Different direction: TRX as solid-axle basher (sort of like racing clods)

[smirk-racing]

Hi all,

I am looking for advice on how to modify, adjust and tune my TRX-4 to be more of a general-purpose basher vs a crawler or trail truck. I don't intend to send it like an Arrma but I'd like to hit 1-2 foot jumps and blast around the yard at medium speed.

I know this is not the typical route for the TRX-4 but I like the truck and wanted to try something different. I don't have access to much in the way of cool crawl spots or even decent trails in the dense area where I live, so backyard bashing with small jumps is basically all I have.

I really enjoy the variety of the lockable diffs and two-speed transmission, which my racing clod does not have, so I think this can be a fun and unique truck.

I'm looking to accomplish a few things:
1. increase speed - easy enough to do by removing portals (that alone will probably deliver enough speed on 3s)

2. improve turning - I've ordered some 10mm extended axles, so the total of 20mm increase in track width might help

3. Lighten it up - lightweight pick up body, remove excess plastic fenders and other bits (I don't run in mud or wet conditions - just grass and dirt around the house)

4. Improve jumping - right now the truck bounces over even modest jumps. I am looking to tame that and get some real damping.

I realize all of this will take away from crawling / trailing performance, but that's ok.

Any advice on how to transform this rig into a basher would be much appreciated. In particular, there was a kit for SCX10s (by RCBros) that would bring the lower links down by about 2 inches, but I've not seen any kit like that for the TRX-4. If anyone knows of any parts like that, I'd be interested.


Thanks!

 

[Inspector86]

Good luck!

 

[Mud bogger]

It might be worth looking at the gearing break down harley designs did on his you tube vids and take away the gear reduction from the portals then plug in the reduction from the under drive ring and pinions? Just a thought but mite be worth looking into. Id be curious of the out come.

 

[OSRC]

The portal delete kit really changes the gearing and lowers the COG of the entire truck. Pricey though. It's almost cheaper to swap in some other axles, though you lose the diff lockers.

You can certainly get the gearing in your range with just pinions/spurs. The TRX takes some absurdly large pinions for some reason (I run a 9t in my trucks and it's still speedy in second gear) running a 22t pinion/39t spur gear gives gives you 11/28:1 gear ratio in first and second gear respectively. That's a pretty tall gear, I can't even fathom how fast that would be hauling. That's 2.5 times faster than stock gearing.

What size tire are you planning on running? That makes a large difference as well.

 

[JatoTheRipper]

Welcome to the site!

Very cool project and I can't wait to see the build. Please post up photos as you go.

Kevin Talbot has bashed the TRX-4 on 6S. I think you'll be just fine with light bashing.

https://www.youtube.com/watch?v=sIQrIwD69kQ
https://www.youtube.com/watch?v=pcUDtmNXGLg

 

[JatoTheRipper]

Welcome to the site!

Very cool project and I can't wait to see the build. Please post up photos as you go.

Kevin Talbot has bashed the TRX-4 on 6S. I think you'll be just fine with light bashing.

https://www.youtube.com/watch?v=sIQrIwD69kQ
https://www.youtube.com/watch?v=pcUDtmNXGLg

 

[smirk-racing]

Good luck!

Thanks! We'll see how it goes.

It might be worth looking at the gearing break down harley designs did on his you tube vids and take away the gear reduction from the portals then plug in the reduction from the under drive ring and pinions? Just a thought but mite be worth looking into. Id be curious of the out come.

I will check out that video - there are a lot of gears to sort out, and of course the 2-speed.

The portal delete kit really changes the gearing and lowers the COG of the entire truck. Pricey though. It's almost cheaper to swap in some other axles, though you lose the diff lockers.

You can certainly get the gearing in your range with just pinions/spurs. The TRX takes some absurdly large pinions for some reason (I run a 9t in my trucks and it's still speedy in second gear) running a 22t pinion/39t spur gear gives gives you 11/28:1 gear ratio in first and second gear respectively. That's a pretty tall gear, I can't even fathom how fast that would be hauling. That's 2.5 times faster than stock gearing.

What size tire are you planning on running? That makes a large difference as well.

Yes, the SSD portal deletes are extremely pricey, unfortunately... I am keeping them in my wishlist, and for now just moving forward with the portals as they are while I work on other aspects of the truck. I am enjoying the diff lockers. I reconfigured the servos so I can get: all open, rear only, rear+front locked. Most folks like the stock "front only" option which is good for crawling but rear-only is fun for whipping the back-end around on loose surfaces.

I've got the 10mm wideners on the way, so hopefully that, plus wider tires, will give me some stability.

In terms of tires, I was looking for 2.2 MT tires and there are a couple of options, but I am also considering 2.8 Mashers. They are a bit large/heavy, but they are very "monster truck" and they provide a lot of damping themselves. They're not all that different in terms of diameter from the stock tires, though, so the gearing won't change a great deal.

 

[mass-hole]

Longer travel shocks with stiffer springs for taking the hits? Stock springs dont seem like they could handle much.

 

[smirk-racing]

Longer travel shocks with stiffer springs for taking the hits? Stock springs dont seem like they could handle much.

Yeah, probably. I have some proline shocks from another built I can use.

Axle wideners (10mm) came today and are installed. I'll test them out tomorrow.

 

[Shinchu]

I have really been thinking about doing the same thing. Like a U4 rig with a stock H frame. The remote diffs lend themselves perfectly to make it both a go fast and crawler.
Just a mamba x and portal deletes would be 90% done.
My next project is either this or a tamiya scorcher.