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  1. #1
    RC Turnbuckle Jr.
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    XO-1 Telemetry Math Gone Crazy

    I discovered this a while ago. I didn't really say anything, because at the time I didn't think anyone would be interested. Now though, with the new crop of XO-1 owners wanting to get into Traxxas telemetry, I wanted to point out this little telemetry boo-boo.

    It all started when I wanted to change my gears, but not my gear ratio. The reason? I wanted bigger gears that would give be a bigger space between my motor and my driveshaft. Why? Because, little rocks was tearing up my driveshaft, and I wanted to see if a bigger motor/driveshaft gap would help. I went to the owners manual, and here's what I saw.



    If you only use the (above) formula and gearing chart, you would never see the problem. The problem came when I went to the (below) Traxxas telemetry "GARAGE" and the "MODEL SETUP."



    What is the correct gear ratio for a 14T pinion gear, and a 46T spur gear? Is it 2.846 or 9.35? I plugged in both numbers (even though the 2.846 is a telemetry default) to see what would happen.

    The telemetry default gear ratio of 2.846 was definitely a good number. The owners manual's final gear ratio of 9.36 for gears 14/46 made my speedometer go crazy.

    So, here's what I did to correct this.



    We know that 46/14 is a good number. The number 9.36 proved to be a bad number when used with Traxxas' telemetry. And, 2.83 proved to be a bad number in our owner manual's formula, but is a good number when used as or final gear ratio default setup.

    So, what needed to be done was to take our Traxxas formula, use the 46/14, make 2.85 unknown (or X), and use our proven 2.842 telemetry number as our formula's solution.

    If we do that, our new corrected formula for our owner's manual is: Spur/Pinion (times) .865 = Final Gear Ratio

    Now, when we use our new corrected formula for our first step: 46/14 = 3.2857

    And, for our second and final step: 3.2857 x .865 = 2.842 (the number used as our default final gear entry, in our Traxxas telemetry setup)

    In conclusion, I have the spacing I wanted, and am able to keep my original OEM gear ratio. I had my choice of using either 54/17 = GR 27476 or 54/16 = GR 2.919. I went with the gear ratio of 15/17. When I plugged in all the numbers into my Traxxas telemetry program, everything worked very well, my top speed was 58mph, and no more shredding of my driveshaft from rocks.
    Last edited by ReglarGuy; 02-24-2018 at 06:29 AM.
    The ReglarGuy is kid tested and father approved.

  2. #2
    RC Racer kzsteve's Avatar
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    WOW you spent some time on that . I haven't got that far yet , but thank you for the effort . should help many users ... steve
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  3. #3
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    so if I use the 34t pinion and 46 spur I should put 2.11 in my final drive on link app?
    Last edited by cliffr17; 02-24-2018 at 02:28 PM.

  4. #4
    RC Turnbuckle Jr.
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    Spur/Pinion (times) .865 = Final Gear Ratio
    46/34 = 1.3529

    1.3529 x .865 = 1.170 Final Gear Ratio for the Traxxas Link
    The ReglarGuy is kid tested and father approved.

  5. #5
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    ok thanks. I actually got that number first, but thought that can't be right.lol.


    thanks again for all your help.

  6. #6
    RC Turnbuckle Jr.
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    You're very welcome.
    The ReglarGuy is kid tested and father approved.

  7. #7
    RC Racer kzsteve's Avatar
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    does anyone make a 3 pin telemetry expander ? or adapters for 4 pin ? ......... thanks .. steve
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  8. #8
    RC Turnbuckle Jr.
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    For inexpensive and simple installation, all you should ever need is the Traxxas telemetry stuff. They make everything you could possibly ever want for telemetry.
    The ReglarGuy is kid tested and father approved.

  9. #9
    RC Racer kzsteve's Avatar
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    yes they do . the expanded telemetry I got is all 4 pin , my stuff is all 3 pin . thanks ... steve
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  10. #10
    RC Turnbuckle Jr.
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    What's 3 pin?
    The ReglarGuy is kid tested and father approved.

  11. #11
    RC Racer kzsteve's Avatar
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    my telemetry box . plug ins are 3 pin , but my expanded telemetry is all 4 pin . ........... thanks .. steve

    -- all my plugins are 3 pin . servos , etc .
    XO-1 GUY SEEKING HELP

  12. #12
    RC Turnbuckle Jr.
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    If you have and are using all Traxxas electronics...everything fits. The 3 pinned servos and basic temp/volt and RPM sensor all go in the 3 pin area of the receiver; and the expansion modules 4 pin cable goes in the 4 pin slot of the receiver and in the 4 pin slot of the expansion module (along with any smart sensors which are also, 4 pinned).
    The ReglarGuy is kid tested and father approved.

