Custom aluminum solid axle monster truck using off the shelf parts

Discussion in 'Tube RC Monster Trucks' started by RCBuilder, Apr 29, 2013.

Help Support RCMT Network by donating:

  1. Apr 29, 2013 #1

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    I was looking at restarting an old clodbuster project I started many years ago (it has a Clodzilla III chassis). After looking at how much it would take to update the axles the way I wanted to, I decided to go a different route and picked up a couple of RC4WD Super Bully Comp axles (http://store.rc4wd.com/Super-Bully-Comp-Axle-with-Knuckles-_p_490.html).

    I paired these with a Terminator chassis from CPE, a few Traxxas links, and some AX10 shocks I had lying around.

    [​IMG]

    For electronics I used two Sidewinder SCT systems, a Castle BEC, and two Hitec HS-7954SH servos. I created some custom Y-harnesses for each ESC to connect the ground and signal leads to the receiver and the ground and positive leads to the ESC fan cable. Here's a picture of everything before installation:

    [​IMG]

    For tires and wheels I already had some Axial 40-series bead locks and Pro-Line Masher tires, so I replaced the 14mm hubs on the RC4WD axles with Ofna 17mm hexes from a LX2 1/8 buggy. Most 1/8 buggy hexes fit the axles, but the Ofna ones used the correct 2.5mm pins. With this setup I ended up with a 13" wheelbase and 14 3/4" track width.

    [​IMG]

    [​IMG]

    The truck weighs in at 10lbs 1.1oz minus the body. The wheel/tire combo account for 15.5oz each. There are some options for lightening the truck (RC4WD sells lighter axle components and a CF chassis could always be used), but based on some quick runs inside the Castle 1410 motors don't seem to have any issues with it. I plan to add some test run videos later this week.
     
    Last edited: Apr 29, 2013
  2. Apr 30, 2013 #2

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    It's going to take a little longer than expected for me to upload a video.
    [​IMG]

    I took the truck outside to check the trims and ran it for about 5 mins. Turns out I forgot to add a small amount of thread lock on the motor mount screws.

    I'm thinking I may want to reduce the breaking on the front ESC as full brake induced nose stands.
     
  3. May 7, 2013 #3

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    The new pinions arrived - decided to move up to 14T pinions over the 12T that came stock with the axles. I reassembled the axles, put thread lock on all the screws, and painted the body.

    As promised here's a quick video with the limited running space I had available.

    http://http://youtu.be/1Jlsb-BaZ1A
     
  4. May 7, 2013 #4

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    I replaced both 12T pinions with 14T ones. I also got around to painting a body and I have a short running video.

    http://youtu.be/1Jlsb-BaZ1A
     
  5. May 7, 2013 #5

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    Video added

    I tried posting this update twice through TapaTalk, so hopefully this doesn't show up three times.

    I replaced the broken 12T pinion and ended up stepping up to 14T pinions. Here's the short running video as promised.

    [video=youtube_share;1Jlsb-BaZ1A]http://youtu.be/1Jlsb-BaZ1A[/video]
     
  6. May 7, 2013 #6

    KingClod27

    KingClod27

    KingClod27

    Well-Known Member

    Joined:
    Feb 3, 2011
    Messages:
    2,323
    Likes Received:
    0
    Location:
    Richmond, Va
    Wow looks good dude! look like it runs great too..there is a guy in our series that is trying to make these axles work I will have to show him your thread
     
  7. May 7, 2013 #7

    OldSchoolDude

    OldSchoolDude

    OldSchoolDude

    Well-Known Member

    Joined:
    Feb 24, 2011
    Messages:
    516
    Likes Received:
    0
    Nice looking truck. I like the rear steering also. Can you actuate the rear steer independently on the fly, or is it a separate mode on the radio?
     
  8. May 8, 2013 #8

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    Thanks guys! I appreciate the feedback.

    @KingClod27 - I don't know if you buddy was looking into using the axles with Clod wheels, but I found the knuckles cleared the wheels no problem. The only problem was track width. The super bully axle's hex-to-hex of 11.4" is way too wide. They do sell a XLD version of the axles at 10.4" hex-to-hex. With Clod wheels that would yield ~16.2" total width. Personally I like having the wheels centered over the knuckles.

    @OldSchoolDude - I currently have the servos mixed on my MT-4 with the servos on independent channels (Ch1 & Ch3). I have one of the switches assigned to the mix so I can cycle between front-only, normal-mix (crab), rear-only, and reverse-mix (4WS). I could also disable the mix and run the rear steer independently.
     
  9. May 12, 2013 #9

    91lxcoupe

    91lxcoupe

    91lxcoupe

    Well-Known Member

    Joined:
    Mar 10, 2013
    Messages:
    114
    Likes Received:
    1
    Location:
    rochester ny
    this rig is sweet. i may look into these axles for my clod pounder project
     
  10. May 17, 2013 #10

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    I was running last weekend and the truck hit a nasty landing.

    [​IMG]

    It ended up bending the chassis.

    [​IMG]

    To remedy this I picked up some Axial 7x87.5mm rods and 3mm washers (Dubro 2109) to better support the lower links.

