This is the Assembly Page

Here you will be able to find information on building your Micro RS4.  I haven't built a lot of R/C cars in my day, okay, so really, this was my first one.  But nevertheless, there are a few pointers I can give to other novice R/C builders so they don't make the same mistakes I did.  I spent several days building my Micro, but only because I'm still waiting to get my radio gear.  The kit is very easy to assemble, the instructions are clear and helpful.  There are  a lot of tiny parts in this kit so it's a good idea to have a table prepared that you can work at for a few days where parts won't get lost if it's all left out overnight.  The only tools I used were a small phillips screwdriver, flat head screwdriver, pliers, Exacto blade, diagonal cutters, small file, Lexan scissors, CA glue, 400 grit sandpaper, body paint, drill and bits and some tape.  That's about it.
... ...

Navigation Menu

Tips on Building a Better Micro

... ...




Putting a standard 1/10th scale Pinion on a Speed 400 Motor Shaft

If you've decided to say good-bye to your 3rd burned out speed 300 and are planning to drop a 400/380 sized motor in your car, then this pinion trick is for you.  Since 400 motors don't spin faster than 300 motors, the only way to get more speed out of them is to gear it up.  This means big pinions and tall gears.  Yet the biggest standard sized pinion you can buy for your Micro is a 14T.  And even if they did make bigger pinions, the shaft diameter of a 400 is larger than a 300, so you'd still be out of luck.  This is where we turn to the 1/10th scale guys and steal some parts from them.  The standard pitch of the Micro spur gear is 48.  They come in many sizes from 10 to 40 teeth.  Somewhere in the middle is where your 400 motor will work best.  What tooth pinion do you need?  Well that's where you're going to have to do some experimenting on your own.  But I can show you how I've attached each of my 540 pinions to a 400 motor.  TO BE CONTINUED...

Rear Deck Modification for Big Motors in 140mm WB

This mod makes it possible to mount just about any motor into a 140mm wheelbase.  Steps are as follows:

  1. Cut existing posts the same height as upper deck mounting locations.
  2. Using any preferred material, cut small "ears" which will attach on each side with 2 screws which will extend the mounting location of the new posts.
  3. Attach new body posts at ends of ears with a screw.
  4. Drill new holes in chassis to accommodate wider rear deck.

Here are the pictures of mine completed.  I fit a 400 motor in a 140mm WB with this setup.  I don't use the upper deck, but if you want to still use the upper deck, just screw the upper deck into the same location underneath the ears or between the rear deck and the ears.  Good luck.  And if this mod seems too difficult, just go to a 150mm WB and add two washers to the stock rear deck and any 300 or 400 motor will fit.

rear_deck_mod.JPG (56435 bytes)    rear_deck_mod_2.JPG (61199 bytes)

Mounting TRC Foams

To properly mount foam tire of any size you will need a few things:

1. Tire glue (not CA) I recommend TRC #902 
2. Lacquer thinner (not nail polish remover, not mineral spirits, not anything besides lacquer thinner) This can be bought at Wal-Mart or your local paint supply or lumber store.
3. A container to hold enough lacquer thinner to dip a tire and rim in.
4. A small paint brush.

First take the tires and small paint brush and coat the insides of the donuts completely with glue. A thin layer is all that is needed. Set these aside for assembly later.

Second take the rims and coat them with glue as well and set them to the side. Now find something to do for a couple of hours.  After at least two hours the tires will be ready for assembly.

Third take the container and fill with enough lacquer thinner to immerse the tire and rim. Splash a little thinner on the tire horn then take the donut and slide it over the horn and all the way down over the rim. Inspect the completed product to make sure there are no bunches in the foam and that the donut is level with the front of the rim. 

Drying time will vary but wait at least 4 hours before use for longest life. 

Remember foams are racing tires for serious completion and are meant to be used up, however if you hit ruts or other sharp edges they will be ruined much more quickly. If using for bashing the smoother the surface the longer they will last. I typically get five or six battery charges out of my lithium ions and big block motor per set of tires. This is running on medium grain asphalt.

-By, Hyper Tech Raci posted on the YourMicro Forum.

Improving Performance from the GH Front Ball Diff

So you bought a regular GH ball differential only days before they came out with the adjustable one.  Now you're kicking yourself wishing you'd held out just a few more days and got the better diff.  Well there may be hope for your old GH non-adjustable front differential after all.

