I've been REALLY liking the 40mm Tufo Gravel Swampero/Thundero combination I've been using recently, but info from folks like wide-tire pimp, Dylan Johnson, has me curious about whether wider is better for the way I ride.
I've had a pair of Schwalbe Thunder Burt 2.1s taking up space in my tire drawer for a while (they were on my MTB when I bought it, but were quickly replaced with something wider and knobbier). Out of curiosity, I mounted the TBs on my second set of gravel wheels, and it turns out they fit in my Niner RDO frame just fine. I wouldn't want to run them in muddy conditions, but for dry riding, there's enough clearance for my comfort. The TBs have one of the best ratings (lowest Crr) for MTB tires on BRR. The data says they're a lower Crr than the Thundero gravel tire. Of course this doesn't take into account aerodynamic or weight factors, but it has my interest enough to give it a try. A concern is how well the front tire will grip in soft/loose conditions. My front-end Swampero has been great in that regard, so was my previous Pirelli Gravel M. This is a factor that matters a lot to me. I didn't use them for long enough on my MTB to get a feel for what they can do.
I plan to ride them tomorrow on one of my local "happy hour" after-work rides. I'll let y'all know how it goes.