New MT410 Build - thoughts on gearing

[mvppsu]

Tekno MT410 Kit
Tekno Aluminum Servo Horn
Tekno Aluminum Spur Gear
T-Bone Basher Front Bumper
T-Bone Wheelie Bar
T-Bone Mud Guards
Derlin Shock Bushings
Aluminum Shock Collars
Aluminum Shock Nuts
Savox 1210TG Servo
Castle MMX ESC with B-Link
Hobbywing Xerun G2 2250kv Sensored Motor
Tekno 15T pinion
dBoots Backflip Tires
Pro-Line 2014 Chevy Silverado Body
Futaba 3PRKA Transmitter & receiver

This was my first ever kit build and it went together pretty easily. It did take longer than I expected, but I didn’t run into any problems. The quality is top notch, maybe even better than I was expecting. I can clearly see and appreciate the difference compared to my Arrma Typhon. I’ve only run it a few times, but it performs really well. Handling is awesome for a truck this size with this much suspension travel. I find that its really easy to drive and control compared to the Typhon, which can be a beast, at least on 6s.

I do have a few issues though.

First, one of my rear shocks is leaking from the bleed hole that I drilled according to the instructions. I saw another post from someone that had a similar problem. I ordered new bladders and aluminum shock caps and hope that fixes it. After a few runs I’ve lost most of the fluid from that shock and it is no longer useable like this.

Next, after my first real bash, I have mostly destroyed the body that I spent a lot of time painting. I think trimming a bit more lexan off the front and rear would help a little since the body was hitting the bumpers when I flipped it over. Giving it more room to flex may help it bend more before cracking. But, I still don’t see the body lasting very long on this truck. There is just no support when it flips over other than the lexan. I even taped it with drywall tape and gave it a coat of shoe goo, but I didn’t cover the entire body and it seems to have cracked everywhere I didn’t tape it. It would really benefit from an under-body support similar to the Arrma Kraton or Outcast. Anyone have any other tips? What is the most durable body for this truck?

 

[mvppsu]

And lastly gearing... The MT410 is based off of a buggy platform and as is stilled geared like a buggy. Since its restricted to a minimum of 15T pinion, its hard to get a low enough gear for its weight when running big tires like the backflips. I should have spent more time calculating this before I chose a motor. The 2250kv motor is probably too high for the weight, tires, and minimum gearing.
On my last run, I had the motor temperature cutoff set to 180deg and hit that with about 15min of hard running on 4S with an ambient temperature of ~45deg. I only measured 155deg with my temp gun on the outside of the motor, so I upped the cutoff temp to 190 and did not hit it again, but I ran out of battery soon after. I don’t have a lot of experience with this, but that seems too high. And I expect in the summer when the ambient temperature is much higher, I’ll have even bigger problems. I know others are running a similar setup? Am I stressing about nothing?

The attached chart shows my calculations. I show the MT410 gearing with Tekno’s recommended motor and tires as well as my current setup. I then list the max performance specs from Hobbywings manual and the stock Arrma vehicles for reference. (The weight for the MT410 is my measured weight setup as shown above).

Based on max specs provided by Hobbywing, the fastest the 4274 size motor can push a truck of this weight is 43mph on 4S or 65mph on 6S. Right now, my gearing gives a theoretical max speed of 52mph on 4S. So, I can either run smaller tires or move to a lower kv motor in order to gear down. And I don’t think I want smaller tires given the terrain I typically drive on. I think I will eventually move down to the 1550kv or 1700kv Hobbystar motor, which will get me below the max speed threshold for this size motor and give me some gearing flexibility. This will allow me to run 4S with a slightly larger pinion or 6S on the 15T. Does this make sense?

 

[jason.g]

Check out eBay RC maniacs unbreakable bodies. They ship from Russia so it takes a couple weeks or so...but very bodies. Check YouTube and Tekno mt410 bashers group on Facebook for some pics and examples. https://www.ebay.com/str/RCManiacs/

 

[performula]

You can reinforce your next body with drywall tape and Shoe Goo/E6000. Buy it from a craft store. I think I found both large tubes at Joann $1-1.50 less than Home Depot ($6.46). Lowes only has 2oz tubes.

You could reinforce the whole thing after the tape/goo method, with 3M undercoating, inside and out, and get the same look as those reinforced bodies.

I still do not know if those are built from scratch. I’d like to buy one to see if lexan is sandwiched in between.

 

[mvppsu]

Thanks guys.

I took apart the leaking shock and discovered that the bladder might have been pinched or not seated correctly. I reinstalled the same bladder with an aluminum shock cap since I had already bought them, and it doesn't seem to be leaking after 1 run.

I also ordered one of the unbreakable bodies from Russia. I like that they now come in multiple colors. I ordered a blue one! Until it gets here I'll add some more Shoe Goo and drywall tape. I'll probably continue to use standard bodies since I like the more scale look, and switch to the unbreakable when I plan to do more serious bashing and jumping.