Conference vmszoo::rc

    I'm going to add some more to the original note here.
    On further observation when running this truck,I noticed at high
    speed turns that the truck understeers.I believe it is this because
    in negotiating the turn the front wheels tend to slide and do a
    lot of bouncing.On medium speed turns usually with no power
    applied(coasting)it oversteers(too tight of a turn)and it flips.
    I think I used the right terms above,correct me if I'm wrong,
    I'm very new at this game.
    Les Borda.
    

    Dear Les,
    
    	I own a couple of Blackfoots and found that there isn't too
    much you can do for turning without flipping the truck.  You will
    just have to slow down before cornering.  I even tried lowering
    the suspension for racing on smooth tracks but still found that
    flipping it over was a little harder but still happens.  I even
    tried to make the left shock softer so that the truck would lean
    to that side on cornering but it didn't make too much difference
    either.  I guess it's not a car and sits high for rough terrain.
    You can play with truck bodies too.  I have a couple different ones
    and found that the heavier body worked better.  The truck would
    roll only once instead of 5 times with a lighter body.  
    	So what I have done to compensate the cornering is to buy a
    hot motor and therefore I make up for my slow cornering by blowing
    the competition away in the straight aways.  Don't race a truck
    against a car unless you plan on running into the car in the beginning
    and wiping him out.
    
    					Good luck,
    
    						Rodney
    

    In the 1988 Annual Edition of Radio Control Car magazine there is
    an article on oversteering and understeering and how to adjust a
    car to cause or eliminate them.  It might offer some help.
    
    If you can't find a copy let me know and I'll try to excerpt it.

    -- Don
    

    Thanks for the info guys.I phoned the boys at MRC the other day
    to try to get some insight into this problem.The guy claims that
    about 95% of all the Tamiya vehicles are being run on and off road
    including the Blackfoot.He realizes the flipping problem is quite
    common and suggests a lot of trial and error in the oil filled shock
    department,softening the front stiffening the rear,trying different
    oil weights.He says that brake fluid and transmission fluid are
    excellent oils to use in shocks.
    Another suggestion he made was to check the radio system,he says
    that the Blackfoot is capable of definately turning TOO far which
    results in too sharp of a turn which on asphalt causes EL-DESTRUCTO
    I think one of my problems is related to this,I recently installed
    a CRP heavt duty steering kit which has an extremely large servo-saver
    and I used the two outside mounting holes for the steering arms.I
    understand(and I could be wrong)that this results in a large change
    in steering for a small change in servo movement.I wonder if moved
    the sterring arms to the inside two holes if it would not change
    the ratio and result in less of a change????
    
    

    
    I was given a completly assembled Blackfoot this summer and now
    I'm hooked on RC.  I've drove the thing so much that I think I 
    stripped the drive gears the last time out.
    
    This may not be a problem for an experienced RC driver, but I'm
    just a beginner and I didn't even build the thing.
    
    I have the tools and the skill (I hope) to fix it myself, but I'm
    a little short on know-how.
    
    Can any one give me some tips, tricks, hard facts to help me through
    the repair process?  A few questions that come to mind are:
    
    Where do I get parts?
    How do I know what size/type gears to by?
    What will I find when I pull off the gear box cover?
    Will a zillion little ball bearings pour out?
    Do I have to repack the box with grease? If so, what kind?
    (etc)
      .
      .
      .             
    
    
    Thanks in advance for any help.
    
       Henry Pozzetta (HP)

    Henry,
    
    In responding to your questions, I'll have to make the following
    assumptions:
    
    1.  the truck was built stock - using only kit parts
    2.  you probably use the truck for backyard bashing and not racing
    3.  you don't have assembly directions
    4.  you want to return the truck to stock condition
    
    So...
    
