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Effective Toptube length and Front Center Distance

I am trying out bikecad free for a first build.

For now I am just copying the geometries of other bikes and there is one thing I can´t understand.

If I look at example the leader Kagero 2013 it has an effective toptube lenght of 540mm and a front center distance of 600mm according to the specifications of the manufacturer.

So if I set the effective toptube lenght to 540mm I end up with a front center distance of 564mm.

If I switch the tab to enter frontcenter distance wich is supposed to be 600mm it then says my effecitve toptupe lenght is 577mm and it also alters the headtube lenght.


Why is this so? All my other measurments are correct.

I get this same error if I for example copy the Cinelli Mash frame.

Would be really grateful for some help to try to get around this problem!



Effective top tube length and front center

The relationship between effective top tube length and front center is discussed at: bikecad.ca/toptube_frontcenter.  I trust you will see from reading that page that you cannot directly input values for effective top tube length and front center at the same time.  Having said that, if you choose to drive your design by front center distance, you can still massage other dimensions to arrive at the effective top tube length that you want.  Once you've set the front center distance and head tube length, you can still alter the effective top tube length by changing fork length, fork rake, head angle, seat angle, bb drop, lower stack height, or the extension of the head tube above the top of the top tube.

See below, I have created a model of the size M Cinelli Mash based on the specs you attached.

I tried to do the same with the Kagero.  However, I found it a bit more tricky.  Part of me thinks those specs may not be accurate.  However, I will give them the benefit of the doubt and allow for the possibility that they define some of their dimensions differently than other manufacturers.

Wow thank you for your

Wow thank you for your explanation!

I actually have been trying out the kagero dimensions and like you said it wasn´t really working out. I see now what you mean!

Thanks a million!!!

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