Hi im doing Ironman Copenhagen in few weeks ive been training on trainer road for last few months, but im struggling to know what power i have to hit to get my time,
Im hoping to ride the 180km bike in about 5 hours 10 mins,
im 5’8 73kg and my FTP is 278 so what kind of watts do i need to hit ?
Too many variables to say. Presumably it’s pretty flat in Copenhagen? What’s the surface like? What will the weather be doing? How aero is your position? What rolling resistance are your tyres? Will there be any traffic on the course (cars or lots of cyclists) that might give an aero pull?
I’d suggest you look at this the other way round - given the training you’ve done, what is a sensible power target?
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there are a lot of charts online for what % of FTP you should target
For IM its 65% to 80% generally, I think most amateur racers will target closer to 65% (for you 181 watts). There are some examples of the charts in this thread Ironman and Half Ironman Percentage of FTP on the Bike
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Best bike split is what you are looking for. You put in your FTP, your target % you want to hit like the 65% above, or a goal time, or a speed? I think there are a few options now. It will then spit out what you need to do over each section of the course to hit that time or speed goal. You can then put that into your head unit and run it like a workout with target power for each segment of the course if you want. Or you can just figure out about what you need from it and try to come as close as you can. like if its flat just know what the target avg power was for hte course and keep an eye on that.
I’ve used it for a few half ironmans and put in that I wanted to hit a % of FTP avg for hte course and had it spit out a time. I did it as a course and tried to follow it a few times but it was more hassle than it was worth to me. I have come close to hitting the time it spit out a few times, like within minutes, but every time I have done it on fewer watts than it said so something wasn’t exactly right whether it was my drag info or even PM error.
The last part is just to point out that it isn’t perfect but is what you are looking for.
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Thanks il check that out
Thanks looks like im too far away from what i tought
5:10 Bike is pretty dang fast, what made you pick that time?
there is a lot of people who want to ride fast in an IM, and not very many who can ride fast and run fast. its trying to find the right balance, riding a bit slower for most, but being able to run the entire run (not having to walk due to being blown up) is faster overall.
I am not racing right now, but playing golf and its so similar in some ways. The old golf adage is “drive for show, putt for dough”. being able to run is like good putting, its where you will make the big gains IMO.
This thread also has a ton of talented people who can help! The Triathlon/Ironman Training Thread 2025
Copenhagen has one of the fastest IM bike courses as its completely flat
Its 1100m of elevation i think
I was hoping to do that in Sweden last time but got a bad headwind and struggled, ended up with 5:23 i think
There’s your best answer. How many watts did you average for 5:23 in Sweden? You’ll need about 10% more for 5:10 if the course, conditions, position and equipment are similar.
Never had a power meter back then, didnt take the cycling too serious, only start using power last few months:man_facepalming:
I agree with others that Best Bike Split is a good tool for something like this but for this sort of thing, chasing a time and making your watts match is a good way to over bike and just blow yourself up.
I’d probably suggest starting from your own performance in similar 4+ hour workouts and then maybe using BBS to fine tune from there for the specific course.
Also, unless you’ve done a bit of testing then BBS will at best be estimating your CdA and rolling resistance values so it might not even be right.
But if you’ve got a 278 FTP and BBS says you need to do 250W to meet your goal time but you’ve never done more than 200W for that amount of time then I’d err much closer to the 200W than the 250W. (Just as an example)
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