    Where do I get the parts? - Just about any hobby shop carries Tamiya
    Blackfoot parts, it's a very popular kit.  Depending upon what you
    need, prices will vary.  You may get away with only buying a "gear
    bag" which will be <$10.00 - but should you need additional parts
    you may wish to buy "trees" of parts - some of which you won't need
    but will have to pay for anyway.  Most good hobby shops will have
    a complete parts breakdown book for your kit.  Even without assembly
    directions you/they will be able to identify what you need.
    
    How do I know what size/type of gears to buy? - you can identify
    what gears are required by taking the damaged ones to your hobby
    shop or getting a copy of the assembly instructions and matching
    the parts at the back of the manual.
    
    What will I find when I pull off the gear box cover?  Probably nothing
    that will surprise (or scare you).  The Blackfoot transmission is
    fairly simple in stock form - grease will probably hold it together
    when disassembled or it will just drop to the table in a "blob"!
    Be sure to check the pinion on the motor.  If it looks good, be
    sure it's tight on the shaft.
    
    Will a zillion little ball bearings pour out?  No.  The Blackfoot
    does not come stock with a ball-diff so you'll have a 3-gear set
    differential rotating on small steel shafts - again, grease will
    probably hold things together.
    
    Do I have to repack the box with grease?  Yes.  Some folks use
    Ceramic grease, I prefer to use the Moly grease which not only
    sticks forever but stands up to higher temperatures.
    
    Then there is the question of not reassembling to stock...but that
    is a whole other conversation...
    
    Good luck!  It's easier than you think!
    
    

    
        HI HENRY, 
     
             MY NAME IS ANGEL AND I'M INTO MONSTER TRUCK ALSO. ONE 
             OF MY TRUCK IS A BLACKFOOT. DON'T BE AFRAID TO 
             DISASSEMBLE AND ASSEMBLE THE TRUCK, IT IS EASY.
    
             SEND ME YOUR MAIL STOP AND I'LL SEND YOU A COPY OF THE
             BLACKFOOT INSTRUCTION MANUAL. THAT WAY IT WILL HELP
             YOU GET THE PARTS AND PUT THE REAR END TOGETHER.
    
             IF YOU HAVE ANY QUESTIONS, SEND ME A MESSAGE.
    
                                                     ANGEL
                                               MONSTER TRUCK MASTER
    

                                                   
    
    Thanks for the help.  I'll start on the repairs after I get Angel's
    assembly instructions.  For now I think I'll stick with 'stock'
    replacement parts.  After a while I'll consider some basic upgrades
    to 'performance' parts.
    
    Any suggestions on what I should upgrade first?
    
    HP

    YEA, change the rear axles. Replace them with the dog bone type.
    Also replace all the nylon berrings with the ball berring type.
    
    Den
    

    
    A previous Blackfoot note mentions shocks.  Any room for improvement
    their?  What about tires/wheels?   How about improvements in the
    electronics?  Motor, Servos, Battery Pack, Speed Controler?

    Hi,got Blackfoot myself that I just started this fall and have made
    lots of changes to.Adding ballbearings instead of the nylon crud
    is an excellent place to start,it takes 8 5X11mm bearings and one
    smaller one in the gear box(stock it has a brass bushing).Two go
    into each of the front wheels,and two each into the trailing arms
    in the rear where the axles go thru.
    I have added Tamiya(yellow)oil filled shocks to mine(not the best,but
    priced right).Also added a Trinity Monster Stock motor,have not
    raced it yet so I don't know how fast it is.Just tried some new
    tires from duratrax,look like tractor tires but the material is
    much softer than the originals,should handle better but I can't
    find out,too much damn snow.
    Talk to Angel about some good stuff from JG Ltd,that you can add,I
    just bought one of there heavy duty front bumpers,looks pretty good.
    Angel's got some info on cheap electronic speed controls that will
    do the job.
    Have Fun
    Les Borda.
    

    I forgot to add one thing in re.6,I added some gold anodized Monster
    Beetle rims to the Blackfoot,they look good compared to the yellow
    plastic stock rims.Proline sells chrome plated rims for the BF as
    well although the gold plated MB rims where a better price.
    Les Borda.
    

