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Traxxas TRX-4 Sport Crawler Mods

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Traxxas TRX-4 Sport Crawler Mods

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Old 01-03-2019, 07:22 PM
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Default Traxxas TRX-4 Sport Crawler Mods

This string is intended for sharing modifications and upgrades to the Traxxas TRX-4 Sport.

Last edited by Still Bill; 01-03-2019 at 08:32 PM.
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Old 01-04-2019, 06:28 AM
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Invert front bumper mount to add more front clearance and then trim the front nose of the truck body.

Invert rear bumper mount to add more rear clearance and then trim the rear bottom tailgate part of the truck body. Or replace the stock rear bumper mount with another front bumper mount and invert it if you prefer not trim too much of the tailgate of the truck.

On the both sides of the truck:

Right rear side of the slider (do the same for the left side)


Right front side of the slider (do the same for the left side)


After trimming the side of the truck's body

You can raise those left and right side rock sliders to improve the clearance on the truck' sides.
Either use an M3x10mm aluminum spacers - (Lumenier M3 x 10mm Aluminum No Thread Spacers Standoffs - 10 Pack 5043)
or
- buy a hollow aluminum or brass hollow tubing from your local hardware store then saw them at 8mm or 10mm height (make 8 pieces of same length)
or
- in my case, I just used the spare hollow metal balls for my E-Revo, you can buy or order 2 packs of these (each pack has 4 pieces) - (Traxxas Revo Hollow Ball)

You will then need to replace the bolts and replace them with M3x16mm button head bolt (cap head bolt will also do) - (M3 x 16mm (0.5mm), Button Head Socket Cap Screw Bolt, A2 18-8 Stainless Steel)

Now, you will cut the side of the truck's body to the top line of the stickers below the doors (see picture).
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Last edited by OverGeared; 01-04-2019 at 06:29 AM. Reason: edit
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Old 01-04-2019, 10:02 AM
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Default Bumpers and Body Mods

Great start!

A few things I did in regard to the bumpers and body on my Sport...
1) Added a Yeah Racing heavy brass front bumper support (with alternate servo location mount);
2) Moved the plastic front bumper support to replace the rear bumper support. Installed in the inverted position;
3) Recessed both bumpers by one hole for more clearance;
4) Trimmed front and rear of body to accommodate the bumper changes; and,
5) Dremeled and sanded away the plastic side steps from the body brackets for more side clearance.
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Old 01-16-2019, 02:33 PM
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Nice mods everyone!

I did basically the same with some differences. For the rock sliders I just used 15mm stand offs so the sliders are flush with the chassis. I also only used the inner mounting point to push the slider in a few mm.

Other thing I did was to remove the battery tray and mount the lipo directly on the front bumper. It's a 3s 2200 mah for a drone.

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Old 01-16-2019, 03:23 PM
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Great pics. Thanks.

Last edited by Still Bill; 01-16-2019 at 04:58 PM.
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Old 01-16-2019, 04:55 PM
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Here are a few pictures of my recent upgrades. Bowhouse battery tray lowered overall CG and allows me to utilize the 2s shorty packs from my racing buggies. Yeah Racing brass bumper support at front allows me to reposition steering servo all the way to the front of the truck body; or, gives me great location to mount a winch. Still waiting for a test day after snow subsides before determining if I want to do one or the other...LOL. Moved available front bumper support to back to raise rear bumper for more clearance. Now has Pro-line Hyrax Predator tires on SSD steel beadlock wheels. Waiting for a new Spektrum Rugged radio to arrive before adding a Hobbywing 1080 brushed ESC.




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Old 01-17-2019, 10:49 AM
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Last night I realized the steering linkage hits the samix servo horn at full articulation. So I shimmed the servo with a couple of 3mm washers. All good now.



Also trimmed the fenders out because the tires rubbed.
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Old 01-17-2019, 11:56 AM
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Furadi,

Not sure now long (C to C) your Samix Servo Arm is in comparison to the stock one. Is your turning circle still under 4' in diameter? Should be about 3'-10". Guess you can adjust the throw with your DX5C radio anyway.

My ProTek Dual-Clamping Long Aluminum Servo Arm is barely touching the cross link below. Did buy the Traxxas Metal Servo Arm #8247X because it appears to be shaped to avoid hitting...But, have not installed it yet.

