jlockwood98

Yes, a 29er will make a much better gravel bike. I remember what a chore it was riding 26-inch mountain bikes on dirt or paved roads.

scubaman

29er may have some advantages, including that they will almost all have disc brake mounts, which gives you more options about wheel size, plus there are more nice 29 and 27.5 tires available than 26.

That said, with the right fit and good tires, I think 26” MTBs really do make fine gravel & bikepacking bikes. What they’re mainly not good for is riding single track - modern MTB geometry is *very* different. Old MTB geometry is pretty similar to many current gravel bikes, with the main difference being that old MTBs have a relatively higher bottom bracket. That hasn’t bothered me, but it might bother some people.

As to whether bigger wheels are superior, Jan Heine makes a good case in a recent René Herse blog post that this isn’t necessarily so (“Why 700C wheels DON’T roll faster”).