20wks to a an easy 5hr IM bike split

I could be dreaming here, and I probably am. But I'm going to really focus my efforts over the next 20wks on producing the easiest 5hr IM bike split. I'll see how close I can go.
I started off by posting a message top Rich Strauss over at Crucible fitness on how I should structure my Long ride. I initially called it my LSD ride and his repsonse was there should be nothing easy about doing your long ride. My immediate thoughts were this is going to be tough, but what the hell lets give it a go anyway.
Here is his suggestion for the long ride and some midweek rides

I would have you rethink several things:

Your bike split is pretty solid. What's your run split? You may want to consider working on your run first, rather than your bike. Having said that, you can do both, but just wanted you to consider that point.

I highly recommend you structure your week like this:

1 x LTHR/FT session, as 30-60' total minutes of z4-5a intervals, a 8-20' long. For example, 3 x 15' (2'), 2 x 20', etc. All at normal, TT cadence and preferably on your tri bike.
1 x Long ride
1 x Long-semi long ride

I don't like the term LSD pace. When I see your description of your long ride below, I think "not that big a deal." If you consider that easy is z1, IM pace is probably z2, then you're looking at primarily a z1-2 ride. With your bike strength you should be doing quite a bit more intensity in your long rides.

I like to weight intensity toward the back end and either tightly prescribe it, or keep it fartlek in nature, and at z3-4/5a effort. Think of these as moderate (8') to long (20') hard pulls in the second half of your ride.

For advanced athletes I like to prescribe low cadence intervals in the last 45-60' of their long ride.

Rich Strauss
Crucible Fitness Founder, Head Coach
Training Log: http://www.trainingpeaks.com/publicview.asp?p=RichStrauss
Swim Clinic E-Book: http://www.cruciblefitness.com/etips/swim1a.htm

Response number 2
Speed on the flat is what it's all about. I don't put much value in big gear work, which seems to be popular these days. In my opinion, it's all about watts to the rear wheel at race specific cadence and riding position. The low cadence work I describe above is to force recruitment of the last remaining fast twitch fibers that you haven't burned yet. You could also do the same just by increasing watts at the end but I think there is value in becoming comfortable at low cadences, and high.

So, in general, I crush myself in the last 2hrs of a long ride. My favorite training tool is to hook up with a roadie right near the end (about 30-45' out) and TT off the front.

Rich Strauss
Crucible Fitness Founder, Head Coach
Training Log: http://www.trainingpeaks.com/publicview.asp?p=RichStrauss
Swim Clinic E-Book: http://www.cruciblefitness.com/etips/swim1a.htm

I'm going to follow his suggestions for a while and see how things pan out. Previously I have trained according to Gordo's principles and they assisted well in riding a 5:11 at IMWA last year. I think if I want to ride around the 5hr mark I'll need to start inserting some intensity work.
Each week I'll try and post as much information as I can in regards to my bike training and would be interested in any feedback.

Hope everyones training is coming along well.

fluro