TRX Based 8x8
 

Howdy folks. after building a couple TRX-4 and SCX10 II 6x6 conversions (pics below), I wanted to challenge myself and go for an 8x8. So, if ya'll are interested follow along!! Disclaimer: I don't have it all figured out, so I might be leaning on the community for ideas and solutions :ror:

Here's my TRX-4 converted rig.

https://i.imgur.com/D71Fy2e.jpg

For which I started a thread: http://www.rccrawler.com/forum/traxx...ion-guide.html

and the SCX10 II based one.

https://i.imgur.com/4HblUts.jpg

This build will be based on the TRX-4/6 platform.

Step one is extending TRX-6 chassis rail to accommodate the additional front axle. After staring at the parts I had on hand, I decided to lop off the front section of the TRX-4 rails and use that as the chassis extnsion.

Proof of concept below:

https://i.imgur.com/UJqimj7.jpg

Re: TRX Based 8x8
 

The rails have to be hammered flat to remove the curve where the stock rails sway outward to accommodate the skid/tranny mount.

https://i.imgur.com/BrgP1hG.jpg

I have brass strips lying around, but for this joint, I really wanted to use steel as there'll be considerable stress (I think) on that joint. Again, scrounging around for something suitable, I decided to use TOOL steel :mrgreen:

https://i.imgur.com/XMbKZ61.jpg

Step one: fit then drill and tap one side.

https://i.imgur.com/HCvD1Bt.jpg

Re: TRX Based 8x8
 

And joined!!

https://i.imgur.com/AP8T4pe.jpg

Here it is with a TRX-6 rail for comparison.

https://i.imgur.com/6sqPOOM.jpg

I purposely left the extension long at the front until I figure out what needs grounded/filed off to accomodate a bumper mount. So that's all for now, I'm waiting for delivery of a second hand TRX-4 I bought on FB Marketplace which will be the donor truck for a lot of the parts.

Re: TRX Based 8x8
 

Sweet build idea man! Good idea with the chassis as well.

When you hammered the frame straight, did you heat it up at all or just a cold bend?


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Re: TRX Based 8x8
 

Very cool, looks good so far [emoji1303]


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Re: TRX Based 8x8
 

Thanks. The frame straightened out nicely just cold hammering it out on my wooden workbench.

Re: TRX Based 8x8
 

Thanks for following along!

Re: TRX Based 8x8
 

Sweet... been debating doing this as well, but on an older SCX platform. Curious to see how it comes along!

Re: TRX Based 8x8
 

OSRC, thanks for following along. Parts have started arriving: a rear axle from Ebay where new parts can be found cheaper than from Traxxas. This one has the locker assembly that will be disabled as I plan to run full locked.

https://i.imgur.com/hT2MOkM.jpg

Re: TRX Based 8x8
 

Mo parts arrived :mrgreen:

https://i.imgur.com/1PRb81Y.jpg

Was slammed at work this week, but over the weekend I hope to move this along. The deal on FB Marketplace fell thru, so I've ordered a new TRX-4 Sport kit from which to source parts.

TRX Based 8x8
 

Three steer axles??[emoji848]


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Amain Addict

Re: TRX Based 8x8
 

If you need a place to send all those un-needed locking diff parts, you just let me know ;)
I just picked up a used sport that could use selectable diffs 👍

Re: TRX Based 8x8
 

The selectable diffs can easily be locked with a washer, but if you send me a couple of spools, I'll trade ya 8)

Re: TRX Based 8x8
 

It begins....

https://i.imgur.com/hVUD8YE.jpg

The challenge of this build will be figuring a way to mount the frontmost axle's links, so for now I'll concentrate on the front end seeing as the rear setup is pretty much the same as the TRX-6's.

Re: TRX Based 8x8
 

I think that for clarity the axles should be referred to from front to back as axle 1, axle 2, axle 3 and axle 4.

I wanted to hang axle 2 today but first had to change it to a "pass thru" axle so that the second pinion will drive axle 1. I used part # 8846 which can be seen in the pic above instead of the stock diff cover. A couple of bearing and a second pinion and it's good to go.

https://i.imgur.com/hTECaLt.jpg

Hung :mrgreen:

https://i.imgur.com/9GOxcjZ.jpg

As I never liked the two-part unit that comes stock, I'm using a Bowhouse RC skid for those wondering.

https://i.imgur.com/TWHMWgZ.jpg

Re: TRX Based 8x8
 

This is very cool, looking forward to seeing how you tackle the “obstacles” [emoji1303]


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Re: TRX Based 8x8
 

Looks good so far!

I’m really interested in seeing how your links will work out on Axle 1.


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Re: TRX Based 8x8
 

It's coming along!

That's definitely the main challenge of this build. Fingers crossed I think I have it figured out.

Rather than fabricate a custom mount for the links, which given my limited skills would've posed a challenge :shock: I decided to try and use the stock rear link mount for the TRX-6. That's part #8830 in the exploded view: https://traxxas.com/explodedviews/TR...assis-Assembly

But.... two problems:

1) There's not enuf room between shock mounts for axles 1 and 2.
2) My front rail extension is not straight, it's "W" shaped.

After staring at this for three days I hit on an idea:

Step 1 reduce the length of the link mount, here is the modified version next to the stock one:

https://i.imgur.com/JPK4isq.jpg

A band saw comes in handy to get an accurate cut here, btw.

Next cut away at the rails to allow the link mount to sit in the channel. I'll clean those cuts and repaint later, I just wanna know if this is gonna work for now.

https://i.imgur.com/48IZuiT.jpg

Trial fit in the chassis rail. With this arrangement the link mount will not interfere with the shock mounts, but I'll really only know if everything also clears the steering mechanism for axel 2 once I reassemble.

https://i.imgur.com/z714lol.jpg

Thanks for following along, and stay tuned! "thumbsup"

Re: TRX Based 8x8
 

I built an 8x8 on Axial frames using HG axles a last year and getting the steering and drive shafts to clear each other took a lot of trial an error. I ended up using fairly short links on the front but the thing still flexes pretty well.

http://www.rccrawler.com/forum/multi...tonka-cab.html

Re: TRX Based 8x8
 

Impressive build, thanks for sharing!

The cab's arrived :mrgreen:

https://i.imgur.com/eIInF36.jpg

Yes, I know it's premature to be buying the cab seeing as I haven't even sorted out the chassis yet, but even if this build's a fail, I can always use it in something else. Check out the detail!

https://i.imgur.com/kbNIvQV.jpg