Bonmaklad wrote:
Hey Everyone, Quick question about estimating speed on a cycle. Swimming and cycling there is a lot of resources but I can't find cycling.
If you want to do a 2:40 90km cycle as part of a 70.3. I have assumed you need to do a 2:25 by itself (feel free to stand corrected)
so what would the estimate or conversion to the following be?
40km
20km
10km
many thanks in advance.
The two main things you would need to understand are
- The power you are able to hold over different period of time
- You coefficient of aerodynamic drag
There are other factors but those are the biggies.
Some people can generate big watts for a short duration and will do really well on a 10km TT. Others can hold power for longer time and will do relatively better on the 70.3 course
Some people have a great CDA that impacts things much more at higher speeds (like in a 10km TT) vs a slower 90km course
That being said you can do some back of the napkin calculations
Let's say your FTP is 240w and your CDA is .3. <pink> Most STers have double that FTP and half that CDA </pink>
A rule of thumb is you could do 105% of that for 20min so 252w. It takes this 252w to go 38.5km/h (assuming crr of .004, air density 1.18 bla bla bla). 15kmTT would be a good test.
If your FTP is 240 you can probably do a 40km TT around that power. It takes that 240w to go 37.8km/h (same bla bla)
If you want to pace a HIM conservatively at 78% of FTP that would be 187 watts, It takes 187watts to go 34.5 km/h which would bring your HIM to 2h36min.
So
38.5 for 15km TT
37.8 for 40km TT
34.5 for 90km HIM
Very rough calculations but with a power meter you can test, refine, model and do some pretty good projections