I’m using Trainer Road for over a year now and last year when I was preparing for my 70.3, the longest rides I had on the weekends were around 2 hours. But this year they are getting longer and longer each week. Last week it was 4 hours, and now I have one that is 4.5 hours. It’s extremely tiring and boring to do 4.5 hours at home and it’s hard to motivate myself to do those since my bike leg will be 2.5 hours.
Why this change?
I can’t speak for that particular plan or why it would change, but volume is king when it comes to building aerobic fitness. There is healthy debate about the benefits of 1 long ride vs. multiple short rides, but not much debate on the benefits of overall volume. If you hate the long ride, break it up into multiple shorter rides and you will likely see similar benefits.
I enjoy long rides outside, but agree that it’s tough on a trainer. You might consider Zwift as an option to keep the long trainer stuff interesting. There is a weekly 100 mile zwift group ride on zwift that I do frequently when the weather isn’t great. Super smooth endurance/tempo and a great workout. No way I could stomach that effort for 4+ hours on the trainer without the group dynamic keeping me engaged.
Hey @Milesprower,
Welcome to the forum! 
This is because you have the max duration cap for your Sunday easy rides set to 5 hours.
We’ll do our best to work you up to your max duration caps, and if you have the experience, abilities, and Progression Levels to warrant a long workout, we’ll likely give it to you!
If you want those workouts to be shorter, simply adjust that Sunday cap down to the max duration you’d like.
If you aren’t sure how to do this, check out the Help Center article below.
Let me know if this helps! 
From a more pragmatic standpoint, what is your usual finishing time for a 70.3? I’m sure it is more than 4 hours.
You are training for a long aerobic event, so IMO, some of your training should reflect that. Sure, the bike leg is only going to be ~2:15 - ~2:45 (give or take), but the whole event is longer than that. So why not have some longer days on the bike, that will help train your body aerobically for longer efforts but without the pounding that your body takes from running?
When I was training for IM races, I would do the occasional 6+ hour bike ride simply to get a longer endurance day without punishing my body. An occasional 4-hour ride for a 70.3 makes all the sense in the world to me.
Occasional, and outside, I’d take a 4 hour ride easily. But each weekend, at home since it’s rainy outside, boring 
Hey miles, welcome to the forums - join us on the triathlon/ironman training thread perhaps?
What is your endurance progression level?
Hey Joex,
Currently 6.0 on Endurance
Hey Power, yes my 70.3 is time is even above 5 hours but after that 4 hour ride on Sunday I have a run in my program anyway. If it was only the cycling, I’d bite it up and do it, but 2 workouts and one being that long, usually I don’t do the second one.
This will be a factor then, as you can’t get short endurance rides at that high a level. Basically for you to keep the progressive overload for Endurance going you need the longer rides.
If your other PLs are high, then an FTP detection or ramp test could be in order, You may have “raised the floor” so that you can hold better Watts at endurance levels at least, and that would shift your endurance PL down to where the shorter rides are.
Move the days around. Long ride after long run is much easier than the other way around.
Hmm ok. But you can’t do al your endurance rides at a level of your PL? I have 7.4 endurance level? WIll have to check my plan how I can progressive overload my endurance rides…
It’s not always about Workout Level though. If an athlete doesn’t have time to take on a long Endurance workout, it’s definitely okay to pick up a shorter one.
Endurance is governed by watts (and HR for some) like other training zones, but not as much by physical capabilities until you really start to push out duration. When training in the higher training zones there is often a physical limit that you reach well within a lower duration so you don’t run into this issue as much.
There’s no need to look to FTP if there aren’t low-level Endurance rides that are technically “productive” by TR standards though. Endurance training is a bit different. I look at it more in line with effort (power or HR) for a given duration, and I typically govern zone 2 by HR and adjust power based on that.
For those of you who are looking to gain the benefits of Endurance riding, but don’t have the time for a really long ride and want to take on a “harder” or higher-level workout, this is where the lesser-used Tempo workouts could come in handy. This might be especially true for those with high Endurance PLs.
There is still some debate in terms of where exactly the “most” aerobic benefits come from in terms of “Z2” training, and many are finding that it’s often at the very top of their Z2 HR and spills into low Z3. If you have high Endurance PLs and want a shorter workout, finding an appropriate Tempo workout might be the best option.
There are places for both, but I’d argue that if you’re an experienced endurance athlete who’s capable of long Z2 endurance rides and looking for a workout with similar benefits but is shorter in duration, tempo (not to be confused with sweet spot) could work really well.
Again, there’s nothing wrong with picking a shorter-duration Endurance workout either. Time training all adds up, but I think the confusion here is whether or not lower-level Endurance workouts are still productive, and the answer is yes, they are. Will they “push the needle” as much as longer rides? Maybe not, but if that’s what you’re looking for, pick up a Tempo workout when you don’t have time.