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  1. #1
    RC Qualifier cazrack's Avatar
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    Want it to do atleast 40 mph, battery and gearing questions

    Planning on buying this truck but I want it to do at least 40 mph.

    1. In some videos I get the impression that this truck won't go any faster with 6s than 4s or 3s unless you change gearing?

    2. Changing gearing to get higher speed up to 45 mph (no need to go faster) what impact does this have while bashing?

    Thanks

  2. #2
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    The more cells is always gonna go faster. Pretty much have to run this truck on 6s. To get in the 40s put a couple extra fans on for cooling and swap to a 18 tooth pinion. I have a 30mm fan blowing in side of esc, and a 50mm over the motor and run a 18tooth with no problems. Truck is way better with this gearing. Way too low geared stock actually wheelies better geared up a little. I highly recommend the 18/54 gearing.

  3. #3
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by rwc2002 View Post
    The more cells is always gonna go faster. Pretty much have to run this truck on 6s. To get in the 40s put a couple extra fans on for cooling and swap to a 18 tooth pinion. I have a 30mm fan blowing in side of esc, and a 50mm over the motor and run a 18tooth with no problems. Truck is way better with this gearing. Way too low geared stock actually wheelies better geared up a little. I highly recommend the 18/54 gearing.
    If I keep it at maximum 50 mph with 6s, what is the pros and cons compared to choosing maximum mph speed gearing?

  4. #4
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    The higher you gear it the more stress it puts on the motor and esc. That's why you will need extra fans to keep them cool. The higher gearing you trade some low end power but this truck has plenty of torque. The 18/54 seems to still have about the same low end power with the added 10 mph over stock. I've had no heat issues either but it is 25 degrees out here lol.

  5. #5
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by rwc2002 View Post
    The higher you gear it the more stress it puts on the motor and esc. That's why you will need extra fans to keep them cool. The higher gearing you trade some low end power but this truck has plenty of torque. The 18/54 seems to still have about the same low end power with the added 10 mph over stock. I've had no heat issues either but it is 25 degrees out here lol.
    With you're choice of gearing , have you tested it with 3s and 6s, please feedback on the difference.

  6. #6
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    I only run the truck on 6s, you can basically only run it on 4s and 6s without changing the wiring it runs 2 packs at once in series so you either run 2 2s packs or 2 3s packs. The truck is way to slow on 4s for me maybe does 20 some mph on 4s.

  7. #7
    RC Champion jeteffect's Avatar
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    There are videos and threads here with details on the X-MAXX doing 60!!

  8. #8
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by rwc2002 View Post
    I only run the truck on 6s, you can basically only run it on 4s and 6s without changing the wiring it runs 2 packs at once in series so you either run 2 2s packs or 2 3s packs. The truck is way to slow on 4s for me maybe does 20 some mph on 4s.
    Traxxas only sell 3s lipos?
    Only 20 mph with 4s?
    Accrording to Traxxas: Top Speed: 35+ MPH with two 3s LiPo Batteries

    https://traxxas.com/products/landing/X-Maxx/

  9. #9
    RC Qualifier cazrack's Avatar
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    ahh me stupid now i get it :-)

    2 2s lipos = 4 lipo power since the car run on both at the same time.
    2 3s lipos = 6 lipo power since the car run on both at the same time.


    EDIT:

    Can this truck handle 2 6s lipo power battery packs at the same time?

    Why doesnt Traxxas sell larger lipo battery packs with more cells like 6s?

    Please do not bypass the language filter. If a word is converted to *s then it is not permitted here. ksb51rl
    Last edited by ksb51rl; 01-01-2016 at 10:57 AM.

  10. #10
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    Quote Originally Posted by cazrack View Post
    ahh me stupid now i get it :-)

    2 2s lipos = 4 lipo power since the car run on both at the same time.
    2 3s lipos = 6 lipo power since the car run on both at the same time.


    EDIT:

    Can this truck handle 2 6s lipo power battery packs at the same time?

    Why doesnt Traxxas sell larger lipo battery packs with more cells like 6s?
    Don't think the xmaxx can handle 2x 6s. Only 6S total so 2x 3S.

