Hill work or Endurance work for Bike Time?

Riding a hilly route is good training hilly Ironman. I try to practice learning how to pace well on both up and down hills so I don't spike up effort while climbing and coast when I can pedal on the down hills. I don't worry about pace or distance when I train. Your body doesn't know distance but only time. So time in the saddle is time in the saddle and good for you.

I tend to recover much better from rides than runs so I wouldn't worry about the ride a week letter.

I think Kathy has a good reply.  I mainly go off of time, especially if you are doing a harder course.  Every Tuesday my group does the Vicksburg Military Park and if one was to look at our average speeds and distance they would surely say we are all slackers.  But it probablly is the hilliest course in MS and it helps to ride those hills at least once a week.

I'm signed up for IMWI and am jealous that you get to ride all those local hills!

I agree with what others have said.  Don't worry about your pace.  Just ride the hills and keep your effort on the uphill sections from spiking too much.  Your goal should be to ride through the top of each climb.  If you have to soft pedal at the top to recover from the climb, you're probably pushing too hard for your current fitness.

A 3:30 hilly ride has no (negative) impact on your ability to go 4:00 the following week.

Thanks for the thoughts.  I completely forgot about the "body doesn't know miles, it knows time" idea.  Now that I've said that, here's a "what if" question (or concern)...

Suppose I ride as efficiently as possible on a hilly course, wouldn't there still be the wall my body meets when it reaches a certain point?  Wouldn't that point be met earlier than if I did a 3:30 rolling hills course?   There's certainly a possibility of injury by going past one's fitness level  (I've gone past my fitness level a couple of times only to be down for 3-4 days).

I'm not trying to talk myself out of doing the hills, I just want to train smart.  Maybe I do two hours of hills and then flats for the last 90 min.

Wiky: hope you get to ride the course sometime.

Don't be afraid of doing more work.  But there is no reason why you can't do the same work on a hilly course as you do on a flat course.  Riding hills for 3+ hours IS endurance work.

KathyG has a great post explaining TSS, and this is the idea that you're getting at.  (TSS = total stress score).  You accumulate stress by time and intensity.  This link gives an interesting take on what you are getting at.  Even without a power meter, the point still stands that there has to be a balance between total time and ride difficulty.

http://www.twowheelblogs.com/intensity-factor-and-training-stress-score

Yes, at some point you would hit a wall where you've hit such a high TSS that you are exhausted.  And yes, theoretically, that point would occur sooner on a hilly course than on a flat course (assuming that hills spike power near or above FTP).  That said, if I were you I'd go out and do the hills as much as possible.  Get the gearing you need to spin up the hills and use the gears to your advantage.  If you're worried about injury now from a 3:30 hilly bike ride, I think you might be undergeared for IMWI.

Don't be afraid to take a few hills a bit easier but stay in your aero bars. Riding hills aero is a good work out, you will be surprised how easy it feels ride aero on flatter roads.

I'm not suggesting your race your IM in aero up the steeper hills, just suggesting mixing it in for a good bike work out.

Thanks for all the suggestions, ideas, and motivation.  I ended up with 4300+ ft elevation within 35 miles.  I ended up overall at 48mi, 4700+, in 3:32 - past 35mi it was generally flat with a couple of rollers.

I'm happy about my little accomplishment (the most hill work I've ever done), and happy that my nutrition was right on.  I got down to 3.4mph on some of the 15%+ grades, but I was okay with that. 

I did pay for it the next day (although the Sat. beverages didn't help) when I was supposed to run.