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  1. #1
    RC Qualifier Panther6834's Avatar
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    TRA 6440 vs TRA6839X vs TRA 6838X

    I have a bit of a "dilemma". I'm in the process of 'converting' one of my Traxxas vehicles, and, in doing so, I've been using parts (some Traxxas, some from other manufacturers) designed for a variety of different Traxxas vehicles (although many are designed specifically for the Slash 4x4). Part of this 'conversion' involves a non-Traxxas body, which is shorter in height than the stock Traxxas body, thus I need a way of lowering the body. Of course, I didn't realize this when I started (I purchased the JConcepts Suspension Conversion Kit, which I'll still be able to use...just not for this project). Both towers in the JConcepts kit are the same height as TRA 6838X (the 'optional' aluminum rear tower for the Slash 4x4). As you can see from the photo, below, the towers have two holes along the top ‘crossbar’ section of the towers, to which “body mount adapters” (shown, in the photo, below the towers) attach to the towers, and then Traxxas body mounts (at least a few options) would be attached.



    Unfortunately, this configuration created a 15-20mm gap between the top of the chassis, and the bottom of the body…thus, I need a way to lower the body. The most logical (actually, the only) answer I was able to come up with is to get shorter shock towers (and, yes, in going this rout, I realize I will might have to replace all 4 'rear' shocks with 4 'front' shocks). This led me on a search, which appears to have ended with the XO-1 towers. I see that the XO-1 rear tower (TRA6839X) is also the optional front tower for the Slash 4x4.

    The JConcepts towers are, from the top of the gearbox, to the top of the tower, 42mm (JConcepts designed front & rear towers with the same height, thus you use rear shocks on all four corners). The XO-1 rear tower (aka the Slash 4x4 front tower) is approx 31mm, thus this could have been a possibility…except that it doesn’t lower the body enough (it would still leave a small gap between the chassis & body). However, I do know that the XO-1 front tower (TRA6440) is approx 15mm shorter in height than the rear tower, which would resolve the "gap problem". However, this raises a question.....

    I see that TRA6400 has two holes along the top of the tower’s ‘crossbar’, similar to the two holes in the same area on TRA6839X. Unfortunately, I can’t find any info on these two towers, specifically, the spacing measurement between these two holes, and whether the spacing measurement on TRA6440 is the same as it is on TRA6839X. If it is, fantastic, I will have found my “solution”...and, if not, then I still have my “problem”. So...I have two questions:

    1) Does anyone know if the spacing of these two holes on TRA6440 is the same as the spacing of the two holes on TRA6839X? The sooner I find out, and the sooner I can get two of these towers ordered (provided the spacing is the same), then the sooner I can finish this project, as this is the final "piece of the puzzle".

    2) I am aware of a few 3rd-party manufacturers producing carbon fiber versions of TRA6839X, but does anyone know of any manufacturers producing (high-quality) carbon fiber versions of TRA6440? As short as TRA6440 is, it probably wouldn't have the same "bending problem" that taller aluminum towers would have...but, at the same time, I would still prefer to not use aluminum shock towers.carbon fiber towers would be preferential.
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  2. #2
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    Can you flip the body post holders to lower the body?
    Last edited by TwoBelugas; 09-13-2019 at 02:18 PM.

  3. #3
    RC Qualifier Panther6834's Avatar
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    Quote Originally Posted by TwoBelugas View Post
    Can you flip the body post holders to lower the body?
    Already did that...still too high. Not only that, but, I'm using the RPM mounts, which (without using the included "adapters") are 1/8" lower than the stock Traxxas body mounts. Before continuing, I should mention that this 'conversion' is actually being performed on a Rustler 4x4...but, since so many of the parts being installed are actually for the Slash 4x4, I felt it better to place this thread in the Slash section (besides, both vehicles use so many of the same parts).

    Although I didn't actually attempt installing it, I did measure the height of the Slash 4x4 stock plastic front tower against the JConcepts carbon fiber towers. If I replaced the two rear towers being used with two front towers, while lowering the body 10mm, that's still not enough...body would still be 1-2mm above the chassis. That's why I'm thinking the XO-1 front towers might be my only option. Would be even better if I could find a manufacturer producing carbon fiber versions (several do carbon fiber rear towers...just can't find front).

    ~ More peace, love, laughter, & kindness would make the world a MUCH better place
    Last edited by Panther6834; 09-13-2019 at 02:31 PM.
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  4. #4
    RC Turnbuckle Jr. Squeegie's Avatar
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    Can you just make your own brackets... bend steel/aluminum into an "L" bracket of your desired height and drill out the holes?

    Hopefully the shock mounting holes will not get in your way when lowered to the height you want. You could also cut out holes in the hood for the top of the shock mounts if you have to...
    Creativity is intelligence having fun. -Einstein

  5. #5
    RC Qualifier Panther6834's Avatar
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    Quote Originally Posted by Squeegie View Post
    Can you just make your own brackets... bend steel/aluminum into an "L" bracket of your desired height and drill out the holes?

    Hopefully the shock mounting holes will not get in your way when lowered to the height you want. You could also cut out holes in the hood for the top of the shock mounts if you have to...
    Don't have that kind of equipment...and, couldn't afford it, even if I wanted it. Besides, I don't want (and, really, can't have) the shocks sticking above the hood. ROAR rules don't allow that (just as with my other Rusty, I'm trying to convert this one into a ROAR-approved race vehicle...in this case, a "true" stadium truck).

