This is very interesting. I'm coming off a 170 mm crankset with 24/34/42 teeth (mountain bike), to a 165 mm crank with 30/39/50 teeth (road bike). I was on the biggest ring on the road bike most of the time -- which is effectively bigger than my middle ring on my mountain bike -- is that right?! (I am still learning about all this.) Ahhhh... no wonder I hurt.

Would it also stand to reason that peddling with a higher cadence on a smaller ring would require a slightly different muscle group than peddling on a slower cadence on a bigger ring -- hence my perceived "sluggishness," which, since it started around 12 miles of my 30 miler, could have actually been simple muscle exhaustion?

I have so much to learn about road biking! I have a 10 mile ride tomorrow and am still a tiny bit sore. I will ice tonight, not ride up any big hills, and stay on my middle ring the! entire! time!