XYZ ONESEATER - trike bicycle

Show off your FreeCAD projects here!
Posts: 9
Joined: Mon Aug 26, 2019 5:52 pm

XYZ ONESEATER - trike bicycle

Postby FreeCutter » Sun Nov 17, 2019 8:47 pm

The XYZ ONESEATER is a trike bicycle which frame and stearing components are mainly build out of 25mm square aluminium tubing.

A Github repository is set up providing the sources of the project as FreeCad-files (.FCStd) as well as the resulting technical drawings summarized in a pdf-document (

The original construction drawings for the XYZ ONESEATER might be downloaded here ... icles.html. Credits to and collaborator Till Wolfer.

Starting point of the repository was to get the original construction drawings transformed to FreeCAD. This transformation procedure is based on the structure of the original construction plan, i.e. each single component is generated in FreeCAD. Subsequently the needed components are used in assembleys like frame and steering bridge resulting in the final vehicle.

As square aluminium tubing is the main material for the ONESEATER the setup of the FreeCAD files starts most often with the characteristic cross-section of the component (e.g. 25x25x2mm square tubing). The Sketcher workbench inside the PartDesign workbench is used to draw the cross-section. The cross-section is subsequently extruded to a solid. Boreholes are drilled to the solid by using the Pocket tool of the PartDesign workbench.

Final assembly of appropriate components e.g. to a frame or steering sub-assembly could be done by using the A2plus workbench. This is done mainly by adding circularEdge constraints between several components to get to sub-assembly as well as constraints between several sub-assembly to get to a final assembly respectively.

Screws, nuts and washers might be added in sub-assembly or final assembly by using the Fasteners workbench.

Technical drawings of components or any assembly could be easily generated by using the TechDraw workbench where the Spreadsheet workbench had been used for documentation text as well as BOM - bill of material.

FreeCad had been used in the version of:

OS: Linux Mint 19
Word size of OS: 64-bit
Word size of FreeCAD: 64-bit
Version: 0.18.3.
Build type: Release
Python version: 3.6.8
Qt version: 5.9.5
Coin version: 4.0.0a
OCC version: 7.3.0

However, deviating therefrom FreeCad 0.19 DailyBuild had been used to generate "ballon" annotations in some overview drawings.

Have fun!

OneSeater_Assembley.png (310.11 KiB) Viewed 1522 times
Last edited by Kunda1 on Tue Nov 19, 2019 1:20 pm, edited 1 time in total.
Reason: Updated thread title
Posts: 18
Joined: Tue Oct 01, 2019 6:37 pm


Postby Rana » Tue Nov 19, 2019 11:57 am

Very Good work.

I saw your drawings pdf file . Just for information, what is the cost of Oneseater ?

Are you going to share your other designs , (three seater ) ??

Posts: 9
Joined: Mon Aug 26, 2019 5:52 pm


Postby FreeCutter » Wed Nov 20, 2019 9:25 pm

Thanks a lot for your feedback!

Well, I just could give a rough estimate, German price level and excl. VAT:
  • Aluminium: appr. 100 EUR
  • Fasteners: appr. 30 ... 40 EUR
  • Plastics: appr. 20 ... 30 EUR
  • Bike front wheels with drum brakes: appr. 200 ... 250 EUR
  • Bike back wheel: really hard, depends on lot of individual requirements
==> Rough total: 600...700 EUR.
As costs depend on so many parameters it's actually just an estimate/order of magnitude!
Maybe you could grab some parts from used bikes.

Other designs:
Yes, later on I will share my own constructions as well. However, I didn't went into the ThreeSeater rather than "optimising" the OneSeater according to my needs.