I built my hardtail with a single front ring a couple of years ago. Didn’t work for anything other than XC with just a top chain guide and so have always run it with an MRP Lopes lightweight top and bottom guide (most expensive piece of alu and plastic I have ever been stupid enough to buy) and it has worked perfectly ever since.
Just had the opprtunity to upgrade because swapping parts around bikes to build a pub bike to send son off to uni.
Tried a Sram X9 short cage type 2 clutch jobby. Ditched the full guide and went back to a top mount only and went for a ride this afternoon. Seemed to work. Only two downhill runs and so early days, some bits rooty, some bits fast, a couple of small drops (2ft) and a few small jumps. I was not super fast this afternoon, roots and ground generally back to being slippery after a long fast dry spell, had dog and son and things on mind but seemed OK.
It was quieter and chain didn’t drop.
Only problem is noise from front ring under load. I think that this is just the noise of a new chain not meshing well with an old ring even if it still looks good (Middleburn Uno)
Just thought I would share on the basis that there is a lot of interest being shown on line in whether it is worth the change.
When i saw them released I thought they were a great idea having been a single ring advocate for years and far more of a practical real world advance (and cheaper) than electronic damper and gear indexing for example.
So far so good but we will see.