Trx4 Sport “The Build”

Welcome to RCTalk

Come join other RC enthusiasts! You'll be able to discuss, share and private message with other members of our community.

This site may earn a commission from merchant affiliate
links, including eBay, Amazon, and others.

Mtbmatty

RCTalk Talkaholic
Build Thread Contributor
Messages
282
Reaction score
242
Location
CT
RC Driving Style
  1. Bashing
  2. Crawling
  3. Flying
We pulled the trigger on a TRX4 sport kit, and wasted no time diving into the build.
We wanted another full size crawler, and I wanted a kit my 9 year old son could work on.
The instructions were great. They were in color and easy to follow. I helped him match up parts, and keep him on track, while he put all the screws in. I needed to start some of them, and finish tightening. I also did the shocks and the paint.

1st up was the transmission. It went together perfectly, which was a recurring theme throughout.
29F87B59-7F1A-467F-BB8C-90187D7ACA00.jpeg

Next up was the axles, and a few modifications that I wanted to make. I was looking to widen the stance a bit, so we installed Yeah Racing 12mm Hex’s w/ 8mm offset. We also replaced the stub axles with MIP wide track kit (4mm offset). I opted to install the Traxxas overdrive gears and Lastly we replaced the stock front diff cover with a brass one from Samix.
3CC83BFC-05FC-4970-BF94-BF5E0F61E078.jpeg


The frame was up next followed by the electronics install. Opted to install the narrow fenders which comes with the up front battery tray.

You need to supply your own battery strap if mounting a shorty pack up front, which was the plan. My only complaint with the build would be the servo mount. It’s a non-issue if using a Traxxas servo. We used a Savox 1210 and made it work despite the mount. The mount has a couple molded posts (where the mounting screws go) on one side so the servo seats nicely. I was able to mount the savox cleanly here, but the opposite side is slightly offset. Again it works albeit slightly annoying.
We also flipped the bumper mounts to improve clearance/approach angles. Doing this required a bit of trimming on the rear of the body.
For the motor I went with the Hobbywing Fusion Pro 2300 kv and stock gearing (pinion was included in kit) spoiler alert this motor is amazing!!
Because of the shorter esc cable I opted to go without the included receiver box. They have it so the wires exit the RX box towards the rear of the truck. I tried to make it work flipping the box around, but it overhangs and interferes with the rock sliders. I may look for another solution; mainly to keep the RX clean as we don’t run in wet condition. Yes, I could have used a cable extension but opted not to. Very happy with the clean look.
5C76620B-40C3-465F-876F-186601306BB8.jpeg


Shocks were assembled, but not fluid filled. I took them apart and put the green slime on the seals (seals were all dry) Decided to use a 20wt oil (TLR 195cst) rather than the stock 30wt. I’m an instant fan of the shock oil, once the air bled out that was it. The team associated oil I’ve used previously seems to keep producing air without end. Shock springs in the rear are slightly stiffer than the front. Overall bleeding the shocks was a pleasure in comparison to others I’ve done, and I felt that all four felt identical once finished.

Next the links are installed on the axles, along with the shocks. Links are preassembled, and easily identifiable. Having the links ready to go is nice in my opinion.
AAF2F32A-20A7-417E-BC1B-2FB6AF901807.jpeg

After that axles, shocks, and links mounted to the chassis and wheels are next.

I wanted to get a set of beadlock wheels that did not have a million micro screws around the outer edge. Bought these Treal wheels and could not be happier! They have 12 screws per wheel. Six bolt the hub to the rim, and six bolt the two halves together they just about fell together. Mounted them with the stock tires; front wheels have the stock foams, while the rear are using the proline dual stage.
82E50DC1-9C7A-495E-9828-CAE375C51D4D.jpeg


The body is painted a Tamiya metallic green (PS-17) we used the whole can. Backed it with a few coats of silver and finally black. I used liquid mask and painted the fenders and the inside of the bed black first. Used Traxxas black paint on that, and will use their paint again; I was very happy with how it went on. Lastly we used tamiya smoke on the windows, they are a bit darker than I intended, but I needed to even out the paint. Super stoked on the finish. The following morning after painting we put on the headlights and taillights and it really gives it a cool look.
Trimmed a small bit of the fenders, just the outer piece that curls down towards the ground To avoid

Last thing we checked all the bolts, programmed the esc, set up the radio (fly sky gt3-b) and cleaned up the wiring.
127F6492-EFD1-4143-8E45-BA37DC731F19.jpeg




only one thing left to do……

First impression: WOW



This thing is stable, it can side hill like a boss, and was super capable climbing. The drag brake is impressive, you can stop anywhere and it will not budge. The slow speed control of the fusion motor is nothing short of freakin awesome!

