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

In my last post on the subject of barometric altimetry, it was discussed that a moving altimeter may report a lower altitude than a stationary one, due to the dynamic pressure of the air piling up in front of the moving cyclist. The amount of this altitude increase is determined by a coefficient between zero and one relating the effective wind speed to the cyclist speed. Before that, I described how I'd combine a barometric altitude signal with a GPS signal to get the best of both: the short-term responsiveness and reliability of the barometric altimeter with the general accuracy of the GPS (at least when there's a signal). I'd applied this to randomly generated data , which were derived using a simple pacing model with the bike power-speed equations. The effect of dynamic pressure on measured altitude is simply derived from Bernoulli's equation : Δz = ‒½ ( k dp v )² / g, where Δz is the error in altitude, v is the speed relative to the wind, k dp is the coeffici...

My torque test I described in my previous post indicated something was wrong: obviously the powertap was reporting substantially less torque than I was applying. So something was up. Of course, it could be one of three things: with my hub, with the rest of the drivetrain, or with my test protocol. An example of a test protocol problem would be error in determining the weight I'd loaded on the pedal, or a problem orienting the frame, or things flexing in a way which modified the actual torque applied by hanging the weight from the spindle. Lots of possibilities. So when doing experiments, you always want a "control case". It's better to compare the results of two similar experiments than to compare the result of one experiment with theory. So I borrowed a wheel, one I suspect works well, and tested that. Here's the result: It's nice having access to a second PowerTap: these things aren't cheap. You can see from the results that this one tests better i...

I've been depressed at my inability to produce the same power up Old La Honda as I used to. Times were fine, just power was off. A lot can affect times, but power is rock-solid reliable, right? So I finally tested my Powertap, using the following procedure: I filled a bucket, first part way, then later further, with water, in each case measuring the mass (actually, the weight) with my Ultimate hanging scale before and after the test, and averaging. Mass values: first fill line = 9.765 kg, filled further = 12.56 kg, further still = 13.955 kg. I hung my bike from my Park stand. I shimmed the stand so the frame measured vertical with a plumb bob which hung vertical from the top tube. I wanted the string to just brush the down tube. My bike (Ritchey Breakway) has round steel tubes so this works. For each gear combination tested: shift into gear of interest, spinning the rear wheel bring rear wheel to a stop zero torque (hold right button on PT) hang bucket from pedal while holdi...

John Summerson's book, The Complete Guide to Climbing by Bike , is a wonderful reference to some of the best cycling climbs in the United States. But the US is obviously vast, and a national guide, while useful for planning trips, may be less useful than guides with a more regional focus. So he's started producing a regional series, as well. First was a book on the Southwest . This is really good, but is mostly a subset of the national guide, with a few more climbs added in. Still recommended. Far closer to home for me is the newly released California edition . Wow! What a resourse! If you ride in California, this is a must-buy. Even if you find one, just one climb here you weren't aware of, one gem of a climb to add to your "done that" list, the cost of the book is more than justified. And I can't imagine any rider not finding some inspiration here. Okay, now to some details. First, the route profiles... at first I was taken aback at the rela...

Today was the Rodeo Beach 18 mile trail race . Unfortunately, I previewed the course map and I thought I knew where I was going. Sure, the map's crude, but that's no excuse. I have a better map I could have compared it to. Or I could have, err, read the course description . But I thought I knew the route. But after descending Coastal Trail onto Bunker Road I didn't see any ribbons, which served as course markers. Weird. I ran up the road, where I was fairly sure the course went, and still didn't see any. I scanned to the right, where there was a dirt road paralleling Bunker Road. Nobody there, and no ribbons there either. Finally I saw a ribbon ahead on the left -- cool. As I approached, though, a runner appeared almost out of nowhere. When I got there I saw he'd come off a side-trail onto Bunker Road. How did he get there? I thought back to the Coastal Trail descent and didn't recall seeing any junctions. Maybe there'd been a frontage trail ...

SportVelo held its winter training camp Thursday through Friday. Each of the first two days, I boarded a Caltrain Limited from Sam Francisco with my bike, stopped off in either Starbucks or Peets, and easily made it well in advance of the 9:15 am start time for the training rides. Caltrain does fairly well for commuters on traditional workdays. Honestly I don't understand why so many persist in driving. Indeed, as I type this, I'm on the train back to San Francisco from my office in Palo Alto. It's the weekends that're the killer. For various reasons I wasn't able to make the weekend rides, but I would have liked to have the option. This is especially true for Sunday's "Queen Stage". Except Caltrain's earliest train on weekends leaves the City at 8:15. And not only does it leave late, it's slower than any weekday train, stopping not only at all the weekday stops, but additionally at Broadway in Burlingame and Atherton, stops which have...

Cervelo has announced a new special project frame, Project California , a frame much like the R3 and R3-SL except with a claimed mass at a super-impressive 700 grams in size 54. Announced price for the California (which I'll call the "R-CA"), presumably for stock sizes, is $9000 US. Damon Rinard shows the Cervelo Test Team the new Project California frame Now, 700 grams is impressive and all. But I judge mass savings based on the marginal cost of attaining them. Usually mass is confounded with functionality, but on the Cervelo R-series, with identical geometry and similar ride characteristics, I think it's safe to say the upgrade progression is mostly a weight weenie play. So I'll resist the temptation to compare it with the Guru Photon, a fully custom frame of comparable mass at half the price. Maybe the Cervelo is simply better. But comparing to the other Cervelos in the R-series, to which Thor Hoshovd himself claims the ride is similar: frame list price g...