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  1. #1
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    Question Whatís this sound? Day 4 of my new X Maxx

    Afternoon all.

    Had an X-Maxx for 4 days now and started to get a bit of a grinding noise from it when running.

    Here’s a video so you know what I mean....

    https://youtu.be/X3CyE8GMBf4

    Can anyone help me out on what it could be?

    I have already updated the the carriers to the RPM carriers and up-rated bearing plus’s outer ABEC3 bearing and front bearings but don’t think it’s them as it’s only when accelerating.

    I have taken the cover off of the front of the motor and the motor pinion looks ok but the big gear off of that has a fair bit of play forward and backwards and a little up and down. Could it be this?

    The Maxx runs ok but just don’t want to explode a bearing or cog and cause more damage.

    If anyone can help out, that would great.
    Last edited by hallamnet; 08-18-2020 at 10:13 AM.

  2. #2
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    You can put it on its back and listen close to see where the sound is coming from.

    Accelerate slowly.

    Iím guessing gear mesh.

    Most people donít like the pin setup.

    Don


    Sent from my iPhone using Tapatalk

  3. #3
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    Quote Originally Posted by hallamnet View Post
    Afternoon all.

    Had an X-Maxx for 4 days now and started to get a bit of a grinding noise from it when running.

    Here’s a video so you know what I mean....

    https://youtu.be/X3CyE8GMBf4

    Can anyone help me out on what it could be?

    I have already updated the the carriers to the RPM carriers and up-rated bearing plus’s outer ABEC3 bearing and front bearings but don’t think it’s them as it’s only when accelerating.

    I have taken the cover off of the front of the motor and the motor pinion looks ok but the big gear off of that has a fair bit of play forward and backwards and a little up and down. Could it be this?

    The Maxx runs ok but just don’t want to explode a bearing or cog and cause more damage.

    If anyone can help out, that would great.
    Hi mate, check the pinion/spur mesh, and the grub screw in the pinion, maybe it is loose, if necessary, took out the pin mesh system and adjust it manually, is better for all.

  4. #4
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    Can you or someone explain the pin mesh system? I came from short course trucks and am used to adjusting mesh manually so I'm not sure how this sysemt works and haven't dug into the X that far yet.

  5. #5
    RC Qualifier Flux Capacitor's Avatar
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    Quote Originally Posted by Goaround28 View Post
    Can you or someone explain the pin mesh system? I came from short course trucks and am used to adjusting mesh manually so I'm not sure how this sysemt works and haven't dug into the X that far yet.

    Sure........The pin mesh system consists of two pins that align a certain gear ratio according to the graphical schematic under the motor. It ranges from "A" to "I". You want both pins seated in the same letter on opposite sides. Some make the mistake of when using 18/54 (stock), they set one pin in "I" and one in "D". You want both pins in "I" on the left and right sides for 18/54.





    Most suggest to set mesh manually; however I have never had a problem with the pin system. Never stripped a pinion or spur in 8 months and they are stock to boot. I bought Hot Racing motor mounts and every gear combination meshes consistently perfect with the pin system for me. Honestly; what I think happens when using the pin system, some take it apart and when they go to align with the pin system, they only get one of the pins aligned correctly and the second pin is usually misaligned (usually the rear one) and it causes problems.

    With the pin system and double checking to make sure pin alignment is proper, you can't go wrong with the pin mesh system. If you manually set gear mesh and forgo using the pin system, you run the risk of the motor mount screws allowing the motor to walk out of alignment (from vibration over time) and you will be starting a thread like the others that ditched the pin system and wonder why they are stripping spurs and pinions.

    With the pins in, even if your motor mount screws come a little loose, the pins will stop the motor from walking out of alignment until you re-tighten the motor mount screws. I don't have to worry about that with the Hot Racing motor mounts because Loctiteģ takes over in that department.

    Also, if you are skilled enough with a Dremel, you'll want to put a divot on your motor shaft for the set screw to seat in so it will stop the pinion from walking up and down the motor shaft.

    A small warning about doing this modification to the motor shaft is that it will only allow you stay with the Traxxas pinion and spur system. The divot point will be useless for aftermarket setups, so be sure what you want out of the stock motor first.
    Last edited by Flux Capacitor; 09-15-2020 at 05:18 PM. Reason: Added information.
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  6. #6
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    Quote Originally Posted by Flux Capacitor View Post
    Sure........The pin mesh system consists of two pins that align a certain gear ratio according to the graphical schematic under the motor. It ranges from "A" to "I"....
    Outstanding post! Thanks a ton for the detailed insight and experienced observations. It definitely won't go to waste. Clearly sometimes it just pays to ask.

