Rigid Axles short Version

by Schraube2u76


first of al, I really like your work!

As I wanted to build my own truck with an similar idea (using cheap components for gears and so on) I came to find your RC Design. And I really like so I decided to throw my own plans away and reuse yours.

While building up my own car (not my own in 1:1) I wanted to use the short Axle with some Crawler tires. And of course I start in design before printing ;) .While I used your parts to set up the arrangement in the CAD System, I came out to find some clearance problems. First of all the clearance between the SBlock_Type B and the rims of an typical crawler tire. I may have done something wrong here?

And then the space for turning the wheel. (steering) It seems to be to small. I used some HSP 296004 Dampers for the arrangement Please refer the Suspension pics for that.

I can try to find out if rearranging would help even in turning and for suspension

Best Regards

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6º caster misfit?

by francisdb

Hi, I get a slight misfit in the front and was wondering if this is expected.
I'm using the reinforced MRCC_MTC_FRD_LA_Holder6c


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Source for the central drive cup

by francisdb

Where did you source the extra central drive cup? They are currently not available on hobbyking...


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Filled wheel cup holders?

by francisdb

Is this on purpose? How do I then get the cups/rods through?
Same thing with the steering towers

cup problem

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by dlb5


This assembly instructions will try to complete the info in MyRCCar 1/10 Monster /Crawler Chassis with Configurable 270 to 330mm Wheelbase. If you read the thing summary and you need more info I hope you can find it here :)

Remember that after publishing the main chassis thing I also published a Reduction Gearbox and some Upgrades you must know as well to fully understand this instructions.

This car is intended to use sourced transmission, the same as in OBTS Chassis. There are many sourced parts, including Wheels, Shocks, CVDs, Central Dogbones, Differentials, Pinions, Bearings, Screws and Nuts... and don't forget All the Electronics!!! including, Motor, ESC, Servo, Battery, Charger, Radio+Reciever...

Remember you can see the MTC Chassis in action in this videos: First VIDEO, Speed Build Test Drive of the MTC Chassis and MyRCCar MTC Chassis with the Typical Pickup Body in Action!


(any correction welcome)

  • Scale: The proportion between the real size of a thing and the size of a model or drawing of it. As you probably know, I like 1/10 scale for its simplicity in metric system. 10 meters in real size will be 1 meter in 1/10 scale. A 500mm diameter real wheel will be a 50mm wheel in 1/10 scale.
  • Wheelbase: The distance between front and rear axles.
  • Caster: The rotation of an axle (front or rear) and its suspension system over itself. They vary caster in sourced RCs in many ways, I try to rotate all the related parts certain degrees over the axle center.
  • Camber: Is the inclination of a wheel relative to its normal position.
  • Toe: The convergency or divergency of wheels in an axle. If the alignment of the wheels of an axle converge into a point in the forward direction I think they call this "Toe-In", while if they diverge they call it "Toe-Out". This "deviation" can also be measured in degrees.

Options, but not so much:

This chassis should allow you to build a Monster Truck, Scale or Crawler RC car. By now, there is only one option for the kind of suspension, independent one, but I hope I can use most part of this chassis in the future to build a multilink suspension version with rigid F/R axles. The transmission system is the same than in OBTS chassis but you can use a reduction gearbox with differential instead of the simple central differential.

The main option in this chassis by now is THE WHEELBASE. The main measures for the chassis are similar to the ones of an Axial SCX10 and allow you to build a model with a wheelbase from 270 to 310 mm just moving the front and rear platforms. If this is your case, align all four holes from the center side bar and the F/R side bar. If you want the extra 10 or 20 mm to build a 320 or 330 mm wheelbase model you will also have to displace Front and/or Rear side bars those extra 10 mm so just 3 of the holes will be aligned.

But wich wheelbase should I use?
If you have in mind to build a Scale car you will want it to have the same wheelbase than your real car model. With this chassis the exact available wheelbases are 270, 280, 290, 300, 310, 320 and 330 mm.
If you want to use the [FJ Cruiser Body]() or the [Typical Pickup Body]() you must build a 270 or 280 mm wheelbase for the FJ Cruiser and a 290 mm wheelbase chassis for the Pickup. I recently published a longer bed for the pickup to make 310 mm wheelbase version.

