Kidriffic Micro RC 4x4 Monster Truck Dissection (pics)

[actofgod]

Under the upper section are the two motors, facing opposite directions. Each motor pinion gear meshes at the top of one gearbox in the lower section. Shown for reference from left to right: a Bit Char-G motor, a motor from my BFM-9000 mod, and a 1/3aaa Tomy battery.

[actofgod]

A close up of one of the motors. Each motor is approximately 11mm in diameter, as opposed to the 6mm Bit motors. The BFM-9000 is roughly the same diameter but is flat on the top and bottom. The capacitors I mentioned have the text "101" on them, if memory serves, and probably help the motor get up to speed quickly, giving it a little extra juice each time it starts.

edit: I looked it up, and the capacitor code stands for 100 picofarads.
edit: Azimov says these are used as noise filters rather than for extra takeoff power.

[actofgod]

All in all, it's a great little truck. I picked it up at Toys 'R' Us for $12.99 I believe. The charger uses 4xAAA and the controller uses 4xAA. It runs pretty slow (1.0-1.6 speed) especially considering it is a dual cell, but that gear ratio explains it; it's built for torque, not speed. It runs great on carpet and will climb many small obstacles. The tank-style steering takes a little getting used to, but it will turn sharper than a bit. In fact, if you put one motor forwards and the other backwards it will spin in place very fast. The range on my 27mhz model is about 20ft stock.

I have a few mod ideas so far:

Wheel swap - increase wheel weight to reduce flipping and improve traction with real rubber wheels.

body swap - there are lots to choose from; SUV bodies will give you extra room for mods.

NIMH cells - 150-200mAh vs. stock 80.

extra cell(s) - in bed of truck, under cab area, or if using SUV body you can put it anywhere. increase speed and give even more torque.

extra weight - small lead weights in empty space of bottom chassis to reduce flipping and increase traction.

light mods - it's been done already, but I have my own ideas.

custom gear ratios - swap gears in the gearbox with bit gears to change gear ratio. Need to do it evenly for each side, but would allow for more torque or more speed depending on which way you wanted to go.

motor swap - see what other motors will fit.

motor capacitor swap - increase capacitor values for extra takeoff power (edit: never mind, those caps are for noise filtering)

bit plane w/ dual props - this pcb is better suited for it

rollbar - automatically put it back on its wheels after flipping.

AC-to-DC charger plug adapter - no batteries needed to charge. Could integrate into controller since it runs on same voltage.

...I'm sure I'll think of more later.

Happy modding.

[SteveGodfrey]

Excellent review great photos too.....focus was a bit dodgy though ;-)

Probably have quite a wait before they're availble in the UK though :-(

[Buzzbait]

Great breakdown on the truck!!!

I purchased a couple of these about a month ago, but haven't had much chance to pop their tops and play. Maybe I should break out my trust screwdriver, and have at it.

[rt450]

very nice review. i've already done most of your mod ideas. the stampeders bodies and tires work great. much better climbing traction with the tires, but not great for carpet. adding another cell works great! lots of speed and torque. i charge mine with a 9v batt. i alsoput a dub van body on mine. fits perfect, but makes the tricell pop wheelies on carpet. i also used superlube on the gears to quiet them down. i wish we had more reviews like yours on other rc's.

[dabigpig]

damn that was detailed good job. i need to keep on the lookout for stampeders to steal some bodys. i don't have the packageing it came in but if someone does then can u check it and see if it says the scale on it. the body's look about 1:64 cuz my diecast H2 body looks just perfect wheelbase and width to fit this big boy.

[Buzzbait]

I added a third battery to my truck last night. The speed improvement was good, but not good enough. I'll try adding a fourth battery tonight for that extra bit of turbo speed. One great thing about these trucks is that it's a piece of cake to add batteries.

My only large concern about these trucks is the run time. They run out of juice very quickly. much more quickly than I'd expect from 80mAh cells. We're talking 3 or 4 minute run times. Fortunately, I have a peak charger arriving this week. So I'll be able to see if the problem stems from a lousy charger, or whether the design is just too much for the small bats.

[dabigpig]

well u can contribute the short runtime to the two huge motors just drinking the battery juice. the first 3-4 runs i did with mine it lasted for a long time. perhaps it's the small AAA batts charging it can't keep up for a very long time. i'm planning to make a 4AA charging system in my car box.

[actofgod]

Thanks for the feedback.

Even with the stock 80mAh NiCd's, you can do a double charge from the controller. It really helps the runtimes, as a single charge doesn't even get close to filling up 80mAh. My first mod will be to hard-wire a Radioshack Adapta-plug lead into the charging base so I can hook it up to an AC-DC adapter easily, since I don't have many AAA's.

Someone post a few pics of their extra-cell mod!

[Lord_Nick_D]

I Put in a 3rd cell a while back it was out of a kit racer but it still worked you probably did not charge it enough if you were not satisfied with its speed I have to charge it multaple times with the extra cell to get it to work its best because they are nimh you loose power earlyer because of thier steeper discharge rate
mine ripped it was equal to over a 3.0 it would go over anything and would do wheelies withought going backwards first on takeoff I have tons of bodies for it also but I need a dremmel for some of them

[actofgod]

Originally posted by Lord_Nick_D
I Put in a 3rd cell a while back it was out of a kit racer but it still worked you probably did not charge it enough if you were not satisfied with its speed I have to charge it multaple times with the extra cell to get it to work its best because they are nimh you loose power earlyer because of thier steeper discharge rate
mine ripped it was equal to over a 3.0 it would go over anything and would do wheelies withought going backwards first on takeoff I have tons of bodies for it also but I need a dremmel for some of them

That is one loooong sentence! I feel out of breath just reading it!

[Lord_Nick_D]

sorry
I didnt think anyone cared for puncuation here

[actofgod]

I'm just messin' with you Nick. Can you post pics of that tri-cell mod? I'm going to start mine soon but would like to see a few examples first.

[Lord_Nick_D]

I already took it off acctually
it was not very nice looking and I couldent have it how it was formy new costom body
it was just done with tape
green painters tape to be specific
honestly its one of the easyest things to do on these
I broke a bit trying to do it but on these its much simpler
if you want I wil redo it and post a pic
but I need to find a camera first