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  1. #1
    RC Racer Storm68's Avatar
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    Servo horn setting

    Hey guys, I recently installed a Savox servo that I'm having trouble with.
    I followed a YouTube video from one of the members here and it said when installing the servo horn to place it upright, twelve o'clock, then place it one click over, one o'clock.
    So I did, turning left seems fine but turning right the bellcranks seems to be hitting the truck's body and I have limited turning.
    I seem to have more left turn than right and the servo wants to keep turning but the bellcranks won't let it.
    So do I reposition the servo horn at twelve o'clock and try again?
    By default where should the servo horn be placed?
    I'm thinking one o'clock isn't right.

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  2. #2
    Marshal carraig042's Avatar
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    Be sure that the steering trim on your controller is centered. When you set your servo horn, are you wheels pointed straight or are they to one direction?

    -Brett
    4wd Sportmaxx 3.3
    E-Revo - Mamba Monster - Neu 4s

  3. #3
    RC Champion Dcuda69's Avatar
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    Plug the servo in then turn the truck on with the steering trim centered the servo should be centered. Now put the horn on at 1 o'clock

    https://traxxas.com/explodedviews/Sl...assis-Assembly
    Slash 4x4 Ult 2150kv
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  4. #4
    RC Racer Storm68's Avatar
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    That's what I did, everything centred , turned the servo on and placed the horn at 1 o'clock.
    I've seen other videos since with it placed by default at 12 o'clock.
    I replaced the stock bellcranks with HR aluminium ones but no size difference.
    It's like the servo wants to keep turning right but can't because the bellcrank is already in max position.

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  5. #5
    RC Racer Storm68's Avatar
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    Not a great pic....and dirt not rust

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  6. #6
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    Set end point adjustment
    Last edited by CrazyXMAXX; 04-27-2018 at 06:40 PM.
    fabricator

  7. #7
    RC Champion RazorRC22's Avatar
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    A couple of things:

    1. The LCG chassis is limited on one side, I was never able to get equal throw left and right.

    2. You might be using too long of a servo horn. I'm not sure what the length of the horn is that you are using, but you need to get one the same distance hole-to-hole as the original Traxxas one.
    youtube.com/c/RazorRCvideos

  8. #8
    RC Racer Storm68's Avatar
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    Yep same servo horn length just a aluminium futaba one instead of the stock plastic.
    I'll set end points and see how it goes, I've found in the past that can be hot and miss.
    But I'll have a go

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  9. #9
    RC Champion RazorRC22's Avatar
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    Your drag link might also be too long or too short. It's the rod that connects the horn to the bellcranks.
    youtube.com/c/RazorRCvideos

  10. #10
    RC Racer Storm68's Avatar
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    Hmmmm... I did think of that but didn't check it. I changed the turning trim and it now doesn't scrape but the turn itself both left and right has reduced a lot.
    I'll try shortening the link between the horn and bellcrank that might work.

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  11. #11
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    Quote Originally Posted by Storm68 View Post
    Hmmmm... I did think of that but didn't check it. I changed the turning trim and it now doesn't scrape but the turn itself both left and right has reduced a lot.
    I'll try shortening the link between the horn and bellcrank that might work.

    Sent from my SM-G955F using Tapatalk
    That'll do the trick. I too had to shorten the servo drag link when installing the Power HD WP-25KG. Since the stock drag link does not have a turnbuckle (only a long screw pin), I changed it out with a 25mm long titanium turnbuckle to be able to adjust it properly.
    https://www.ebay.com/itm/3Racing-64-...item58bac34966

    A 23mm long turnbuckle would also have been long enough.

  12. #12
    RC Racer Storm68's Avatar
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    Thanks mate I'll source them on eBay today and see what I can do short term.

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  13. #13
    RC Racer Storm68's Avatar
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    Ok after spending a fair bit of time on this today I finally found the issue.