Or...I could just relocate the servo to the brass front bumper mount. LOL

Bill

Last edited by Still Bill; 01-17-2019 at 12:14 PM.
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Old 01-18-2019, 07:08 AM
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Originally Posted by Furadi View Post
Last night I realized the steering linkage hits the samix servo horn at full articulation. So I shimmed the servo with a couple of 3mm washers. All good now.
We've tried different servo horns over here, this is the one that works best without hitting any part of the steering linkages when the front shock absorbers are fully compressed.
https://www.amainhobbies.com/protek-...819-bk/p292307
or you can also opt for the aluminum version of the box stock Traxxas TRX-4 servo horn.
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Old 01-18-2019, 09:23 AM
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Originally Posted by OverGeared View Post
We've tried different servo horns over here, this is the one that works best without hitting any part of the steering linkages when the front shock absorbers are fully compressed.
https://www.amainhobbies.com/protek-...819-bk/p292307
or you can also opt for the aluminum version of the box stock Traxxas TRX-4 servo horn.
All good with the 3mm spacers.
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Old 01-18-2019, 11:55 AM
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Originally Posted by OverGeared View Post
We've tried different servo horns over here, this is the one that works best without hitting any part of the steering linkages when the front shock absorbers are fully compressed.
https://www.amainhobbies.com/protek-...819-bk/p292307
or you can also opt for the aluminum version of the box stock Traxxas TRX-4 servo horn.
Although the ProTek servo horn is aluminum, the Traxxas version #8247X is made of steel and weighs about twice as much.

Just researched servo horns more extensively...Found that none of the ProTek servo horns comply with the stock 22mm length (center to center dimension of the TRX-4 plastic horn #8247) as specified on the Traxxas forum. Which length needs to be maintained when using the supplied Traxxas transmitter because it has no adjustment for end-to-end servo throw. Otherwise, steering angles are affected by the length of the servo arm.

So, I am ditching the ProTek #7819 servo arm (having 16.5mm and 20mm hole spacing) and the #7800 (having 19.75mm & 24.25mm hole spacing) in favor of the Traxxas #8247X unit to maintain the proper overall length of 22mm C to C.

However, all bets are off when I receive my new Spektrum Rugged transmitter and have servo throw adjustability to play with.

Bill
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Old 01-18-2019, 12:11 PM
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Originally Posted by Furadi View Post
All good with the 3mm spacers.
With the TRX-4 having a "panhard bar" steering setup, raising the servo (and servo arm) upward does negatively affect the angle of the steering linkage to slightly increase the inherent "bump steer" of the vehicle.

And bump steer can be noticeable to me.

So, now I am already installing on my third replacement arm for my Sport...LOL
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Old 01-18-2019, 12:12 PM
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Originally Posted by Still Bill View Post
Although the ProTek servo horn is aluminum, the Traxxas version #8247X is made of steel and weighs about twice as much.

Just researched servo horns more extensively...Found that none of the ProTek servo horns comply with the stock 22mm length (center to center dimension of the TRX-4 plastic horn #8247) as specified on the Traxxas forum. Which length needs to be maintained when using the supplied Traxxas transmitter because it has no adjustment for end-to-end servo throw. Otherwise, steering angles are affected by the length of the servo arm.

So, I am ditching the ProTek #7819 servo arm (having 16.5mm and 20mm hole spacing) and the #7800 (having 19.75mm & 24.25mm hole spacing) in favor of the Traxxas #8247X unit to maintain the proper overall length of 22mm C to C.

However, all bets are off when I receive my new Spektrum Rugged transmitter and have servo throw adjustability to play with.

Bill
Yeah my samix is the same length and I get way more travel with my DX5C radio vs stock.
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Old 03-04-2019, 04:16 PM
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Have a quick question...Has anyone noticed the rear wheels on their TRX-4 having positive camber (about +1 degree)? I assume either the plastic rear axle housing is bowed or the portals have pivoted slightly inwards.

Thinking that an aluminum rear axle housing may be in order (because I am not interested in adding any more weight to my Sport).

Or I gotta quit climbing all those V-shaped obstacles...LOL
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