Surly Mr. Whirly Singlespeed CrankBottom Brackets Sets with stainless steel chainrings. Complete crankset, assembled. Comes with spindle and bearings Forged and machined AL7075 9speed compatible All armsets utilize 58mm BCD to mount spiders. This BCD remains the granny ring size regardless of spider's larger ring BCD Singlespeed version comes with Surly stainless steel chainring installed Complete crankset, assembled. Comes with spindle and bearings
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