Here you will find all the latest parts to build your unique, customized RC cars. Most of the content of this publication has been really created time ago but I have not stopped improving parts when I have had the chance.
I finally activated my PayPal account, so please, feel free to tip me if you want to help :)
During this time I have made some videos about this chassis in different configurations and uploaded them to my Youtube channel. Take a look to the related videos and remember to suscribe to be updated!
This is the latest one :
MyRCCar, OBTS... What Does It Mean?
MyRCCar is just a keyword I chose time ago to name all my new projects but can be of course used by all those designers which want to share the same design line.
The main goal of MyRCCar is being adaptable to use the most common and easy to source parts of the moment so if some of this parts change with time, we re-design the related printed part... So the idea is being as much independent from parts and commercial car models as possible. We depend from good cheap easy to find parts, and if they change, we change with them. But just one person is not able to do that work forever so that's why MyRCCar is also a community and it should include YOU!
OBTS is just an acronym for On-Road, Buggy, Truggy and SCT types of RC cars.
All MyRCCar projects has been developed to reach the most people possible, and that's why there are many options for some parts, maybe you can’t find a specific sourced part but you can easily find another one with the same function. Let's see a pair of examples:
- You can't get Quanum Vandal or Reely CVDs but you can get HSP 166015 CVDs...
- You can't get 6x12x4 bearings but you easily find 5x10x4 bearings...
You will be able to build a Buggy or Truggy with any of those CVDs and you will be able to build your steering system with any of those bearings. I had to create specific 3d printable parts for specific sourced parts, not only for the ones I chose but for the most common and easy to find sourced parts so my designs can really be built in many ways...
If you are starting in the RC Car world as I did some months ago maybe you don't really know what to spect or what you want... I had to research "a little" to understand some of the concepts stablished in the RC car world... I mean types of cars and characteristics from each type... I made kind of an "informative table" for myself to visualize easily this characteristics, but maybe it can help you too :) You can find this table at the end of the drawings.
With the parts in this publication you should be able to build a Drifting, Touring, Rally, Buggy, Truggy or Short Course Truck chassis. Look to the first part of the table in this step, the characteristics of the car type. Some of the variations are in the spected speed, wheel size, height to the ground, wide of the car... But there are more, as the wheelbase...
Now look at the second part of the table, they are the params needed to calculate a final max speed for each type. You can see 3 files of the table in green, those are parameters I change to get the final max speed. Just playing with the Motor KV and Nº of Teeth from motor pinion you can achieve many different max, speeds. If you need help with the formula, just say something :)
The parts you print depend on the sourced parts you buy, and the sourced parts you buy depend on the kind of car you want to build... so dedicate some thinking to this before going on "crazy printing"
Required Electronics and Common Sourced Parts
Now I list those elements you need to buy and the range of price you could expect... I have been over watching prices for these things over a year and the range of price tries to reflect the cheapest, the good/recommended and a pro pricing. So for example, Motor (4-25-60) would mean you need a motor, the cheapest you will find can be a brushed one for about 4€, a good one, a brushless 4Poles can be around 25€ and finally a powerful 3670 brushless for 1/8 can cost 60€ or more... So let's start!
- Radio + Receiver (15-20-60)
- ESC Electronic Speed Controller (5-25-50)
- Motor Brushed / Brushless 3650 or bigger for 1/10 (4-25-60)
- Servo 5-15KG (4-10-30)
- 2S LiPo Battery (9-15-25)
- LiPo Charger (5-12-40)
- Lights (4-8-20)
- Battery/Motor/ESC adaptors and thermo shrink tube (0-2-10)
No way to 3D print any of those parts, don't you think?¿? So let's see... That would be 46€ for the cheapest config, 117€ for a good/recommended config and pfffff 295€ for a pro config electronics... Maybe that's too much to put into some printed plastic... It's your task to find the intermediate point where your pocket and your wishes meet...
But the thing doesn't finish there... there are some other parts you will need anyway. To have a good RC car you need differentials, and they need pinions, vases and bearings. The same way, you will need CVDs to transmit the rotation to the wheels and more bearings for them. And let's not forget the central dogbones... Wheels and shocks are really better if sourced...
