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  1. #1
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    Front rockers in the rear?

    What exactly does this do? Any downsides?

    Thanks!

  2. #2
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    I would like to know as well. Anyone have a side by side pic of the two?

  3. #3
    RC Turnbuckle Jr. Dadx2mj's Avatar
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    If memory serves me correctly it will raise the ride height of the rear of the MERV. This will keep the truck from bottoming out but also raise the COG
    BlindMan Racing
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  4. #4
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    For me the ride height is the same,the reason I did it was to lessen the e-revo squat under acceleration.It drives better than ever

  5. #5
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    yes i did this on my 1/10 revo and it took away almost all of the sag in the rear under a good amount of acceleration. it doesnt just like scrape under acceleration, or even almost scrape. it holds the back end up quite a bit and helps it not bottom out as often. it does make the rear suspension a bit stiffer than the front so i just switched the rear springs to the front and front to the rear and now it is very even. my ride hight still gets as low as i would ever want it..
    Later!

  6. #6
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    The springs should be the same front-and-rear, aren't they?

  7. #7
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    on the mini i think they are but i did the switch on the mini it seems to help alot lookin for rockers fro the big one now

  8. #8
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    i know i was just saying that on my 1/10 nitro thats what i did...

    Later

  9. #9
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    Quote Originally Posted by BAC5.2
    The springs should be the same front-and-rear, aren't they?
    The springs stock are the same. But people run different springs based on preference.

    To give some insight into what is happening when the rockers are changed you have to understand the concept of motion ratio.

    All suspensions have some motion ratio due to the kinematic differences in the mechanism that actuates the damper.

    In our ERBE/MERBE/mini slash case we have a PRD configuration (Pushrod Rocker Damper) setup

    The geometry of the setup determines many things about the suspension. By changing the rocker you can change a couple of main things. But the biggest change is to the motion ratio of the suspension.

    You can calculate the motion ratio of a suspension system my measuring the amount of wheel movement to the amount of damper movement. By changing rockers on our trucks we effectively change the motion ratio. Changing the motion ratio changes the wheel rate so it would appear that we now have a stiffer spring on the rear, when in fact the spring is the same.

    Since the motion ratio effects the relationship of wheel movement (up & down) to damper movement it would make sense that the motion ratio also effects the relationship of wheel compression velocity to damper compression velocity.

    This is important because damping is velocity sensitive. More speed=more force.

    This is because fluid resistance increases at the square of velocity. That means that when changing the rockers you should also change the damping (shock oil weight change or piston configuration change)

    If anyone has more questions let me know. Suspension just happens to be my day job.

  10. #10
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    My brother put front rockers in the back. It lifted the back way up an made it look funny. It rolled to easy because the center of gravity was higher.
    E-Revo BE, E-Revo VXL, Rustler VXL, Jato 3.3.

  11. #11
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    You just gotta drop the rear preload, raise the front preload to match what your selection of the rear preload and it shouldn't roll near as much ..

  12. #12
    RC Turnbuckle Jr. Dadx2mj's Avatar
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    Quote Originally Posted by revo_maniack
    You just gotta drop the rear preload, raise the front preload to match what your selection of the rear preload and it shouldn't roll near as much ..
    So what is the point of putting front rockers on the rear if you are just going to readjust the suspension to make the ride height the same as it was before?
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  13. #13
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    I run with the opposite mod lately. I installed rear rockers up front (with an extra bearing underneath).

    Since I mounted huge tires (diameter of 4.5") to run in the snow, my ride height was too high. I could not bottom out the front. Therefore on full shock compression all the remaining force was being transfer to the shock mount. I am sure something would have break sooner or later... So I found a way out by doing this reversed mod!

    Don't forget to give credit to Zrau17 for the original idea. Ref Thread : Bahers Read!!!
    Last edited by Papino; 01-14-2010 at 09:25 PM.
    What have you learned today?

