I just did 132 miles on my Strada not too many weeks ago and was amazed at how long the carbon seat stayed comfortable. I had achy knees as well (have been doing centuries sporadically through the summer but it had been close to 2 months since my last one so 132 miles was probably pushing it for me too (had epic heat too which I am sure did not help much either). I had Butt pain on long rides too but found I eliminated it by pulling my seat closer to the pedals.
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Sunrise saturday,
I was biking the backroads,
lost in the moment.