Trx4m bronco torque twist

[Martin trj]

Ok so here is my next project…my bronco has a lot of torque twist. I bought it already upgraded and as far as I can gather it has a powerful and fast Meus motor along with the transmission with high speed gears. Also the 59mm injora shocks but I have no idea what oil weight they come with, can’t be too thick since the torque twist sinks down the rear passenger side. I’ve watched a couple of videos and they suggest heavier rear shock oil. How heavy would you guys go with or what other solutions would you suggest?
Thanks

 

[WickedFog]

The best way I know of to get rid of some of it is by adding more droop (softer springs), and adding a tad more pre-load to the right rear shock. But it's a catch-22. Softer springs might make it worse. More droop may make it so it can't dip down as much on the right, but then it could lift the left side up as well. Changing the oil weight may help, but I kinda doubt it. It may be less noticeable getting on and off the gas, but you can't get rid of it completely. Looking top down, I assume your driveshafts rotate the same direction, both turning towards the driver's side of the truck at the top of the shaft? Or do they rotate opposite each other? I would think if you had a transmission that has them running reverse from each other, that would prevent it. Never had a small scale crawler that did that too badly, so just taking stabs at a solution.

But it could also be a little binding in the drivetrain. I would test the axles and make sure you can rotate them freely. Check the bearings on the pinion input shaft, and at the axle ends behind the wheel hex.

 

[Weezel]

You said you bought the truck with the upgrades already installed. Just a possibility, but have you checked to see if the shocks have oil in them? You never know. Lol
I don't believe any of the Injora shocks come with oil so it'll definitely be anyone's guess. The stock shocks from Traxxas are filled with SAE-20w.
I don't remember my TRX4m Bronco having any bothersome twisting. (But it was stock. )

 

[WickedFog]

Do you have your wheel lugs too tight?

 

[Martin trj]

You said you bought the truck with the upgrades already installed. Just a possibility, but have you checked to see if the shocks have oil in them? You never know. Lol
I don't believe any of the Injora shocks come with oil so it'll definitely be anyone's guess. The stock shocks from Traxxas are filled with SAE-20w.
I don't remember my TRX4m Bronco having any bothersome twisting. (But it was stock. )

So let’s day they’re empty, I have some 25 SAE-wt oil.
I will check the shocks and wheel lugs when I get home.

 

[Martin trj]

So it has the “high speed” gears. I might start by swapping those to the crawler ones. Shocks have oil (30 SAW-wt), all the bushings have been replaced with bearings and nothing was over tightened. I can only assume it is the speed of the motor creating the torque twist.

 

[Weezel]

I can picture what you're thinking. If it's jumpy on take off instead of having a smooth startup on acceleration the truck will rock.

 

[Lostinthewoods86]

So it has the “high speed” gears. I might start by swapping those to the crawler ones.

Can also have both if you would like

https://www.amainhobbies.com/traxxas-trx4m-two-speed-transmission-tra9891/p1569443

Edit: meus also has a 2 speed that has provision to add servo to operate the shifting

https://a.co/d/aGIzO5Z

We have this on one of our trx4ms


Another edit:just went back and saw you were still running the stock esc/receiver so that would have to go for the meus to work with servo. It can be manually shifted but the Traxxas one looks easier to shift then the meus

 

[Martin trj]

I can picture what you're thinking. If it's jumpy on take off instead of having a smooth startup on acceleration the truck will rock.

Yep, a jolt of speed. Not so sure I want speed. Maybe a motor with more torque and less speed but maybe the crawler gears will do that.

These maybe?

https://a.co/d/1gMieeJ

 

[Martin trj]

Can also have both if you would like

https://www.amainhobbies.com/traxxas-trx4m-two-speed-transmission-tra9891/p1569443

Edit: meus also has a 2 speed that has provision to add servo to operate the shifting

https://a.co/d/aGIzO5Z

We have this on one of our trx4ms


Another edit:just went back and saw you were still running the stock esc/receiver so that would have to go for the meus to work with servo. It can be manually shifted but the Traxxas one looks easier to shift then the meus

So what would I have to swap the esc/receiver combo to in order to being able to swap to the meus transmission? Being able to shift remotely would be awesome!

 

[Lostinthewoods86]

So what would I have to swap the esc/receiver combo to in order to being able to swap to the meus transmission? Being able to shift remotely would be awesome!

This is our set up, we used the radiolink rc6gs for rx/tx, but you would only need a three channel radio to add remote shift. We got 4 wheel steer on this one so we needed at least 4 channels

We used the Injora brushed esc. I wouldn’t recommend it. Furitek would be the best esc to get I think. We have one in our ax24 and it’s great, will likely be what I put in this one too eventually. My main issue with it is it only goes 50%throttle in reverse.

I’m new enough to this to only know what not to buy

Oh you also need a micro servo to shift it, it doesn’t come with one. We just used the original Traxxas steering servo for that

 

[Martin trj]

I love furitek, my deadbolt and wrangler have the lizard pro paired with a micro Komodo. That thing is awesome!

 

[Martin trj]

…so what about this?

https://a.co/d/7VnaOy9

 

[Lostinthewoods86]

I'm not sure about that, but I also forgot wicked posted this a little while ago, have you seen these yet?

https://furitek.com/products/furitek-unity-pro-3500kv-2-in-1-micro-foc-brushless-system-for-trx4m

They still pre order right now, I may try it in my daughters bronco

 

[Martin trj]

I guess the solution would be to go brushless but I’ve been spending a bit on these money pits, I’m really happy with the SCX24 trucks and I fully upgraded 2 of the 3 that I own. Not sure I wanna go all the way with the trx4m .

 

[Martin trj]

Done! I replaced the high speed gears and it minimized the torque twist by a bunch. I will have to double check that there’s nothing over tightened.
I was thinking about buying an aftermarket buggy body. Any recommendations?
This? https://a.co/d/00ow6KQ
Thanks

 

[Doom!]

That body looks good installed, Injora also has a nice pickup body too.
https://www.injora.com/products/inj...ack-for-1-18-rc-crawler-trx4m-defender-bronco

 

[WickedFog]

I really like this Meus Racing body for the TRX4M too.

 

[Lostinthewoods86]

Did they update that buggy shell? We did one…

 

[WickedFog]

Did they update that buggy shell? We did one…

View attachment 199395

Yours definitely looks different huh?