My current project is the construction of a remote-controlled tractor (our own tractor as a model) with Lego technic, including motors and servos.

Through the whole engines for the tractor must have a certain minimum size it became already difficult to get suitable tires (original from Lego). Especially since the tires look the same at the front and rear, but are of different sizes. The rims wouldn't even have mattered to me. However, the tyres are also very narrow, in contrast to large Lego tyres, which are almost always significantly wider, e.g. in the CLAAS (Lego Set 42054).

The solution: Print it myself

With Sketchup I modeled the rims and tires separately, so that I can print them later with hard or flexible resin. I used the Anycubic Photon because of its high resolution and the just right print volume.

As flexible resin I used Photocentric UV DLP flexible and for the stable rims Monocure 3D Resin Rapid in transparent.

Photocentric UV DLP flexible:

• Layer thickness: 0,05mm
• Normal exposure time: 40s
• Off time: 6,5s (Why? Here is the answer)
• Bottom exposure time: 100s
• Bottom layers: 5s

Monocure 3D Resin Rapid:

• Layer thickness: 0,05mm
• Normal exposure time: 12s
• Off time: 6,5s
• Bottom exposure time: 100s
• Bottom layers: 5s

Tires

After an incredible print of almost 32 hours the first tire was ready. I am very satisfied with the result of the flexible tires. Unfortunately, some vertical lines can be seen. These probably come from an intermediate "pause" at the photon. However, these are only visible when you look closely at them. Sufficient for my purposes.

Material consumption:

• approx. 84ml (without support) per large tire
• approx. 35ml (without support) per small tire

Rims

Material consumption:

• approx. 42ml (without support) per large rim
• approx. 20ml (without support) per small rim