Changing the stock TRX-4 shocks

[xagoras]

Hi. I have a question about changing the shocks of my TRX-4. Not sure if this is the correct place to ask it, but if it needs to be moved elsewhere, then a mod please take care of it.


So, I got myself a TRX-4 Kit and a hard plastic TRC D110 body to fit on top. The body itself is quite heavy and with all the extra things I put on it, it weights like the 1:1 Defender


My issue is that because of the way it is mounted, the ride height is too high and I don't like how it looks. So I'm thinking to change the stock 90mm shocks to some 80mm or even 70mm ones.



Is that wise to do, since the body will constantly putting all this weight to the shocks? If it won't cause more problems than it will solve, do you suggest any decent set that could be value for money too?


Sorry for the long post

[Phildirt]

Don't own one of those but aren't the fenders part of the body/could you just lower it on the posts a little? I move my truck up and down on the body posts quite a bit just to adjust after making changes to various components and it is much easier than a shock swap if you are just looking to gain or lost a few milimeters. Of course that won't help if it is already sitting on the bumpers.

[xagoras]

I have the inner fenders installed on the front and only the shock towers on the back. It's the ride height that needs to lower.

[Inspector86]

There is more to this than just the length of the shocks. The TRX4 GTS shocks are considered some of the better shocks on the market and are a common upgrade choice for other brands. Which TRX4 model do you have and are you still running the stock spring rates? Traxxas sells a range of GTS spring rates that will allow you to taylor the shock function to the vehicle. Ideally you want to run little or no pre-load on the springs but the spring rate needs to be adjusted in order that the shocks are at about mid stroke when the vehicle is static with it's full weight on the wheels (also referred to as droop). My TRX4s generally run heavy 11-14 pounds and I run the .30 rate GTS springs. Depending on which TRX4 model you have the typical stock spring rate is .45. The other thing to consider is there are a number of aftermarket shock mounts which will allow you to adjust both the upper and lower shock mount locations.

[kincer]

I agree with Inspector86, The TRX shocks are some of the best are around, I would for sure experiment with different springs before I went to a shorter shock. Ride height is sometimes a pain to figure out while still having max suspension performance, well worth it in the end though.

[xagoras]

I have the Chassis Kit, and fitting a TRC Defender D110 plastic body. The rig is quite heavy as it now. But I was going to experiment with different shock oils anyway.

The main reason I was thinking about changing the shocks, was to lower the ride height, for scale purposes. If I change the springs only, I can achieve that?

[Topher Builds]

By changing springs you’d soften it up which then lower the static ride height of the truck, while maintaining all of the travel of the shock. I’d definitely recommend a thicker shock oil if you go that route to help slow the body roll.

You could consider an internal limiter as well, such as a pen spring. Check out pen spring mod on YouTube for an idea of how it works.

Some shorter shock options, incision (80mm), proline, gmade. Of course, the shorter the shock the less travel you’ll have, not necessarily a bad thing depending on what you want to do, but it will be noticeably different.

[xagoras]

The problem is that with the pre-load set to what Traxxas reccomends in the manual (5mm) the front is OK, but the rear simply goes all the way down, so there's no travel at all.


I've been trying to find the sweet spot, but when I get to the point that I have decent amount of traveling, the ride height is too high.

Originally Posted by Topher Builds

By changing springs you’d soften it up which then lower the static ride height of the truck, while maintaining all of the travel of the shock. I’d definitely recommend a thicker shock oil if you go that route to help slow the body roll.

You could consider an internal limiter as well, such as a pen spring. Check out pen spring mod on YouTube for an idea of how it works.

Some shorter shock options, incision (80mm), proline, gmade. Of course, the shorter the shock the less travel you’ll have, not necessarily a bad thing depending on what you want to do, but it will be noticeably different.

This looks a pretty good mod. Fairly easy and inexpensive to try.


Not sure if it's going to work in my situation, but I will definitely begin with this, before starting to mess with the spring rates.

[HumboldtEF]

Originally Posted by xagoras

The problem is that with the pre-load set to what Traxxas reccomends in the manual (5mm) the front is OK, but the rear simply goes all the way down, so there's no travel at all.

that may be part of your problem, step away from the manual


I'd just ignore the recommendations in the manual, you're no longer stock and your setup should be altered to best work with it.


