Dwarves are not heroes?

[William Cloud Hicklin]

At the time Tolkien began The Hobbit the Dwarves in his legendarium were conceived as being not merely morally dubious, but (if not as wicked as Orcs) then compulsively selfish, dishonest and untrustworthy, their antecedents being Andvari and Regin/Mimir of Norse legend. It was The Hobbit itself which led Tolkien to rehabilitate them somewhat in the Quenta Silmarillion of 1937; and the LR which brought Dwarves (or at least Durin's Folk) solidly into the 'mostly good' column in later Silmarillion texts.