    [​IMG]
     
  11. May 17, 2013 #11

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    I've also been working on lowering the weight of the truck. When I ordered the replacement pinions from RC4WD I also snagged the bully light weight gear box (Part # Z-S0069). This shaved 8.2oz off and brought the new total (body & battery included) down to 9lbs 11oz.

    I have a set of pre mounted 3.8" Trenchers so I threw them on and that brought the total weight down to 9lbs 0.8oz. The 1/2" offset of the Pro-line Desparado wheels is just a tad wider than the Axial Oversized beadlocks and has the added benefit of being compatible with more readily available tire choices. In fact the upcoming Pro-line Shockwave 3.8" tires could be very promising.

    http://prolineracing.com/tires/shockwave-3.8-traxxas-style-bead-all-terrain-truck-tires/

    Here's what the Trenchers look like on the truck.

    [​IMG]
     
  12. Jun 14, 2013 #12

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    I picked up the ProLine Shockwave tires mounted on F-11 black wheels (17mm 1/2" offset) today at my LHS. It's hard to leave there empty handed sometimes ;)

    I like the low profile tread pattern, but I have to wait for the rain to stop to find out how they handle. I can say they're a lot lighter than anything else I've had on this truck (9.9 oz each). It brings the total weight (minus battery) down to 8lbs exactly.

    The lighting in my basement is pretty bad, but her are some pics:

    [​IMG]

    [​IMG]
     
  13. Jun 17, 2013 #13

    Cool_Hand_Luke

    Cool_Hand_Luke

    Cool_Hand_Luke

    Member

    Joined:
    Jun 4, 2013
    Messages:
    17
    Likes Received:
    0
    Location:
    FT Campbell KY
    I like how you left the box part of the body unpainted. The light coming through it really shows off the frame.
     
  14. Jun 22, 2013 #14

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    So there I was having a blast driving my truck on Father's Day when I noticed the front gear box making a weird noise. At first glance the pinion and the gear mesh looked fine, but turning the wheels by hand indicated something wasn't quite right.

    Expecting the worst, I was somewhat relieved to find out it was in fact the pinion that had failed. Not as bad as the missing teeth that ended the original pinion, but they were pretty warped, in a I-can-still-engage-the-gear-but-my-teeth-look-nothing-like-they-used-to kind of way.

    So my current plan is to try tried and true Robinson Racing Absolute pinions. This means, however, stepping up two teeth to 16T pinions, so we'll see how that turns out.

    While I had the truck on the bench I decided to invest in some better shocks. After looking around a bit I went with the SC10 4x4 rear shocks mainly so I could try out MIP's Bypass1 shock pistons.

    To keep the mounting simple I used the SC10 4x4 upper mounting parts and just lengthened the thread on the shock mount so that I could attach it to the thiner chassis plates. Here's a few shots of before and after extending the threads and attaching the shock mounts:

    [​IMG]

    [​IMG]

    Here's what the truck looks like with new shocks installed:

    [​IMG]

    I'm running 30wt oil as recommend by MIP and white (2.5 rate) springs as a starting point.
     
  15. Jul 3, 2013 #15

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    The Robinson Racing pinions worked great until this happened:

    Front:
    [​IMG]

    Rear:
    [​IMG]
     
    Last edited: Jul 4, 2013
  16. Jul 4, 2013 #16

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    As much as I like these axles I don't think this setup is well suited for a brushless monster truck. I don't think I've got more than two runs in with the same pinions and I really don't drive my cars too hard.

    Between the locked diff and metal gears, there really is no give in the drivetrain. Ideally I'd add a slipper to relieve the stress or smaller pitch gears to strengthen the teeth but that would require custom work.

    I may have missed it, but I haven't heard of too many horror stories with clod buster transmissions going brushless. Maybe I'll dig out my old clod buster gear boxes and see how they compare. Any thoughts?
     
  17. Jul 4, 2013 #17

    JKRacing37

    JKRacing37

    JKRacing37

    Well-Known Member

    Joined:
    May 26, 2006
    Messages:
    3,585
    Likes Received:
    0
    Which pinions are you using? Robinson makes several different grades of pinions. They make some really cheap pinions that are basically designed to test out gearing then switch to a higher grade pinion for long term running.


    Sent from my iPhone using Tapatalk
     
  18. Jul 5, 2013 #18

    RCBuilder

    RCBuilder

    RCBuilder

    Well-Known Member

    Joined:
    Apr 27, 2011
    Messages:
    89
    Likes Received:
    0
    Location:
    New England
    These are Absolute hardened pinions #1416.
     
  19. Jul 5, 2013 #19

    JKRacing37

    JKRacing37

    JKRacing37

    Well-Known Member

    Joined:
    May 26, 2006
    Messages:
    3,585
    Likes Received:
    0
    Ugh. There goes that theory. :(
     
  20. Jul 5, 2013 #20

    BigStu

    BigStu

    BigStu

    Well-Known Member

    Joined:
    May 14, 2013
    Messages:
    75
    Likes Received:
    0
    Location:
    Auburn, MI
    Remember, very hard can mean very brittle.
    The way they are both breaking like that makes me wonder if a cheap soft one would work.
     

Share This Page