Originally posted by dhk
Sounds like you're not doing anything wrong. I'd say the hills at the end of a long ride are tougher for most everyone, unless they've done a lot of long distance training.
Did my first century of the season yesterday, and returning over the hills at mile 95-98 was definately tougher than the same ones going out at mile 2-5. My longest ride so far this season was 60 miles, so expected to suffer some past this point....and did. I didn't bonk, but noticed that my HR was just staying higher after mile 70 as the fatigue set in. My legs felt OK, but I was running 80% HR and over for the last couple of hours vs. 70-75% for the first half. Only fix I know for this is more long hilly rides.....a Century a month is my goal this year.
I can't eat much at the reststops without feeling it on the next hill. I'm better off topping up the Powerade bottle, maybe having some small portion of fruit or a fig newton or two, stuff something in the jersey and get back on the bike. A steady flow of carbs or sip of sugar drink every 10-15 minutes work better for me.