Results 1 to 15 of 15
  1. #1
    RC Enthusiast
    Join Date
    Jan 2021
    Location
    SF Bay Area
    Posts
    27

    2 same cars, same abuse, same mileage, BUT: different speed and acceleration?!?

    Hey guys

    Question, although most probably just a confirmation of my thoughts:
    I got 2 2WD Slashes, both have same parts, same everything.
    1 Slash is always the faster one in terms of acceleration as well as top speed. All maintainance is the same, same oils and so on.
    We even swapped the battery from one to the other to tule this out.
    All bearings seem to run fine.

    Now my question:
    Is there anything beside typical tolerances that could cause this?

    I mean... everything has tolerances and so does the motor. If one just has a bit more punch... could be it, but perhaps you have more ideas what I could check.

  2. #2
    RC Champion RCWilly's Avatar
    Join Date
    Feb 2019
    Location
    California Bay Area
    Posts
    1,327
    Assuming same battery, motor and gearing, it's probably the slipper clutch settings. One may be set looser than the other. Tighten it, and it should have better acceleration and top speed.
    Everyday's a gift, thus now is called the present.

  3. #3
    RC Turnbuckle Jr. Squeegie's Avatar
    Join Date
    Jun 2014
    Location
    San Gabriel, California
    Posts
    8,827
    Hmmm...
    Bearings
    Throttle EPAs
    Mesh Settings
    ?

    Good luck and let us know what it is when you find it!
    Creativity is intelligence having fun. -Einstein

  4. #4
    RC Racer
    Join Date
    Apr 2012
    Location
    Space Coast, Florida
    Posts
    196
    Yeah, I'd go with RCWilly first and check the slipper clutch on each truck. Just as the parts have allowable tolerances, so do the people assembling them at the factory. One clutch could be set at the "loosest" allowed spec while the other is set to the "tightest" allowable spec. If you find the slippers to be the same and you still have the issue, you can start to swap parts from one to the other to see if the problem follows along. You already tried the battery, which is where I would have started. The next step would be to swap motors over. If it still stays within on model, then try swapping the ESCs. If it's somehow STILL present in that one truck and not the other, try swapping the transmission assemblies. Yes, it's a pain to tear it all down and rebuild, but it will help narrow down the root cause of one being slower than the other.

  5. #5
    RC Enthusiast
    Join Date
    Jan 2021
    Location
    SF Bay Area
    Posts
    27
    Ok, so clutch is first.

    I know it disassembeled both 1-2 weeks back, tightened both fully and then reversed by 1 turn.
    But perhaps due to different wear it still isn’t the same “position”.

    To understand: if the clutch is too tight, would I loose top speed?
    I understand you shouldn’t tighten the clutch too much to avoid transmission damage. If so it means I tighten both up fully and see how it goes. One try will not damage the transmission immediately...

  6. #6
    RC Champion RCWilly's Avatar
    Join Date
    Feb 2019
    Location
    California Bay Area
    Posts
    1,327
    Sometimes if there is too little thread lock on the threads, the slipper tends to loosen easier (mines loosened fairly easily, but I just added a bit of blue thread lock and it stopped).

    If the clutch is set tight, you will not lose speed. If the clutch is set loose, you will have to wait longer at full throttle in order for the car to achieve top speed, since the clutch will be slipping under acceleration.

    The transmission should be fine as long as you don't punch the throttle all the way down.
    Everyday's a gift, thus now is called the present.

  7. #7
    RC Qualifier
    Join Date
    Mar 2017
    Posts
    642
    Quote Originally Posted by Dad of a son View Post
    Ok, so clutch is first.
    I know it disassembeled both 1-2 weeks back, tightened both fully and then reversed by 1 turn.
    But perhaps due to different wear it still isn’t the same “position”.

