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How To: Free Up Your Losi Micro SC/ Rally Drive Train

Let me start by first saying that I LOVE MY LOSI MICRO SC! I have spent countless hours indoors running the Losi Chassis on my Living Room Carpet Floor. I have re-arranged the furniture to make way for a track. I have made jumps and obstacles out of cardboard boxes, magazines, broom sticks and other miscellaneous furniture. I have even marked my lane with 3" blue painters' tape. As I said, I LOVE this truck.

Not only is this truck a blast to drive, but it costs only $110.00 on the street. COMPLETELY READY TO RUN!!! The electronics are at least as good as the Mini-Z AM boards, AND they handle voltage much better. The little chassis also comes fully ball-raced and with Big Bore Micro Oil Shocks. It includes a NiMH battery pack and charger, plus it even includes the 8 x AA batteries that you need for the transmitter.

There are 3 complaints that I have though:

1.The Drive Train binds WAAAAAAYYYYYYYY too much.

2.The Battery pack last WAAAAAAAYYYYYYYYYYY too little.

3.The Truck is too slow.

With that, we set out to see what we could do with ours, examining the possibilities for upgrades. To deal with the Bound Up Drive Train, we opened the truck up to see what we could come up with. What we found out is that the differentials are too tight inside the gear cases. This causes the diff action to nearly lock up and it also makes the drive train strain entirely too much under power. The result is decreased run time, over heated electronics and slow speed.

What we came up for was a really simple solution. All it took was 2 narrower bearings and a couple of M3 0.3mm shims. Below is how to install these in your truck.

We start with the rear diff. In the picture above we also have the 3x6x2mm bearing and the M3 Shim.

 

In order to get the drive train to free up properly, we not only need a narrower overall diff, but also to move the teeth a little further away from the main shaft pinion. To do this, we will replace the bearing on the side opposite to the ring gear of the diff.

 

Here are all the drive train parts from the side we are replacing the bearing.

 

Above we have the outdrive gear, the M3 shim and the narrower 3x6x2mm bearing.

 

Slide the M3 Shim over the outdrive.

 

Now instal the narrow bearing on the outdrive.

 

Insert the "re-shimed" outdrive inside the bearing carrier.

Now slide the outdrive assembly back on to the main diff.

 

Insert your drive cup and you are done with the rear!

Next is the front diff (the front diff is even quicker). Above we have the parts involved.

 

Again dissasemble the side of the diff away from the ring gear teeth. We are looking to free up the drivetrain!

Same as last time, remove the 2.5mm bearing.

 

Get your new parts ready.

 

Slide the M3 shim over the outdrive.

Now the 3x6x2mm bearing.

 

Hold up the outdrive assembly up against the main diff.

 

Re insert the drive cup... DONE!

Now all you have left to do is re-install the differentials in your Losi Chassis. This upgrade will give you longer run times, smoother handling, cooler electronics and MORE SPEED (not much but enough to make it respectable). We are now selling this little upgrade package on our web store.

NOTICE!!!

If you have already run your truck, 1 washer on each side WILL NOT BE ENOUGH!!! The gears are probably worn in a bit so your best bet is to use an extra washer on each side or replace the gears with new ones, otherwise YOUR GEARS MIGHT STRIP!!!

 

Written by Cristian Tabush