    So far, everything is within ROAR compliance, right down to the 13.5T motor (which isn't installed, yet...I've temporarily reinstalled the VXL motor & ESC). The body, btw, is a Jato body from Pro-Line (no photos, yet...once it's complete, be on the lookout for a new thread that had both "Jato" & "Rustler" in the thread title).

    ~ More peace, love, laughter, & kindness would make the world a MUCH better place
    Last edited by Panther6834; 09-13-2019 at 02:56 PM.
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  6. #6
    RC Qualifier Panther6834's Avatar
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    Since I haven't been able to get a definitive answer regarding the hole spacing measurement, and knowing that the TRA6440 is in shower supply, I decided to just "bite the bullet", and order two of them. Worst-case scenario, I find out they won't work, them I'll give the TRA6839X (or a carbon fiber version) a try. Best-case scenario, I discovered they work, exactly as needed (even if I have to slightly modify one/both of them), and my "problem" ended up being resolved.

    I should receive them no later than 9/23. Whatever the results are, I'll update here.

    ~ More peace, love, laughter, & kindness would make the world a MUCH better place
    ~ Love, laughter & kindness makes the world better

  7. #7
    RC Turnbuckle Jr. Squeegie's Avatar
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    Does the Jato body qualify under ROAR rules?

    See rule 6.1.1 (page 31):
    http://www.roarracing.com/downloads/..._Rule_Book.pdf
    Creativity is intelligence having fun. -Einstein

  8. #8
    RC Qualifier Panther6834's Avatar
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    Quote Originally Posted by Squeegie View Post
    Does the Jato body qualify under ROAR rules?

    See rule 6.1.1 (page 31):
    http://www.roarracing.com/downloads/..._Rule_Book.pdf
    LFirst, the Jato body is a more accurate "stadium truck" body than the body included in most stadium truck kits. Second, I'll actually be using the body made by Pro-Line, which is technically even more accurate. Third, if ROAR approved the use of the bodies that came with order stadium truck kits (TLR 22T, AE SC10 T, etc), then they'd have had no problem approving the Jato, or Pro-Line Crowd Pleazer bodies.

    Not that this point had anything to do with the other three points, but, it should be noted that ROAR officially (at least for now) ceased operation of the Stadium Truck classes at all National events...so, the only races for Stadium Truck classes are being held at regional, and lower, races. Some tracks don't even bother with ROAR rules, it they 'fudge' a little on the ROAR rules (for example, they might allow 2WD & 4WD vehicles, of a specific type (ie. 1/8 buggy, 1/10 SCT, etc) to compete in the same heats.

    ~ More peace, love, laughter, & kindness would make the world a MUCH better place
    ~ Love, laughter & kindness makes the world better

  9. #9
    RC Turnbuckle Jr. Squeegie's Avatar
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    Quote Originally Posted by Panther6834 View Post
    Don't have that kind of equipment...and, couldn't afford it, even if I wanted it.
    All you basically need is a hacksaw/Dremmel, drill, and hammer. Nothing fancy.

    Quote Originally Posted by Panther6834 View Post
    LFirst, the Jato body is a more accurate "stadium truck" body than the body included in most stadium truck kits. Second, I'll actually be using the body made by Pro-Line, which is technically even more accurate. Third, if ROAR approved the use of the bodies that came with order stadium truck kits (TLR 22T, AE SC10 T, etc), then they'd have had no problem approving the Jato, or Pro-Line Crowd Pleazer bodies.

    Not that this point had anything to do with the other three points, but, it should be noted that ROAR officially (at least for now) ceased operation of the Stadium Truck classes at all National events...so, the only races for Stadium Truck classes are being held at regional, and lower, races. Some tracks don't even bother with ROAR rules, it they 'fudge' a little on the ROAR rules (for example, they might allow 2WD & 4WD vehicles, of a specific type (ie. 1/8 buggy, 1/10 SCT, etc) to compete in the same heats.

    ~ More peace, love, laughter, & kindness would make the world a MUCH better place
    Thanks for the lesson. I do not race and do not know rules (past or present).
    Good luck to you with your builds and always remember to have fun!
    Creativity is intelligence having fun. -Einstein

  10. #10
    RC Qualifier Panther6834's Avatar
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    Quote Originally Posted by Squeegie View Post
    I do not race and do not know rules (past or present).
    Good luck to you with your builds and always remember to have fun!
    Thanks...and, having fun is my primary "goal" in having gotten back into RC. 35 years was a long time to be "gone" (tho I was involved in MANY things during that time - track athlete, competitive swimmer, dancer, musician, 82nd Airborne...oh, yea, and working...lol), but I'm glad I found my way "back", and I'm definitely enjoying it. Not exactly to the level of being ready to attend any Nats...but, maybe, one day...again, just for the "fun" (I wouldn't expect to come closer to even making it into any A-mains, but just bring able to say, "I raced at a Nat.").

    ~ More peace, love, laughter, & kindness would make the world a MUCH better place
    ~ Love, laughter & kindness makes the world better

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