I've got a hilly century coming up in a month and I'd like to put in a good, hard effort since I plan to ride with a group of fairly hard-core riders. I've done centuries before, including one with ~5000' of climbing, but I've always taken it easy to up to the final 20 miles.

Currently my endurance isn't bad. I can do 70-80 miles at a moderate pace (< 90% of LT). If I go hard (just below LT with some efforts above), my limit is about 45-55 miles. I expect I'll be in a small paceline of 4-5 riders for the century, so it'll be a lot of moderate efforts punctuated with hard efforts about every 5 minutes or so.

So I'm thinking of doing some 70-100 mile rides where I do a moderate pace until the last 30-40 miles and then try to maintain a hard pace or do intervals over the last part. Alternately I could try and do moderate rides where I lift the pace for 1 minute out of every 5, but I feel like I'd spend the whole ride looking at my computer instead of the road. I'm not exactly sure how to augment this during the week. Probably at least one good set of hill intervals each week, and one easy ride with some distance to it (maybe 40-50 miles).

Is there a better way to approach this? What kind of workout would give me the best "bang for the buck"?

Well, if you have decent endurance, you're not going to see a lot of gains in that area in a month. I have two recommendations.

First, intervals are a pretty good simulation for what you experience in a paceline. Make sure you are well rested before hand - the better you are rested, the more benefit you get from doing intervals.

Second, some tempo rides can also help. You do a ride right at your LT but only for 20-30 minutes.

Both of those should help.

I don't think much of your idea of trying to do both intervals and long rides. You need training specificity rather than big long general efforts.

You might also consider some hill repeats or over/under intervals.

What's the longest distance you've done? You might want to go out and do a 125 mile ride this coming weekend. Ride it at a comfortable pace to the 100 mile mark, then give it whatever you've got left for the last 25. Once you've done a distance longer than a century, the century distance isn't as intimidating anymore.

And also train on hills ... preferably hills similar to what you'll encounter on the century.

I'll give your ideas some serious thought. Your second suggestion sounds basically like an extended TT interval, which sounds like a good idea.

But, OK, I'm an idiot -- what is an over/under interval? Over/under LT? Is it like 1 minute above, one minute under for so many minutes?

Both of these sound like things I can do with hills in the mix. And I'm able to go ride the same hills I'll be doing for the century, which is a bonus.

The longest ride I've ever done was 106 miles, but the longest ride this year was about 82, though it involved a lot of climbing. I'm actually more intimidated by the intensity than the distance, so I think ericgu's suggestions make the most sense.

I still plan to get in a nice, long ride at least a couple of times before the event. It'll maintain my endurance, plus I just like doing long, relaxing rides.