OK, I'll finish this thread off with a summary of what I have learnt.
This won't tell you how to prepare and train for a half marathon. This is a cycling forum, and you are better getting such information of a running expert/forum. Here you will find information on foot striking, pronation, soft vs thin shoes, diet, IT band failures, training regime, cadence, mid-race fuelling, pace, targets. What it will tell you is what I think a cyclist starting to run needs to know. I have started with the following assumption:
1) You have done a Sportive or two of at least 50 miles You have come in (or close to) the top third for 50 miles, or in top half of 100 miles. Therefore you are reasonably fit (rather fit compared to general population), and understand such issues as cadence, food and water requirements pre, during and post event.
2) You have been on here for a while, and have read various threads recommending how to improve your cycling. And have taken them on board.
3) You are committed to running as good a time as you can reasonably expect. Its not about finishing, its about finishing well and enjoying it.
My advice therefore is:
1) Take advice from runners - either a trainer, expert, forum or running group.
2) Listen to your legs, not your heart/lungs. At the start, your cardio system will be able to do much more than your legs will. Don't push your legs to match them. Steadily increase running distances by no more than a mile each run, as for any normal person. If your lower legs or base of feet start to hurt, listen to them, and give them a rest.
3) You may suffer short calf muscles. Add extra exercises and stretches (I'd recommend doing this before running) to this part, e.g. standing toes on steps, or specific calf stretches.
4) Parkrun. Look it up, and use it as a training aid.
5) You'll probably love hills more than most runners, particularly when you get better, so use that as a strength.
6) Aim high. I did it in 1hr 45min 11s, from never having done any running before.
