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

I've never taken my Powertap wheel with me when traveling with the Ritchey Breakaway because of the bulge in the hub. When packing with the Ritchey-recommended method ( see Oleg's blog post ), in which the rear wheel goes in first with the cassette in the bulge in the case, the front wheel goes in immediately after, each hub fitting in gaps of the spokes of the opposite wheel. Wheels go first in Ritchey packing method. Note hubs extend between spokes. ( Oleg's Cycling Adventures ) The Powertap wheel, however, has a bulbous extension on the non-drive side of the hub which prevents them from extending between gaps in the spokes. Without that, the stack height of the wheels is too large. So for years I would just do without the Powertap when traveling. But then I saw Oleg's post on packing the Ritchey using the S&S case method . I was skeptical at first, but sure enough, it all fit without problem. I'm spatially challenged, so needed check, double chec...

The plan: after running my 50 km race in April, the plan was that I'd do some climb workouts to find my cycling legs again, ride the Memorial Day Ride (MDR), a 4-day supported tour from San Jose to Santa Barbara, to provide the base, then top it off with some hard climbing to get my top end. Running to cycling transitions are easier than cycling to running, in my experience. And running prepares you for the sustained effort of climbing in many ways better than riding does. I'd been able to run essentially continuously for 5+ hours at the Woodside Ramble 50 km. All I needed to do was to push out my top end and I'd be in for a strong Diablo. The truth: I had some solid climb workouts, albeit slow, before MDR. MDR left me tired, compounded by other life pressures like work, looking for a new place to live, and finally dealing with the process of organizing my life to move. My weekends were essentially dead, and my Caltrain commute is crippling to my weekdays, leaving S...

After the last comparison, which was a ride with some steep hills in San Francisco, I did a few more rides comparing Vector to Powertap. On that previous ride, my maximal power curve had been somewhat depressed on the Vector. Further investigation showed it appeared to be due to two points where cadence anomalously dropped on the Vector (but not the Powertap). Since Vector multiplied force by cadence by crank length to get power, if any of the three is off, the power is off. The first of these two rides was a spin around Mountain View at lunch, stopping along the way to drop a package at the post office, then pick up some cherries at the local market (Ava's), then after a bit of a loop, a stop at Trader Joe's for figs and apricots. I made good use of my handlebar bag, combing some solid power efforts with fresh summer fruit for the afternoon. Here's the maximal power curve from that ride: The next day I rode into work with SF2G, the Dawn of the Dead variant of Bayway....

Last time I showed a comparison of Powertap to Vector power with a least-square line through the points. I noted this was "hard to interpret". Here's why. A traditional least-square fit begins by assuming that the x-values are perfectly known, the y-values are uncertain. It additionally assumes that the y-values are normally distributed, with a Gaussian probability distribution, with the error distribution the same for all points, or with variances inversely proportional to the weighting factors for a weighted least-square fit. This seems like a lot of technicality, but it introduces subtle biases in the result when comparing two values whcih contribute relatively equally to the error. For example, consider my power comparison for the Garmin Vector to the Powertap: The slope was 0.97. Therefore, if I flip the axis the slope should be 1.03%. If the Vector is 3% lower than Powertap than the Powertap is 3% more than Vector, on average. But that's not what I ...

Today was my third consecutive week of Old La Honda. So I moved the Powertap wheel to the Ritchey Breakaway and took that to work. At the start, my legs felt fairly good. I'd ridden into work Tue morning (75 km) with some moderate intensity. On Monday I'd ridden a short ride with some brief efforts, mostly on the flats, partly to compare Vector to Powertap on the Winter Allaban. Sunday I'd done nothing. Saturday I'd done some steep hills, again to compare Vector to Powertap. So there'd been no really depleting rides in the bunch. If I had one thing against me my calories the previous day had been on the low side, considering I'd ridden in. It was nice seeing my old friend Randy at the start. He'd been traveling and it was good hearing about that. Also there was Chris & Greg, two very fast climbers. Kieran wasn't there, nor was Mark. This was to be the last Wed noon ride before the NCNCA championship race on Saturday, up the north face of Mo...

Last time I compared Powertap to Vector on my Winter Allaban, I had failed to properly set the crank length on the Garmin 800. I'd set it on the Vector, but the menu item on the Garmin is a bit tricky to find, as it only appears when it is in communication with a Vector, so if you scan the menus without activating the Vector and pairing the Edge to the Vector you'll never see it, as I did not. I actually first confirmed my Edge was asserting the wrong cranklength by running the settings.fit file through fitdump. But this is a digression. I basically repeated my first calibration ride, heading steep 14th Street to Buena Vista in San Francisco and doing one-legged climbing on a more gradual grade, then riding home and doing a sprint. I previously did three comparisons where the maximal power curves of the Powertap and Vector were remarkably coincident after I scaled one of the powers by an empirically determined factor close to the 85% value which I later discovered was the r...

