[python] Re: frame flexibility

Jürgen Mages wrote: 
Hi Dirk,

at first glance I would blame this on the 30x10x1 tubing. 

If it were only true! It is 30x10x1.5 :-)

Does Torben, who uses the same material has flexing? 

yes, please, test it out!

Secondly, there is an upward bend in the front frame which
does not appear in the original python design. Maybe adding
a fillet here might help.

I just made a small test. I taped a wire from where the frontpiece meets the pivot to somwhere before the BB. I figured if the front piece would be flexing, I should see some movement on that wire.

I could not see any movement at all on the wire!

May be it is the pivot that is bendable or the rest of the frame. Thinking of stiffness, it actually should be the 30x30x1.5 that is less stiff then the 2 times 30x10x1.5, because of the double amount of vertical walling.

At last: good are two horizontal struts between the two
halfes of the front frame, just where a fender would be
fastened.

This I will do, I will make horizontal triangles. I also still need to close the square tubings. Both on the front and the back the square tube is open ended. This doesn't help tortional stiffness I suppose.

Hope that helps.

On my P1 with 30x20x1.5 tubing I had some minor flexing.
On my P3 with 40x10x1.5 and better welding skill I do not
notice any flexing.


Hmm, higher tubing and experience certainly does help.

At the endo f next week I have some time again, and I will try to find out what exactly it is that is flexing.

greatings,
Dirk
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