If you're car tends to spinout easily around turns, or can't keep going in a straight line to save its life, you need this ball diff mod.  The GH ball differential has one very big adjustment for tension.  So what you wind up with is a differential that acts more like a stripped spur gear.  Every time you gas the throttle, the gear just spins and the tires go no where.  You end up with nothing better than a 2WD spinout machine. 

So this is what I did to make my differential work killer.  I pulled the thing apart, completely apart.  I found a small washer that looked similar to the beveled washer that fits inside the housing unit and against the rubber friction washer.  The washer I added fit exactly inside the small inner portion of the housing, yet had an opening that was big enough to allow the outdrives to fit through.  I placed this washer inside the diff between the beveled washer and the rubber washer.  Then I put the thing back together.  Once together I noticed immediately that the differential was quite a bit longer than it was before.  The gap between the two halves of the housing was nearly 1/8".  It took quite a bit of pressure to push the two pieces together fully.  But I knew that if I could get them to stay together, I'd have all the friction I'd need to get power to the wheels no matter the circumstances.  The trick is getting the whole unit to stay together.

Well as it turns out CA is plenty strong to hold it all together, even with the massive tension from the rubber washer  and added washer trying to pull it apart.  I set up a simple jig with a C-clamp and a small piece of wood.  I clamped the C-clamp onto the ends of the outdrives just enough to hold it in place, without closing the gap.  Then I ran a nice bead of CA along the seam between the two housings and tightened the clamp till the gap completely closed and glue oozed out.  I wiped up the excess glue with a cotton swab and let the unit dry at room temperature for over 16 hours,  just to be sure it was going to hold.

When I pulled the clamp off, the piece was solid and stuck together great.  With the newly pressurized diff all together, I got my first feel at how well it was going to work.  It felt  quite a bit tighter.  Turning the right outdrive caused the left  one to move in the opposite direction and felt very snug and stiff at the same time.   So I dropped the unit into my Micro and tried turning the wheels, since I could get a better grasp on the wheels then the outdrives.  Wow, it felt  exactly like my rear GH ball diff, which took hours to dial in to the perfect amount of friction.  The tension was tight.  It was firm yet smooth.  And no matter what I did, I couldn't get the belt and pulley to slip.  Now I knew that power  would never be lost to a weak differential.

After driving my Micro with my newly outfitted front ball diff for a few days I've come to this conclusion: this thing rocks!  Never again does my car peel out unwildly.  When I gun it, the car launches straight as an arrow.  I can come into turns and pile on the power around corners and the front drives just keep pulling the car along as hard as they can.  No more spin outs and no more out of control turns.  When everyone says this car handles like a "real 1/10th scale touring car", I can definitely vouch for that.  It handles awesome.  Which only means that the new adjustable ball diff must be even better so do not hesitate to pick up this little unit from Golden Horizons. 

ball_not_glued.JPG (98528 bytes) ball_clamped.JPG (277555 bytes) ball_glued_2.JPG (49583 bytes) ball_glued_car.JPG (344134 bytes)

Getting the stock differentials to turn smoothly

Now as I understand it, the differentials are one of the weakest links in the Micro RS4.  When I first put together the rear differential and then tried turning it, I couldn't believe the device would actually work as it's intended to.  It felt gritty, and notchy and seemed to get hung up in spots.  Those tiny plastic gears just weren't meshing well.  So I pulled apart the differential and inspected all the gears for flat spots on the teeth or other debris inside.  I sanded down a few little plastic pieces left over from having been cut form the parts tree.  I had done this before, but I did it again to make sure it was very smooth around the diameter of the gear.  Then I piled in about twice as lube and put the differential back together again.  There was an improvement, but after having decided that all the parts looked good, and it was built as good as I could do it, this must just be how the differential works.  

So then I ran the car with just a set of 4 AA batteries and held one of the wheels still, while allowing the differential to do it's thing and turn the other wheel.  It slowed the motor down quite a bit but really broke in the gears inside the differential.  Now they turn smoothly enough that I think they'll work fine for the task.

The front differential was the same way.  Only worse.  But after pulling them apart, inspecting the gears and doing a little bit more sanding and a lot more lube, I was able to get the front diffs to also turn freely and not get hung up in any spots.  Once again I ran the motor with some AA batteries and held on of the front wheels to break in the gears and lubrication inside the differential.  This seemed to help out.  It slowed the motor down considerably once again as did the rear, but no more so than the rear so I concluded that both diffs were operating as well as they ever would.  One of my first hop-up parts will have to be new differentials for the front and rear.  That's all I've got for now.  Check back for other tips and tricks in the future.



w w w . d a n m a r x . o r g / m i c r o