Stock tires aren’t bad, definitely a pleasant surprise. The sidewalls aren’t too thin so they don’t cave in on themselves easily.

We ran three batteries through it and would have kept going but it was getting late. Overall stoked with the build and the few mods we did.
Although it doesn’t need a heck of a lot more, here are a few things that I may want to play with moving forward.
Tires: vent, cut center lugs and play around with foams

Rock sliders: remove or raise them up level with the bottom of the chassis, they hung up once, but was able to push through.

Shocks: lighter springs and or lighter shock oil.

Brass: rear diff cover, I felt the rear end might have been a little light and slid out coming down a couple times. I would also prefer that it matches the front.

outer portal covers

Lower gearing: stock gearing is 17t pinion and a 39 spur.

F2101900-170F-4F51-A7E3-39DB07A0081D.jpeg


D9EEB9DE-D077-4B77-924D-C74E3DBD0330.jpeg


7603A702-56F0-4ADE-8AEF-7050157F2970.jpeg


8D241C52-CE98-4143-86C6-EB36160AB385.jpeg


..

5BE56D61-38C9-46FF-8175-86F5D82A1E2D.jpeg
 
Last edited:
Looking good. If you want to keep the inside of the truck really clean add the rubber fender extensions and trim to fit. Bashing around in the snow over an hour when I pulled the body off there was barely any snow at all inside. Just the fenders made a big difference but adding the extensions and a modded LCG battery tray keep it very clean inside.

The Fusion Pro 2300 has been great for me so far. I haven't been out much in the last couple months because of weather and an couple injuries but I can't wait to get it back on the trail again.
 
Looking good. If you want to keep the inside of the truck really clean add the rubber fender extensions and trim to fit. Bashing around in the snow over an hour when I pulled the body off there was barely any snow at all inside. Just the fenders made a big difference but adding the extensions and a modded LCG battery tray keep it very clean inside.

The Fusion Pro 2300 has been great for me so far. I haven't been out much in the last couple months because of weather and an couple injuries but I can't wait to get it back on the trail again.
We of course got a little snow when we were finishing up the build, but are fortunate enough to be able to take it to the track where they also have a pretty fun indoor crawling area.
Great write up, and good looking truck. Love the color. :thumbs-up: 😍 :thumbs-up:
We are wicked stoked on the color and how it came out. It’s like having a new baby, you catch yourself just staring at it
 
Love it bro. The color, the wheels, etc. And that looks like one helluva indoor course.
 
Love it bro. The color, the wheels, etc. And that looks like one helluva indoor course.
Thanks man, big problem is only one of us can drive it at a time.
Here is a better look at the indoor course, it’s pretty awesome. You can’t see rhe back side of it but there is some built up stuff behind what’s shown in this video. They also have a huge outdoor course. the place is awesome, and the guys that work there are great.
 
Another great outing with the new truck! Initially used the stock foams up front, but swapped the out for a set of proline foams that came with a set of Hyrax’.
Gave up a little on the side hills but overall a nice improvement. I may put the proline dual stage up front also and try them out.
We were able to drive up this slab, had to give it a goose to hop up and get started. My son was looking from the other side and said the passenger rear was lifting up slightly. Drag brake held no problem. I love this rig!!
C58FF714-9434-4808-A2F1-4C125B0C3038.jpeg
832348D7-B59E-43AB-81A5-3D4A594091B3.jpeg
 
Nice build, the trx4 in all its forms is a wonderful platform. Fusion Pro is really nice, l also have two axe systems. The Se version is not bad either and is only 70-80$, been running that too. You don’t give up much with it.
 
Nice build, the trx4 in all its forms is a wonderful platform. Fusion Pro is really nice, l also have two axe systems. The Se version is not bad either and is only 70-80$, been running that too. You don’t give up much with it.
I was torn, but ultimately went with the fusion pro for the higher amp rating. I saw the difference swapping out the esc on my sons associated buggy. Went from an 80 amp to 160 and wow. Granted this isn’t as dramatic…..
So much to love about the motor. This is only our second crawler and 1st good crawler motor but damn this thing is impressive
 
Back
Top