And now that you know your main wheelbase you must know wich front partial wheelbase and rear partial wheelbase you want. If you plan to use big motors (longer than 50mm) you will need 145 mm front partial wheelbase or bigger, 135 mm version won't be enough. Also, if you use same partial wheelbase in the front and the rear, you will be able to use same length central dogbones.

If you don't want to "re-design" the adaptors for the FJCruiser and the 290 Pickup Bodies use 145mm front partial wheelbase and 135mm rear wheelbase, is also the one I will use as an example.

Let's start building!

I tryed to minimize the need to reprint parts when making config changes, but it is not possible 100%. Let's start printing some parts that will not change.

Bars and platforms: Printing

With this parts you will build the main structure for the chassis. It consists on 2 side bars (formed by 3 parts) and 3 platforms, the Front one, with its support for the servo, the Rear one, wich have options to maximize battery size availabe space, and the Central platform.

Print1: You can print two MRCC_MTC_CentralSideBar.
They are swappable, so no need to mirror them.

Print2: Print four MRCC-MTC_FrontRearSideBar.
If you mirror two of them, you will be able to have the same surface finish for all of them when assembled. If this doesn't mind you, they are swappable too.
If you plan to use the motor dissipator+fan upgrade you will need some little extra space, maybe you need to print one of this MRCC_MTC_FrontSideBar_SHORTER to replace the front left one.

Print3: Time to print the MRCC_MTC_Platform_Central_NEW. With this one you will be able to use the gearbox or the simple central differential housing.

Print4: The MRCC_MTC_Platform_Front has no versions by now. So just print it. If you need some extra distance for your servo as it happened to me, you can use the spacers I attach.

Print5: Now you could print MRCC_MTC_Platform_Rear. You will be able to move this platform to have different rear partial wheelbases, but if you want the maximum space for the battery you will need to print MRCC_MTC_Platform_Rear_PLUS10 for a 145mm rear partial wheelbase or MRCC_MTC_Platform_Rear_PLUS20 for a 135mm rear partial wheelbase.

Print6: Print two MRCC_MTC_Platform_Holder to have all the needed parts to do the first assembly!

Bars and platforms: Assembling

The next drawing shows how to assemble the previous printed parts to get a chassis with 145mm partial front wheelbase and 135mm partial rear wheelbase. The more colorful parts are the ones with options, so pay special attention to them when selecting the ones you need. You can see in the left bottom corner of the drawing that im using the middle hole of the 3 in the front of the chassis side bars. That one would be for the 145mm partial front wheelbase while the others are for 135mm and 155mm partial front wheelbases. Use the drawing as a guide to know wich screws use and where, but you will need to use them in the right holes for your build.


Now that you have this in your hands you can start feeling the size of your truck! Remember to test if you are printing things "the right size". I would pay special attention to the size of the holes, they are two kind, "passing" and "screwable". Your M3 screws should pass quite easy through "passing" holes. The same way be sure they make a good connection when you screw up one quite strong :S (be careful about how much strong :S).

If you are happy with the results, you are ready for the next step!!!

Front/Rear Axles: Printing

There are just few parts this time that has no options... I mean, you must know wich CVDs you want to use in your build to be able to select the proper parts to build your F/R axles.

Print7: Print one MRCC_MTC_FRD_BOTTOM_5104. You will have to add supports in your slicing program to print this correctly.
The F/R housings are the same than in OBTS chassis, and they are designed to house a HSP 02024 differential and pinion or similar ones. They use two 10x15x4 bearings to hold each diff. and two 5x10x4 bearings to hold each pinion. Remember you will also need two 1/10 standard vases for the diff pinions.
Test the bearings, the pinion and the 02024 differential to see if everything is printing fine. If it is, print another one for the other axle.

