rattleCAD 4.0 - FAQ

How does one parameter influence others?

.. to be continued!

At first try to do a step backwards and maybee also make a step to the side from your current understanding of bicycles and bicycle geometry.

In theory:

the bicycle geometry is the abstraction of bike. It just defines the driving behaviour of the bike and the position of the saddle. that is all e.g: this work is mainly done in bikefit or an early concept phase of the bike and does not belong to any tubing. the frame geometry supports the concretisation of a bicycle. e.g: this work is mainly done by a framebuilder and is an answer to the requirement of the bikefitting

In praxis:

based on the bicycle geometry you can build a lot of different frames with the same driving behaviour, but different headtube lengths and different toptubes or angles of the top tubes. The frames will look different but supports the same bicycle geometry. so far my understanding and the implementation in rattleCAD

Step by step:

you can follow this when you do the following: define a bicycle geometry you like and important for the show case with different headtube and seattube angles, maybee 74° for the seattube and 72° for the headtube. Stack & Reach in bicycle Geometry, as you like change to the frame details: now change headtube length and toptube angle. What you can see is that Stack & Reach changes, but the position of the handlebar is kept, only the spacing between headset and stem is changed. if you change the toptube angle to 0° and you change the headtube length, you will see that the toptube length changes depending on your headtube-length. The cause for this are the different angles of seattube and headtube ...