Frame parametrization issues

[Anonymous]

I'm making a bike frame using parameters in order to optimize the best tube diameter I can pick for my model. I'm having trouble with the Headtube (picture below) offsetting from the plane it was extruded in whenever I change the front tubes Diameter. side viewtop view

Whenever I increase the diameter of the front tubes to a bigger one, from 3/4" to 2" for example, the headtube does this 

The headtube was extruded using a sweep function and the path it's a sketch in the XY plane. Also I tried extruding the tube with the same result. Can anyone have a clue on what body relationship could be causing this? I need the headtube to remain in the midplane of the solid.

Any help could be useful, Javier 

P.D. I'm attaching the solid, it's already parametrized, so you can give it a look for yourselves.

[johnsonshiue · Accepted solution]

Hi! I have taken a look at the part. I think I have found where the problem is. The faulty relationship is within Sketch8. If you edit Sketch8, you will see the circle center is dimensionally constrained to the silhouette of the tube on the side. As a result, when the tube diameter changes, the center moves with it. To correctly, simply delete the vertical dimension and the project edge. Then it will work fine.

Many thanks!

[Anonymous]

Thank you!

Now I remember I was trying to completely define the sketch8 so I set that distance and never thought of it again.