Most of us swap the front springs to the rear by the way. This setup is fairly typical with a softer spring up front and stiffer in the rear. the idea being on a climb with all of the weight shifting to the rear you want to avoid the rear just bottoming out as this increases the angle the truck is at making the climb even more difficult.

[Sniper4370]

Can you post a pic of the truck?
Also, what are you planning on doing with it? Trailing or rock crawling?
As others suggested, start with maybe changing springs and oil to get the suspension tuned. Then, play with body posts to adjust the body lower. If you are running the fenders, they may need trimmed to allow the body to be moved lower.

[xagoras]

Crawling will be next to impossible with the weight it carries up top. The body is around 2.5kg already. Mostly trailing.

Here's how it sits with the pre-load set at stock value (0.5mm)

[IMG]2021-01-15 11.19.27 by Giorgos Xagorarakis, on Flickr[/IMG]

2021-01-15 11.20.49 by Giorgos Xagorarakis, on Flickr


Here's with the pre-load set about half way

2021-01-15 11.22.58 by Giorgos Xagorarakis, on Flickr

2021-01-15 11.23.17 by Giorgos Xagorarakis, on Flickr


And here's set almost all the way down

2021-01-15 11.24.47 by Giorgos Xagorarakis, on Flickr

2021-01-15 11.25.05 by Giorgos Xagorarakis, on Flickr


The front is the same in all pictures, set at 0.5mm

[mmn]

What about the foam? those tires are looking pretty flat.

Regards,
Michael

[xagoras]

Originally Posted by mmn

What about the foam? those tires are looking pretty flat.

Regards,
Michael

I know, it's ridiculous. It's the stock foam that came with those Dirt Grabbers. I'm waiting some Dual Stage from Pro-Line at the moment, but not sure if they will fit into these tires.

[Cyclist]

I would suggest stiffer springs with no preload on them for your setup.

[HumboldtEF]

Originally Posted by xagoras

I know, it's ridiculous. It's the stock foam that came with those Dirt Grabbers. I'm waiting some Dual Stage from Pro-Line at the moment, but not sure if they will fit into these tires.

The Proline foams only come in a few sizes and are unlikely to fit small tires.


Check out Crawler Innovations foams, they have many, many sizes to choose from which should make finding a good fit easier. Typically you want the foam to be 1/4" smaller than the tire itself but if you want a stiffer setup you can go with the same size or larger.

You might even want their stiffer single stage foams.

[xagoras]

I managed to get hold of a pack of pens and did the pen mod on the springs. Not the exact pens with that particular spring that are on Youtube videos, but very similar, just a bit shorter. There was some improvement, but not what I expected to see.

I definitely need foams changed, but that will not solve the ride height issue. I don't know. Maybe I'll think of a different way to mount the body. It could give me a few mm or a full cm if I change the back magnets.

[Phildirt]

Body does appear to be sitting a hair too high from the angles I can see.

That is a darn good looking rig though, once you get it sorted out it is going to be sweet. I can see why you want to get it a little lower, my response back in the beginning was going to be "put bigger tires on" but that wouldn't suit the theme you have going there. Should be a fun to photograph trail rig when you are done. Post some photos of it.

[xagoras]

Originally Posted by HumboldtEF

Check out Crawler Innovations foams, they have many, many sizes to choose from which should make finding a good fit easier. Typically you want the foam to be 1/4" smaller than the tire itself but if you want a stiffer setup you can go with the same size or larger.

You might even want their stiffer single stage foams.

I ordered 2 pairs of their Single Stage Heavy Weight Deuce's, so hopefully the foam issue will be solved. They look pretty good for their price. Waterproof too.


Her's the gain from the pen mod spring, maybe 5mm lower

[IMG]2021-01-16 01.35.44 by Giorgos Xagorarakis, on Flickr[/IMG]

[fyrstormer]

If you're going to run a body that heavy, you need to find a swaybar kit that you can adapt to fit the TRX-4 frame. Otherwise, to prevent the body from tilting wildly every time the truck accelerates, you will have to use springs so stiff the suspension won't absorb bumps like it's supposed to.

[xagoras]

It seems that the Chassis kit has the same springs front and rear, Traxxas 8041 (0.45 rate). To stiffen it up I should I go higher rate springs like the one with the blue stripe (Traxxas 8045, 0.61 rate)?