    What size pinions does the xmaxx need? I'm in the UK and can't buy off the traxxas site. Do Pinions/Spurs from other cars fit it?
    Last edited by ksb51rl; 01-01-2016 at 10:56 AM.

  11. #11
    RC Champion MaXXL's Avatar
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    Yeah I havn't heard of anyone running more than 6s. Most 1/8 electronics are only rated to 6s max.

    About gearing vs voltage for top speed. 3 things limiting your trucks top speed are max temp, max current draw, and max RPM

    You can gear it to the moon and get 40 mph on 4s. Just make sure you dont over temp and make sure your not drawing too much current from your battery as your battery wont last long if this is the case.

    You can up the voltage but then you have to be concerned with temp (always have to consider temp) and max rpm. The reason why certain motors are limited to 4s while others are limited to 6s is because of the rpm they are rated to spin at. If you take a motor rated for 4s and you use it in a 6s application, your spinning the motor faster than it was designed to and you could have a centrifugal time bomb in your truck.

    Also, more battery = more weight and more space
    And remember if you change the timing of your motor via ESC programming (turbo, boost, timing advance etc.) you change the RPM, amp draw, and temp characteristics of your system.
    10 RCs and counting 😅

  12. #12
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by MaXXL View Post
    Yeah I havn't heard of anyone running more than 6s. Most 1/8 electronics are only rated to 6s max.

    About gearing vs voltage for top speed. 3 things limiting your trucks top speed are max temp, max current draw, and max RPM

    You can gear it to the moon and get 40 mph on 4s. Just make sure you dont over temp and make sure your not drawing too much current from your battery as your battery wont last long if this is the case.

    You can up the voltage but then you have to be concerned with temp (always have to consider temp) and max rpm. The reason why certain motors are limited to 4s while others are limited to 6s is because of the rpm they are rated to spin at. If you take a motor rated for 4s and you use it in a 6s application, your spinning the motor faster than it was designed to and you could have a centrifugal time bomb in your truck.

    Also, more battery = more weight and more space
    And remember if you change the timing of your motor via ESC programming (turbo, boost, timing advance etc.) you change the RPM, amp draw, and temp characteristics of your system.

    1.If you gear it to the (moon) do you lose torque and acceleration on rough grass or do you only add heat and faster battery loss?

    2. How much does outdoor temperature help with keeping it cool ?

    For example in

    5 Fahrenheit
    25 Fahrenheit
    50 Fahrenheit
    Last edited by cazrack; 01-01-2016 at 10:36 AM.

  13. #13
    RC Champion MaXXL's Avatar
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    Your not really losing acceleration by gearing it to the moon. Your motor will make up for the gearing change by creating more torque (too an extent), drawing more amps (draining your batteries faster), and creating more heat.

    Outside air temps def make a considerable difference in motor temps, especially if your talking a dramatic difference like 5 F vs 50 F.
    10 RCs and counting 😅

  14. #14
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by MaXXL View Post
    Your not really losing acceleration by gearing it to the moon. Your motor will make up for the gearing change by creating more torque (too an extent), drawing more amps (draining your batteries faster), and creating more heat.

    Outside air temps def make a considerable difference in motor temps, especially if your talking a dramatic difference like 5 F vs 50 F.
    But then why do you think Traxxas have (undergeard) it so much according to some forum members here?

  15. #15
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    Quote Originally Posted by cazrack View Post
    But then why do you think Traxxas have (undergeard) it so much according to some forum members here?
    This is a BIG truck. I think they geared it so it would be a good balance for everyone. I am sure there were many factors such as motor Temps and the fact that something this large and heavy can be very dangerous at high speeds. They knew that people would change the gearing and they made it very easy for those who wanted to do so. If you read the comments you can see there are just as many people who think it has plenty of speed out of the box as there are who thinks it needs more. There are also those who want to gear it lower as well for more of a crawler experience. The point is that you can never please everyone at the same time, so you find a middle ground and let the tinkerers go from there
    XMAXX (Red), Tmaxx 2.5 (converting to electric)

  16. #16
    RC Champion MaXXL's Avatar
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    Probably to account for most buyers in the market for an X-Maxx. If they sell the truck with a conservative gear ratio, it will pretty much never overtemp. Any buyer regardless of location, age, environment, etc etc can drive the truck and not worry about temp.

