

After weighing driving and riding comfort, I should clarify that using aluminum tubing might yield a superior driving experience for this project. This includes replacing the aforementioned 15mm carbon fiber reinforcement plate with an aluminum plate. However, lacking testing with aluminum tubing, I will still refer to the tubes as carbon fiber tubes in the materials list below.

This project's go-kart uses 40mm outer diameter, 2mm wall thickness, and 30mm outer diameter, 1.5mm wall thickness carbon fiber round tubes (T300) as the chassis framework.

Components printed from H2D and PA6-CF material serve as connectors and structural components; parts made of ABS-GF material are used for decoration and cladding; PETG-CF+TPU is used for the integrated 3D printing of the front wheel assembly via AMS.

Road testing (driver 183cm, 82kg) verified that the structural strength is adequate and possesses considerable reserve strength.

This project has been released as a video on Bilibili:

The current design has evolved to version V2.1

V2.1 specifications

1. Added a chassis reinforcement component under the seat

2. Replaced the steering rod from a hexagonal carbon fiber tube to a metal hexagonal tube

Preparatory Work:

➡️Go-Kart Components

30mm diameter, 900mm long solid rear axle with 6x3 keyway x1

https://e.tb.cn/h.hOmuBzRRiv3aP90?tk=1r7D4VACVCA

Regrettably, I couldn't find an exact match for this rear axle in North America, but I found a seemingly similar kit on eBay

https://www.ebay.com/itm/205140649784?

Its shaft is 100mm longer than mine. This kit includes the bearings and gears needed for this project, and the aluminum tire mounting bracket should theoretically be superior to a printed one (though it will still necessitate discarding the brake disc and its mounting bracket).

My shaft is quite simple—a 900mm long, 30mm diameter solid shaft with four keyways for mounting the two rear wheels, brake mounts, and gear mounts. You can simply purchase a plain shaft and machine a through keyway to address this.

Rear axle bearing to fit 30mm round shaft x2

https://e.tb.cn/h.hmbZ7nbazO7hfez?tk=yY1k4VABkSh

I found this component on eBay; the dimensions are compatible.

https://www.ebay.com/itm/114702313582?

Rear axle 32-tooth 428 split gear x1

https://e.tb.cn/h.hONY9WCyJo9Jr2G?tk=2JS94VAAjDX

I found this gear on eBay; it's compatible with two keyways, 31 teeth, and should be usable.

https://www.ebay.com/itm/126481903809?

Pair of front wheel handlebars

https://e.tb.cn/h.hOmxnOjMVgtzvyo?tk=oeFL44aZNQb

This one appears to have the same dimensions.

https://www.ebay.com/itm/277180035004?

Pair of 210mm long steering tie rods with ball joints, secured with 8mm screws

https://e.tb.cn/h.hOQlCNY3MFntr6K?tk=gvmB44aXWVj

This seems usable.

https://www.ebay.com/itm/286212039902?

Pair of 10x4.50 tires, 5-inch 3-hole hub go-kart wheels

https://e.tb.cn/h.hONYxjJHWJVPRb2?tk=CDui44a3wS4

Tires and hubs are generic; I won't provide links for North American purchases.

Go-kart seat

https://e.tb.cn/h.hmbD89AClKNdhRk?tk=v8rM44aD3Zu

This is identical to the one I purchased.

https://www.ebay.com/itm/353780728828?

➡️Hardware (Since these are standard components, I've only provided links for mainland China)

6203-ZZ bearings x4 for front hub

htts://e.tb.cn/h.hONnl543R5RotEw?tk=x62u44a9MzO

6004-ZZ bearings x2 for steering column

https://e.tb.cn/h.hONqxLs02I2kzTB?tk=2FlY44annT0

Hexagonal aluminum tube with 16mm opposing distance, to be used as the steering column

https://e.tb.cn/h.hmbBe5Ppul4C20X?tk=ZgLz44ayeLG

➡️Chassis Tubing

I used carbon fiber; you may try aluminum alloy.

40mm outer diameter, 36mm inner diameter tube, 1100mm x2

30mm outer diameter, 27mm inner diameter tube, 322mm/592mm/642mm/750mm/750mm/456mm/456mm/456mm

Total of 10 tubes

Additionally, acquire some 7mm carbon fiber tubes, cut into 90mm lengths; approximately 20 are needed.

➡️Bolts and Nuts (8.8 grade is sufficient for securing composites and 3D-printed parts) (Since these are standard components, I've only provided links for mainland China)

All bolts and nuts mentioned below are sold in pairs (matching nuts are required; locking nuts are recommended).

It's advisable to purchase at least 10% more of each type of hardware component.

