Suomeksi Image Map


In the first version the track tension was too loose. I had to make longer sidebars.

Basically the only difference are the longer sidebars.

The flex was huge, but it didn't work so well. I had to move the mounting of the rear arm backward.

I installed small bearings in the upper track wheels.

I installed a 12-T motor and Nosram Evil ESC, after which the powerful engine broke the gears.

At the first test run I wasn't able to drive even a whole battery.

Reedy T1

The first test run showed that the suspension appeared to follow the terrain really well. There was still something to do: Drive wheel was still slipping and the sled was eager to roll over. I noticed that the rear arm spring had to be tighter than one could think and the front arm spring could be quite loose.

I also noticed that the front arm moved too little. It didn't "sink" enough inside the track tunnel.


I really had to engineer a new transmission. I decided to make a drive belt system instead of gears. A pinion gear circulates a spur gear, which is attached to a small belt pulley. That circulates a bigger belt pulley which is attached to the original gear attached to a drive shaft. I had to order many different kind of belt pulleys and belts randomly form RC-Mart to test and make right ratio and size. I made an aluminium rack.

My belt pulley collection


New Team Losi kevlar-made spur.


Then started the fight against the sliding drive wheel. At the same time the other half of my brain tried to develop longer flex to the front arm of the track. Increasing the flexibility was the easier task. There were two problems: 1. the bar where bumpers were attached (marked on red arrow) blocked the front arm from bending enough and 2. the fact that the front bumper was not able to bend forward enough because of the front turning wheels in the middle.

The front suspension arm was blocked by the bar marked on red arrow from moving as much I wanted.

I changed the attachment of the rear suspension to allow the front suspension arm "sink" between the bumpers. I also changed the shape of front suspension arm. Because the end of the arm is bended, the bumper doesn't have to bend so much down and forward between the front wheels.

Here you can see the new attachment of suspension and the reformed front arm.

The front arm was now able to go quite down.

The fact that the sled used to roll over easily was connected to the way the track front suspension worked. Fast acceleration made the front of the sled too light. That's why I decided to change the track front arm once again. I made it a little bit longer and I moved the attachment backward in the slider. I also removed the narrow middle front wheels. This last movement finally allowed the front bumper to bend down enough.

The new front suspension arm. The attachment point is moved 1 cm farther backward.

I moved three of six batteries to the front. The rest were still under the seat.

To prevent the sled from rolling over, most significant operation was to move three of the batteries in the front. The centre of weight moved forward and down. I also lowered the front suspension a little bit by shortening the bumpers.