at what point is a good cross-country hardtail going to be superior?
Almost all the time unless on tarmac or super smooth gravel with average speeds over 25kph. Unless it's a insta-wagon steel gravel bike with a high and wide bars, then a 29er XC race bike will be faster everywhere.
Gravel bikes are a good compromise "one-bike quiver" but if you already have a road bike, especially a modern one with 28mm tyres, an XC bike is definitely the way forward as a 2nd bike.
I've really had the urge to build myself a rigid xc bike as of late. However, I'd only ride the same trails as I would on my cx/grave bike so I don't see the point. Specially as there are some decent rode sections between...
I don’t see the point of a rigid XC if you have a gravel bike, but an XC with front suspension would open up a bunch of options for riding in UK national parks, which are often more rocky than gravely IME.
Almost all the time unless on tarmac or super smooth gravel with average speeds over 25kph. Unless it's a insta-wagon steel gravel bike with a high and wide bars, then a 29er XC race bike will be faster everywhere.
Gravel bikes are a good compromise "one-bike quiver" but if you already have a road bike, especially a modern one with 28mm tyres, an XC bike is definitely the way forward as a 2nd bike.