Brake disc M5*40 hemispherical head x6

Brake disc fastener M5*30 hemispherical head x4

Brake caliper mount M6*45 cup head x2

Rear axle nylon fastener M5*120 hemispherical head x8

Crossbeam nylon fastener M5*100 hemispherical head x8

Motor mount M8*25 hemispherical head x2

Motor mount bracket M5*50 hemispherical head x2

Seat mount M5*30 x2, M5*50 x2 hemispherical head

Front axle fastener M10*140 hemispherical head x8

Steering column screw M5*50 hemispherical head x2

Rear wheel fixing screw M8*65 hex x6

Rear wheel flange locking component M5*30 hemispherical head x2

Front bumper through-bolt M10*140 hemispherical head x2

Throttle pedal hemispherical head M5*40 x2

Brake pedal reinforcement screw hex M12*120 x1

Steering wheel installation and flange locking component hemispherical head M5*30 x4

Steering tie rod M8*50 hemispherical head x4

➡️Drive System

500W 36V 1020 motor, requiring a 428 gear

https://e.tb.cn/h.hO9pqdw9UFhsRp7?tk=BKaW44ZeRM3

Controller to match the motor

https://e.tb.cn/h.hO9pqdw9UFhsRp7?tk=BKaW44ZeRM3

I found an identical motor and controller on eBay.

https://www.ebay.com/itm/195831936268?

Makita 18V battery power tap x2 (for power extraction only; not essential)

https://e.tb.cn/h.hOnXHte3R1fKCwq?tk=pgz244Z4jTx

I use two Makita brand 18V power tool batteries connected in series to drive the rear axle motor. All related equipment is wired to the side box on the left side of the vehicle.

After careful consideration, I opted for higher flexibility in the electrical components, creating a large side box. You can determine your desired drive components and neatly house them within the side box.

Go-kart throttle pedal

https://e.tb.cn/h.hO9IX9Cury1qLea?tk=3cdg44ZfIRc

I found an identical one on eBay.

https://www.ebay.com/itm/235556599640?

428 chain, approximately 40 links required (this is a standard part; links for overseas customers will not be provided).

https://e.tb.cn/h.hO9HXt3RWi2SkSy?tk=QnNL44ZU95M

➡️Braking System

Shimano MT200 brake kit (requires reconnecting oil lines and bleeding during assembly)

https://e.tb.cn/h.hmYOXaZ8oRJjv9X?tk=TF0f44ZPlxb

This is also a standard component; purchase a right-hand brake lever and a front brake caliper, along with approximately 3 meters of brake line and related components for brake line fabrication.

➡️Additional Fan Power

12V 8085 server fan x4

https://e.tb.cn/h.hOnnOQmaccmT9tU?tk=ZO5w44ZQMmK

This is a standard component, used in this project to enhance sound effects.

I use a 3S model aircraft battery and a simple switch to drive the rear fan.

Like the rear axle power, I've retained flexibility in the electrical components; the right-side box is reserved for you to place the fan's related drive components.

➡️Consumables

Adhesive

It should be noted that due to the bonding of carbon fiber tubes, epoxy adhesive is optimal, such as 3M DP460 or SikaPower 1200.

Furthermore, as this is an integrated project, it's advisable to disassemble each part after ensuring all components are correctly assembled, apply additional adhesive, and securely fasten the nuts.

The total consumption for this project is within 100ml.

100ml of brake fluid

Note that Shimano MT200 uses mineral brake fluid. Reconnecting lines and refilling brake fluid during installation, considering air bleeding, will consume at least several tens of milliliters.

➡️Tools

Small or medium-sized automotive repair tool set (must include socket wrenches of common sizes; two of each size are recommended because of double-locking requirements).

Common size drill bits (for enlarging 3D-printed holes when extrusion is not properly calibrated).

Carbon fiber tube cutting tools (fixture/specialized saw).

Soldering iron (for electrical wiring, etc.).

Forced-air oven (for annealing 3D-printed parts containing carbon fiber/glass fiber).

➡️3D Printing Filaments

Black PA6-CF 5KG

Gray PETG-CF 2KG

Black TPU for AMS 3KG

Black PLA Basic 1KG

Black ABS-GF 1KG

White ABS-GF 4KG

Red ABS-GF 3KG

Blue ABS-GF 3KG

Yellow PA-GF 1KG

Concluding Remarks, Before Assembly Instructions:

The above lists all the required materials. In addition, I've prepared assembly instructions in PDF format (listed below). The document uses component drawings and annotations to illustrate the installation process. However, due to the project's considerable scale, I cannot provide comprehensive, step-by-step instructions for everyone. Many minor details require your own ingenuity. For any unresolved issues, please feel free to discuss them in the comments section. I will respond promptly upon seeing your comments.