  13. #13
    RC Racer kzsteve's Avatar
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    thanks . I think I got that . new problem . LOL seems all I have are problems . when trying to bind transmitter to receiver .........
    red light goes to fast blinking red but never goes to green ............. thanks again .... steve
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  14. #14
    RC Turnbuckle Jr.
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    Assuming you're doing everything right, I would swop out your receiver with a known good. If no results, then the transmitter. It's got to be one or the other. Note: make sure you don't use your telemetry to bind. Use only your Tx and Rx buttons the way the owners manual tells you.
    Last edited by ReglarGuy; 03-09-2018 at 07:56 PM.
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  15. #15
    RC Racer kzsteve's Avatar
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    that is a major assumption . I have 2 transmitters & 3 receivers , the one I have in is the best effort so far . I think I have unhooked all the telemetry , but will go over it again tomorrow . staring to feel really stupid about now , but I do preserver to the end . thanks once more ................ steve ................... if I figure it out I will let you know !
    XO-1 GUY SEEKING HELP

  16. #16
    RC Turnbuckle Jr.
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    Make sure you consult your owners manual, and (if need be) you can look up how to do it on YouTube. I use YouTube a lot with computer, home networking, and iPad issues I can't figure out on my own. It's comes in handy.
    The ReglarGuy is kid tested and father approved.

  17. #17
    RC Racer kzsteve's Avatar
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    ive been using some tutorials on line . down loaded manual for xo-1 . working on my hot rod today , but later on xo-1 ........... thanks .. steve
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  18. #18
    RC Racer kzsteve's Avatar
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    got my control & receiver working together . all green lights , but no steering or motor functions . any ideas appreciated ........ thanks .. steve
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  19. #19
    RC Turnbuckle Jr.
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    Unfortunately, we can't get together for me to see exactly what you have, and exactly what you're doing. I suspect that due to your experience level you may be overlooking tidbits of information that might be important in solving your problem. Not a big deal, let's see if we can go another route that might get you better results...quicker.

    A forum isn't bad for simple questions and answers, but for trouble shooting serious problems a telephone is much better and faster. I suggest calling your nearest hobby store, Traxxas, or me. With that said, let me tell you how I get to the bottom of my RC electronic problems fast.

    I use the substitute method. I keep in a box a new, known good transmitter, receiver, 4 servos, 6vdc battery pack, a servo tester, MM2 ESC, an extra iPod, a smart temp sensor, and a brushless motor tester. Also, all my surface vehicles' electronics are the same (Traxxas), and all my air vehicles electronics are same (Spectrum).

    You may want to do this for yourself (in the near future) for your trouble shooting needs, but until then I think you should do as I suggested above. You should call your nearest hobby store, Traxxas Customer Service, or me; because I think your needs are more than what can be efficiently done on a forum. If you need/want to get a hold of me by phone, I don't mind and we can Private Message the necessary arrangements.
    The ReglarGuy is kid tested and father approved.

  20. #20
    RC Racer kzsteve's Avatar
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    REG GUY .. I finally got the car sorta out . ive run it some & no problems so far . apparently my esc was bad . 2 of them in a row . blx-180 blx-185 (replacement for blx-180). I'm going to stay with GOOD parts rather than cheap parts . I want to thank you for your help & info . apparently I bought a USED & mismatched left overs . the learning curve took me awhile to grasp ................. thank you again .... steve
    XO-1 GUY SEEKING HELP

  21. #21
    RC Racer kzsteve's Avatar
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    I now have a Bluetooth transmitter . I can hook it up to the traxxas app & modify it thru my phone , but it will not read temp or rpm , nothing . what do I check or do to fix this ? ............ thanks .. steve
    XO-1 GUY SEEKING HELP

  22. #22
    RC Turnbuckle Jr.
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    I want to thank you for your help & info. Apparently, I bought a USED & mismatched left overs.
    You are very welcome. But, yes, I knew you weren't trouble shooting with components that were 100% good, because if you do in the future what I wrote to you above you will always get to the cause of your problem.

    I use the substitute method. I keep in a box a new, known good transmitter, receiver, 4 servos, 6vdc battery pack, a servo tester, MM2 ESC, an extra iPod, a smart temp sensor, and a brushless motor tester. Also, all my surface vehicles' electronics are the same (Traxxas), and all my air vehicles electronics are same (Spectrum).
    Above is what I wrote you.

    It will not read temp, rpm , or anything.
    I would call Traxxas on that one, because I know there was an update a little while ago, and people have been having issues with it.
    Last edited by ReglarGuy; 04-16-2018 at 06:36 PM.
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  23. #23
    RC Racer kzsteve's Avatar
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    again thank you . I'm learning from the forum , slow learning curve , but getting there . when I got the car running again , I set it on normal mode , darn fast until I hit the tree . no harm but reset it to training mode . LOL I will call traxxas this morning . thanks ............ steve
    XO-1 GUY SEEKING HELP

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