Print8: Print one MRCC_MTC_FRD_TOP. Hold it with the bottom part and test it with the rest of the sourced parts. If everything looks ok, print the other one for the other axle ;)

Print9: Print one MRCC_MTC_FRD_UAS_6C to have 6º caster in the front axle. This pair is an easy print. If you want 0º Caster in the rear axle print one MRCC_MTC_FRD_UAS_0C. This is the caster combination I choosed, but you should be able to use 0º or 6º in any of them.

Print10: Print one MRCC_MTC_FRD_LA_Holder6c for the front axle and one MRCC_MTC_FRD_LA_Holder0c if you use my caster combination. Choose the right ones for yours. I recommend to print this parts in the provided position adding some easy supports in your slicer.

Print11: Print two MRCC_MTC_FRD_C-HUB_Front. This parts are needed to have steering in the front axle and they have no options, but the rest of the parts to print depend of the CVDs you want to use.

Print12: The suspension arms, the upper and the lower ones depend of the CVD you want to use.

  • With the 715mm from pin to pin version you can use many CVDs, including HSP 106015, HSP 166015, Quanum Vandal Front CVDs and OpenRC Truggy Reely CVDs. If this is your case, print one MRCC-MTC-SUS_UpperArm_715 and one MRCC-MTC-SUS_LowerArm_715. Wait to print the ones for the rest of the arms until you know everything works good with your CVDs.
  • With the 769mm from pin to pin version you should be able to use HSP 108015 and HSP 188015 CVDs. If you have some of this ones you will need to print one MRCC_MTC_SUS_UpperArm_769 and one MRCC_MTC_SUS_LowerArm_769 to be able to do the proper tests with your CVDs before printing the ones for the rest of the arms.

Print13: Now lets print what i call the Front Steering Blocks and the Rear Fixed Blocks, wich are completely dependent of your CVDs so...

This parts use bearings so be sure they get properly in place. TypeA and TypeD use two 5x10x4 bearings for each wheel. TypeB and TypeC use one 5x10x4 and one 10x15x4 bearings for each wheel.

Front/Rear Axles: Assembling

Let's first assemble the front axle with 6º Caster. If your diff housing upper and lower parts are working good, attach them the 6º Caster Lower Arm Holder
and one of the 6º Caster Upper Arm Supports. Use the single M3x8mm Countersunk screw and the simple M3 Nut to hold everything together by now.
As a second step, you must try the rest of the parts of a front suspension arm, so use the drawing below to figure out how to assemble it. The 3mm piano wire represented by blue cilinders must pass easy enough to enter with some little hits but not very hard ones, so use some 3mm tool to re-do the holes if needed.


In this stage, you must be able to test if the transmission system works well enough, mostly the CVDs, so if everything works as spected you can print the rest of your upper and lower arms:)

Central Diff. / Gearbox: Printing

One more time you have options here. You can print the normal central diff. housing or you can print a configurable reduction gearbox. But there is something you maybe don't know... YOU CAN USE THE REDUCTION GEARBOX AS A SIMPLE CENTRAL DIFFERENTIAL HOUSING.

If you don't know very good how your motor is going to perform with this "plastic beast", print the gearbox. It allows you to mount the differential in the normal direction and use it with the gearings to have a reduction or you can mount it in the other direction and "attack" the differential direct with the motor pinion. Only if you want to reduce weight at maximum and if you are sure you want the simple pinion/diff central transmission, print the simple central diff housing.

Print14: Let's print the MRCC_MTC_CD_GEARBOX_BOTTOM_V3. Botyoyo made some corrections because the gearbox was not correctly designed to fit the SST differentials. The version of the gearbox I link here is modified to correct those problems.

Print15: Some options here one more time, you can use a "Trooper" central differential or an "SST" central differential. Some users are trying using 02024 as central differential making some mods to it. Look for their published parts or read the comments and forums for more info ;) If you want the bearings to fit good into this parts and them fitting good into the gearbox or the central diff housing, use "horizontal expansion" in your slicer (I use -0.02mm in mine) to make parts "smaller" and holes "bigger" :S

Print16: Print MRCC_MTC_CD_TOP_NEW It will be also compatible with the simple central differential housing, the same than the adaptors.

As for a first try we are going to use the "reduction gearbox" as a simple central diff, those are all the parts we need by now.

