Singlespeed with 9 speed chain

will running a 9 speed chain on a singlespeed set up with 42×18 be ok?

The tensioner I have is for a 9 speed chain only, it's for my commute bike.

Yes, I don't think a 9spd chain is any weaker. I ran my SS on 9speed chain when my 8spd had stretched too much.

Saying that though, I just bought a new 18t sprocket. Turns out to be 1/8 so I now have a KMC half-link chain that looks like it's come of a motorbike.

It's not weaker, just more flexible sideways so it can slip off the sprockets easier. Not a quality I look for in a SS chain 🙂

It's a chain, they're chain like, y'know? Run the chain that suits your sprokets, they whole "you must use a bmx chain on your ss" is mostly bollockywankshite

Not from my own knowledgebase, but a chap we were riding with last week, who is obviously a sser judging by the speeds he went up hills. He said SRAM 9 speeds were the best ss chains.
So there you go.

I've run my inbred SS for the last year with my 9spd SRAMs that were about a year old prior to that.

Good chainline will see you right nearly all the time, irrespective of what you're using.

I use a 9 speed Rohloff chain with a Rohloff. If it mattered, I'm sure Rohloff would make a single speed chain.

Thanks for the replies, I thought it would be ok but just wanted to confirm incase anyone had any issues.

It's not a strength issue. The 9 speed chains are really strong, it's the sideways flexibility.

I have found lower cost BMX chains just as effective.

Chain life on a SS has more to do with lubrication than which chain so long as it is a semi decent one.

Question i'm running a half link chain !
It don't half make some noise 👿 If not lubbed enough and i'm unable to use a light oil on it (noise gets worse).
Currently using bearing grease (black thick stuff)
Would this noise be due to chain wear (is it ducked)?

Chain life on any bike has more to do with cleaning and lubrication than anything. Period.