Wearing through the drivechain on my 2011 bike I've steadily been upgrading as I go, so going 1x has actually been a progressive process, and bearing in mind the cost, this is something I can recommend. I started at 2x9, so the first stage was in replacing the casette, chain and rear mech and going 2x10.
if you look carefully you can see the bolt is bent
This was the most expensive stage, but having worn the chain and cassette to the point that they needed replacing anyway, and then finally doing a proper job on the poor SRAM X9 rear mech the whole lot needed replaced anyway (once I'd saved up). If you've owned an X9 rear mech, then you'll know that these are pretty robust so when I say proper job I mean really proper: I had to use 2 rocks (hammer and anvil) on it to get a running repair in the middle of the Pentlands last year. The shifter was also pretty worn and starting to mis-behave, so there was some cost coming my way anyway.
What follows is just an account of what I did to go from 2x9 to 1x10 really just in order to show how straightforward it was – I saw a lot of stuff on the internet that made it sound really complicated, but once I dived in, realised that it needn't be at all. This isn't a blow by blow 'how to' as each component and bike has its own little foibles, but you can use the contact page to ask any questions you have about specific parts of the process and I'll get back to you.
Upgrading the rear mech
The new rear mechs are now often type 2 (with a clutch) which will keep your chain tighter and cut out chain slap, so replacing the old X9 was actually quite welcome. I decided to go 10 speed as it offered the potential to go 1x10 at some point in the future, and also offered a range of alternative designs. In the end I opted for the Zee shadow mid travel rear mech as it tucks in, is robust, and 'of course' was on offer at CRC at the time.
This worked fine – I 'simply' purchased a 10 speed casette, shifter and mech, but there was an issue with chain length – in order to have enough chain to go round the rear big ring, there was quite a bit of slack when it was on the smallest ring. At this point I found the B screw (the one that pushes against the mech hanger), removed it, took out the plastic grommet it goes through, and then replaced the screw – this effectively gave it a couple of extra mm of travel which was just enough to get the tension right. Alternatively, if I'd had a longer mech then the 'swing' would have taken care of this - but I wanted as compact a mech as possible.
the B screw is the lone screw that pushes the mech around the casette, here you see it with the plactic grommet removed and given a few extra mm travel to the mech.
Finally submitting to 1x10
This now needed a new front chainring, and a casette expander. Thick thin chainring came from Superstar, and the expander (although you can get them from Superstar) from Absolute black on sale at CRC at the time – I also purchased a locknut direct from them too.
On The 'Cheap' – back end
Several articles I'd read suggest you need to take the 17 tooth ring out of the casette, but as my rear casette wasn't particularly flash I had to just take the smallest ring out that would separate from the casette. I did make sure that I had brought the correct expander for the right manufacturer – Absolute black required you to pick SRAM or Shimano according to your casette. Chain whip and casette tool out I simply took off the casette, slipped the expander on the wheel, put the cogs back on but without the first set of cogs, slipped the casette lockring on and tightened it up, and I was ready to go. This really surprised me; I was expecting it to be much more tricky. With minimal adjustment of the B screw and upper and lower limit screws I was ready to go. Being 10 speed still, even the indexing was spot on, amazingly.
So the fun bit was taking off the front mech and shifter and unravelling the cable – it's quite liberating really. Now there will be a lot of dirt flying about so I plugged any bolt holes with bolts dipped in anti-sieze so I could go back if I needed to. This was a great opportunity to grease up the bottom bracket too. The bike was fitted with a chain tensioner, so this came off, but I did go back a stage and fit a superstar plasma chain device as although the thick/thin chain should keep the chain on I ride some fairly rough stuff so I wanted some extra security. I noted that some of the pros use chain retention even running the expensive kit, but even they normally only go with a top retainer – I think I went a bit over the top with top and bottom, but that's just me.
The chainring went straight onto my newly stripped crank spider with no problems. I used the chainring bolts from what I'd just dismantled, but this meant that the bash ring had to go as the chainring was too thick to attach both at the same time.
with the front mech off and down to a single ring, things start to look and feel neater (and lighter)
I was pretty hesitant about this but having run this for a few weeks now on some pretty rough and rocky trails I am now pretty comfortable with the amount of clearance I have. I do though have a set of extra long chainring bolts from Blackspire (from CRC again) in case I want to slap a bash ring on after-all. If I do this, having a superstar plasma means that I can order a bashring specific top retainer for my plasma rather than having to fit a whole new device (and pay for it) – I could even pick the colour I wanted! Their range meant that I also had the choice of a top only chain device with a 'taco' bash plate too.
Having run this for a few weeks
So, I've run this now for two trips, 12 days solid of biking on Skye and Torridon and around the Aviemore area, so not the most time, but a good test to start with. First off, I really find the lack of front shifter aesthetically very pleasing. Secondly the simplicity is fantastic. I really don't miss the extra gears, shifting is fast and smooth.
The expander ring is getting well used, but although having done the maths and realising I am missing out on some of the ratios offered by two rings up front I haven't found myself at a significant disadvantage. I did have to spin hard quite a bit when riding down Aviemore high street in a group, but that's the only time, even including some journeys along Glen Torridon on the road a couple of weeks ago were absolutely fine.
For the record I have a 32 tooth front ring and a 40 tooth expander, so I could still go slightly easier on the hills if my knees complain. As I noted above I also have additional clearance, which means there was a palpable lack of bottoming out on some of the rockier routes, and with the clutch mech It's also much much quieter too.
You're obviously spending a fair bit on doing this (even if you follow the bargain e-mail circuit), so I wouldn't rush out today with the intent of 'getting the latest setup', but doing this a stage at a time I can thoroughly recommend. Even if you just get a clutch mech next time you will improve the performance of your bike if it doesn't have one, and certainly the shadow rear mech for me really does tuck in and looks like I'll damage it much less than previous ones. There are pitfalls and difficulties - I'm still not sure I got it quite right when I was at 2x10 as I had to be careful not to end up crossing the chain and ripping the mech off, but for me, in this instance, it works really well and I am very happy with my quieter, possibly lighter, and definitely simpler set-up. So if you're really intent on doing this, then the message from me is to get stuck in, it can be transformational and is much easier than it seems.