Remove: shifters, cables deraillers, cassette, 44t and 22t chainrings, chainstay protector. Total weight savig – quite a lot.
Google for a set of various width freehub body spacers – by moving them around you position the single sprocket can get a straight-ish chainline with the chainring. It usually comes with a 1/8 width cog, you can pick 16t or 18t normally. You will need a 1/8th (BMX) chain to run this.
Or you can do what I did and lever apart a cheap, but not too worn, 8sp/9sp cassette to rob the individual sprockets – this gives you a choice of ratios to suite your fitness and terrain, and you can cut-down and use your existing 9sp chain if it isn’t too worn.
When you take the chain down, you want it as close-fitting as possible without tensioning. If it seems slightly too tight then you feel some drag, but it relax after a couple of rides. If it seems much too loose even with the minimum number of links, you can buy a half-link to replace one of the full links and get it just so. The problem with “magic” fit i.e. no using a chain tensioner, is that the drivetrain wears in quite quickly and becomes too loose.
You’ll need a tensioner that screws into mech hanger instead of the derailler. It pushes the shortened chain up, to tension it, otherwise it will drop frequently. Two main types – sprung and unsprung (cheaper). The unsprung ones need more frequent adjusting as the drivetrain wears – but they are OK. The roller tensioners are more draggy than the jockey wheel variety.
It’s nice to have an unramped chainring, but the 32t (middle) ring from a normal chainset will do OK. Just unbolt all three chairings and bolt the middle one back on – but you will need to buy some short-chainring bolts to refit it.
Finally, I recommend some reasonably wide bars and soft grips, or flats and bar-ends because they help with wrestling the bike up steeper climbs.
I really enjoyed my 6 months stint at SS, and would have continued had my left knee not suffered.