I just got a new IRO Mark V frame in the mail and am going to transfer parts from my old bike/build onto the new frame. Only problem is that I cannot seem to find any definitive instructions on the net about what to do about attaching my fork to my frame.

The fork came with a very long steerer tube. I know I need to cut that, but don't really know how or how much room to leave when cutting, and I know IRO uses a threadless headset, but do I need to use exactly that, and i really have no idea how to install a headset once i get it.

Is all of this difficult to do? I've got basic tools and am enjoying learning about/working on my current bike. I'd love to avoid having it done at my LBS as I'm a do-it-yourselfer, but hey... I'm also realistic. Est-il possible por moi?

Any instructions, instructional links, and/or confidence builders would be greatly appreciated.

You need the tool to attach the race to the fork. You will need to buy a new headset in most cases. I know campagnolo spare races cost as much as a new HS... I would cut the fork to same length as your current fork. From how you are explaining your situation, I would go to the LBS and pay the forty bucks or so to do it.

But to answer your question. The work you need to do is easy with the right tools and the instructions on the Park site..

You actually won't necessarily cut the new fork to the same length as your old fork, because your new frame may have a different head tube length.

to cut the fork and install the frame you will need:

a new threadless headset
your new stem
any spacers you plan on using
a crown race slide hammer (see below)
a hacksaw
a steerer tube cutting guide

Here's how it works:

First you will need to install your crown race.

the best/cheapest way to do this is to find a length of pvc pipe with an inner diameter that will just slip over your steerer tube.

make a perfectly square cut on the end of this pipe, and use it as a slide hammer to seat the crown race on your fork (be careful to ensure the the race doesn't go on crooked) You can also purchase a specific tool.

The process of installing the headset races is one you may want to take to your LBS. With the correct tool, it is a snap, but especially with a new frame, which may need some prep work, you might want to have them do it.

if you still want to do it yourself, here is what I recommend:
either purchase a headset cup press, or manufacture your own, using a 24" piece of 3/4" threaded rod, two nuts, and two washers.
You will need two 10 mm headset spacers.
stack as follows:
nut
washer
spacer
top race (lightly greased)
frame
bottom race (lightly greased)
spacer
washer
nut

Center everything and ensure that the spacers are pressing on the flat at the base of the races, and that pressure is not being applied to the raised rim of the races.
slowly tighten until both races are snug against the frame.

if the races resist seating, don't force it - your frame may need to be prepped to the proper diameter to allow the races to seat properly.

At this point you can stack everything up in order:
fork(with crown race)
bottom bearing
frame (with races installed)
top bearing
top bearing race
spacers
stem
spacers (optional)

mark the steerer tube at the place it emerges from the stem, or top spacers

cut the fork using the cutting guide about 2-3 mm below this mark.
if it is a carbon steerer tube, you will need an expansion plug (otherwise you use a star-nut)
The cutting guide isn't obligatory, but it certainly helps your peace of mind, and it's not all that expensive.

re-assemble the entire stack, install the top-cap and screw, and tighten to the torque setting recommended by the headset manufacturer. (or until there is no play in the headset)
then securely tighten the stem clamp screws and you're all set!

this info is also on the Park Tool website, and I'm sure it's on Sheldon Brown as well.

Note - it may be good to plan on using extra spacers above your stem, in case you find your handlebar placement needs tweaking later. However if you're sure of the geometry, they are completely unnecessary.

Just go to the LBS. Paying whatever they charge is better than trying to DIY the first time and risking a new fork.

If you're a do it yourselfer I think trying your own installation is a good way to go. Squintal's write up is very good, and his diy crown race installer/headset press suggestions have been used by many. The one thing that is hard to do yourself (unless you have some unusual tools in your shed) is face/ream the headtube (if needed, some manufacturers do a good job of prepping the frame, some don't; you might ask IRO). Just be patient and follow instructions as laid out by Squintal (or go to Parktool and review theirs as well, search these forums or roadbikereview.com or mtbr.com for more input). Good luck!

Wow. A lot more work than I supposed. Thank you all very much for the help. I'll make my final judgment call once I get all the parts in.

If you are a do it yourself guy like you said, go out buy the few tools you need and do it. You won't regret it. Just make sure you get the cutting guide from park or something similar to avoid cutting the fork unevenly.

In truth, I find that a tubing cutter with the right (steel) cutting wheel does a much better job than a hacksaw and a guide. (just a little bur inside and out to clean up) When you move on to carbon steerer tubes however, you will have to deep six that and go back to the hacksaw.

You need to be absolutely sure how long the fork must be before you cut. Assemble everything, race, bearings, compresson ring, spacers, stem and the kitchen sink. Get everything in place and tight. Mark, disassemble, double check, think about it.......repeat.....think some more.......and cut.

Whats the old saying , measure twice cut once.

...or that I've never cut a steerer too long.

If you already have a hacksaw and no pipe cutter (which I don't like personally, sloppy cuts IME), it's easy to fashion your own saw guide with a variety of stuff, hose clamps work great. (although I have a Park guide which works well on handlebars as well as steerer tubes...). Just be sure to cut square (again where pipe cutters tend to suck) and finish the rough edges with a file/sandpaper...