Dale Gribble

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I wanted to share some mods that I have done to my Mini Rock Crawler that I can say make a huge difference to the capability of this crawler out of the box. I have the benefit of testing my before/after changes on J&C Hobbies Raceway's rock crawling course so these mods come with field testing to support the results.

The first mod is to take apart the stock 1100mAh battery pack and split up the pack to put 3 cells over the back axle and three cells over the front axle. This requires a good soldering iron, some battery bars and some hot glue or other conveyance to hold the battery packs together. This cost me about $5 to setup. Here is a simple wiring diagram. You must remember to make sure the wires have slack and don't bind throughout the crawler's suspension travel.

Diagram



Here is a front shot of the mod. Also note that you will need to cut the body back to prevent the battery from binding against the body.

Dale Gribble

My Feedback: (4)

The next set of mods deal with modding the tires/wheels for optimum performance. Instead of spending $100 for aluminum wheels/tires, I found a way to mod the stock wheels/tires for the cost of some CA glue and stick on wheel weights. This changes each wheel and tire from about 2.5 ounces each stock to 4.5 ounces each. This mod almost doubles the weight of the stock wheel/tire combo. This adds almost 1/2 a pound of weight to the lowest part of the truck and makes a very large difference in side-hill and hill climbing performance.

While you are at it, start cut the foams to allow the tires to flatten out more over obstacles. So, let's get started.

#1, get the wheels and tires off the truck. Once a wheel is off the truck, you need to get the front or back tire bead unseated from the rim. The tires are glued lightly to the rim. You can carefully unseat one of the sides with an exacto knife and patience. I was able to get one bead off of each rim with an exacto knife and patience so I could access the rim.

Step 1, Get a bead unseated and get the foam out from the tire.



Step 2, Fold the tire over itself to access the center of the rim as shown.



Step 3, fit stick on wheel weights to the center portion of the rim. You can get these wheel weights at hobby stores and most auto part stores. I used 1/4 oz. weights and had to trim about 20% off of each one of the sides to get the weights to fit in between the wheel's lips. I was able to fit 8 trimmed weights onto each wheel. Don't forget that these weights are made with lead, so wash your hands after doing this.

Dale Gribble

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Next, run a strip of electric tape over the stick on weights to make sure they stay put.



Next, star cut the foams. I used some body cutting scissors and just hand cut out the foam. This wasn't a scientific method and not symmetrical. Don't let the foam break apart.



Next, flip the tire back to normal, stuff the foam in and reglue the tire. Voila! You have a heavier wheel/tire combo with foams that are cut to allow more conformity over rocks and other obstacles.

Dale Gribble

My Feedback: (4)

Finally, enjoy. These mods give this already capable crawler MUCH more crawling capability.

sfar785

lead weights are expensive near me, $2 a stick to be exact. That's also for 8 oz sticks, we don't have the heavier ones around, so what we do is use solder. It's $3 for a spool of solder and each spool weighs 1lbs. We wrap 8oz around each front wheel and 6oz around each rear, it's a cheap and easy method to weigh a wheel down.

Dale Gribble

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Are you talking about 8/6 oz per wheel for a 2.2 or 1.9 crawler?

sfar785

oh, the 2.2, sorry i didn't mention that one

yeah, i'd say 8/6oz is a litte much on an MRC, i was just trying to give a little example if you can't get your hands on inexpensive lead weights. Also, anywhere that sells Pinewood Derby cars should have the wheel weights, they use the sticky weights to weigh down the car.

MORNINGSTAR

i gotta get me one of these........