John Mayer paid tribute to his Dead & Company bandmate Bob Weir late Sunday, a day after the Grateful Dead legend died at age 78 over the weekend.

Bob Weir, a founding member of the Grateful Dead whose death at 78 was announced on Saturday, was a grounding force in a band known for its wanderings.

The ponytailed guitarist and songwriter sang verses on Truckin’, the band’s most indelible boogie — beloved, among others, by Apple co-founder Steve Jobs — and wrote and co-wrote songs that became fix...