Reaching a biking goal...20 mph HIM

Yeah, RIDE LOTS!

Generally I quantify this as 100 miles per week, for a HIM you might want to up it by 50%. Purpose of this is to build your strength and endurance. Cycling training is no different than running training or anything else: first you build the base.

Once you've established this base and ridden this much for a couple months, THEN you can introduce tempo rides, intervals, big gear drills, etc.

Maybe use a shorter Time Trial as a way to measure progress (20 miles, even 10 miles?).

There is plenty of material on cycling and how to improve performance.

For a beginner, you need to ride a lot! As for how much mileage, that will vary & depends on many factors such as time available, & your condition. One good method to get faster is ride with others who will push you to ride faster...if you haven't, join a riding group that rides 18-24mph.

Log your times & pace so you can track progress...

Good luck!

It's going to depend on the course as much as your legs. Check the results from the last few years and see what percentage of  men in your age group had an average bike speed over 20mph. Then ask yourself if you can reasonably perform in that percentile and not kill your run.

A lot will depend on the course too.  I averaged 20 mph at Timberman, though I over-extended myself in doing so and was trashed for the run.  There's no way I can keep the same pace at Mooseman, since the course is harder.  I've done 22+ for an Oly on the Cranberry loop, but that's a lot flatter.  The hills will do you in.

Like Bear says, ride lots.  I think 100-150 miles per week as a steady diet for several years is really a good base from which to work.

Can you ride 56 @ 20 mph now as a stand-alone ride? How about 22mph?

I'll chime in here as one of the "rode too hard (19.9mph) and was toasted like a cherry pop-tart for the run" in my first and only 1/2 IM. my best 1/2 marathon is 1:45 and I was 2:15 or some such crap for the run.

I'm not a professional coaching type and am just now starting to train via heart rate, but I would further qualify this: Until you can do a stand-alone 56-mile ride @ 20mph+ while remaining below your LTHR, then it is probably an unrealistic goal to expect to do so in between the swim and the run.

First HIM?

20 mph is a realistic goal but I don't think you should go in thinking that way.  You really want to think in terms of riding as fast as you can following your race strategy dictated by HR and perceived exertion.  Working a little to hard on the bike so you can hit that arbitrary number can lead to a long painful walk.

Maybe you can go average 20 mph and stay 10 beats below ltr (or wahteverr your plan is).  I don't know - hopefully by the race you will.

The bear is right. You might be able to knock out a 21 mph pace in a 50 miler today, but will you be able to run after? You have to think in terms of 3 here not one, and if you are training based on HR, PE power etc. you have to learn at what effort or intensity you can go the distance as fast and efficient as possible and still have gas for the next sport. Developing biking fitness takes time and "RIDE LOTS" (Bear 2004 or 2005 )

There is a common phrase at the end of every triathlon which goes like this: "I had an awesome ride, I even rode faster than I usually do, unfortunately my run sucked!" (I wonder why )

I would tend to train with a LOT of miles above your goal speed.  Keep your cadence up in the 100's or 120's if you can.  That means your strong enough to push the gear you are in and not be whipped getting off the bike.

I don't normally ride that fast for distance rides.  I am working on speed, but many of the rides I do are with family riding along.  I am generally just happy to finish without crashing or losing someone.