    They prob designed it so that the truck can be run at full throttle, for an entire battery pack, in the middle of the Sahara desert, in 110 F weather, without overheating.

    Also the slower your truck is, the easier it is to drive and the less parts you'll break.
    10 RCs and counting 😅

  17. #17
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    I just changed to an 18t pinion on 6s and I am very happy with the results. I have no way to actually record speed, but there is a noticeable difference in top speed. (I'd guess somewhere around 40mph.) My temps are about the same as well. I'm hitting 160F in about 15 mins of going up and down the street in front of my house. Ordered the fan for the castle 2028 motor, so when that goes on I should be able to go thru full packs without the motor getting too hot. I've been stopping once it gets around 160F.

  18. #18
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    Quote Originally Posted by rwc2002 View Post
    The higher you gear it the more stress it puts on the motor and esc. That's why you will need extra fans to keep them cool. The higher gearing you trade some low end power but this truck has plenty of torque. The 18/54 seems to still have about the same low end power with the added 10 mph over stock. I've had no heat issues either but it is 25 degrees out here lol.
    how are you measuring speed? I did the same gear change but have no way to measure the speed increase.

  19. #19
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by bigtim1985 View Post
    I just changed to an 18t pinion on 6s and I am very happy with the results. I have no way to actually record speed, but there is a noticeable difference in top speed. (I'd guess somewhere around 40mph.) My temps are about the same as well. I'm hitting 160F in about 15 mins of going up and down the street in front of my house. Ordered the fan for the castle 2028 motor, so when that goes on I should be able to go thru full packs without the motor getting too hot. I've been stopping once it gets around 160F.
    How much is stock motor to hot in Fahrenheit on x-maxx?

  20. #20
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    I dont think people quite understand how fast 35mph is for a 20lb 1/6th scale truck! More than fast enough!

  21. #21
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    Quote Originally Posted by bigtim1985 View Post
    how are you measuring speed? I did the same gear change but have no way to measure the speed increase.
    If you have a smart phone, you can get an app such as digihud speedometer. It will record max speed using GPS . You just need to attach the phone to the truck and do some runs.
    XMAXX (Red), Tmaxx 2.5 (converting to electric)

  22. #22
    RC Qualifier cazrack's Avatar
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    Traxxas list
    Servo: Torque: 365oz. Speed: 0.17 sec/ 60 degrees(6.0V)

    Do anyone know how much or little 365oz is compared to other products or upgrades to this truck?

  23. #23
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    Quote Originally Posted by Kpowell911 View Post
    I dont think people quite understand how fast 35mph is for a 20lb 1/6th scale truck! More than fast enough!
    Everyone's opinion will differ on that. 35 is not bad but out out of the box only gets like 29 or 30 which looks really slow on a big truck, when your used to 65mph revos and buggies. I think 40 is the sweet spot for the truck still controllable but a little more fun just have to watch surroundings and kids.

  24. #24
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    My truck with the 18 tooth pinion did 39.5 on GPS so yeah it's basically 40. My motor runs 130 ish but I run a fan on it.
    Also agree on 40 being the sweet spot! The tires just start to balloon and it still has amazing torque.

  25. #25
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    Quote Originally Posted by cazrack View Post
    How much is stock motor to hot in Fahrenheit on x-maxx?
    I'd say 160F is getting there but safe, 180f is hot and 200d is too hot......... but I like my stuff to last.

  26. #26
    RC Qualifier cazrack's Avatar
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    Quote Originally Posted by bigtim1985 View Post
    I'd say 160F is getting there but safe, 180f is hot and 200d is too hot......... but I like my stuff to last.
    And temp on Xmaxx ESC?

    Is it possible to monitor temps without changing motor and esc?


    Thanks.

  27. #27
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    there is already a temp probe on the motor. You just have to buy the Bluetooth module for the transmitter to get it to work. I supposed you could add another temp probe for the ESC but i think you would need the telemetry expansion module, and you'd have to take the esc apart to get the probe in the right spot.

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