    I too have a blackfoot. You know all decked out. Frog gears bearing,
    shocks, r/p servo saver,big bear tires,bumper,skid plate hurricane
    motor. My problem is speed control!! I used the stock one for about
    a week, and a handful of resistors. I bought a mechanical(parma)
    and that lasted 2 minutes, as it burned (melted) a line off at a
    time. Be handy in soldering I fixed it being less one line. After
    my 4th attempt and like barely any lines  I gave up. Then I bought
    a FUTABA 112B. It lasted to the end of the kitchen floor!!! There
    is no drag in the drive train and I don't beat it yet.
    
    
    
    Any help will be great.
    
    
    Bill 

    My son, with some "help" from me, is constructing a Monster Beetle,
    and a question has come up concerning the differential (the same
    diff used on the Blackfoot).  The shafts which extend from the diff
    (they're called short joint shafts, and mate with the dogbone axles)
    do not extend by the same distance.  One of them looks like it could
    be pushed another 1/8 inch into the diff, but the gears inside prevent
    that.  It seems to work fine, and we've opened it up and it appears
    to be assembled correctly.
    
    Is this correct for this diff?  Any BF or MB types out there that
    noticed this on theirs?
    
    Tony

I think my Blackfoot had the same symptom, and it caused a problem:
The offset of the outdrive was enough to make one of the dogbones bind
at the midpoint of the rear suspension travel.

I wish I could tell you how to fix the problem easily and cheaply,
but I can't.  I went the expensive route and replaced the diff &
outdrives, counter gear, dogbones, and axles with Thorp parts (#4550,
#4520, #4510, and #4511 respectively.)  I was making my Blackfoot into
a racing machine and I mistrusted the Tamiya diff and dogbones even
before I notice the binding problem.

If your truck has the binding problem, you might try shimming at the
gearbox-to-frame mounting points to increase the clearance slightly
on one side.

* * * * *

Perhaps one of the moderators out there could merge this topic with
758 and 838 to produce a single "Blackfoot/Monster Beetle/Mud Blaster
note."

    re -.15
    
    Thanks for the information.  I'll have to check for binding of the
    dogbones.  From what I've read about the longevity of the stock
    dogbones, your course of action sounds good.  I had hoped to find a
    cheaper way by using replacement dogbones, axles, and output shafts
    without replacing the diff itself, but perhaps that is not possible.
    I plan to send for a Thorp catalog, and a catalog from Tower should
    be arriving soon.  I'm sure it will be easy to spend more money
    on this. -)
    
    Tony 

Last time I checked, the best deal on a Thorp upgrade was from Sheldon's
Hobbies in San Jose, CA. They will sell you the Blackfoot diff, dog
bones, and hub/axle kit (Thorp #4550, #4510, and #4511 respectively)
for $59.96.

I think you are correct in thinking that parts are available to convert
the Blackfoot to "real" dogbones without replacing the diff, but I
don't know the part numbers.

    --mark

    I got my monster beetle at the very end of last summer.
    When I started i thought all that i would need was the
    monster beetle kit, controller, battery charger, and a
    couple of batteries.  I was mistaken.  Within about 
    fifteen times of using my truck(for fun only, no racing)
    I had stripped my stock hex shafts.  Instead of buying 
    new ones I went with the Thorpe.  The total for mine was
    about $65 out here in Acton, Massachusetts.  It has been
    a good investment.  It is almost impossible to strip these
    dog bones and the way i drive it, that is important.  The
    next thing that i got was a new motor called "monster Mash",
    another good investment.  It was only $36 and now i blow
    away everyone who still has there stock motor.  It is almost
    as fast as the turbo 08.  My run time has been cut by only
    about four minutes with a six cell battery but it is worth
    it.  
          -With the weather out here I havn't been able to run
           it for about two months now.  I am getting eager for
           spring to get here.
    Rob