Can you post a picture of the set up.

Almost every bike I have in the garage except for 2 are all 1x and I worked pretty hard to get a good chainline on all of them. Some might say too close tot he frame but I am not putting out massive amounts of power and they all work exceptionally well. Some of them this way for a decade with zero issues and before all this 1x stuff was happening.

EDIT: on the MTB's I have been able to play with the 1x rings in sizes to make them fit and normally am running 32t. On one of the builds I have to place a right on the outside because the teeth on the Narrow/Wide ring were longer than standard rings and hit the chainstay.

Do you have a 3 ft level that you could hold against the chainring and tell us where it's lining up with the cassette in the back? The eyeball test for chainline can be deceiving.

Cheers, I'll have a look in the garage for that, but I'm pretty sure it is way off. It shifts down 2 sprockets whenever I backpedal, which I think is a sure sign of chain line being off.

Cheers BMANX, not sure if these are the best but this is taken as close to inline with the chainring as I can get it.

As I mention in other reply above, chain slips down two sprockets as soon as I backpedal.

I'm wondering if it is a peculiarity of this triple crankset or simply loads of extra width with the square taper BB.



This is on middle sprocket #6 at back.



This is on biggest.



Cheers for the help.

Rich.

It's normal to fall off at least the biggest sprocket when backpedaling. I *think* the chainline for a mtb triple is only a few mm wider than a modern 1x chainline, so I would grab a pack of "chainline spacers" (also called chainline shims) to push the chainring in a little like you suggested.

Judging from these pictures, there's no need to grab the level. I find the level useful when having to be exact with single speed setups, but it's pretty obvious you need to push that chainring towards the frame.

Sheldon Brown has a ton of great info on chainline:

https://www.sheldonbrown.com/chainline.html

An MTB triple middle ring should be 47.5 mm from cl of frame, with the exceptions noted in the chainline table on the above link.

Thanks dangle.

I'm wondering what crazy size of spacer I would need in this situation. I've been reading that typical 1x chainline for MTB is maybe 49mm and I'm getting close to 60 here. So I need to space it in 1cm which seems an awful lot.

I'm comparing how the Suntour xcm triple cranks mount their chainrings compared to SRAM/Shimano. The big ring mounts to the inside of the spider, therefore spacing the middle ring further inwards? Whereas other brands tend to put the big ring on the outside, so the middle ring is directly facing the inner surface of the spider.

Suntour triple (square taper);


SRAM triple (hollowtech);


I wonder if Suntour do this to accommodate the longer (guessing?) spindle length with square taper. It looks wide as anything, so it would make sense in a square taper design crankset to bring the middle ring further in. If I had replicated the actual middle ring position it might not be so bad, but I've got the n/w ring mounted directly to the spider with nothing in between.

So I'm wondering if the advice I read that you can usually bung the 1x ring on a triple in the middle ring position is correct most of the time, but not with my awkward Suntour/square taper setup. Or perhaps more accurately, I haven't seen actually placed it in the middle ring position because of the different arrangement.

Cheers, Rich.

Something is definitely wrong when the chain line is that crooked even in the smallest cog

Was it like this before making it 1x?

Hmm, that's definitely interesting. The chainrings *seem* pretty far out, but I really don't know how something would have been designed with a greater than 50 mm chainline. Unless the wrong bottom bracket spindle is in there?

You could try shifting the chainring over 2.5 mm and see if it's 'good enough' for what you're doing. There's no need for a perfect chainline because it's sort of a dynamic thing. You're just trying to get it good enough to work with all of your gears.
These chainring spacers with your current crank, current ring, and old (longer) chainring bolts might be enough to get it riding better. Under $10 and not much time.

Another option is to forget the ring that you bought and run a 64 bcd 1x ring in your innermost position. It might be a little ugly unless you mounted a bash guard in the mounts for the 104 rings. A 30t elliptical or 28t round is about as big as I think you can run in a 64. Here's the 30t - https://absoluteblack.cc/xx1-style-shimano.html.

Otherwise, I think you're stuck with a new crank and new bottom bracket.