Custom rig guidelines, at least my take on it!

[Lashlee]

This post is meant not to be an end all, answer to every question, but to be more of a guide of what to buy, and what to expect when you decide it’s time to venture into the world of a more custom build. I’ve had my share of kits in the past, as well as a few RTR’s but when it came time to take the next step in the world of crawling, I couldn’t find much in the way of a post of what to get and what to expect for building a crawler out of parts. I’ll try to be concise with what to buy but realize you can come at this from a variety of angles.

In general you’ll need to purchase the following:
Chassis

Skid plate

Transmission

Axles

Shocks

Links

Driveshafts

Braces/servo mount

Hardware

Body mounts

Wheels/tires

Bumpers/sliders

And of course electronics. I’m not gonna get into the realm of “superlight” or “comp” builds since you can always steer your build that way from the start, this is a general build post to get you in the ballpark. The brands/vendors I mention are those that I’ve had direct experience with but are no means the only option you have or the best option. I’ve recently built a TGH Sherpa and a GSpeed V3 so many of my examples/info may reference these two options but can be adapted to other variations. Also, some companies may sell a “bundle” that’s designed around a certain platform that may help those in the beginning. Also be aware that if you are leaning towards a “comp” build you may have to adhere to specific rules based on the class you plan on competing in.

Let’s get started:
Start with the chassis you have some direct experience with (maybe a local with a similar setup) or a build on here. My first purchase was on the recommendation of a fellow RCC poster who was very accommodating of my questions, thus leading to my choice.

The next choice may be the hardest since you’ve got to pick a skid based on the transmission you plan to use. Some companies offer a skid with many mounting options and some offer a few based on some popular comp style of transmission. Most will be machined delrin which is very dense and machines very well but I recommend getting a 3mm tap to aid in the build.

My chassis choice led me into what transmission to pick since they offered a bundle (making many of the choices simpler).

My choice of axles was based on a currently used rig of mine, making the “cost” slightly cheaper though you can pick up some axles prebuilt (like the 10.3 straight axle kit) or something like a Boom racing/Beef Tubes/SSD where you purchase parts/pieces to make up what you need.

Shocks were again an easy choice since I used the shocks from the car that was generous enough to donate its axles! Again, Traxxas GTS or Big Bore, Dravtech, Enduro, as well as some other options are out there if you want to truly go all custom. Don’t forget to take into account the length of shock to complement your axle choice (i.e. portal axles so slightly shorter shocks).

Links are available from a few places, depending on your choice of chassis and the material you wish to use for the actual links. I’ve bought more than a few sets from In The Works RC but Hardcore RC is another option if you want something a little more specific (like Titanium or Brass as well as straight or high clearance). Also make sure that you verify the wheelbase you plan on having since in some cases you may be able to have a super short link for an 11.0” WB or super long 12.8” WB.

Driveshafts come in many configurations from a simple plastic Axial wildboar to an Element plastic/aluminum up to an metal MIP/Supershafty/Boom Racing. One of my rigs uses a separate motor mount and transfer case so I needed a third driveshaft. If you plan on using an Axial style 3 gear (or Vanquish version or Enduro version) you’ll only need a pair. Also make sure that you refer to the original build plan/link length since you may stretch out a standard length shaft and need to purchase a few option pieces to make your driveshaft match your WB.

One place to make a choice is the servo mount/bracing. Some companies like TGH sell a two servo upright mount that’s found in many kit or RTR models like the 4-10 or Enduro. GSpeed offers a G-LD mount to lay down the servo if you are in the realm of a lower center of gravity. Some chassis choices (like the 4-10 chassis kit offer molded plastic braces which makes the chassis very rigid) but a flat plate chassis will need some additional braces. The common size of 67mm will allow you have a wider skid plate and narrower front and rear allowing the chassis to be “pre-loaded” to help create additional stiffness.

As for hardware, you’ve got one choice in my book: KNK. They offer a “Monster Bag” that should get a great start. You can always use what you’ve got laying around but it makes it a big help to have it all there in one place.