Central Diff. / Gearbox and Front/Rear Axles: Assembling

If you have your electronics, your central diff and your pinion for the motor, I'm quite sure you will want to do some tests. First of all, prepare the two M3 screws and washers you are going to use to hold the motor in their places inside gearbox. You can mount the motor and pinion then. For that, insert the pinion inside the gearbox and then put the motor in place while you insert the shaft of the motor in the pinion. This is kind of tricky ;) You must then screw the motor in place using your tool through the holes in front of the motor screw's heads. Leave it a little loose so you can adjust the final position after inserting the differential. For that, put your adapters in your differential and insert the assembly into the gearbox or central diff housing.

Now it's time to adjust and screw the motor in it's "final" position. This position is also a hard thing to find, because very far and you are not using the full teeth of your gears and you could have problems. So near with no gap and you will have extra heat wich could cause problems too...

WARNING This kind of transmission is probably not good for you, it depends of the kind of motor, if you have full metal transmission, big or small wheels, the quality of your build and printed parts... so spect having problems of heat in your motor, maybe in your plastic parts if there is something not adjusted... many things can go wrong so I hope you can be patient to make things work good :)

Sooooooo... Now it's time to put all that we printed together!!! You can see it in the next drawing but it is so easy! Use four M3x12 Countersunk screws to mount each axle on the chassis and six M3x20-30mm (from 20mm to 30mm length) Countersunk screws to mount the gearbox. If your central diff with it's adaptors is on place, you can screw the gearbox/central diff. housing TOP with two M3x12 Grub screws.


At this stage, with all printed parts together, the chassis structure is a little weak. You can take advantage of this to get the central dogbones in their places. Maybe you can do the chassis to flex a little so you can put them in their places, then you release your strength to make the chassis come back to normal position. You can of course put them in place holding them in their position before screwing the 4 screws of an axle.

Steering and Covers : Printing

What I call "covers" in this chassis are not just that, they have a structural function. They will join important parts of the structure in a geometry wich will make the whole chassis be more rigid and strong. The steering parts are easy this time because no options. You will need four 6x12x4 bearings for the steering towers.

Print17: Print two MRCC_MTC_Steering_Pivot and one MRCC_MTC_Steering_Plate

Print18: Let's print the upgraded version of the left tower with the arm for the servo. So print MRCC_MTC_Steering_Tower1ServoSTRONGER. This print will require supports for the servo arm so add them in your slicer. Finally print one MRCC_MTC_Steering_Tower2 to finish with the steering parts :)

Print19: Ok print two MRCC_MTC_FRD_SteeringHolder. This ones are needed to hold the steering system in place but are also part of the bottom cover of the car, so you will need one also for the rear axle without steering.

Print20: Time to choose again! To finish the bottom part of the car we need the bottom covers. This parts are dependent of the partial wheelbases you are using. They can be mounted in the front or the rear for a given partial wheelbase. You can be using 145 in the front and 155 in the back or 165 in the front and 135 in the back... So print the ones wich fit your build. They are MRCC_MTC_Cover_Bottom135, MRCC_MTC_Cover_Bottom145, MRCC_MTC_Cover_Bottom155 and MRCC_MTC_Cover_Bottom165. I only used the first two ones by now...

Print21: Now is time to choose if you want to use motor dissipator with fan or not.

Print22: Let's also print this upgraded MRCC_MTC_Cover_TopFR_MaxBattSize for the rear part so we can use big batteries. The user Saccco also made a version of this part to get also more space!

Print23: If you want your battery to go a little more secure, you can print a battery holder (Published in Upgrades) but it depends on your rear partial wheelbase to have the max battery space available for each wheelbase.

Steering and Covers : Assembling

First of all you must insert the 6x12x4 bearings into the towers, then insert the steering pivots in the towers. Is a good moment to screw the "balljoints" in the servo arm of the left tower and the steering arms of both towers if you are going to use this "balljoint" system. Also attach the steering plate to one of the towers and give it a little loose.

Now put the steering parts over the front steering holder and the front bottom cover and use two M3x12mm Countersunk screws to hold them together. Do the same with the rear steering holder and rear bottom cover. Screw them together with two M3x12mm Countersunk screws and two self-locking M3 Nuts.

