Matt's AR60 based MT

[marinearmeni]

Nice! Who cut the chassis for you?

And where did you get those blue wires for your Castle ESC?

There's a local water jet company that I use for prototyping parts. They have a quick turnaround and a low order minimum.

I'm pretty sure the wire is Deans Ultra Wire. It could also be Novak, neither name is printed on the wire, but those are the only 2 types I ever really buy.

 

[marinearmeni]

My 3D parts had a shipping delay but I couldn't wait for them to arrive before giving the truck a quick test run in the street last night. I drove gingerly around at first to just a feel for it, then gave it a quick burst of throttle and heard some clicking. Crap, I’m thinking I forgot to tighten the motor mount and the spur stripped. I walked over and inspected - spur is fine. Weird. I drove around a little more and it seemed fine. So another quick burst and it clicks again. Now I’m thinking I didn’t tighten the pinion down tight enough on the motor shaft. Bring it in, pull it apart and the pinion was nice and tight. So now I’m a little stumped and it’s nearly 11 at night. No way I can go to sleep without knowing what’s going on. I continued to drive around, got the clicking, then lost almost all drive. Looking at the truck outside in the dark I thought I snapped the rear center diff outdrive or broke a spider gear. Brought it in and I disassembled the center diff and realized I left the e-clip that retains the gear/outdrive off when I initially assembled the diff. :roll: I think I’m so used to building diffs that retain the outdrive with a pin that when I looked at it I thought it was ready to install.

As the suspension compresses the center driveshaft pulls out of the center diff drive cup. The friction of the pin on the cup pulled the cup with it, pulling it straight out of the diff. It was clicking on the internal gear since it was only partially in. It would slide back into place and seem fine again at low speeds. pretty tricky problem.

Rebuilt everything last night (also went up in center diff weight from 30k to mostly 100k with some 30k mixed in) and did another test run this morning. Truck felt pretty good but underpowered, took too long to get up to speed, and the brakes felt much too weak. I felt the esc and motor and both were hotter than they should have been. Head back in and re-check my gearing calculations. I had this system installed in my ET410 and liked the speed and performance it had, so I worked backwards from that truck to get my gearing for this truck. I looked at everything and saw that I had put the diff/pinion ratio at 4.3 and not 3.3. Pretty big difference, lol. I swapped out my 15 tooth pinion and installed a 10 tooth. Re-ran and it was great! Nice snappy response, I actually had to turn my brakes down, and top speed seemed like a good pace. So now I’m just waiting for the strong 3D parts to
get here (should be today) so I can drive the truck harder without any worry.

 

[svt923]

So when do the new Tekno monster truck axle get installed?

That is the whole point of this build, right? :lmao:

 

[marinearmeni]

So when do the new Tekno monster truck axle get installed?

That is the whole point of this build, right? :lmao:

I really wish the straight axle monster truck market were big enough for us to do that, but unfortunately that's not the case . I will probably design and 3D print some axles based on our EB410/ET410 cars for me to run around, but that's about it. I'd like to use our SCT410 parts as the diffs would be bulletproof, but using those axles would make the truck much too wide. Also the clod wheels/tires fit onto our ET410 with no mods so that also makes it easier for me to use the spindles and other parts from those cars.

If I do start a build around all Tekno parts, I will definitely start a thread on it.

 

[marinearmeni]

Couldn't resist jumping with my home printed parts Shocks need some tuning but I'm pretty happy where it's at for a first run.
Quick slomo video

 

[AK KRAWLER]

That was awesome man!

 

[RedRider]

Mind if I ask what body mounts you are using. I have a project I think they may work well on. Thanks!

 

[marinearmeni]

Mind if I ask what body mounts you are using. I have a project I think they may work well on. Thanks!

Lol, well... those are actually a cut up prototype Tekno part from one of our kits. Something similar would be the body mounts for the Losi SC truck, Losi body mounts on Amain.

 

[RedRider]

Thanks! I could tell it was a cut up part but searched all the Tekno kits and came up empty. Appreciate the heads-up on the Losi part.

 

[JatoTheRipper]

There's a local water jet company that I use for prototyping parts. They have a quick turnaround and a low order minimum.

I'm pretty sure the wire is Deans Ultra Wire. It could also be Novak, neither name is printed on the wire, but those are the only 2 types I ever really buy.

Thank you. I may have to try the Deans Ultra Wire. I doubt I'll be able to find much Novak wire (RIP Novak ).

Cool video. It jumps perfectly - just a little rough on the landing, but you can fix that like you said.

 

[marinearmeni]

Got a few more videos up, shocks still aren't where I want them. Had them tuned with very little pack and slow rebound before, now they have too much pack and the rebound is much too fast.

full throttle launch

highest jump of the day

fairly flat landing

little nose down

little whip after going off the unsupported side of the ramp

 

[MaX-D]

What servo are you using?

Sent from my LM-G710VM using Tapatalk

 

[marinearmeni]

What servo are you using?

Sent from my LM-G710VM using Tapatalk

It was a Highest servo. I couldn't find the specs for it but it was a high speed and torque servo. Having said that, I stripped it while running on the off road track at Revelation Raceway. I put in a new one and made a servo saver combining the Proline one and some Tekno parts. Going to test it out tomorrow.

 

[marinearmeni]

So I tested my servo saver on Tuesday at Revelation Raceway again. I'm pretty happy with it, it could have been set a little tighter but for being loose it worked really well. I took the Pro-Line big hit servo saver and modified it to hopefully make it a little better. I tapped the spindle side of the aluminum post for M4 threads so I could use Revo rod ends. On the other end I used a throttle rod from a nitro buggy that has M3 threads on the end. The I took our NB48 2.0 aluminum throttle servo horn so I could use its bearing supported pivot ball. It held up quite well but the throttle rod did start to unthread from the aluminum post, I'll just need to use more loctite.

 

[svt923]

Nice job on the servo saver. "thumbsup"

That simple part has been the biggest problem on my SMT10 when running the Clod sized tires. I have sheered all the teeth off a Protek aluminum arm and mangled an all metal HPI servo saver setup in the first 2 runs. I'm back to the good, old Kimbrough unit but still on the hunt for a better option. This looks like it has potential.