This time the pricing is more related to the luck you have buying the parts or the size or type of them
- Shocks and shock oil (8-15-40)
- Wheels and tyres (12-20-60)
- Trooper or STT09304 like Center Diff (7-10-20)
- Motor Pinion M1 14-21T
- 2x Front / Rear Diff HSP 02024 or similar (8-16-30)
- 2x Front / Rear Pinion HSP 02030 or similar (3-5-10)
- 2x 1/10 universal cup / vase (2-5-8)
- 6x 4.7mm balljoints with M3 screw (1-3-10)
- 20x bearings for wheels, FR diffs and steering (10-20-40)
- 4x CVDs from HSP, Vandal or Reely (12-18-35)
- 2x central 1/10 dogbones (4-8-20)
- 4x 12mm Wheel HEX and pins (2-5-15)
- 4x Typical Clips for battery/shell Holders (0-1-3)
- A lot of M3 Screws and 4x M4 self-locking Nuts (6-12-30)
- 3mm piano wire (1-2-6)
- Double Side Tape (1-2-6)
OMG is so heart hurting doing this totals but there they go: The cheapest you could get this parts would be around 80€, if you are not so lucky or you want more expensive wheels, shocks, you could pay around 147€ for this parts, and if you always want the best, easy and fast you could pay a very pro quantity of 343€!!!
Now the big totals:
- To buy all the listed parts will cost around 126€ in the cheapest config
- A good/recommended but smart (cheapest of second list) buy will cost around 197€
- A good /recommended but relaxed (mid price in second list) buy will cost around 264€
- A PRO relaxed and not recommended for MyRCCar config will cost you around 638€
Now let's focus on the 2 first ones... There are many commercial models available between 100€ and 200€ which could include many or mostly all the parts you need for your build, depending on what you want. They sell the cars in KIT (just chassis with mechanics, shocks, wheels and sometimes body), ARR (Almost Ready to Run), which use to include Motor, ESC and Servo, and RTR (Ready to Run), wich also includes the radio + reciever and sometimes the battery and charger. So why to 3d print one then?¿?¿? :S
Getting a kit?
Ok let's go back to money talking :S The cheapest config was 125€ and that's quite good for me, but I considered I wanted to choose some brushless motor and ESC and a good battery... in the end I was talking more about 200€ than 125€... So I started considering buying a commercial car kit to see if I could save some extra money and you can!
I used a Quanum Vandal KIT to source many of the parts you need for making a MyRCCar Buggy and in fact, I could assemble it with the electronics and use it for a while and it feels like a serious car for someone not expert as me... It has a slipper instead of center differential, but the F/R diffs, the shocks, the wheels, the F/R vases and pinions, the bearings, the CVDs, the upper suspension arms, steering arms, servo arm, the wheel HEX, the pins, the screws... I also used the center large dogbone to create my own central dogbones for a 270 wheelbase config...
Now it's your time to make numbers... A Vandal Kit is about 60€, and the cheapest you can get the same parts included in the vandal is around 67€ but, can you buy sooo cheap? There is no center diff, motor pinion, piano wire or tape in a Vandal Kit and it only brings one 1/10 cup /vase you can use.
But the thing about Vandal gets more interesting when you see the ARR version including brushless motor and ESC and servo for around 100€... You can also buy there the rest of the electronics, the Trooper center differential and Motor pinion, the tape, the piano wire, the extra screws needed, maybe other wheels or more bearings... and with free shipping from EU or UK warehouses to Europe in less than 10 days and with no extra taxes or customs... If you are thinking about doing the chassis for the Tesla Model S Body then you can also get the Mission-D CVDs from there, are the ones I have used.
There "Overseas" in America or Asia I think you are more familiar with HSP cheap products... Maybe some of you can recommend a cheap rc car kit or RTR wich would make this shopping list easier and cover some of the OBTS chassis needs... That's something I would spect from the community as I can’t risk buying all the kits of cars in the world!!!
Recently the thingiverse user Francisdb found Vandal is the same platform than many other rc cars. FTX Vantage, INTEGY i10B and maybe more! I don't know if the instructables comunity is active around published instructables. By now, you can take a look to the MyRCCar Thingiverse Group until the info is spreaded somewhere else.
You can save even some money printing some of the parts as the motor pinion, the wheel HEX or the shocks (except the spring) or maybe if you are going to use the center diff in centred position you can use 3d printed central transmission. If you don't mind your center diff to be blocked, you can do a locked 3d printed one with some 3mm piano wire and 2 extra universal 1/10 cups / vases...
Choosing the sourced parts is the first customization you need, as they depend of the type of car you want to build. If you are reading this, you want an On-Road, Buggy, Truggy or SCT chassis. I have done a body or shell for the first 3 types but I imagine you could try other bodies from other designers or sourced ones. To adapt to those bodies you will have to choose a wheelbase and wide of the axle.
