I use a single speed mountain bike as a winter commuter. Would there be any benefit to swapping out the 104mm bcd crankset for a 130? One of the reasons would be to be able to use a stainless steel 42 tooth chainring that is only available in a 130 (I find aluminum gets eaten by salt fairly quickly). What is the easiest way to get the chainline right - I assume the BB spindle length will have to be longer. I have a Surly single speed hub on the rear.