Long Ride/Brick Observations -- Insight?

Hope everyone is having a WONDERFUL Labor day weekend!  I had beautiful weather for my long ride today when rain was in the forecast so I am one happy camper!

Ok, here is the back story for my question (to follow) ...

I am training for IMFL and just entered the "peak" training phase in Don Fink's Be Iron Fit training plan.  My long rides have consistently been 4:00ish hours with a 30 minute run for some time now but I did do a century in mid-July followed by a 30 minute run.

Here are my observation from that century and the 90 mile ride I did today, followed by a 45 min run. 

- After 85 miles I start to get less comfortable on the bike.  My feet start to hurt and I feel the need to shift around more in the saddle to relieve pressure down below.  I am able to stay aero though. 
- My calves felt tighter and in general my legs felt heavier on the runs following my two longest rides  (90 and 100 miles).  I consistently ride 75ish miles and run without experiencing the same feelings in my legs.

So, I am looking for feedback / suggestions.  The next 2 weekends I will be repeating today's experiment with another century and then the Redman Aquabike, followed by a short run and I would like to see if there are any changes I can test out to keep my legs feeling like they do after a 75 mile ride.

Do my legs feel good after a 75 mile ride because I have done that distance consistently and they have adapted?  My avg MPH and RPE is about the same on my 75 mile rides vs my 90 and 100 mile rides.  If I dial it back a bit on my longer rides will my legs feel better on the run or will my body just get used to this distance as I consistently ride longer?


I was still able to hold a 9:15 pace for the 5 miles I did today post ride but it just didn't feel as good as the same pace after my 75 mile rides.  I wasn't looking to keep a certain pace, I was just running but I did see my pace start to drop towards the end.  I am hoping to hold a 10:30 or so pace for the IM Marathon and based on how I felt today, I am not sure that would have been possible for 26 miles.  My training partner would tell me that it is not a fair comparison because I was not rested, properly pre-workout hydrated or tapered, but I digress. 

Ok, enough rambling from me.  If you read my whole post, thank you!  Any BTDT experience or advice would be greatly appreciated!