  7. #7
    RC Qualifier Flux Capacitor's Avatar
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    Quote Originally Posted by Goaround28 View Post
    Outstanding post! Thanks a ton for the detailed insight and experienced observations. It definitely won't go to waste. Clearly sometimes it just pays to ask.
    Thanks and

    You are most Welcome!

    Everyone is here to help in some way and each and everyone of us has a different take on the pin mesh system. Some have had what I consider luck in manually setting the mesh on a system designed to be used with the pins. The pins serve two purposes (Firstly, the fitment of the gear mesh and Secondly, to make sure the motor doesn't walk out of alignment parameters) of which I see the second of the two being more important.

    Without the pins, (and I swear I measured this at some point) the motor has the capability to slide out of position by as much as 1/8th of an inch. Some would argue this is not too big of a deal; but consider for a moment if just one section (front or back) of the motor slide out of alignment by as much as 1/8th of an inch.

    Now consider what that would do to the gear mesh angle. If both sections of the motor slid evenly away from the spur because the pins weren't used, there would probably not be a problem; but again this would be wishful thinking to assume that it would walk evenly away from the spur and probably the biggest factor of why when you hear someone say: "I did away with the pin system and then trashed my spur and/or pinion." Gee, I wonder what happened?

    I can tell you what happened, one end of their motor (not both) walked away from the spur and caused an oblique mesh angle with the pinion causing a catastrophic loss of the pinion and/or spur.

    However, in reality, either the rear or front of the motor is going to slide at different rates away from the spur when, not if, the motor mount screws work their way loose and the pins are not there to prevent the walking away issue that will arise.

    My overall assessment is that the pin system wasn't just designed to fit different pinion/spur ratios; it was designed to save the spur/pinion from that moment when the motor mount screws loosen just enough to allow the motor to start walking in the cradle and the pins take over as a fail-safe until you re-tighten those screws.

    So I really can't understand how some are manually (without the pins) meshing their spur/pinions without the worry of the motor walking in that cradle space. And like I said, I looked at the mesh when using the pin system and I don't think I could honestly line it up better by listening/eyeballing it and I've been manually meshing pinion/spurs since the induction of the other Traxxas models that require manual meshing techniques.
    Last edited by Flux Capacitor; 09-15-2020 at 09:31 PM. Reason: Fixed.
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  8. #8
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    Hi guys.

    So I bought off of eBay a complete set of up-rated ABEC-3 bearings and thought Iíd strip out the pinion and gears and replace the 2 bearings on the shaft and have a look to see what I can find.

    When I went to take off the grey cover, the 2 screws Closet to the motor had been done up but not all of the way. So I stripped down the spur gear and replaced the 2 bearings and fitted back everything and tightened the 2 screws that were loose and guess what, I now have almost no play in the gear meshing with the pinion. Looks like someone got distracted in the factory when assembling and didnít tighten as they should have been.

    Not tested driven the Maxx yet but will report back my findings but thanks to all with the suggestions. I never got to run the Maxx upside down as the little one was fast asleep on the sofa 😌

    Hereís a photo of the offending screws...


  9. #9
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    Just given it a test run and sounding sweet! No grinding noise and if anything, wheelies a bit easier. Problem solved!

    I hope this helps someone else if they have the same!

  10. #10
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    Quote Originally Posted by hallamnet View Post
    Just given it a test run and sounding sweet! No grinding noise and if anything, wheelies a bit easier. Problem solved!

    I hope this helps someone else if they have the same!
    Happy to read this mate.

  11. #11
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    Great news that you found the issue! Thanks for providing the follow-up.

    For those of us seasoned in the hobby it is a good reminder that a new product should be checked over. As with anyone new to RC - we all were at one point - it was something that didn't cross my mind either.
    The Super Derecho

  12. #12
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    Quote Originally Posted by Double G View Post
    Great news that you found the issue! Thanks for providing the follow-up.

    For those of us seasoned in the hobby it is a good reminder that a new product should be checked over. As with anyone new to RC - we all were at one point - it was something that didn't cross my mind either.
    I must admit, I read through the forum and a load of YouTube videos and found that the pinion is a common issue coming off when people do not check along with loose wheel nuts and these were the only parts I did check but nothing else.

    Really did not expect that part to be loose. I will strip and rebuild section by section and will put a bit of light thread lock on screws.


  13. #13
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    Remove the motor, then remove the pins
    Then able to set mesh manually
    fabricator

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