Thursday of both last week and this week I did a sprint workout. This involved cruising over the Sunnyvale Trader Joes, buying some rice tortillas, goat chedder, and organic blueberries, stuffing them in my pocket, then cruising residential Sunnyvale streets to the Steven's Creek trail. Along the way, on roads of relatively smooth pavement and with enough length between intersections, I do some sprints (4 each of the weeks). Then I cruise the Steven's Creek trail back across the freeway mess and do a few more (2 the first week, an extra the 2nd week when I sprinted for a green light). I'm not sure how much these help the sort of riding I do. But I think improving the top end potentially offers benefits at lower powers, as well as if I need to put in hard efforts to close gaps. I've not been a position where I was sprinting to win races in quite a long time. But sprint repeats challenge multiple aspects of riding: muscle strength, neuoromuscular coordination, pedal ...

After last week's disappointment on Old La Honda, I did a sprint workout the following day (Thursday), then rode in at tempo on Friday with Jason. But there was no riding through it. I was cooked. I needed some days off. Saturday & Sunday were total "rest" (actually doing home stuff which absolutely needed doing). Monday and Tuesday I was still feeling fatigued, so I took the train to work, riding only to-from the train. Finally, today, I felt energetic again, ready for another try at Old La Honda. Like last week, Greg and Kieran set a ferocious pace from the start, with Mark in tow. I let them go. But unlike last week, I wasn't in a chase pack, but rather solo. But also unlike last week, Mark didn't try to hang with the leaders too long. He dropped off and paced himself very nicely the rest of the way. And the whole rest of the way I chased him. I focused on trying to maintain a steadier pace this time: keep a cap on it at the beginning when I felt ...

I typically use my Powertap on training rides, but when racing, I've not done so since I placed third Ross's Epic Hillclimb up Pine Flat Road in Sonoma back around 2008 or so, At the climb, I'd decided the added weight of my Powertap wheel was worth it for the pacing advantage of power. Unfortunately, my battery died on the start line, so I carried the substantial extra mass of the Powertap up the hill for no advantage. Despite the lack of power, though, I had arguably the best climb of my life, staying with a critical surge I might well have not gone with had I been pacing off the meter. That surge led into a flat/slightly descending part where being with the group was a critical advantage. When the climbing began again, steeply, I felt as if I was going to crack, but then most of the others cracked more. Without the weight of that wheel I may well have been one place better. But power is also useful for post-ride analysis. But for that, I rely on the standard power...

I did the Noon Ride again on Wednesday, up Old La Honda, and I had high hopes. I'd had a recent block of training since the last time I'd done it 6 weeks prior , including the 4-day Memorial Day Tour, always good for a fitness boost. But I'd been feeling fatigued in the 1.5 weeks since the tour. Wednesday, riding out to the Noon Ride start, was the first time I felt legitimately good. Not frisky, race-ready good, but "I can climb Old La Honda" good. At the start, Maciek from SF2G asked what my goal was. "I've got to do 18:30", I told him. I figured just lay it on the line there. 18:30 is a decent time on the Ritchey Breakaway, which I was riding. With Powertap wheel, no bottle, no GPS, no toolbag, but with pump and two cages it's 18.32 lb. That probably made it the heaviest bike on the ride by a decent margin, but still, not too bad. Hitting the base of the climb I was near the front, but got pushed toward the back when we had to wait fo...

The plot thickens... Another day, another ride. This time I made sure to do a static zero test before the ride. I further checked that I had the latest firmware in my Edge units (Mac WebUpdater says I did). I was full of hope that the crank length fix had corrected things. So I set off on a ride to fetch new contact lenses, but where I took "scenic detours" up five significantly steep, significantly painful climbs in San Francisco. For the record: 17th from Market to Twin Peaks (and on to Twin Peaks summit), Sanchez from 17th to 18th, Church from 18th to 21st, 21st from Church to Sanchez (these two are contiguous, but I took a break in between, not initially planning to ride 21st, which is daunting), and finally, just because I felt like I could, the ever-painful 22nd from Vermont to Carolina. No luck. My suspicion now is that the head unit is overriding the crank length setting. Issue is I don't know how to change the crank length in the head units. In the 510 ...

Last time I did a comparison of my Powertap versus Vector. I'd had strong reason to believe the Vector was reporting low, and the test confirmed it. The maximal power curves lined up fairly nicely when I multiplied the Vector power by 0.84 (emphasis on fit to high powers). Since the Vector should measure more power than the Powertap, this indicated an error somewhat greater than this. You'd expect the Vector to measure more power, because the Vector power includes power which doesn't make it to the rear hub and is instead lost in the drivetrain. This power loss includes losses which are proportional to load (like bending the chain under a high-tension state at the top of the run) and losses which are independent of load (like spinning the pulleys). The result is that drive train losses, as a fraction of total power, are higher at lower powers than higher powers. What I saw was consistent with this, which was a good sign. The obvious candidate was that I'd not inse...

On my relatively new randonneuring bike, which got its first serious long-distance test in the Memorial Day Ride (MDR) this past week, I've been using Garmin Vector Pedals I was lucky enough to get. The Garmin Vector, of course, offers the advantage of "true" left-right power, since it is effectively two independent power meters, one for the left, one for the right. But even though I've had the pedals on there for awhile, I've been ignoring the power data. I didn't trust it. It's not that I didn't think the Vector is a good product, but rather I didn't trust the installation decision I made to not install any washers. Of course, I could have just added the washers, but that would lose interesting data. I wanted to do a direct comparison with Powertap to quantify what the reduction in power, if any, was. Being generally lazy about this sort of thing, I procrastinated... until today. In this post I compared power data versus climbing rate on ...