Episode 2: Drivetrain | How to build your own rock crawler/buggy/bouncer

[@mhmdozeir3839]

Hello great work bro, could you tell us more about the type and the sizes of the tubes (thiknesss and diameter and stuff..)

[@JM0097]

Great Job 👌 Do you have plans for chassis build?

[@rgsabat]

Thank you, I don't have chassis plans.

[@kentmaulson8716]

This is great George, looking forward to more cool stuff.

[@rgsabat]

Thank you Kent!

[@dirtrider6090]

Can’t wait to see the rest of the build I’m just starting to watch all the episodes!! What type of differential are you using? Never seen them, I like how u explain everything very good video

[@rgsabat]

Thanks, these are 2.5 ton Rockwell axles, they come from military trucks.

[@LMG6989]

How do you determine/set ride height on a rock crawler buggy? Obviously lower the COG is best, but how do you balance lowering COG without sacrificing ground clearance,shock travel, or having the rockwell top hat contact whats above it?

[@rgsabat]

Good questions. It all depends on the terrain and what you use the buggy for, it is different for rockcrawling than hillclimbing. It also depends on the wheelbase and personal preference. That's why when you are building a chassis, It is best to start by laying the drivetrain in place at full suspension compression. For instance, If you know you want 8" shock shaft showing at ride height and you want 22" belly height at ride height, you set the lowest part of the drivetrain at 22"-8"=14" above the ground (or neutral plane), plus you add 1" for safety and the thickness of belly skid/braces. Once you have these measurements figured out, you build everything to match. I lay the drivetrain at about 6 degrees titled back, with the transfer case clocked as flat as possible. After that, you are almost guaranteed that the lowest part of the drivetrain will be the back part of the TC. You set the axles at a height equal to the belly at full compression. This is one way to do it, there are a ton more ways to build a chassis and everyone has their opinion. It took me several tries to figure it out, maybe by sharing what I learned, it will save someone time.

[@LMG6989]

@@rgsabat Thank you so much for your reply! You answered my follow up which was do you build at full compression from the start. That makes total sense and what I wanted to verify. My buggy is going to be built for high dessert rock crawling. The big event we have here in NM is the Chile Challenge in Las Cruses,NM. I wanted to build for mainly rocks, dry waterfalls, and high desert landscape of the SW USA (UT, NV, NM, AZ, and probably CO. My next decision is to run driveline disc brakes or hub disc brakes on 2.5 rockwells. Thank you again for answering my questions and this will definitely save my time on layout and building. Are your axles locked all the time or what kind of differential do you run?

[@rgsabat]

@@LMG6989 Yes, my rockwells are locked at all times, I have Ouverson spools front and rear, simple and strong. No issues with turning because I have rear steer too. Hub disc brakes are nice for sure, but they increase total track width unless you cut down the long side of the rockwell to use 2 short inners. I never had any issues with my driveline brakes (front and rear are operated by different pedals and totally separate systems, I press both pedals at the same time to stop). However, I am not sure how well they would be descending a long steep slope because the driveshafts are spinning 6.7 times more than the wheel hubs, so there will be brake fade in this case . You are lucky to be off-roading some of the best places in the continent, enjoy :)

[@LMG6989]

@@rgsabat I had a couple more questions if you don't mind. 1.Does heim joint orientation matter. Correct me if I am wrong, but I thought I saw on your rig that the axle links are essentially mounted vertically (bolts go through horizontally) and the frame links looked like they were mounted in a horizontal orientation (bolts go through vertically). Is there any benefit to mounting in this orientation? 2.What degree of shock angle would you consider as excessive when building your suspension? Does shock angle even matter whether that angle is front to back or side to side for proper operation? Thanks again.

[@rgsabat]

@@LMG6989 For (1), you can mount your heim joints in the direction that you want, as long as you can flex the suspension through its entire travel without the heim joints binding. I chose to mount my lower links frame mount heim joints with the bolts vertical because, with the links triangulation, the him joints could withstand with strong side loading without them breaking (example a side hit on the tire would be transferred to the links and the heim joints would be in the best position to absorb the hit). For (2), yes, shock angle matters according to the cosine law (you could use trigonometry to calculate the actual numbers), but to sum it up, the larger the tilt angle, the more you have to increase the spring rates and the worst the shock dampening. Ultimately, it's all about packaging, you want your lower shock mounts as far apart as possible on the axle to maximize stability, but you also want the upper shock mounts to be inward to protect the shocks during rollover. I would not worry about the shock angles as long as they are below 10 degrees in any direction.

[@peterbuilttough3406]

Great vid! You've inspired me to build my own rock buggy, I'm almost done but I have little knowledge of selecting the right camshaft I'm running a 496 with efi intake. Any recommendations I would like something competitive?

[@rgsabat]

Thanks. Camshaft choice is not easy to make, it really depends on a lot of factors, including how stout the engine short block is, how much does the heads flow, exhaust size, drivetrain, etc... You need to set a HP goal in mind and work from there to get what you want. I personally prefer all forged bottom end for an engine that makes over 500 hp. Plus, you need to match the camshaft with the torque converter, otherwise you won't be happy with it. Anyways, I can't really give you valve lift numbers and duration for the cam because it depend son many factors. I recommend that you talk with an engine builder so he can get you what you need. good luck.

[@peterbuilttough3406]

@@rgsabat awesome thanks!

[@timbollinger3209]

Yes please continue, vary interesting to say the least, keep them coming 👍🏻

[@rgsabat]

Thank you for your comment!

[@ИванАндреев-у8т]

Hello! Tell me please, what transfer case do you use?

[@rgsabat]

atlas 4 speed

[@1096Ghost]

Again awesome video, love you more and more mate :D more episodes

[@rgsabat]

Thanks!

[@Dreadz530]

Would it be possible to get some. Better dimensions on the main double frame? What's the length of the bars that are between the two?

[@rgsabat]

They are 11" top to bottom.

[@ladicinappe80]

Very Nice build buggy car, need to learn bulid at indonesian hehe..

[@mrmidnight32]

How much did it cost to build all this?

[@rgsabat]

I didn't really keep a tab on the total cost because I have been re-using some of the same components that I have collected for years. A guess would be around 30-40k$.

[@bertsbug]

@@rgsabat wow

[@hghlyoffensve2850]

You should keep making fabrication videos you do a good job

[@rgsabat]

Thank you so much! I will have a new video up soon.

[@Matthew_931]

Hey what about a $10,000 budget or under that

[@rgsabat]

Sure, why not. I have seen it done before. Use a junkyard engine, trans and transfer case, plus the price of steel.

[@Douw_Steyn]

Awesome!!

[@rgsabat]

Thanks

[@theredheadredneck1781]

What are those axles called

[@rgsabat]

2.5-ton rockwells