Been using the extralight black Switch Back Hills for a few months now, setup tubeless. Was careful with setup and sealant installation. Pretty much sealed up from the go. Used OrangeSeal Endurance.
A few weeks later as the tyre stretched more, a handful of air holes appeared in the sidewalls (dunked the tyre/wheel in water to find them), though they sealed up with a sealant top up.
Been running them on all kinds of gravel and singletrack. Had a couple of thorn punctures which sealed right up. Other than that, nothing.
What I do remember coming across online when looking at these tyres was one forum comment saying the tan tyres were more prone to weeping than the black tyres, due to some difference in the sidewall makeup? Not sure if that is true though.
I think they're awesome. Have a set of extralight 42's now waiting for a new wheelbuild.