    To understand: if the clutch is too tight, would I loose top speed?
    I understand you shouldn’t tighten the clutch too much to avoid transmission damage. If so it means I tighten both up fully and see how it goes. One try will not damage the transmission immediately...
    Other way around. If it slips, you lose acceleration and top speed.
    I actually smoked a clutch trying to go stupid fast as it was slipping.
    Also when you go to slow down, excess slipping robs power and turns it to heat.
    Once thing get hot, tolerances tighten, electronics work less efficiently.
    You may have heat glazed the pads.
    If so, a little circular rubbing on fine sandpaper will renew the pads.
    If fouled with grease or oil, clean and dry, then sand lightly.
    If cracked/damaged or heavily soaked with oil, replace in sets.
    Lastly check the clutch plate. Clean? Smooth? Flip over if heavily grooved.

  8. #8
    RC Champion grizzly03's Avatar
    Join Date
    Dec 2014
    Location
    Adirondacks
    Posts
    2,804
    If everything is the same it could just be the motors. Are you running brushed motors? In my experience I've never had two brushed motors perform the same.

  9. #9
    RC Racer
    Join Date
    Mar 2020
    Posts
    174
    I've seen similar with our two (mostly) identical Rustlers. The clutch setting can make a huge difference. Setting it is a matter of preference; some people like it super tight and others a little looser. Having it adjusted in and out from run to run shouldn't damage anything; you just don't want to leave it too tight or loose across multiple high speed runs. That's where it can get damaged.

    Sent from my moto e5 cruise using Tapatalk

  10. #10
    Marshal Double G's Avatar
    Join Date
    May 2008
    Posts
    14,338
    Switch out the ESCs and test. Then switch out the motors and test. See what component the "problem" follows. If the one vehicle still remains slower after switching then it could be something else deeper.
    The Super Derecho

  11. #11
    RC Qualifier Calebs0615's Avatar
    Join Date
    May 2020
    Location
    Maine
    Posts
    982
    Quote Originally Posted by RCWilly View Post
    Sometimes if there is too little thread lock on the threads, the slipper tends to loosen easier (mines loosened fairly easily, but I just added a bit of blue thread lock and it stopped).

    If the clutch is set tight, you will not lose speed. If the clutch is set loose, you will have to wait longer at full throttle in order for the car to achieve top speed, since the clutch will be slipping under acceleration.

    The transmission should be fine as long as you don't punch the throttle all the way down.
    I broke my slipper shaft pin when i tightened mine all the way. But i think what helped was 3s and the vxl system for sure. And the belted 2.8 badlands lol. I drove a piece of a hex in the hole and it hasnt moved since. I have a new one for when it does. They're only like 4$ i think.

    Sent from my LGL722DL using Tapatalk

  12. #12
    RC Enthusiast
    Join Date
    Jan 2021
    Location
    SF Bay Area
    Posts
    27
    Here’s the update:
    I made sure both clutches are set at the nominal same position. Then I swapped the motor and we started a drag race.

    Outcome: the motor it is! And grizzly has also been right: brushed motors (the regular Titan 550 12T).

    The “slower” car has now been faster. Not to the same extend than the other way around, but just a little bit.

    So now we could move ahead, keep the “faster” motor and Powered Up the slower one :-)

  13. #13
    RC Qualifier Calebs0615's Avatar
    Join Date
    May 2020
    Location
    Maine
    Posts
    982
    If you want a new power plant and you want to stay traxxas, you'd be impressed with the vxl system. And youd save some money using the power up program too by trading in your older components.

    Sent from my LGL722DL using Tapatalk

  14. #14
    RC Enthusiast
    Join Date
    Jan 2021
    Location
    SF Bay Area
    Posts
    27
    Yep, got the first VXL in and it's really great! even with NiMh it's a big difference.

    see my other post on the "upgrade topic": https://forums.traxxas.com/showthrea...d-alternatives

  15. #15
    RC Qualifier Calebs0615's Avatar
    Join Date
    May 2020
    Location
    Maine
    Posts
    982
    Quote Originally Posted by Dad of a son View Post
    Yep, got the first VXL in and it's really great! even with NiMh it's a big difference.

    see my other post on the "upgrade topic": https://forums.traxxas.com/showthrea...d-alternatives
    I see. Wait until you get lipos There's a chance itll be too fast for the kiddos but a battery change is pretty easy.

    Sent from my LGL722DL using Tapatalk

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •