Dec 07

I have a few questions about bottom bracket rise/drop. I have set the rise to 7.5 inches, but I need your input to figure out whether Caroline will be comfortable with that much rise. (see below for the definition of BB rise)

With the current seating position (as in the sketches from the last review on Friday). We need to have rise, otherwise Carolines heels will get too close to the ground. If you think that this is too much rise then we can raise the seating position and lower the cranks. That way her heels will not protrude downwards so steeply.

For most riders 7.5 of rise should be an ergonomic and aerodynamic seating position, and if Caroline will be comfortable in this configuration, then it will give you the highest performance.

You guys are going to be the best judge of this. Let me know your thoughts, so that I can make changes. Bear in mind that the throw will be adjustable but the rise may not be.

For our purposes BB rise is defined as the perpendicular distance of the bottom bracket above the seat line.

Here is a geometry drawing for your reference:

geometry caroline

In this study, I have set the comfortable cranking position to be at the point where the leg is bent 10 degrees at the most extended position while pedaling. The throw will be adjustable, so at this stage I am just trying to pin down the neutral location of the pedals.

The other measurement that I am going to need is the distance from the seat corner to hip joint. I have assumed it to be 5 inches (as you can see in the geometry study above. If you could get this measurement also that would be great.

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