recommended experience and pace before beginning IM Training

I'm in the same boat. I've done one Olympic and am a marathoner. I'm slow. Didn't do a half-marathon before going for a full. A 70.3 doesn't have the same appeal as iron-distance. I think you know you best. Have you plugged your "all day" paces into a triathlon calculator to figure out your range of possible finish times? Are you cool with financial and time situation for training? 

Right now I'm trying to decide whether I want to do Louisville or the Rev 3 race at Cedar Point...so maybe we'll end up seeing each other on race day? 

11 months is a long time. Work on your weakness. I just joined a tri club so I have a group to regularly OWS with. 

You'll get a lot of people who think you're coo-coo for cocoa puffs. Ignore them. Or listen to them. I mean, be aware of what you're getting yourself into and no whining afterwards. But I know what you mean about falling asleep thinking about that specific goal. Whatever gets you out of bed in the morning trying to lead a healthy, active lifestyle is the key. 

Started my first triathlon training in 2006.  Wasn't a swimmer, just tooled around on the bike as a means of fun transportation around the town, and was more of a short-distance runner and did a couple of half-marathons.

My first race was a HIM, and my second was an IM in 2007.  You want to talk about being coo-coo?

I just finished my 3rd IM this past weekend at the age of 48 (but I look like I'm in my 30s).

11 months is MORE than enough time to train.  I HIGHLY suggest looking for a training plan, and hopefully, a coach to keep you motivated and focused, and to work on swim drills for improving that aspect.

Work on nutrition, BALANCE with family/social life, and rest.  Rest during training IS important since that is how you recover and build muscle and improve.

GOOD LUCK!

What are your current paces for swim/bike/run? 

I am also slower, finishing my three IM races between 15 and a little over 16 hours. Slow is okay, assuming you are not in danger of missing cut-offs, as long as endurance is there. 

For reference in the IM distance I am about a 1:20 (1:55/100yd) swimmer, 7:30-7:45 (14.5-15mph) biker, and 6:00-6:15 (13-14 minute miles average) runner. 

For my first I followed a plan from Matt Fitzgerald's book "Essential Week By Week Training Guide" - it offers 10 levels of plans for every distance of race. I think I did the IM level 3 or 4. The 2nd one I hired a coach and he wrote a custom plan for me - and I followed that one again for my 3rd.

In general, it would be my recommendation to have a solid fitness base before signing up for an IM...even if it's 11 months out.  Solid as in having the experience in training volume that is similar to a HIM.  Don't actually have to race a HIM...but be used to and comfortable with 10+ hours a week of training.

By no means a requirement, but that would at least be my recommendation.

One of the hardest parts of IM is showing up race day injury free. I've done 4....2 injury free.

How much consistent training have you done? How realistic is it for your to bump that up to 10 hours a week in off season and rising from there. Will training, tiredness, lifestyle fit into your work, romantic, friend, family life well?

This year were you consistent in your training? FOllowed a plan and missed few sessions?

I worry about new to the sport folks jumping right into the IM training level without a significant base of fitness or longevity in doing a sport. Yes it can be done, but it is harder on both your mind and body.

Think of your motivation, is it big enough, excite you enough to help you change to move fitness up from priority to necessity.

Being a slower triathlete means time cut offs are real, so being as well trained as possible is important come race day.

Know IMKY doesn't fill for months so there is no urgency to sign up soon. For 2013 it was open 3 weeks before the race.

Be smart about thinking this thru. I know how easy it is to get sucked into the excitement and vortex of IM.

I tend to think something like that too. It's not the IM directly, but the workload in the training to look at. Do you have enough experience to handle both the volume planned and the larger workouts planned for the IM. Handling the workload of on HIM is probably a good start, even if one does not actually do the HIM. It tends to work better if one can go beyond just meeting the starting workouts for the IM plan, but is actually backing down at this point. Or has done a bigger load than that in the past. The start should be rather easy.

I'm in almost the same situation as you: I've only done one official Olympic Triathlon and one Marathon and I just signed up for Ironman Canada 2014.  Only 10 and a half months to train.

In my opinion the issue isn't what events you have done in the past it's how committed you are to training over the next 11 months.

Personally so far this year I've put in 198 hours of training (147 hours running, 41 biking and 9 hours swimming  (It's pretty obvious where my strength and opportunities lie)) and I'm committed to At Least doubling that in the next 10 months.   So I'm confident I should be ok.

If you are willing and able to put in the time then I say Do It. 

As always, Kathy is the voice of reason....my concern has a little to do with you not wanting to do a 70.3. It's ok to not like a particular distance, and you are entitled but as KAthy said, the jump up in training volume is huge with a IM....so if you are going from essentialy a running base and some smaller tris to an IM , you will need to take that big leap also trying to avoid injury.

Now if your lifestyle allows you tremendous amounts of free time to train, then never mind and get going asap and build up that fitness.

My quick story was in 2010 when I was new to tri specific training  I planned to do my first HIM at the end of 2011 and a IM in 2012.....well I trained an entire year and finished my HIM and it was a sufferfest and I knew I had to "shelf" the IM idea for another year to build the fitness to be ready for the rigors of a IM......well thankfully this year I accomplished it at LP

So , can you do it? yes.....noone knows your life schedule and current fitness as well as yourself and people close to you....get a plan to accomplish it and look at your life schedule and be sure you can devote the time....if so, go for it and good luck.....if not, then take your time and build up for it in another year.

I understand some people are enamored about the IM distance and they want to get it done ASAP, but you do want to do it safely also

good luck

X4 on all this, and I'll add some more.

It's more and more common for beginners to look at Ironman distance races and fail to respect the distance.  An IM is a long, long day with a long swim, a long bike, and a long, long run.  Yet there are so many IM finishers here on BT and elsewhere that it's easy to think "how hard can it be, really?"  It is hard.  It's very hard.  It's very, very hard to change your life to fit in the necessary training, avoid serious injury, work through the small injuries you can't avoid, and arrive on IM race day fit and trained and ready.  If you are properly trained, then that race day is going to be easier than you thought.  If you're not properly trained, then the day will suck in ways you can't imagine.

You could get from there to "just finishing" an Ironman race in 11 months, but chances are you won't.  Unless you have a strong fitness base beyond that, you have a ton of work ahead of you to get to IM day confident and ready to go. 

You asked about recommended experience and pace in your title, so my answer is "you have to have strength in two of the three legs, then you can work on the other".   So what is enough strength?  Here's my opnion:

Running: This is the hard part of IM.  Yes, people say you can walk the run, but really, it's a run not a walk, and time cut-offs are very real.  You say you've done a open half marathon which is child's play compared to an IM run.  And btw, it's a run, not a marathon - there is zero similarity between an IM run and an open marathon except the length is 26.2 miles.  If you can finish an open marathon is say 4 hours, you're ready to tackle IM.  That indicates a running base and cardio fitness needed for the 12-16 hour IM race day. 

Swimming: Swimming is a technique sport and it takes a lot of time to get fast.  You don't have to be fast, but you have to be able to go long. Swimming is dangerous. People die.  Do you swim 3-4 times a week, 40-60 minutes per outing? Is your T-pace less than or equal to 2:00?  If so, you're ready for IM training.

Cycling: Cycling is easy to train for but it's the longest leg of the race by far, and poor cycling ability hurts the run for so many people.  The IM run course is dotted with walkers who planned to run but cooked themselves on the bike.  Can you complete a century with a 16 mph average?  If so, you're ready for IM training.

Again, you don't need all 3 of the above but you need 2.  If you have one or none, well, seize the day and all that but wow what a mountain to climb.