1x7 drivetrain

[FluffyChicken]

I think they've found the newer 'more speed' chains can last longer.
And then it varies between manufacturers of course.

So speed isn't an indicator of being a good quality long lasting chain.

 

[novocaine]

the width is to do with the length of pin and overhang beyond the plates.
to accommodate more speeds the distance between sprockets has to be reduced.
so a 3x11 speed front have a smaller gap between chainrings technically. they don't tend to though because other things are at play too (chain line being the most obvious as it can lead to rub if you are in the inner ring and outer cog on the rear).

chain stretch has nothing to do with the plates, it's wear of the roller element and pin.

 

[joglo]

To my experience, if the chain drops on 1xX conversions (just running the middle chain ring) depends of course on riding style, but a lot also on the rear derailer. You have to found one or adjust that this is keeping the chain tight. A proper chain lenght, rather short, helps also a lot.

Instead of an still a bit expensive NW chainring I'm using at some 1xX conversions an bash guard at the outer position and sometimes an anti drop clamp on the inner side.
Something like this

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but it depends on the frame is this fits well enough to do a proper job.

Different topic: as a lot of the old cassettes, especially also 7 speed have very limited bandwidth, e.g. just 14 to 28.
That's fine for completely flat ground, for me ideally with a 38 or 40T front chain ring.
Just in case you need a bit more flexibility for short uphills or higher speed, or if the cassette has anyhow a lot of wear. There are nowadays also 12-32 cassettes for 7 speed, which work well also with old rear derailleurs, giving then a bit of more broad choice for gear ratios.
For 8 or 9 speed set-up I'm using always 11-36 cassettes, because this gives a nice choice but still works with all old derailleurs.

 

[Chopper the ex Copper]

I used to commute on a 1 x 9 using a middle ring. Didn't need the low gears on tarmac, and the journey and weight of kit I had to shift were such that the high gears never got a look in, so it seemed daft to be lugging the weight and complication around for 18 miles every day.

Never dropped the chain once, although did use a cheap tensioner.

 

[DrDaveTampa]

Thanks for the advice, so in theory if I get a 9 speed chain then that should work fine with a narrow wide chainring ( was thinking something between 36-42 teeth) and a 7 speed cassette and derailleur? If I decide to go that route… I’m still not really sure if a narrow wide is necessary , the chain has never come off my bike on the front ring whilst riding on the road (without a FD) and finding a cheap 5 bolt 110 bcd narrow wide (to fit the existing cranks) isn’t proving that easy

I have a collection of Chinese narrow-wide chainrings on hand (Ybecki, Ganhopper, and VXM) and so far they are fine, no drops and they don't look half bad either (I guess it's not rocket science). 94bcd is tricky to find; 110 is everywhere. For as little as $7 on Amazon; I imagine you can also find similar stuff on Ali for even less. The 1x7 happens to be running an old 8 spd chain without issues.

There's no way I coulda squoze a 42t chainring in there and still get a decent chain line, even 38 was *really* tight. 36t gives a range of ~28-86 gear inches with the Sunrace 11-34 7spd cassette, which is fine for commuter duty on an old mtb frame I think -- you're not gonna be setting any land speed records, but you may want to peel off into the dirt from time to time...

 

[Stanflashm4n]

I have a collection of Chinese narrow-wide chainrings on hand (Ybecki, Ganhopper, and VXM) and so far they are fine, no drops and they don't look half bad either (I guess it's not rocket science). 94bcd is tricky to find; 110 is everywhere. For as little as $7 on Amazon; I imagine you can also find similar stuff on Ali for even less. The 1x7 happens to be running an old 8 spd chain without issues.

There's no way I coulda squoze a 42t chainring in there and still get a decent chain line, even 38 was *really* tight. 36t gives a range of ~28-86 gear inches with the Sunrace 11-34 7spd cassette, which is fine for commuter duty on an old mtb frame I think -- you're not gonna be setting any land speed records, but you may want to peel off into the dirt from time to time...

When you say there’s no way you could have got a 42t chainring in and still got a decent chain line, how do you mean? Aren’t most triple chainrings biggest rings that size or bigger?

 

[Graham_hkr]

When you say there’s no way you could have got a 42t chainring in and still got a decent chain line, how do you mean? Aren’t most triple chainrings biggest rings that size or bigger?

I've got a 48 on my 1x - it's the same size & position as the original 3x no issues.
I did have an issue with a different bike where the larger chainring teeth hit the chain stay!

 

[DrDaveTampa]

When you say there’s no way you could have got a 42t chainring in and still got a decent chain line, how do you mean? Aren’t most triple chainrings biggest rings that size or bigger?

Yeah, mounted to the outer position. And if you're mostly gonna be riding in the upper range it'll be fine. Chain line isn't gonna look great in 1st gear tho.

I remember bitd it was supposed to be bad to run the big ring up front and the big cog in back, I dunno.

Granted that's kind of the nature of 1x... Chain line is bound to look bad somewhere. I read somewhere 10spd+ chains are designed to accommodate that anyway. So, I'm sure you'll be fine

 

[FluffyChicken]

Ah, Big-Big was because it would pull the mech into a position it shouldn't be in for a long time.
Also if you'd set your chain up poorly, or chopped it down after a snap. You'd lock the chain in big big and maybe snap it again.

It was less about the side rubbing.

Small-small had similar problems, but that was usually lack of tension as it went floppy.

Depending on your crank style, you may be able to shorter your bb length and use the outside.

 

[hamster]

I think they've found the newer 'more speed' chains can last longer.
And then it waves between manufacturers of course.

So speed isn't an indicator of being a good quality long lasting chain.

It's because they sadly don't bother with 7/8s, which would last even longer with the same treatment.