What’s the rear hub? Many of the Shimano splined hubs will fit more cogs. I built this one for my brother, it’s a 1x11 using SLX the hubs are Shimano pattern Coda which were probably 7 or 8 speed originally. Think he bought shifter/cassette/chain/chainring for me to fit. The front chainring needs be a narrow-wide. You can get away with all sorts of bodging/experimentation but this lot worked out of the box as a combo. Reusing a grannie ring meant it kept falling off hence buying the narrow wide.
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Can’t say I’m a fan of it but it’s what he wanted. To be honest there’s plenty of Bear Valleys out there and it’s giving an old frame a new life!