Originally Posted by
Bigbus
Maybe I need to learn how to use the chart? It's always suggested a much longer BB than I've needed and caused me problems so I've grown to be a tad miscalcontent over it.
Symmetrical equivalent is simply-
52mm +(2X DS length)
Actual length is 52mm +DSL+NDSL. The "D" length is what you should be looking at.
Since the OP has the longest spindle made (DSL) and since Shimano doesn't make anything over 127mm (to my knowledge) a 127mm is about the only option unless one wants to get into the far more expensive "adjustable etc." BB's. One then has to hope the FDER has enough adjustment left to accommodate the closer position of the chain rings with the 1.5mm shorter DS spindle length.
According to the chart, the longest DS length available is 39mm vs the 40.5mm of the "U".