    The Futaba servo horn I was using is slightly longer then the stock plastic Traxxas one.
    This caused the extra travel to the right plus I also noticed it was hitting the top of the truck's chassis.
    This in turn would put more pressure on the Savox servo I have with the weight of the trucks body pushing down on it whilst its trying to turn.

    Not good.

    So I changed back to the stock plastic servo horn and everything works fine now, no issues at all after a few fine tuning adjustments.

    Here's what I was using:

    https://www.mildtowildrc.com.au/futa...rn-18-5mm.html

    Does anyone know if theres an aluminum servo horn the exact same size as the plastic stock Traxxas one?
    The Futaba is 25T, I've seen a couple at 24T, that means its shorter like the stock one?

    https://www.mildtowildrc.com.au/hudy...-horn-24t.html

    I have a Savox servo and HR aluminum bellcranks so the only weak part of my steering now is the plastic servo horn.
    Last edited by Storm68; 04-28-2018 at 11:30 PM.

  14. #14
    RC Turnbuckle Jr. Squeegie's Avatar
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    I don't have it, but it is listed with the Rally/Slash/Stampede stuff:
    https://hot-racing.com/?partnumber=SLF25SH06;c=805
    Creativity is intelligence having fun. -Einstein

  15. #15
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    Quote Originally Posted by Storm68 View Post
    Does anyone know if theres an aluminum servo horn the exact same size as the plastic stock Traxxas one?
    The Futaba is 25T, I've seen a couple at 24T, that means its shorter like the stock one?

    https://www.mildtowildrc.com.au/hudy...-horn-24t.html

    I have a Savox servo and HR aluminum bellcranks so the only weak part of my steering now is the plastic servo horn.
    No. 24T and 25T refers to the number of teeth on the splined outdrive of the servo. The stock servo and Savox use 25T. A 24T servo horn will not fit.

    I use this one. You'll have to cut off the outer hole and use the inner one. The length is then 15mm c/c from the servo spline to the M3 hole for the drag link.
    https://www.hudy.net/xhudy/products/...8&kategoria=67

  16. #16
    RC Champion RazorRC22's Avatar
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    Quote Originally Posted by RazorRC22 View Post
    2. You might be using too long of a servo horn. I'm not sure what the length of the horn is that you are using, but you need to get one the same distance hole-to-hole as the original Traxxas one.
    Quote Originally Posted by Storm68 View Post
    Yep same servo horn length just a aluminium futaba one instead of the stock plastic.
    Quote Originally Posted by Storm68 View Post
    Ok after spending a fair bit of time on this today I finally found the issue.

    The Futaba servo horn I was using is slightly longer then the stock plastic Traxxas one.
    youtube.com/c/RazorRCvideos

  17. #17
    RC Racer Storm68's Avatar
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    Haha, looked the same at first glance

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  18. #18
    RC Racer Storm68's Avatar
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    If anyone is able to can they tell me the length of the stock Traxxas servo horn?
    My local RC shop wants me to measure it so they can get the right one in and I'm at work right now.
    I know it's 25T to fit my Savox servo.

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  19. #19
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    The stock plastic servo horn is 16mm long, measured c/c between the servo spline and the drag link hole.

    I've always found it strange that many manufacturers does not give you the exact c/c length. Some will give you the total length or only the number of holes, both are meaningless. It's really often a hit and miss when you order a servo horn without having measured it yourself.

    That being said, many servo arms with multiple M3 holes have a c/c length of 15-19-23mm. 16mm may be hard to find, but you will be just fine using 15mm on a Slash 4x4 (especially combined with the Hot Racing bellcranks which gives a little more steering throw than stock).

    Edit: I found this 16mm long one from Samix (you'll have to cut off the outer hole):
    https://www.rcsamix.com/index.php/fo...-ax10-exo.html
    Last edited by Viking; 04-30-2018 at 01:18 AM.

  20. #20
    RC Racer Storm68's Avatar
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    Awesome mate thank you so much.

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