[ozvena]

I lived under a rock and decided to convert the old shimano 3x9 (135mm QR rear hub) to 1x9 by removal of the smallest and largest chainring. It is a failure as the chain keeps falling off.

How do the 1x10/11/12 system prevent chains from falling off?

 

[DeoreDX]

Narrow Wide chainring is the search term you are looking for.

Or alternatively a chain guide.

 

[Shadow4eva]

Narrow Wide chainring is the search term you are looking for.

Or alternatively a chain guide.

OP, this is the definite answer you're searching for.

Sent from my iPhone using Tapatalk

 

[ozvena]

Perfect, thanks!

 

[boomn]

Narrow wide chain rings really help, but they aren't the only piece of the puzzle.

Shortening your chain to the right length for a single ring is really important too. A 3x9 length chain will have a lot of extra links that make it bounce around more and come off the chain ring

A derailleur with a shorter cage helps control the chain flapping too. But that is of course an investment that only makes sense if you're committing to 1x9

 

[sgltrak]

Clutch derailleur. You should be able to use SRAM 9 speed shifters with 11 speed Shimano clutch derailleurs if you are ready to invest in the 1x9 drivetrain. Alternately, you can put the front derailleur back on and set the limit screws to keep the chain on.

 

[boomn]

I've been doing 1x9 and now 1x10 for probably 10 years. I still don't have a clutch derailleur, but I haven't dropped a chain in years. Proper chain length combined with a narrow-wide chainring has done the trick for me.

You can run a 10 or 11spd chain even with a 1x9, and that will increase the retention on a narrow-wide chainring.

Disclaimers: I'm not sure how all brands and models of non-clutch derailleurs compare at preventing the derailleur and chain from bouncing. I have always had SRAM and it worked great. My wife's Deore derailleur bounced really bad while the SLX replacement seemed much better

If it's a full suspension bike, then the chain movement through the suspension travel could make be making it worse and really necessitate the next-level investments.

 

[ozvena]

My hub is 135mm QR/10mm axle. Are there 135mm QR/10mm hubs supporting 1x12? If not, are there hubs supporting 1x11 or cassettes with a higher range like 11-40?

 

[Harold]

My hub is 135mm QR/10mm axle. Are there 135mm QR/10mm hubs supporting 1x12? If not, are there hubs supporting 1x11 or cassettes with a higher range like 11-40?

The answer to this is yes*

* as you get into 11 and 12spd cassettes, you see different freehub bodies popping up to support some of the cassettes. You will still be able to find 11 and 12spd cassettes that will fit on your existing freehub, though. They'll just be a bit heavier. Shimano, Sunrace, and others will make 11spd cassettes that you can use. Mostly just Sunrace if you want a 12spd cassette you can use. If you want to use a lighter cassette for 11 or 12spd, then you could probably find a relatively affordable wheel with an xd freehub body so you can use SRAM cassettes. At this point, I wouldn't bother with Shimano 12spd cassettes for your bike. A hub that'll work on your bike with the new Shimano micro spline freehub body will be obscenely expensive, and prebuilt wheels that'll work are going to be quite rare still, since the interface is so new.

Also, I think you made your chain too short. When sizing a chain for a full suspension bike, you need to account for changes in chain length during suspension compression. Most require extra chain length as the suspension compresses, so 2 things are likely to happen. First, the short chain will prevent the suspension from moving under lighter loads. Second, hit something big enough with enough force, and your drivetrain is likely to get mangled.