Adjusting to Aero Position

Aero on the trainer vs aero on the road is very, very different for me.  I can ride the 112 miles of an Ironman 99% in the aero position with no issues at all.  I can't ride for more than 15 minutes in aero while on the trainer.  100% of my trainer riding is done on my road bike.

I'd slog through it as best you can and see how it feels once you hit the road in the spring.

You'll get some opinions saying "train how you race" and all that but cycling is cycling.  Getting used to the aero position isn't all it's cracked up to be, especially in the off-season.  You'll have plenty of time in the spring to adapt to the aero position.

I just started riding a Felt B12 and I'm wondering the same thing. One thing I've noticed is that I have more tolerance to aero when I'm on a flat or downhill false flat. When there is any sort of elevation gain I tend to come out of aero much sooner.

(ps, nice avatar pic)

There are small subtleties that happen on the bike that you don't really notice until they're gone. In this case it's the light swaying that your bike makes as you're pedaling. It's only millimeters, but that minor amount of movement translates to small weight shifts from one arm to the other. This allows your blood to flow better. When you take away that sway on the trainer it makes the ride less comfortable. This is where rollers have a huge advantage over a trainer.

The trainer is the best place to really get acclimated to aero. Yes, it's hard, and yes, it's harder than aero on the roads due to the static position. But you can be sure that if you can hold aero comfortably on the trainer for "X" hours, holding it that long on race day will be absolutely no problem. 

Aside from a reasonable fit (doesn't have to be perfect, but not glaringly off), the key is to build slowly and gradually . Treat it like you're building bike mileage. It'll come quickly enough.

^^^^^ This ^^^^

However, at 20 hours of riding you should be more comfortable than it sounds like you are. You should consider it might be the bike's components or your fit. 

On my P3C, I had a lot of trouble with long aero rides regardless of trainer rides, outside rides, or race day.  After 4 years, I went and made some changes to it, and had a fit done.  Man what a difference. 

Don't wait 4 years to figure this out, like I did. Give the links below a read.  The titles are self-explanatory.

seat + new cockpit + fitting = amazing improvement

I was wrong, bike fit IS everything

double post deleted

I thought about this more, so I have more to say :-)

I recently purchased a 2013 Felt B2, and had a professional fit done. I've logged 19 hours or so in the saddle, 18 of which were on the trainer. This bike is my first tribike.

The longest I have spent in the aero bars is about 15 minutes, and usually it's 5 minute duration, and then I'll come out for a few minutes and stretch.
Last session, I did 2 minutes in, 1 minute out mostly.

Aero isn't really uncomfortable, but it isn't comfortable either. I've also seen some discomfort in my right bicep. Things haven't gotten noticeably better or worse yet. I'm off season training, following Trainer Road's high volume base plan.

>>>> Really?  This doesn't sound good. Only 15 minutes?  2 minutes on 1 minute off?  You can't race like that, so you shouldn't train like that.  You bought a tri bike so you can ride it aero (it's the only benefit of a tri bike, after all). 

How long should I be spending in aero on the trainer? Does it matter all that much?

>>>> Answered above.  The trainer is the best place to train for aero.  All elements are controlled.

How long of an adjustment period should I expect (presuming no pain or significant discomfort) to the new position?

>>>> If the fit is right, then it should already feel great when you drop into aero.  But after 30-60 minute ride, your neck may hurt from holding your head up, and maybe your upper shoulder muscles.  This takes whatever it takes.  I did a lot of strength exercises to help those muscles.  In fact, I find that some of my fancy dress shirts from 7-8 years ago no longer fit in the neck, I went up about an inch in neck circumference.

 Should I not worry about it until I hit the road in the spring, and just keep pedaling

>>>> Winter is the best time for trainer training.  If you're not going to train in aero, then why not return your tri bike to the store and just ride your road bike?  Seriously.  The only benefit you get from a tri bike is being able to ride it in aero.  If you can't, then riding one is pointless.