DIY RC Street Racing Car V2

“Less is more” -Ludwig Mies Van Der Rohe

Our concept for V2 of the RC Street Racing Car was to design a no-compromise, high-performance RC car while maintaining the elegance of simplicity. After the initial success of the popular V1 RC Street Racing Car (https://www.thingiverse.com/thing:2653508), we decided to take a critical look at what key features made it so awesome and what could use improving. After combining nearly 6 months of development with your community feedback, we are finally proud to present version 2 of the RC Street Racing Car.Here are some of the key improvements we've made over the first version:

1) up to 3.5x improved battery life with a new 18650 cell based battery system
2) modular battery system allows quick swapping of batteries
3) new design eliminates unnecessary hardware while maintaining structural integrity.
4) completely redesigned motor mount and other 3D printed parts to remove unnecessary complexity and maximize strength
5) wheels each have an integrated suspension
6) new and improved tire options for all terrain
7) increased tire thickness for improved traction, higher ground clearance, and a smoother ride
8) modular tires easily snap on and off of rims allowing you to tune your car for any conditions. Modular tires also remove the need for dual extrusion
9) improved wire management and component placement
10) improved low throttle control (lower KV motor and a slightly larger drive gear)
11) removable electronics hatch (cover) helps keep dust out and your electronics in.
12) an easily accessible power switch gets you up and running in no time
13) now can drive upside down as well

Specs
-Estimated cost: $100- USD
-Estimated build time: 2-3 hours
-Top speed: really, really freaking fast
-Weight: 636g
-Dimensions (LxWxH): 314x147x65mm

Parts number of each individual part needed in ()
-2430 4500kv motor (1)
-25a esc (1)
-9g metal gear servo (1)
-GoolRC TG3 transmitter and receiver (1)
-MT30 connector (1)
-XT30 connector (1)
-16awg silicone wire (1)
-LG HG2 3000mah 20a 18650 battery (2)
-JST XH 3 pin connector (1)
-14T 2mm pinion gear (1)
-M5x150 fully threaded bolt (1)
-M5x40 bolt (2)
-M5 nut (12)
-M5 lock nut (6)
-M3x8 bolt (30)
-M3x16 bolt (2)
-M3x14 bolt (4)
-M3x4 knurled nut (31)
-M3 press nut (5)
-M2.5x8 bolt (2)
-625 bearing (4)
-medium strength thread locker
-music wire (.047")

Printed Parts Number of each part needed in () If material or print settings aren't mentioned, use your default settings.

Steering knuckle positive/negative (2) These mounts sandwich together to mount your front 625 bearings. For maximum strength, print at 100% infill with PETG or nylon filament. PLA will work well though it won’t be as strong. The positive and negative files are just mirrors of each other for your right and left wheels.

Steering rack (1) The steering rack connects the 9g servo to your steering knuckles. The servo attaches with some custom bent music wire (see attached photos for more information).

Side plate (2) The right and left side plates provide rigidity as well as direct airflow towards your ESC.

Motor mount (1) The updated motor mount meets both side plates in a flush, clean transition to keep out unwanted grit and dust.

Servo mount (1) Securely mounts your 9g servo to the bottom plate. Use any material at 100% infill.

ESC mount (2) Securely mounts your 25a ESC to the bottom plant. Use any material at 100% infill.

Battery mount Snaps around your battery to hold it in place and allow easy removal.

Battery tab Pull on the battery tab to lift up your battery for easy removal. Similar to the tires, print in a highly flexible TPU such as Ninjaflex for best results. Installs under your battery pack with a M3 press nut.

Front & rear bumper (1) These provide critical protection for your steering knuckles which can easily break from a hard, direct impact. Hence, it’s important to print them such that they are rigid yet flex just the right amount on impact. Print with a minimum of 50% infill and 3 shells in TPU. Note that the M3 knurled nuts should be inserted into the face that attaches to the bottom plate and not on top of it.

Drive gear (1) The 80 tooth drive gear creates a roughly 5:1 gear ratio between the 4500kv motor and your rear wheels optimizing torque and speed. It is essential that it be printed at 100% infill with at least 3 shells to maximize its strength. Any material will work but the print should be very clean.

Wheel hub (4) Each hub boasts an integrated suspension which greatly improves performance across a variety of terrains. There are different hubs for the front and rear wheels. To improve traction and maximize the degrees of steering movement, the rear wheel hubs are 10mm wider. The hubs MUST be printed in TPU to allow the spokes to flex.

Tire (4) We've included all terrain, slick, sand, and paddle tires. Paddle tires use a “flap” tread design that also functions as a partial suspension though decreases efficiency due to the enormous contact patches. Sand tires work great on flat, loosely packed terrain such as gravel or sandy dunes. The tire thickness of each wheel can also be configured between regular and thick. Thick tires add an additional 5mm of clearance for riding over bumpy terrain. There are of course different widths of tires as well to accommodate both front and rear hubs. Finally, all tires are designed such that they easily snap on and off hubs with a unique slider mechanism allowing you to easily swap all of your tires in under a minute. For best results, print tires in an ultra flexible TPU filament such as Ninjaflex

Bottom plate (1) We have included STL and SVG files for the bottom
Plate so it can be milled, printed, or laser cut. We recommend using 1/16” birch ply or 50% infill PETG for best results.

Upper plate (1) Use the same materials as the bottom plate. Both STL and SVG files are included.

Cover (1) The cover keeps your electronics in and the dust out! Print, cut, or mill in any material 1/16" in thickness. The cover secures to the front cover finger with a single M3x8 bolt.

Front cover finger (1) The front cover finger simply bolts into your upper plate and provides a place to bolt your cover in place.

Rear cover finger (1) The rear cover finger holds the back of your cover in place.

Note: All 3D printed parts use M3x4 knurled insert nuts for mounting. There nuts are easily inserted into the plastic part itself using a soldering iron. For more details, check out our build video (coming soon).