Gates frame approval process must, I presume, also take into account frame alignment.
What I'd like to know is what's involved in adjusting the ratios? I assume there's a chart or formula if you want to swap from (whatever the equivalent is of) 52/11 to (whatever the eqivalent is of) 48/12 which takes into account the length of the bike's chainstay.
I'd also like to know if it's possible to retrofit a Gates belt drive to my bakfiets - it would be ideal.
What Gates say....
"Gates Carbon Drive does not recommend retrofitting a belt drive to a frame that was not designed for a belt. There are several things that may cause you problems. 1) modification of the frame is most likely necessary; you can’t break the belt to get it into the rear triangle, so you need the frame to have a ‘break’ in it to get the belt inside. 2) You need a method of tension adjustment. This could range from sliding vertical dropouts, horizontal dropouts, or even an EBB, but some sort of tensioning is needed.
3) Frame stiffness - if your current frame (with the modification) is not stiff enough, you may not be able to get rid of tooth jump problems.
4) Clearance - Our sprockets are wider than chain sprockets, and so you may run into chainstay clearance issues, especially when trying to get the needed ratio and belt line for IGH’s.
5) Gearing selections and belt lengths - While we are trying to continuously expand our product line, we may not have the specific belt or sprocket size that you need to fit your frame and/or hub choice.
Again, while we don’t recommend trying to retrofit your frame, we are here to help. If you have read the above considerations, and still want to try, please contact us so that we can make sure to answer any questions you may still have."
But clearly it can be done, if you can sort splitting the rear triangle
[media]
]View: http://www.youtube.com/watch?v=0Ih-5yiRz-g[/media]
You may find
this calculator useful
that one caught my notice as well, claiming a product is perfect and then bringing out an upgrade