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Thread: Rock crawler specific build

  1. #1
    Join Date
    Mar 2020
    Posts
    64

    Default Rock crawler specific build

    I am going to build a new rig. I want this to be specific to rock crawling. I have learned some things from my last build and that is a really good trail truck. But I want this to be a crawler. I could buy a Capra but wanted to go a different route. I like the low CG power wagon bodies. I was going to get an SCX10ii builders kit. But they did not have one at the local hobby shop. And it cost 200 dollars. I bought the UMG10 instead. For the extra 100 bucks I get five wheels and tires. Metal shocks and the two speed transmission option. I don’t think I’m going to use the body. So I’ll save that for later.
    I ordered a bunch of stuff . Metal shock mounts and metal frame bracing. I also bought metal shock offsets. I got some high clearance links. 1080 ESC with an RC4WD 35T motor. Now that Holmes hobbies has motors in stock I might get one of the crawler pro ones.

    I have some good servos so I’ll decide on that later.

    Should I change the front gear ratio in the AR44 axles?

    What is the best approach to getting a low CG? I want to keep the weight down low. So I don’t want a roll bar set low, But also don’t want the body to get smashed falling down the rocks.

  2. #2
    Join Date
    Apr 2020
    Posts
    170

    Default

    to get a low center of gravity you can use axle and wheel weights , a shorty pack usually helps because its not high in the vehicle
    but it's not low , low cog isn't the only problem you also have to worry about axle scraping and your weight balance which should be to the front something as simple as a brass diff cover in the front and plastic in the back , in my old rig i used fishing weights to near perfect my vehicles balance , those are the basics full droop can also help but it's harder on the shocks and can cause body rub and looks less scale brass gets expensive fast especially with the excess wear , look for things like this, nothings lower then your wheels: https://www.ebay.com/itm/Heavy-Brass...r=414220369751

  3. #3
    Join Date
    Mar 2020
    Posts
    64

    Default

    Thanks
    So what I have done so far is add shock extensions. This dropped the suspension level. Then I cut the body down and raised the mounting points. This required removal of rear fenders. But the Toyota bed fills in the are that was taken by the fenders. I have portals and steel wheels. Still playing with shock springs but it’s better. I put some tire weights on the bottom also. It is about 1/2 to 3/4 of an inch lower . But only has 1/4 inch of travel before it bottoms out. Although it can still articulate 41/2 inches down. It’s much much better at side hills now. And seems to craw better. I’m going to give it a real test tonight.

  4. #4
    Join Date
    Mar 2020
    Posts
    64

    Default Rock crawler specific build


    I just sorta bolted this together to see what I need to do. There is no frame yet just the links and drive shaft. Links are 71 top and 80 bottom. I need longer top links to get a better drive shaft angle.
    Wheel base is 11 inch. It will be a couple weeks before I have the frame together.

    I do know the links are on upside down and backwards. I just put them on that way to clear the short uppers while I’m fooling around with the set up


    Sent from my iPhone using Tapatalk

  5. #5
    Join Date
    Apr 2020
    Posts
    170

    Default

    if you're having high center issues on the center plate or scraping you can use skateboard wax it'll look slightly off on the bottom but it'll help a lil you can also try other shocks and softer springs if they're not soft already on my current project(not my blackout) think im going blaz3r style with a builders kit


    Edit: you can use any wax just not in competition i like spitfire or thunder wax or hard luck but any skate wax or candle wax you find will work fine

  6. #6
    Join Date
    Apr 2020
    Posts
    170

    Default

    you can also try longer shock shafts then stretching the springs/ ordering longer ones then making some bump stops from a rubber bracelet or old shock o rings

  7. #7
    Join Date
    Mar 2020
    Posts
    64

    Default Rock crawler specific build



    This is my low CG build so far. I removed the portals and modified the drivetrain to minimize backlash. I lowered the body as far down as I can. I cut the bottom rocker panels by 10mm and removed a bunch of fender arch. The suspension sits about 10-12mm from bottoming out and has 95 mm of total. I changed the battery to a 2s because the 3s was to jumpy. I think it needs a gearing change.
    It is much better at side hilling. But I do need to pick better lines. But that is just because of the portals being gone. I got spoiled by them.
    Now its a fast woods truck that can climb better on rocks

  8. #8
    Join Date
    Mar 2020
    Posts
    64

    Default

    I ended up making a set of high clearance links for a 313 mm wheel base. That was way more work than it was worth. I think it made a big difference. I also changed out the Injora axles for real Axial AR44 differentials and I also replace my skid plat because a couple holes got a little worn on the Injora one.

    Now there is almost no Injora parts in this rig. I can?t fault the Injora rig. It cost 100 bucks and got me started. The only thing left is the battery tray and frame rails.


    Sent from my iPhone using Tapatalk

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