Quote Originally Posted by LizeEmm View Post
So, is there no accounting for the fact that the action actually happened in the past? Is it absolutely unacceptable to use the past tense or is the rule flexible?
The first part of the sentence describes the actions as happened in the past. The second part is in the present because it happened in the same time as the first one.

There is a grammar phenomenon which is called Sequence of tenses in subordinate sentences and indirect speech. Russians that learn English often forget to backshift tenses in English sentences. That fact proves that backsifting is very unnatural for Russian. I don't know why iCake is so surprised.

By the way "Дима знал, но боялся" isn't a sentence with subordinate clauses, so both clauses in the past. Subordinate clauses are like that: "Дима знал, что он может не бояться".