You don't need to be an 'investor' to invest in Singletrack: 6 days left: 95% of target - Find out more
Any recommendations for something pretty minimalist but not overly spendy?
I'm dropping the chain off the ring several times a ride at the moment - most likely culprit is a worn ring, but as I want a 40T oval to replace the current round GRX one, I'm looking at a 6 week wait from Garbaruk, during which time I could do with getting quite a lot of miles in to prepare for the Frontier 300.
A few years ago there seemed to be lots of options, but all the MTB ones seem to be ISCG only now.
There's a Praxis/Gusset/XLC generic seat tube mount one that looks like it will work, but any other suggestions gratefully received.
(and yes - I've serviced the mech clutch and tightened it up a bit, but to no avail)
Thanks!
Got an old front mech lying around? You could try just bolting that on.
Paul's chainkeeper? I've got one in a drawer I could dig out. 28.6mm clamp, I think.

most likely culprit is a worn ring,
Buy a round 40T and then keep as a spare?
Would a BB mount one work? I might have an old one in the shed but bound to be loads on ebay..
cheapest option use an old front mech untill the new ring arrives & tighten the Shimano clutch (assuming your using Shimano).
Cheapest option is repurposed reflector mount.