  14. #14
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    bumping this up. did this today:
    switched front rockers with rear rockers and adjusted suspension. There is wayy more travel in the rear, and i no longer have the saggy rear problem i was having before.
    I also like the way there isnt as much movement upfront.

    for me it HANDLES WAY BETTER.

  15. #15
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    Bumping this thread up to this decade...

    Does anyone use this mod or one similar? What results have you seen and how did you have to adjust springs?

  16. #16
    RC Champion zedorda's Avatar
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    After reading through the thread there is not much to add. Post 9 pretty much explains what you should expect. I can't say this is a mod anyone would do for long plus it depends on which model you have since not all of them have the same rocker setup.

    I bought the long travel rocker set for my revo and it made the suspension super soft with more travel. Increased traction rolling and made the chassis slap more. The longer the rocker the thicker the shock oil needs to be. I hated how it drove and switched back after 2 packs.

    https://www.amazon.com/Traxxas-Rocke.../dp/B0049MCK76
    Last edited by zedorda; 09-22-2020 at 12:40 PM.

  17. #17
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    Thanks - yeah I am not looking for additional height per say because that would be disastrous like you found out in regards to control. Long travel rockers won't do, but having the progressive rockers from the front on the rear to allow more droop when in the air might be useful. I would still want to adjust it all so that the control arms are mostly level when at rest for best control in turns. Just curious what other people found when trying it out.

  18. #18
    RC Champion zedorda's Avatar
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    The Merv comes stock with the long travel rocker on the front. So all I actually switched were the rears. The Slash comes with short travel front and back while the Summit has the long travel front and back.

  19. #19
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    Quote Originally Posted by zedorda View Post
    The Merv comes stock with the long travel rocker on the front. So all I actually switched were the rears. The Slash comes with short travel front and back while the Summit has the long travel front and back.
    The exploded map says it comes stock with progressive rockers in front and back (Part# 7158). The front are longer than the rear, but do not appear to be the same as the actual long travel rockers (Part#7156), which come standard on the 1/16 Summit. Comparing the pics of each I see the subtle differences.

    So it sounds like you put the progressive front rockers on the rear and found that it made the suspension supersoft and increase rolling. What springs did you use and did you reduce the preload to lower the truck back down to normal heights?
    Last edited by halygon; 09-23-2020 at 08:44 AM.

  20. #20
    RC Champion zedorda's Avatar
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    Quote Originally Posted by halygon View Post
    The exploded map says it comes stock with progressive rockers in front and back (Part# 7158). The front are longer than the rear, but do not appear to be the same as the actual long travel rockers (Part#7156), which come standard on the 1/16 Summit. Comparing the pics of each I see the subtle differences.

    So it sounds like you put the progressive front rockers on the rear and found that it made the suspension supersoft and increase rolling. What springs did you use and did you reduce the preload to lower the truck back down to normal heights?
    I only did a simply look over them but they seemed the same. PRS style suspensions are always progressive by design so not sure what could be different between the two but I don't doubt I lack the knowledge to identify the difference that would make them progressive or not. As for springs I run the purple in the back and blue in the front.




    Left is rear, right is front. I only used the rears. But I think I see the difference now. The shock mounting hole and the pivot are closer in the long travel rockers. I am guessing that affects the progressive nature to some degree.
    Last edited by zedorda; 09-23-2020 at 11:20 PM.

  21. #21
    RC Champion grizzly03's Avatar
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    Quote Originally Posted by zedorda View Post
    The Merv comes stock with the long travel rocker on the front...
    Quote Originally Posted by halygon View Post
    The exploded map says it comes stock with progressive rockers in front and back (Part# 7158)...
    My mini Erevo came with progressive 2 rockers on the front and the rear.

    They are different than the long travel rockers. The distance from the pivot point (rocker post) to the shock mount (shock end) point is closer together on the LT rockers and farther apart on the P2 rockers.

    The pushrod end to rocker post is longer on the LT rockers and shorter on the P2 rockers.
    Last edited by grizzly03; 09-24-2020 at 12:59 AM.

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