You could do the ironman on either type of bike. Depends on a number of factors. I have a road bike, and a steeper - angled tri bike. The road bike, I find climbs better, and is more nimble when riding on a tight course or in a group. The tri bike for me feels more comfortable in aero position for longer periods of time, and is a little easier to run off of. It's awesome and fast on a long course that doesn't have a lot of tight turns. If your ironman has a very hilly course, you might consider a road geometry. If you like doing group rides a lot, and are going to use the bike for other than triathlons, you might consider a road geometry. Maybe try a couple of bikes out at a bike shop, and get a sense of what the difference is. In the end, you will probably get a lot of different opinions from people you talk to, but comfort and fit - especially on iron distance is most important.

I agree with Argonaut66. I live in central Maine, where hills and curves are par for the course, and flat sections of road are rare. I train and race on a Giant road bike and wouldn't trade it for a tri bike unless I moved to a part of the country where the topography is considerably different than it is here!

Weight of the bike will become a more significant factor than aerodynamics if it is a hilly course, like say the St Croix half ironman. I have a cervelo p3 tri bike and a trek 5200 carbon road bike, and the trek would be better for the hilly half ironman. It is of course modified to move the seat position forward, and lower the forward body with angled seatpost and cowhorn/aero bars/ bar-end shifters.

You can get a lot of the tri bike feel and features on your road bike by using a profile design type fast forward angled seatpost which will put your body position forward 2 to 3 inches. A longer stem might be in order also to achieve the most aero and best hip angles possible. Making these changes to your road bike can give you a better idea of how you are going to feel on a tri or time trial bike.

Lastly, don't forget that it is the training to ride aero that is more important than equipment. Take the spacers out from under your stem and get the stem agle pointed downward as much as you can. Train yourself into holding aero as long as possible, which will be difficult and hard on your low back at first..

IM MOO 06 will be my first ironman-distance race as well, and I will be riding a tri bike there. Having looked at a lot of pictures, I would say that the vast majority of riders at previous Madison races have ridden tri bikes, but there were plenty of road geometry bikes as well; if you chose your road bike you would not be alone.

There are definitely advantages to both types of bikes on a course like this, so I say go with what you are most comfortable with. My tri bike is the only good bike I own so that's what I'll be on. Regardless of which way you go, IM WI is less than eight months away, so you need to make a decision soon. Pick a bike, get properly fitted, and stick with it.

Something else you might want to consider is the age of your bike. You mentioned that it was older...how old? Buying a new bike might not only get you a new frame, but also all new components. You don't want to go through all the training and sacrifice of preparing for your race, only to have something to **** out on you at mile 80. Having all new componentry is an insurance policy against a day-ending mechanical.

And, more than anything any particular bike can do for you, YOU need to be prepared for a long and grueling day on the bike. Practice hills, practice in the heat and wind, practice going long. People suffered on that course last year...over 200 of them didn't make the bike cutoff. Commit right now to not be one of them in September 2006.

An Ironman represents a huge investment of your money and your time. Do what it takes to get there and enjoy your day.

Best of luck! I'm off to go ride my trainer.

mm

I can't believe I even still see this debate. If you look at the times from Kona (I know it's a little flatter there), the average person on a tri bike rode 10 minutes faster than road geo, and RAN 5 MINUTES FASTER! It's not just a bike race it's a triathlon.