Sometimes I feel like an analog man who's been trapped in a digital universe. I think that you're working at this too hard.
1. Forget about speed for a minute. If you put a Ferrari transmission into some econo box car, it still won't go 150 MPH. You have to have the power to push it.
2. As you ride, when you feel like your feet are spinning too fast, shift into the next hardest gear. If that gear feels too hard, you need a cassette with closer gear spacing.
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My greatest fear is all of my kids standing around my coffin and talking about "how sensible" dad was.