The Grand Bois Hetre is the best 650bx42 tire available today and for the foreseeable future. It’s true to size, very long wearing and can be run tubeless on Stan’s Rims.
I read a few posts about converting Hetres to tubeless and came away with the idea it was simple, just use a little more tape. My set-up was Stan’s Crest 650b rims with three layers of Stan’s Tape. The tire was a little difficult to mount dry as the rubber is extremely sticky when new and the additional layer of tape was preventing the beads from seating in the center channel for installation. I ended up giving a little spray with mild soap spray and it slipped right on after that.
The tire held air immediately and the beads seated with a loud pop using only a floor pump. Over the next 3500 miles I had three punctures that required plugs. Two sealed and then lost their seal after a few hundred miles and one never sealed. Later one of the small plugs was sucked into the tire and I had to replace with a large plug. Overall I was a little disappointed in the amount of flats as I had 0 on the tubeless Compass Babyshoe Pass. Stan’s Race sealant was used in both tires.
Of note, the tires were in use from December to August and did not ever exhibit the sidewall weeping I saw with the Compass tires. The tires held air well and I had no issues with burping or bead failure. Usual pressure was 33-38 psi.
Here’s the larger of the two large punctures before and after I removed the plug:
Inside the tire after final removal. I over filled with Stan’s after the first plug failure and probably should have just patched the inside instead.
I’ve been hesitant to use Hetre’s tubeless on other rim types as there are stories of blow-offs happening.