While you’re planning your build, I suggest you also think of what body you plan on using. Look at both GSpeed and KNK for some awesome machined aluminum body post mounts since you may need to get creative.
Wheels/Tires are a personal choice and I won’t go much into options other than making sure you’ve got a big enough wheel to cover the axle option you chose. This also may be an area where your rule book may narrow your options.

One last thing to think of are bumpers/sliders. Some companies make bumpers to go along with the 67mm spacing like The Crawl Space but you could also try Werty, IERC, DSM Offroad or a ScalerFab version. Sliders can be custom versions like what GSpeed offer (one version allows you to mount certain hard bodies) and others have provisions for a strap to hold down your battery. You can always break out the torch/welder and make your own if you want to set yourself apart, but that adds complexity and time to an already lengthy build.

Don't forget electronics. This is one area where there won't be a right or wrong choice, but a little forethought will save you some headache in the future. You'll need to make two significant choices, servo(s) and motor/ESC combo. I would choose what servo you are running first since that can shift what specs are important when it comes to picking an ESC. A direct power servo can allow you to run a smaller/lighter ESC, whereas a standard servo will need a beefy BEC (I would recommend an outboard version, make sure it's wired correctly to support your receiver/ESC). If you plan on using a winch will also play into the BEC/ESC choice. Also verify that your winch choice has some way to control it, either built in like the Holmes or Reefs version or a separate one like a HeyOK version. There are pros and cons to both brushed and brushless (I won't go into all of that here) but I will say that I have both!

In closing, this is not meant to be the hard line to follow. Some people may have an extra transmission laying around which leads to which skid to choose. Or a set of axles…this can start anywhere and go anywhere! One last thing to consider, batteries. Most of these build will use smaller than normal batteries. I use a 3S 1300 mah pack in one rig and a 4S 1500 mah pack in the other with about an hour of runtime. The slider/battery mount won’t handle much bigger unless you start with a builders kit from Traxxas/Axial/Enduro or Vanquish. The most important part is to get out there and have fun.


Feel free to add what you’ve experienced when building your chassis to this!

[HumboldtEF]

Hey nice idea starting up a thread for this

Regarding delrin or an other plastic thats really tight when threading and you dont have a tap try using some chapstick or wax on the screw first. Then if you need to take a step further you can use a drill to thread in the screw quickly which will heat up the plastic and slightly melt the treads in but thread the screw in first. Be careful if you're working with something with very little thread depth as you may strip it out.

3D printing can come in very handy for prototyping and making brackets, spacers, mounts, battery trays you name it. I've also made a ton of jigs to be used making various metal components, transferring bolt patterns, making sheet metal brackets or just parts for mock up purposes. It can also be good for making panel templates to be transferred to lexan or maybe sheet metal.

Patience is key, I enjoy building and have plenty of rigs to enjoy so I can usually resist the temptation to slap something together in a rush. IMHO taking your time can really be worth it and give the best results. Sometimes I get stuck on a certain aspect of the build and I'll take a break while I wait for the solution to come to me.

[twade984]

Thanks for the write up, that must have taken a minute.

[Lashlee]

Thanks guys!! I'm like you Humbolt, I've got a few other rigs to drive that I can wait on getting the correct part ordered instead of rushing to get it together.

And it didn't take too long, especially since I was bored at work with nothing better to do. Hopefully someone will find some benefit to it in the future.

[ScaleLifeNewbie]

Awesome post Lashlee! This will definitely help people, including me




_________________
SCX10 ii
TRX4

[dna4engr]

Thanks for taking the time to write this up. If I could make a couple suggestions based on my personal experiences.

Maybe edit the title from "custom rig guidelines" to something more along the lines of "custom rig assembly guidelines" or "custom rig selection guidelines". I don't say this to be critical, only that there are tons of truly custom builds on this forum and SBG where parts are scratch made from the chassis, body, skid (hell even sometimes axles). I've made more than a few custom tube chassis and rail chassis rigs.
Starting from scratch or starting from a base. I only make the suggestion as it seems your intent is to give new people to the hobby some background on how to buy parts that mostly will just bolt together to make a customized rig without having to have fabrication tools.

