Tatra 130 RC car tires by David Řehoř December 04 2020

Ing. David Řehoř, better known as D.R.racer, was fascinated by Tatra vehicles from a very young age. Tatra is a Czech vehicle manufacturer that is the third oldest truck-producing company with an unbroken history in the world.

As a young kid, he started to put together paper models, some of which he designed himself. Later he's got his hands on ZX Spectrum, a now retro 8-bit personal home computer. This was the beginning of his programming career. At the university, he got influenced by then-revolutionary VRML97 technology. The possibilities of recreating his favorite brand of vehicles in virtual environments were fascinating. However, he felt kind of limited with 3D Studio Max R3, so he started implementing his own 3D editor for VRML97, simply called D3Ded. His own models' creation was a natural process as many vehicles made as games addons had incorrect proportions that David has seen as a considerable fault. Slowly, several models of passenger and truck Tatras were created. "I was especially fascinated by vintage cars and trucks that survived just in few specimens or didn't survive to these days at all," David says. 

In 2004, David first saw a functional model chassis of Tatra 815 4x4 built for an RC model. As he says, "Every car fan knows that Tatra has its own distinct chassis, this model was mechanically identical. I thought this wasn't possible to replicate in model scale with enough durability." Later, he found an article about the Tatra 128 model made by the same author. "The accuracy of the model was absolutely breathtaking. I soon met the author of the models personally. Shortly after, we agreed on the construction of another complete RC model. I chose the almost forgotten prototype of Tatra 130 from 1951. It's a legend among dedicated experts - the prototype was created by modifying the mass-produced Tatra 128 by adding one more axle." David tells us.

After David stepped into the 3D printing world first as a customer, he has decided to implement this technique in his own model building workflow. From 3D scanning to cleaning up and augmenting the models in his own 3D editor, finally to 3D printing. "We initially went for stock RC truck tires for Tatra 130. Honestly, we had no other options at that time. Although Tatra managed to overcome incredible terrains with them (especially with off-road chains), the appearance wasn't correct. Now we had a possibility of recreating exactly the same tires as the real prototype truck had in 1951. One of the biggest challenges was to find a real tire for 3D scanning. Fortunately, there were used on Tatra 128's as well." David tells us.

After his first tries with PLA, he's decided to try flexible materials as well. Initial tests with now discontinued experimental Elastic by Fillamentum led him to consult the outcomes with our CEO Josef Doleček where David chose to try a sample of our Flexfill TPU 98A "Metallic Grey". "Without expecting any usable result, I observed printing behavior. This material performed the best of all previously tested samples," David talks about his experiences. Later that year, the release of Flexfill TPU 98A "Traffic Black" followed. "When I've ordered this Flexfill, I received an email from Mr. Doleček, stating that he had added a sample of a new softer Flexfill TPU 92A. The softer sample behaved great as well, the only trouble was its color. This experience made me very happy, and I was looking forward to the package. In fact, I'm now proud to say that my request for a black variant contributed to the development of the soft material for model tires by Fillamentum," says David. 

After the test from Flexfill TPU 92A "Natural" came out above expectations, David was really looking forward to the Flexfill TPU 92A "Traffic Black", which was later released. As he says, "I loaded the material into the printer and carefully began to check that its properties corresponded to the development sample with which I realized the test tire."

In particular, David was interested in whether the material still met the following:

  • perfect adhesion to the printing surface
  • printing with a layer thickness of 0.05 mm
  • the print will not deform when cooled
  • it will not jam in the feeder or try to slip out

After the first tests, it was confirmed that the above properties are still as excellent as the development sample.

After a few more iterations, the tires were ready for testing in various conditions: such are hard stony surface under the dam of a reservoir, a passage through muddy terrain, loose and wet sand, and with chains, even snowy conditions. David was overjoyed with the result, saying that "the RC model now sways a little due to all six tires' suspension when slipping from a rock or other obstacle. That is another realistic element of the model's behavior, the original hard road tires did not allow this."

As with any project, this one also gave David a lot to learn and try. "The experience with Fillamentum products is, in a word, excellent. I have never had to solve a problem with the filament itself. But it is true that I already have some experience with collecting and estimating the appropriate temperature or when the filament is wet. But there is always something to discover, explore, and learn," he tells us.

You can read more detailed findings of this project on Davids' blog here.

Printed with: 
Flexfill TPU 98A "Metallic Grey"
Flexfill TPU 98A "Traffic Black"
Flexfill TPU 92A "Natural"
Fexfill TPU 92A "Traffic Black"

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