ElJamoquio

Much more to follow... eventually, I'm pressed for time right now.

The 'good' news is that the model is reasonably insensitive to an arbitrary maximum power constraint - in other words, going to 600 watts for a small amount of time isn't going to help much.

There's only a predicted 8 seconds difference between the two power profiles. I didn't get a chance to finish the 'smoothed' power profile yet.

ElJamoquio

Hold on (a little)... changed my normalized power calc's a little and got the delta to ~15 seconds.

Enthalpic

Very nice. I like how none of the prescribed power outputs are all that unreasonable (for DrWJ) and that there is some <FTP recovery in between each of the “attacks.”

waterrockets 

Nice work there. Cool.

waterrockets 

You know, if you packaged that up into some software, and someone (me?) wrote an app for the Qranium to follow the prescribed profile, we could tell riders when to spike and how much. When they see a hill coming, look down to see the target, then ease into it...

patentcad

I'm impressed that anyone here understands the Original Post. You guys are all bike weenie rocket scientists.

KendallF

now that might be the ultimate power geek app. Collaborate, you two. I'll be a beta tester.

CastIron

timmhaan

i opened the thread, said "WTF?" and then pressed the back button. not sure why i returned...

Racer Ex 

It's like Jens says... "All the blood is in your legs and your brain is empty".

garysol1 

Can someone in a hundred words or less tell me what I am looking at and what it means?

ElJamoquio

Put out more power on the uphills; and in a relative sense, rest on the downhills...

....and you gain 15 seconds over your competition, who presumably is putting out roughly constant power.

garysol1 

easy enough even for me to understand ...thanks

esammuli

If he were to vary how hard he goes based on the terrain he would be 15 seconds faster than if he maintained a constant wattage for the whole course.

-The first graph shows the course profile
- The top right shows how he should vary his wattage for a given section of the course
- The bottom left show the speed difference when comparing steady vs. variable wattage
-The bottom left shows how long it will take to go a specific distance. The variable pacing is faster.

garysol1 

Is this figured with a readily available program or is ElJamoquio just that damn smart?

ElJamoquio

It isn't that hard to write, Gary. But I haven't made it very user friendly.

ElJamoquio

I'm game, WR; but this stuff is on the back burner compared to my hobby (I ride a road bike from time to time) and my job (which pays for my hobby). Right now it's not even in a good-enough version to ship to someone who knows what's going on.

curveship

ElJ -- Neat stuff. I had thought of doing something similar as a web app. A couple questions coming out of my own thinking about the problem: what's your optimization algorithm? And do you account for inertia?

ElJamoquio

I account for inertia.

I optimize by artificially increasing wattage, and seeing which points have the most 'value'. I then scale up or down the wattage as the case may be.

Enthalpic

How long does this take computationally?

In quantum chemistry labs we had to model small molecules using Maple programming and a iterative algorithm - the thing took forever to run. It was bloody comical… wait forever to get back a tiny text file containing the couple bond lengths and angles you wanted. To actually get your homework done you had to send jobs to other computers in the neighboring labs.

GatorFL

We do nuclear criticality calcs on clusters that take 12 hours. The only cluster they let us undergrads use broke last week. Laptops are great for BF, but not so much so otherwise....

waterrockets 

Funny, my cube neighbor manages ACML for high-performance computing (Crays and the like). You're probably a customer

patentcad

Can anybody seriously regulate their power output that closely? Since I started riding with a PM, it helps me sustain power @ times, but it's often how bad I'm hurting in any given moment or the terrain that will determine if I'm cranking 200 watts or 400 watts. The PM tells me I'm off my intended curve and helps me get back on it - when I'm able to. That is not always the case. My power output looks like a seismograph, not like the smoother lines in the charts above.

Hocam

That makes sense because pedaling on the downhills will create more air resistance due to the higher speed than on the flats. Basically you get fewer mph/watt than using that power on the up hill where wind resistance is lower.

waterrockets 

Yes, it's just another part of the sport. I was able to do this before I had a power meter. It's kind of like when you realize you can put spin on a ball in a racquet sport. Just practice it, and you'll see it's not that tough.

Here are two hill repeats I did on the same day. The first one had a goal of even pacing until the finale (note the speed swings and the power doesn't for most of the climb). The second one, I did an exaggerated attack of the steep sections, recovered on the shallows. I hit nearly the same average wattage (415W vs 413W).

What's interesting is that the 2nd one is 12 seconds faster at (4:46 vs. 4:34), with 2W lower average.





For another pair, I went for the same time, with different approaches (instead of the same wattage). These were both on the same day as well, and I ended up getting the exact same time with a 15W difference. When I varied my effort, I was able to hit the same time with less energy (115kJ vs 110kJ).