I think the role of teaching at R1 universities is generally underestimated on the fora. Of course they have research expectations, but some of these universities care greatly about teaching experience and potential. Like everything else, I'm sure this focus varies from field to field. I am a finalist for a TT position at an R1 and I can tell you that at least 75% of the 45-minute phone interview was devoted to teaching.
In my experience, I have never heard of/experienced a TT search at a R1 which involved a phone interview. Usually, it's just a short call to see if the candidate is still available, and interested in the position, before inviting them out for a campus interview. I agree this is probably field dependent, so perhaps you could share if you're in the humanities, social sciences, or STEM? Another thing is that R1s still constitute a fairly broad range of research universities.
For the record, I've been a finalist in about a dozen tenure track/tenured searches at R1s over the last decade.
I am in a professional field, so I would not be surprised if there are significant deviations from searches in the humanities, etc.
