If you have been following Gates Carbon Drive at all, you may be aware of the CDX Center Track system for bicycles. This system has changed bicycle belts completely. But beyond the simple performance and size benefits of the system, we are also offering an larger sprocket product line than we have in the past. Because Carbon Drive is 11mm specific, none of our other design programs will help you design for the proper ratio and center distance, including our online calculators at www.gatescarbondrive.com That is until now. We have a new online spreadsheet loaded up that has all of the new Gates Carbon Drive sprockets loaded into it. Check it out at: http://www.gatescarbondrive.com/installation.php?lang=us To get to the calculator, click on the link for Belt and Sprocket Size Calculator listed on the lower right hand side of the screen. Happy riding!