- Wheelbase: The distance between the axles. You can build different wheelbase chassis choosing different parts to print. Combine one front and one rear part to have your final wheelbase, which should match the body you want to use. The length of the center dogbones will depend on this. Many drifting cars are around 255mm wheelbase, while MyRCCar buggy and truggy shells are for 270mm wheelbase, and the Tesla Model S is a 295mm wheelbase car.
- Wide of the axle: The distance between the wheels of an axle. You will need to use short CVDs and 3d printed arms for On-Road cars and longer ones for Off-road ones.
- Center differential: You can choose using different 1/8 1/10 differentials, The Trooper one (44T), the SST one(46T), and I'm sure there is a HSP compatible one! You can also use some 02024 mods and 3d printed locked diff for the straight transmission system; see it in the next custom option.
- Position of center differential: You can place the center diff. housing in a position in which the center diff axle is centred in the chassis, or 9.5mm displaced to the right side. This allows you to have the center transmission totally aligned and straight, making it possible to use 3d printed "dogbones" or a bigger battery space if you displace the diff to the right.
- Caster and Camber: These parameters can be controlled for each axle, the same than the toe-in toe-out, but I recommend starting with 6º in the front and 0º in the rear axle. You can adjust the Toe with some "adjustable steering pins" which you can print to use 4.7mm balljoints or use the ones from a Vandal Kit or similar kit.
- Riding height: You can use 2 different butterflies for the on-road and off-road configs with different holes in the butterfly and lower arms so you can control the height of the car to the floor, the extension and position of your shocks.
So 11 possible wheelbases, 4 axle widths, 3 different Differentials, 2 positions for differential, 2 different butterflies... just with this options you can make 528 different builds. If we consider also 6 positions for shocks, 7 different caster angles, 5 different pre-made upper suspension arms for different cambers... Just multiply 528 x 210 and you get it!
Ok I think you understood it, The OBTS chassis is customizable / configurable... isn't it? Do you know any commercial model or 3d printed one as customizable as this chassis?¿?
Here you have what you need to build a chassis of 150 mm width and from 255 to 315 mm wheelbase for your rc car.
As many of us can't print beyond 200x200 mm I had to split the chassis, but doing this the same time I had the opportunity to achieve bigger wheelbases.
So the key of this design is the combination of a front and rear chassis of your like so you can achieve your desired wheelbase. The front chassis will accommodate the servo, the steering system and part of the battery. The rear chassis will accommodate the motor, part of the battery and maybe some electronics.
To select the correct front and rear chassis you need to know your desired wheelbase.
Your desired wheelbase = front wheelbase + rear wheelbase. As you can see in the drawings, the front wheelbase goes from 135 to 150, and the rear one goes from 120 to 165.
So the minimal wheelbase will be 255 and the maximum 315 mm. Many touring or drifting 1/10 cars have a wheelbase of 255-265. I think buggys must have little longer ones, and Truggys or Trucks probably more than 280 mm.
In 1/8 scale, a 315 mm wheelbase would be the one of a normal car, i think 255x1.25 = 318.75, so near. If there would be the need to reach 330 i could create the versions of front chassis from 155 to 165 mm, but anyway you can't print in 200x200 the bottom part beyond 155mm partial wheelbase.
The 4 parts conforming a SET are in the same .stl file but they are separated 0.01 mm so you can "separate shells" in MeshMixer or your slicing software. I'm sure it will help you having them together like that to make your own mods easily :) I use to print the bottom parts the first. The top parts after the CD, FRDs, ST and the sides the last of all.
I want to build a 270 mm wheelbase car. I select both 135 mm wheelbase for front and rear sets. This would be:
If you are using the sides from the kit files also print 2 "side links". Remember to do not print the sides of the kit files if you want to build a "Frogger Build", "Titan Build" or "Tesla Model S Build", the shells for buggy and truggy and on-road I created, wich must be mounted in 270mm wheelbase OBTS Chassis for buggy/truggy and 295mm wheelbase for the Tesla
As is said in the photos, i have 66+84 mm = 150 mm max. battery length.
Also print 2 battery holder towers, the battery holder, and the servo holder. This would be:
- 2x MRCC_OBTS_UP_SD_LINK.stl
- 2x MRCC_OBTS_UP_BT_TOWER.stl
All the holes are for M3 screws. They are 2.85 mm in diameter for screwing ones and 3.2mm for "passing" ones. All the screws can be 16 mm long but you can use 30mm ones for the central diff. from its bottom (through the bottom chassis).
Front / Rear Differentials
I made this housing for the HSP 02024 Front Rear differential or similar because i think is one of the easiest to find in the market and also with very cheap chinese compatible ones. I think most 1/10 4x4 kits include this kind of differential, at least cheap ones.
