Originally Posted by slopvehicle
but...what about the deraileur hanger?
it could be set up just so that the deraileur acted as a tensioner. I don't think two different chainrings would be used...if both "low" and "high" configurations took up the same length of chain, wouldn't that produce the same resistance (making this mod useless)?
no. it is about ratio or front to back, not chain length.