Mini RC truck chassis

Inspired by Tatra Truck this mini RC chassis featured independent swinging half axle suspension and 4wd design in a small package under 15cm long. The dimensions are planned for a 1/35 concept expedition vehicle, but can also be modified into a 1/24 Tatra T813. While most of the parts are printed this project does requires a little bit of handcraft mainly in fabricating the front drive shaft and adjusting tolerance, other non-printed parts will also be listed down below.

Indoor test run video: https://www.youtube.com/watch?v=QJ6crgnzKj8

Update 2021/01/09: Upgraded parts- steering knuckle 2.0, half axle l 2.0, half axle r 2.0. This version is design to be structurally stronger than previous counterpart and uses standard M2 6mm screw instead of M2X6.7 (M2x8 Filed down) and M2X6.5 (M2x8 Filed down), and also Tamiya AO-1049 instead of 2x2.5x4mm and 2x2.5x3mm copper pipe.

Update 2021/02/06: Upgraded parts- steering arm 2.0
Bump steer reduce for steering knuckle 2.0(the ackermann angle have been reduce on steering knuckle 2.0 and therefore with the change of geometry this part is required to reduce bump steer)

Update 2021/03/17: Part list update-Kyosho mini-z front spring set for MA-020 (MDW201) will also work without modification

Update 2021/06/20: Upgraded parts- geargrab, reduce gear slippage on center drive shaft
/ remove old files- steering knuckle and half axle only v2.0 counterpart remain
/WIP label remove- the chassis is mostly finished and only the electronic parts haven't been assemble in the build video yet

Update 2021/11/22: Upgraded parts- 5 mm shaft jig, the new jig offers a more precise dimension on the 4mm receiving slot cut

Specs
Suspension: Independent swinging half axle
Drivetrain: 4wd (no diff) full ball bearing
Power: 130 motor on 7.4v LiPo battery
Length : 142mm
Width : 115mm
Height : 98mm
Wheelbase : 93mm
Track width : 68mm
Weight: approximately 280g

Please refer to my youtube channel https://www.youtube.com/channel/UC_KGyhIyWl54IifiVNnBs1A for assemble video

Important note
1.Print a mirrored copy of the part "steering knuckle2.0" for the other side
2.Mirror the parts "half axle r 2.0" and "half axle l 2.0" if you find it running in reverse which it most likely will, I accidentally set my motor on reverse when designing this chassis it didnt cause a problem since the motor isn't directional but I leave this note here just in case (the rotation direction of crown gears can be decide by which side it is placed relatively to the pinion gears )
3.Step file of "steering knuckle 2.0" "half axle r 2.0" "half axle l 2.0" "rear half axle" "rear lockout" "front shaft" "rear shaft" "center shaft" are provided for tolerance editing which is possible in FreeCAD other step file may be added in the future

Caution: Please be careful when operating tools and remember to wear safety gears

Printer setting
Flashforge Creator Pro
I prefer printing small amount of parts each time
(For reference only please set accordingly to the filament and printer used)

ABS: First layer height: 0.25 mm
Layer height: 0.2 mm
Temperature Exturder: 220° Platform: 100° Room temperature about: 27°
Printer enclosed
Cooling: OFF
Delay for cooling Deceleration area thershold: 150mm^2 Delay area thershold: 100mm^2
Maximum delay time: 6.0s
Shell count: 4
Infill density: 35% pattern:hexagon
Support occasionally (no support in any bearing hole or screw hole)
Brim margin: 5.0mm No Raft
Internal compensation: 0.15mm
Z compensation: 0.05%

PLA: (Somehow I am having more trouble making PLA stick to the platform)
First layer height: 0.27 mm
Layer height: 0.2 mm
Temperature Exturder: 200° Platform: 50° Room temperature about: 27°
Printer not enclosed
Cooling: ON
Shell count: 3
Infill density: 30% pattern:hexagon
Support occasionally (no support in any bearing hole or screw hole)
Raft margin: 3.0mm No Brim
Internal compensation: NA
Z compensation: NA

Part list
Tamiya parts
Tamiya AO-1049 x1 Eyelets(4) (for 2.0 front axle)
Tamiya AO-1019 x1 crown gear (4) modified
Tamiya AO-1040 x1 G22 gear(3)
Tamiya AO-1014 x1 8T motor gear(7)
Tamiya AO-1046 x1 spring(4 gold soft)
Tamiya AO-1043 x1 2x72mm hex shaft
Plastic tube (inner diameters of 2mm outer diameter<4mm)

Electronics
130 motor (7.4v compatible)
Sanwa/Airtronics 94809 Micro servo
7.4v 2s LiPo battery about 300mAh (Height<17mm Length<43mm Width<20mm)
30A brushed motor ESC

Others parts
4mm plastic bead for bracelet
1.2mm steel wire/rod
M2 ball joint tie rod end (Height 4mm)
Offroad tires outer diameter<55mm

Machine screws (note: I added a few spare into the required number)
M2x30 x6pcs
M2x20 x6
M2x16 x3
M2x14 x12
M2x10 x9
M2x8 x18
M2x6 x5 +4 (for 2.0 front axle)
M2x5 x2
M2x4 x4
M2X6.7 x2 (M2x8 Filed down)(not required for in 2.0 front axle)
M2X6.5 x2 (M2x8 Filed down)(not required for in 2.0 front axle)

Brass pipe
5mm brass pipe 34.72
5mm brass pipe 22.52
5mm brass pipe 10*1
Wave Option System C Pipe outer diameter 2.5mm (alternative copper/brass tube with inner diameters of 2mm outer diameter<3mm copper tube)

Ball bearing
2x6x2.5 *9
2x5x2.5 *7
2x5x2.3 *2
5x8x2.5 *6

Tool list
Drill bits
1.2mm 1.6mm 1.8mm 2.0mm 5.0mm 6.0mm 2.5mm(depends on the outer diameter of the thin copper tube used) or 2.4mm(for 2.0 front axle using Tamiya AO-1049 Eyelets )
Small power drill
Mini file set, Steel Nail File
Screwdriver, Long Nose Pliers, Model clippers, Metal hacksaw blade, Cutter knife, Sharpie pen, Instant glue(or other strong adhesives)

Nice to have tool list
Small rotary tools (Dremel)
Abrasive cut-off wheels
Drill bits 1.7mm
Mini flathead screwdriver
Caliper

Please consider like, share or even post a make if you enjoy this project. Thank you very much!

Important note: Feel free to ask any question related to this project in the comment section, but notice I do not own any email account with names related to this page or my youtube channel, and I don't feel comfortable opening any links from unknown source myself, so please understand that I would not be responding any email with links or files at this point, instead I would try to answer by replying the comment or posting on other public platform such as Thingiverse or youtube.