Patterns for stem changing -ir verbs

Question

I have been trying to find a pattern for which -ir verbs have stem changes and which are e->i instead of e->ie.

It seems to me that all -ir verbs with stems that end in oX, where "X" indicates one or more consonants, change o->ue.

Those that have stems ending in eX change e->ie if X={n,nt,r,rt}, otherwise they change e->i with the exception of hervir (the u occurring in qu and gu endings is being lumped in with the consonants here.)

Are there any other exceptions you can think of?

Answer 1

I understand how the stem changing occurs when conjugating. My question is about determining which words have which type of stem change. Some websites say there is no pattern or rule, so you have to memorize all of the words that change. Other sites say that native speakers can tell whether a word they've never heard before undergoes stem changing just from the infinitive, so there must be some kind of pattern, albeit a fairly complicated one.

Answer 2

Here are the rules for the stem changing IR verbs in just the preterite tense. There is a reason why stem changing verbs are sometimes listed with irregular verbs.

ir stem changing in preterite