The Tallac’s sole is moderately stiff, but not nearly as stout as most truly XC-oriented shoes. The Tallac is a little stiffer than the Specialized 2FO DH, a bit more so than the Shimano AM9 and Endura MT500 Burner, but a little softer than the Ride Concepts Transition, for example. It’s a nice balance between offering enough stiffness for efficient pedaling and foot support when riding hard, while still being nicer to walk in than a super-stiff, XC-oriented shoe, and having just enough give to engage the platform of larger, more DH-oriented pedals if you’re running those.
The extended tread on the heel of the Tallac isn’t great for heel clearance against the chainstays / seatstays of the bike. It wasn’t too big a deal for me on most of the bikes I rode with the Tallac, apart from the YT Capra (which has fairly poor heel clearance itself), but I did notice more rubbing than average on a variety of bikes. It would probably be pretty easy to trim some of the offending tread with a razor blade if you’re so inclined, but folks who tend to get a lot of heel rub should take note.
The Tallac also takes a little fiddling to play nice with HT X2 SX pedals, due to the shoe’s slightly deeper than average cleat slot making for a bit of interference with the pedal body and the shoe sole, especially if you’re running the cleat fairly far back on the shoe. HT includes cleat shims to deal with such issues, and this isn’t the first shoe that I’ve had a little trouble dialing in with the X2 SX, but if you happen to be interested in running that combo, take note. Adding one of the black plastic shims under the cleat, plus removing the rear traction pins from the pedals, worked great, and the Tallac played nice with both Shimano XTR Trail and Saint pedals without any fuss.