The other suggestion I'd make is to put hyperlinks to some of these suppliers, then if people add suppliers in the comments section, you can add them to the OP.

I'll put one here for you

https://www.fishscrawlerparts.com/shop.html#/ for chassis, skids and shocks

powershift RC for winches, lights, and other electronic components

Last suggestion I'd make is if you wanted to put some info on electronic selection. The biggest questions that get asked on FB all the friggen time are "what is the best motor for my TRX4" or "what tires should I run on my Capra"
Harley did an "ultimate wraith" spec thread years ago. maybe even an "ultimate scx10" spec thread years ago. Talking through where to start and what upgrades to make. It's likely out of date.

Maybe the best option in the electronic space isn't to pick out esc, servo, or motor brands, but talk about what components you need to use.
Like if you are going to run a high power servo, get a BEC, but make sure you wire it correctly (many people fry something because they didn't unhook the bec power wire from the esc when they plugged their bec into the rx).
If you're going to run a winch, be sure to understand the control that you will need. Not just your winch, but a controller or separate esc, your radio, etc.

Just my $0.02

Thanks for starting something like this. Hope it helps new folks get off to a good start.

[WildsideVT]

Super helpful post. Yes, it seems much easier to have multiple rigs, and be able to take your time getting individual parts ordered and then to make them work. The barrier to entry on doing that for newbies is real. Appreciate the time you took to write this up.

My own plan is to go something like this:

1. RTR plus upgrades (done, and ongoing)
2. Kit for vehicle that compliments my first RTR (straight axle vs RTR w/ portals) plus upgrades
3. Either take one of the above vehicles and begin swapping over parts to custom chassis, etc., OR start from scratch and build up

Good to know I won't get bored or weighed down by too much extra cash laying around anytime soon.

[Lashlee]

Originally Posted by dna4engr

Thanks for taking the time to write this up. If I could make a couple suggestions based on my personal experiences.

Maybe edit the title from "custom rig guidelines" to something more along the lines of "custom rig assembly guidelines" or "custom rig selection guidelines". I don't say this to be critical, only that there are tons of truly custom builds on this forum and SBG where parts are scratch made from the chassis, body, skid (hell even sometimes axles). I've made more than a few custom tube chassis and rail chassis rigs.
Starting from scratch or starting from a base. I only make the suggestion as it seems your intent is to give new people to the hobby some background on how to buy parts that mostly will just bolt together to make a customized rig without having to have fabrication tools.

The other suggestion I'd make is to put hyperlinks to some of these suppliers, then if people add suppliers in the comments section, you can add them to the OP.

I'll put one here for you

https://www.fishscrawlerparts.com/shop.html#/ for chassis, skids and shocks

powershift RC for winches, lights, and other electronic components

Last suggestion I'd make is if you wanted to put some info on electronic selection. The biggest questions that get asked on FB all the friggen time are "what is the best motor for my TRX4" or "what tires should I run on my Capra"
Harley did an "ultimate wraith" spec thread years ago. maybe even an "ultimate scx10" spec thread years ago. Talking through where to start and what upgrades to make. It's likely out of date.

Maybe the best option in the electronic space isn't to pick out esc, servo, or motor brands, but talk about what components you need to use.
Like if you are going to run a high power servo, get a BEC, but make sure you wire it correctly (many people fry something because they didn't unhook the bec power wire from the esc when they plugged their bec into the rx).
If you're going to run a winch, be sure to understand the control that you will need. Not just your winch, but a controller or separate esc, your radio, etc.

Just my $0.02

Thanks for starting something like this. Hope it helps new folks get off to a good start.

Great suggestions!! Unfortunately I can't change the title, maybe a moderator can. I'll add some additional info on the electronics section!