On Bicycles, and.... what else is there?

Strava reports the VAM, or rate of vertical altitude gain, for riders on different climbs. VAM allows comparison of climb efforts on climbs gaining different altitudes. It's correlated relatively strongly with power-to-mass ratio, and is considered a decent gauge of fitness. For example, I may climb Old La Honda while someone in France may climb Col de la Madone . We obviously can't simply compare times, or even average speeds, but the rider with the better VAM is probably the better climber. However, one issue with VAM is that it is easier to produce a higher VAM on shorter climbs. It is well understood riders can produce a higher average power for shorter durations than for longer ones. So you certainly do not want to provide an unfair advantage to those riding shorter climbs. Well, whenever one brings up the subject of the time-dependence of power, the CP model is the first thing to pop into mind. The CP model says: maximum power = critical power + anaerobic w...

Yawn... Seriously: they should have done a pre-release to magazines like VeloNews, Bicycling, etc and implied there were substantial mechanical advantages to what is actually just a paint job. It would have been fun to see how many of the reviewers reported on the "subtly improved shifting", "enhanced brake modulation", or "superior power transfer".

Almost every year, I've helped Kevin Winterfield put on his " MegaMonster Enduro Ride ", which goes back to 1996. It's a sort of unique event: a timed 100 mile (actually 102 mile) ride with checkpoints along the way. It's either a very short Paris-Brest-Paris or a very long time trial, depending on how you view it. The goal was to formalize the competitive side of "century" rides, which are typically inappropriate for "racing" since the courses are not well controlled, but allowing riders to keep a healthy emphasis on endurance and success-in-finishing, unlike the "fast-or-total-loser" culture of bike racing yet without the massive distances of the more serious brevets. The course is simple: out 51 miles, back 51 miles. There's a checkpoint @ 32 miles on the way out (Bitterwater), another at the turnaround @ 51 miles, then back at Bitterwater @ 70 miles, then of course the finish, at 102 miles. Since it's not a mass-s...

My friend John Murphy is rather negative on the proposed "scaled back" Caltrain schedule , designed to reduce expenses in a time of reduced support from the counties. Caltrain, surprisingly, has no dedicated funding source, but rather must rely on the good-faith contributions from San Francisco, San Mateo, and Santa Clara counties. This is because the Bay area has such a hopelessly fragmented transit system. Counting Marin, 511.org lists 22 bus agencies, 6 rail agencies (not counting Amtrak), and 7 ferries. Really it makes a lot more sense for there to be a "Bay Area Transit" agency, since with so many interregional routes (San Francisco to Marin, Marin to San Francisco, between San Francisco, San Mateo, and Santa Clara counties) there's extensive duplication of service, and seemingly arbitrary rules to avoid competition (like SamTrans can't pick anyone up on northbound trips which enter San Francisco). It's a mess. With all of the fragmentation...

Many years ago, Kestrel Bicycles came out with the "Talon" road frame which was targeted as spanning the bounds between triathlon and mass-start racing. There were no wind tunnel data, no scientific tests: it was simply designed to look aero, and who knew if it was or not? Kestrel, who was among the early groundbreakers in building and selling carbon frames, was sold by a Japanese group. However, the Talon survives, both with a standard model and a lighter a Talon SL . It got redesigned for 2009 ( see video review ). I've always found the bike attractive, in part because of its Santa Cruz roots. Years later Cervelo, a long time leader in time trial frames, came out with their Soloist aluminum-frame bike. CSC showed the bike to be quite race-worthy at the highest level, notably with Bobby Julich winning the 2005 Paris-Nice . Then they developed the SLC, a carbon version, for that year's Tour de France. An SLC-SL followed in 2006, and for the 2008 Olympics, t...

I implemented the biexponential filter, along with power filtering, in my motorized segments detection code. This program, along with my other Garmin Perl codes, can be found here . I made a few changes from previous descriptions. One is I changed the anaerobic time constant to 120. This is more the upper end, rather than the median, of typical numbers. This may provide a bit more margin against falsely identifying a segment as motorized. The other change I made was to separate the altitude-smoothing time constant from the anaerobic time constant. Oversmoothing of altitude can result in the overprediction of power when a rider descends small dips. I set the default to 30 seconds. I also added some speed smoothing but only 5 seconds. Without any speed smoothing and there's too much effect from when the Garmin occasionally spits out a single point with ridiculously high speed. But too much longer than 5 seconds and I lost more of the train segments in Italy where the tra...

Linear filters are characterized by their impulse responses. To test my exponential filter algorithm, I created an input data set with zero-value points randomly spaced in time. At zero I put a finite approximation to a unit impulse: ‒0.01, 0 0, 100 0.01 0 I then ran this through my exponential filter in various ways. One way is to run the points in time-forward order. This is the "causal" approach: I'm analyzing data as it comes, and I want a smoothed result as I am receiving data. Also causal is to run the smoothed curve again through the exponential filter. You'd expect this second smoothed result to be even smoother than the first time through, and of course it is. Then there's a single and double application of the exponential filter in reverse time order. You'd expect the result to be flipped from the forward-time order (there's nothing special about forward time versus reverse time which should make the shape different; if it were th...