For me, the interesting characteristic about this housing is that it allows you to change the caster of the axle just printing and changing 3 little parts, instead of rotating the whole housing or changing the chassis.
Remember the "Caster" concept?¿? You will see many cars which have some caster in the front axle, for example 6º the top part towards the inside of the car is very common, and a little or 0 caster in the rear axle is also common. I have tried 6º in the front and 0º and -3º in the rear axle. I provided many more options but i did not try them. I'm sure you can find a lot of info about caster, camber and toe, i always make a mess with the names but concepts are there.
You must print the right Lower Arms Supports and Butterfly Support to achieve your desired caster angles.
You will need two 10x15x4 bearings to hold the differential in place, but some of the bought differentials come with this bearings. You will also need two 5x10x4 bearings to hold the diff. pinion in place. The same way, you will need one universal 1/10 cup / vase for each pinion.
There are now two different butterflies... the big one will allow you to mount 80-100 mm big bore shocks in a buggy/truggy style rc car. The smaller one will let you mount 60-80 mm big bore shocks to be able to build a On-Road car.
To join the bottom and top part of the housings you will need one M3 nut and M3x8-10 countersunk screw. To put those housings on the main chassis use M3 countersunk screws with 12-14mm length. You will need 4 for each diff housing. But i recommend you before doing this, to put the part of the LAS that goes in the inner side of the diff housing. Use M3x16 Countersunk to join LAS parts to the diff. housings. You will need 8 screws for that.
Most 1/10 cars don’t use center diff, so probably the ones you will find will be 1/8 scale. Anyway I provide here some adaptors tu use an HSP 02024 diff to make it be a Mod1 46T diff.
You have two possibilities for the center diff. housing. You can place it centred in the chassis to use straight central transmission or displaced to the right side to allow bigger batteries in the left side.
The center diff. housing will allow you to use 2 different 1/8 center diffs, the SST and the Trooper one. Avoid the center diff adaptors for 02024 if you want the car to be reliable. So if you are going to use one of the 1/8 center diffs, look for the drawings of your chosen partial wheelbases and look for the length of your needed center dogbones for a 1/8 centred or deviated center diff.
You have to print the bottom and the top of the box, then print your appropriate adapters to your diff. If you don't want to spend 10$ in a pinion and an adaptor, print the provided Mod1 14T pinion (made for the trooper diff), or make your own motor pinion with my Motor Pinion Generator.
One time you have it printed, you can put it on chassis and screw it from the bottom with 5x M3x30 Countersunk screws. They can be shorter but this way (30mm) they contribute to strength up the chassis structure.
You must pay special attention to the drawings to know which pin to pin length dogbones you need for your build. I'm using 1/10 dogbones even knowing the center diff is 1/8 and the vases are not 1/10 sized.
To put the central dogbones in place you can put the adaptors in the diff. align them over their final place, insert the dogbones heads in the F/R diffs vases and then go down with the diff into its housing while you make the other heads of the dogbones enter in center diff vases.
If your chosen central dogbones are too short, you can use some kind of "soft plastic or silicone" tube to cut near 1mm sections to put inside the related vases so the short dogbone can't move to the end of a vase and get out of place in the other side...
Mounting the motor
If you have not screwed the central housing to the chassis you will probably be able to put the motor and its screws easier. Use some M3 washers to secure the motor better in its final place. Very probably, if your motor gets hot, it will transmit its heat to the screws and those to their zone, so the PLA of the housing near the motor zone can get some heat too... that can make the PLA "melt" a little and then the screws of the motor can get a little loose. I'm quite sure you will have some problems with this during some time because the motor pinion will separate from the diff's spur due to one of the screws of the motor to get a little loose.
A last important thing about this is the distance between the motor pinion and the diff's spur. Remember they can’t be too far but also too near will be a bad thing. I put them very near and screw very hard one of the 2 motor screws. Then I separate it very very little, so i can hear there is some play when i move the spur of the diff or the pinion. That's when I screw strongly the second motor screw.
And that's it! If you reached this point is time to put the Top Cover to give the car chassis its final strength and maybe do your first transmission tests! You must be sure the center dogbones don't get out of their places. For this you will need 8x M3x16 Countersunk screws. When you are screwing the ones of the F/R diffs, remember that the holes of the bottom and top FR diff. parts are "screwing holes", not "passing holes", so use one of your hands to get both parts and the top cover firmly together while you screw those ones.
The steering system consists in two pivots and two "steering towers" over them. Both towers are linked by the steering plate, so if the one with the servo arm rotates, the other will do the same way.
