Seeking a small spider
Double chainsets with a PCD smaller than 110mm are rare, and those available with really long crank arms vanishingly so. Only one option immediately presents itself: TA, distributed in the UK by Chicken Cycle Kit (chickencyclekit.co.uk), make a five-arm 94mm PCD double spider that will fit your existing cranks and allow you to fit a 29t or 30t inner chainring (also made by TA). RRP is £69.99.
Cycle’s Technical Editor