I finished (sadly) a little short of my goal. I was hoping to make it up in less than 2 hours, ended up at 2:02:38. Still, that is about 7.5 minutes better than my last attempt 2 years ago. (to review, it was an 18 mile climb up a mountain, average grade 6.3%, max grade 10.6%) Not too many rode past me, but a few.
I noted that for the duration I was not comfortable trying to run at 90% heart rate, but a steady 85-86% had me at the edge of my lung capacity. Damn steep and unrelenting hill, starting out at about 8% grade for the first 5 miles. Not having a mountain pass nearby to use as a training ground I found it difficult to trust I could maintain a higher effort all the way to the top. Even a 40K time trial is around an hour effort, and while riding hard and fast regularly is great training, I will need to have a couple long duration climbs to find just how much I can sustain.
I will study this ride's metrics against the prior effort—if the heart rate is similar then I've become more efficient. Could also be a reason to start training with a power meter.