[Closed] Going from old 3X to 1X?

I still run 2x9 on most of my bikes, with 22-36 rings up front, 3x9 on my commuter. I tried one with 1x11 (with a 32 tooth ring), but missed the range of the 2x for cruising on road, so converted to 2x11 with 28-38 rings.

Apart from that, it should all be compatible.

Not really, 1 went 3x9 to 1x9 just using a 30t 104 BCD chainring, narrow wide chain and an 11-40 cassette.(standard long cage SLX rear mech)
You can get 11-46 9 spd cassetes now for cheap now but you might need a goatlink to clear the biggest sprocket depending on your derailleur hanger.

Chain doesn't drop but as there's no clutch in the rear mech the chain hits the chainstay a bit more especially on a hardtail so you will need a protector or just wind some old inner tuber around it.

I had the same situation and concern when going 1x11 on a gravel bike, but it's fine as long as you pick a suitable set of gearing, I'm running a 40t ring and 42-10 cassette, and the only times I've struggled are places where I would be in the granny and largest 2 sprockets (on a 3x with 32-11 casette).
I run out of top-end gearing at about 36mph.
I am a 1x convert.

but missed the range of the 2x for cruising on road

As hols2 pointed out, this I think is really one of the few downsides downsides to 1x systems. In terms of fit, it should go straight on.

Ta. I suppose SRAM SX or NX would be another option, switch to their BB?

I'm comfortable with 1X, have it on the other bike. Shame, but the old XT mechs are now so sloppy I think I'll upgrade the lot before the winter.

If the mech's that old I think you are due a new one 😉 Octalink and HT2 use the same threaded BB shell so can be swapped.

Never sure about SRAM BBs, my experiences with them have been shite but others like them.

your new HT-II bottom brackets won't last as your Octalink one did, I would keep your existing cranks and fit a new chainring.

Won't it? I thought that was the point of outboard bearings, they were bigger so lasted longer. These old ES BBs do last though. Certainly got my money's worth from this transmission.

No, the point in HT-II is that it allows for a larger diameter axle which is stiffer and stronger for the same weight. They should have increased the size of the BB shell to something like the T47 standard that just came out but back then they had no idea how gullible we would be for new standards every year, so fudged it to work with an ancient Non-metric standard BB.

your new HT-II bottom brackets won’t last as your Octalink one did

I don’t entirely agree with that. Early HT11 was not great but the later ones are fine and last perfectly well.

One thing I have noticed is that when out of the saddle lugging a big gear there's not many teeth on the cassette end. My chains tended to stretch quickly back in the 3 9 days so I can't see them lasting very long when the angle is so acute. On motorbikes anything less than 13 was said to wear chains a lot faster.

Slight highjack, can anyone offer me a link to a wide range 9 speed cassette? Larger than 40t. Every time I Google it like links ends up pointing to 10 speed...

I've converted several of my 26" wheeled bikes to 1x now - some 10 speed and some 11 speed. The best option at the moment for me is the 11-speed 11-51 Deore cassette and matching Deore mech, as that means you can run something like a 36t chainring (or even bigger if it'll fit) and get a very decent spread of gears. Given the mech is designed for that size of cassette it's very easy to set-up.

The stuff can be a little difficult to locate in the UK however I've just had a cassette, rear mech, chain and shifter arrive in China (bought via Ebay) in 3-weeks for something like £107 (including delivery) and that's all genuine Shimano bits.

The best option at the moment for me is the 11-speed 11-51 Deore cassette and matching Deore mech

Thanks for the tip. I've been looking at either SLX M7000 or XT M8000 so far, will take a look at Deore M5100 too.

Just switched to 1x9 using an 11-42 microshift cassette from bike24 in Germany (and SRAM chain) and cheap eBay narrow-wide ring and hanger extender.  All bolted straight on and adjusted up easily (X0 mech and X7 shifters).

Spent several weeks riding my usual trails in specifically either the middle ring or the big ring to work out preferred ratios, and went with a 38t oval ring in the end.  Gives me most of the top end of the old 44t big ring, but a lower bottom gear than I had in the middle ring.  Worked out nicely!  Also got a 32t ring at the same time to swap in for big days out!!

I specifically went with the microshift cassette as it's the same ratios as an old school 11-32 ,8speed cassette, but with an additional  big sprocket bolted on the back!  The 18-15t jump from gears 6-7 is slightly noticeable at times (9 speed was developed to resolve this jump by re-spacing the 11-32t ratios over more gears), but it's totally fine in reality.

I switched to a HT11 BB in the change, purely because I had some cranks unused in the spares box and I wanted to see how much weight I could shed in the process.  420g is the answer, and I had a light XT cassette on it to begin with!

Really like it so far, and the chain seems to stay on fine with a narrow-wide ring and no clutch on the mech.

Decided to go for that new Deore 5100 groupset (minus brakes) epicsteve mentioned 👍🏻 I can play around with 34t vs 36t upfront.

If you have a bike designed for 3x, what is achieved by changing to 1x? 1x is the answer to a problem you don't have, surely?

Well, the problem is my 3X needs replacing. If I can get the range I need from 1X, I've concluded no point having a front mech, shifter plus extra chainrings. The frame is adaptable, can be singlespeed, IGH, 2X, whatever.