Best Bike Split Power Course
This may be a long post but am writing it to put this out there for those data die hards and power users -- I think as a tool it could be very useful for predicting bike splits on courses people have not yet ridden as well as using it as an adjunct to pacing the IM bike.
First -- some background -- Best Bike Split is a website that is powered by a complicated math/physics algorithm. They have several pros that utilize it as a too including recent Mt Tremblant winner TJ Tollakson (pro triathlete and Industrial Engineer).
Basically you create a profile and enter a ton of infomation. Weight, FTP, bike weigt, superbike or regular, agressive or moderate aero position -- High end or moderate componets, wheels, deep dish, disc?, latex or butyl tubes, aero helmet etc. All of the data goes into the athlete and bike profile. Then, you load up a course that has GPS data. This can come from a garmin file generated from a computer with an altimeter or from a GPX file generated from Garmin connect or Ride with GPS. The modeling engine will even look up weather data, wind speed, direction, etc. and lnclude that in the model. Then you simulate a race by entering your planned IF -- There are some advanced power tools like limits for certain zone but the model seems to be optimized for a low VI ride so that it will calculate your best possible split. I have already done this for IM Chattanooga course and it estimated a 5:26 split which having ridden the course and compared to my race rehearsals and training seems reasonable.
The real benefit however may be the power course option. After you generate your race model, you export a garmin power course file and load it into your bike computer. Then you select this as a course just like you would a navigation course. The difference is, the program anaylzed the course for elevation change and hill lenght and recommends a power target for segments. 100's of them. Once you start it though, all you have to do is keep in on your lap screen like normal, and as you approach a hill (usually) The computer will beep and suggest a power target for the hill. In general, those recommendations line up will with long hill/short hill/ flat riding guidance. When you get back to level ground -- A short reminder comes up that is usually the goal watts based on the IF you entered. Its not perfect -- It seems to suggest higher power targets for steeper hills than I would plan to ride as well as lower power targets for downhills. I did however test this on my race rehearsal last weekend and using it as a guide (I usually did not go as high or low as it recommended) I rode within 6 minutes of its prediciton (slower) at a 1 watt difference between NP and Avg power on a rolling course with 3800 total gain.
I think there is incredible potential here -- There is an article on their website about Tollakson and his ride at Mt. Tremblant thats worth a read. I plan to use it at Chattanooga but only as a guide-- I'm more confident in my own abilty to ride steady but It is a nice reminder about when to change "gears" when riding with power.
Comments
When planning a race you can run several simulations -- change the IF and see what the effect is on Race time and TSS
You can also set a TSS and it will calculate the IF and VI you need to ride to get closest to the target.
And when riding with a power course -- if you are riding signficantly under or OVER the recommended watts -- It wil beep and flash goal watts at you -- basically a warning to quit riding stupid!
I took the power profile from BBS and tore it appart in major sections (flats, hills, downhills, etc) then I created an outdoor course nearby my home that fit these profile as good as possible (in fact it was a little harder/steeper).
During my last 10 weeks of training I did both RR on that course and also did as many rides as I could on the "important" sections of the course which was a major hill right at the beginning!
It was pretty challenging at the beginning to start every ride with a 25' WU followed by a 40' @ low-Z4 (95%) but it helped me a lot to learn how my body/legs will feel like on race-day.
In the end I managed to have the fastest bike split in my AG by over a minute
Bottomline of all that is that BBS is just AWESOME!!
Mark, when I first messed around with BBS and used my estimated FTP and IF for past races, it spit out times that were surprisingly accurate. Since then, with power, it's been dead-on. When I rode 15NP lower than planned at my last IM, I went home, put in my actual race NP, and BBS gave me my actual ride time within 30 seconds. So . . . it definitely works. For me. Like you mentioned, the only thing that concerns me about the power guidance is that it recommends climbing hills at higher wattage than traditional EN guidance - which brings obvious, potential side effects.
The other feature I like is being able to reverse-plan my next race with it. For example, with a goal to break 10 on a particular course and knowing where my swim and run should be, I take the needed bike split (i.e., 5:15), plug that into BBS, and it'll tell me where my FTP needs to be on race day in order to give myself a legitimate shot. Then, after hyperventilating at what my goal FTP needs to be, I get to work.
For me what was interesting was that entering my very unfit state data from May this year when I last raced there, BBS showed that on the steepest hill on the course (it's a 2 lap course) I needed over 230 watts whereas my FTP was about 200 watts. That explains why I faded so badly on the second bike loop and the run was a nightmare. I could hardly get up the hill standing and pulling on the bars.
I had to walk up that hill on the second loop.
Even if my FTP was 230 watts and my weight 60 kgs (it was 72 in May), BBS still shows I need to use more than FTP to get up that hill. Based on this, I am going to walk up that hill both times next May.
The guy (PhD in Math, I believe) that does the math and tech stuff behind it, one of the founders, is a member of my local tri club as well. Real smart fella.
There's more cool stuff coming too, from what he told me.