To finally put this bottom parts on the chassis, use eight M3x16 Countersunk screws. The chassis should become quite more rigid after screwing all this bottom parts.


Maybe it's time for you to complete the steering system with the servo link and steering links... You can of course mount the servo on place and make your first steering moves to see if everything is working fine. Remember to screw the steering pivots from the upside, near the servo housing with two M3x10 Countersunk screws.


You are almost there! You only need to mount the top cover, those 4 extra parts over your desktop. Just place the Top cover parts on their final position and screw them with four M3x12mm Countersunk screws for the extreme positions and four M3x16mm Countersunk screws for the central positions. Use the last two drawings as a guide to assemble the parts of this last chapter.

And the last thing, place the battery holder. For that, un-screw the two proper screws of the rear axle of the four in the rear platform, put the battery holder in place and screw them again :)

Now with this and some double sided tape and maybe a velcro strap you can mount all the electronics in the car and make your first trys!!!

I'm forgetting a lot of things!!! Like the shock holders!

Print24: Quickly but with quality print the shock holders.

  • If you have long (95-105mm) shocks print this pair for the front axle with 6º Caster and this other pair for the rear axle with 0º Caster.
  • If you have shorter (80-95mm) shocks print this pair for the front axle with 6º Caster and this other pair for the rear axle with 0º Caster.

You will need some extra screws for the steering links, the servo, the motor, the shocks... The shock holders must be mounted in the right position with a M3x12-16 ButtonHead screw. Can you figure out wich hole will be the right one?

About the central dogbones... I just tested the Trooper diff and the SST diff. I use a 80mm from pin to pin dogbone for 145mm front partial wheelbase (should be 82mm) and a 73mm from pin to pin dogbone for 135mm rear partial wheelbase. Maybe something near 91-92mm works for 155 partial wheelbase and 100-101mm for 165mm partial wheelbase but i did not test those.

Hey :) Now you should have a functional RC Monster, more than crawler because of the actual transmission... give it a try but always reading temperature somehow... in the motor and the nearbys! Break and re-print as much plastic parts as you want but take special care of the sourced ones... you are trying to avoid to make an order or have to visit a store with your 3d printed RC car!

Have fun and remember to share your make with us, the same than your experiences with it... let's learn ones from the others :)

I forgot many things and many others can be done to improve this building instructions, including printed parts list, sourced parts list, links to parts in internet shops... Anyway if you find something important missing or some error in this info please tell me and I'll try to correct it as soon as possible :)

I hope you enjoy reading or building this chassis! See you in MyRCCar Group?¿?

MyRCCar 1/10 Monster /Crawler Chassis with Configurable 270 to 330mm Wheelbase
by dlb5
MyRCCar 1/10 Monster / Crawler 1:4 Gearbox
by dlb5
MyRCCar 1/10 MTC Chassis Upgrades
by dlb5
1/10 Chassis crawler CVD gearbox HSP monster monster_truck quanum_vandal_4WD RC_Car
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MTC Chassis steering

by mario260776

The twin rod reinforces the construction and simplifies installation.

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Pickup body with LEDs

by BotYoyo

Really love the pickup body's headlights and taillights which support LED installation. Just 4 white LEDs for front and 6 red LEDs for tail. The voltage from the receiver is 5V which will burn the LEDs (safe voltage is around 3V). You need to install 300ohm resistor to lower the voltage.

The final result came out super cool! Here are some pictures:

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Found a weak spot on Lower Arm Holder

by BotYoyo

Hi dlb5,

I just broke the front lower arm holder today by a jump landing from 0.3m height on a soft surface. I was really shocked because I thought the MTC's suspension should be overkill to handle that level of the impact. After I analysis on the model, I noticed there is a obvious weak spot on the lower arm holder. It should be very easy to improve the design to fix this issue.

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Clip-On links are ready for download!

by BotYoyo
Clip-On links for pickup body with Light Weight roll cage (MyRCCar MTC)
by BotYoyo
Light weight roll cage for MyRCCar MTC
by BotYoyo
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