So just 5 parts but... One more time you have to choose. I made the system for 3 different bearing sizes. I recommend you to use 5x10x4 if those are easy to find for you. You will need 4. If you can get for the same price 6x12x4 bearings, they will also do the job, maybe better.
When you have the 5 parts printed, start introducing the bearings in the towers and then the towers into the pivots. You could also screw the plate to one of the towers.
To screw the towers on their place you will need 4x M3x8-10 countersunk screws. if you have the rest of the chassis in one piece, you will have to screw the upper and lower screws of a tower the same time. You will probably need some pliers to hold the pivot base while you screw. After putting towers in place, remember to screw the second plate screw.
We will have to link the towers to the front steering blocks and also to the servo. For that i designed some "balljoint" steering pins which are also valid for the servo link. If you want to use this system to link them, I use 4.7mm balljoints with M3Screws. If you buy a Vandal Kit as i did you will be able to use its steering pins and probably the servo link instead of this 3d printed balljoint steering pins.
This last chapter will be about the suspension arms, the C-hubs, the steering blocks and the rear fixed blocks. All this parts will be dependent of the CVD you want to use.
So one more time, you have to choose between a lot of options! The cheapest option for me is acquiring the CVDs as part of a car kit.
- As i know the "Quanum Vandal Kit", i did parts to use its CVDs, rear wheel vases and dogbones
- As i had the OpenRC Truggy recommended and expensive Reely CVDs, i also did the parts to use them
- As HSP CVDs are some of the cheapest ones and easy to find, i made various versions of parts for various HSP CVDs. This include 102015 and 122015 for short arms, 106015 and 166015 for normal long arms (715 version) and 108015 and 188015 for extra long arms (769 version)
- Now I also made a version of the arms, Front C-Hubs and Rear Hubs for the Mission-D On-Road CVDs to build my Tesla. These are the shortest ones, around 10mm shorter than HSP 102015 and 122015
So now there are also an ONROAD type and an OFFROAD one. In combination with the proper C-HUB or RFBlock (RearFixedBLock) the ONROAD type will let you mount smaller wheels while the OFFROAD one is the old tested one for bigger wheels
You will need 3mm piano wire to cut out 4x 56mm long pieces. Insert this 3x56mm pins in the long hole of the arms. You will also need to cut 4x 33mm (off-road) or 4x 26mm (on-road) long pins from 3mm piano wire to link the front C-Hubs or rear Fixed Blocks to the arms.
Now it's time to put the lower arm with the front C-hub in place. For that, insert the rear part of the 3x56mm pin (already in the lower arm) in the Lower Arm Support hole you screwed to the diff. housing before. Then use the other "LAS" and screw it (remember, 2 M3x16mm countersunk) to the diff. housing.
If you are building the front suspension arms, you will need to print two C-HUBS and two Front Steering Blocks, the correct type for your CVDs, the same way you will have to print two rear fixed blocks of the correct type for the rear axle. I explain next the types of steering blocks and rear fixed blocks:
- Type A: For Quanum Vandal CVDs and Mission-D CVDs
- Type B: For HSP 122015, 166015 and 188015
- Type C: For HSP 102015, 106015 and 108015
- Type D: For OpenRC Truggy Reely CVDs
- Type X: For Vandal rear dogbones and wheel vases
Now you must also choose the right length of the arms for your CVD like this:
- 375 arms for Mission-D CVDs
- 475 arms for HSP 102015 and 122015
- 715 arms for Vandal and Reely, HSP 106015 and 166015
- 769 arms for HSP 108015 and 188015
Now that you have the front steering blocks printed, put the bearings into them and place one into the front C-HUB. To do this, enter the steering block near its final position and then rotate it until holes in the Chub and steering block are aligned. Use 2x M3x14-16mm to secure the steering block in place. This system needs to be improved but it works quite well by now.
Now would be the moment to put one of those CVDs in its place, entering the screw extreme through the bearings of the steering block. Then rotate the C-HUB to its final position while you align the other extreme of the CVD to enter into the diff. vase.
If you don't have sourced upper arms you can print the proper version for your lower arms. This can be a little tricky, as you can choose for various lengths. This is because the "camber" of the wheel can be adjusted using one or other length for the upper arms. To have 0º camber, use the UAS_XXX with the same number as your lower arms. You can choose a little longer or shorter ones to alter the camber from 0º.
For each of the upper arms, you will need to print some little supports, which can be found in the UPLink_KITs. Use the short one for an On-Road build and the other for the Off-Road builds. Use proper length M3 screws to secure the upper arms over their supports in their final place.