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

After the data presented by VeloNews on the effect of going from 23 mm to 25 mm tires, at the same pressure, on vibration reduction (measured with accelerometers: see this post) I was inspired to get fatter tires for the MDR ride (which I described last post). Bicycle Quarterly has published several reviews and tests of the rolling resistance of randonneuring tires, and the Gran Bois tires, "hand-built" by Panaracer in Japan, have always tested well. Jan Heine, the publisher and main contributer to Bicycle Quarterly imports these tires and sells them through his web-based retail business, Compass Cycles , so can be said to have a profit interest in reviewing these tires positively. Neverthless, his reviews are well written and his tests are well documented, so I had good reason to believe him when he said they are supple, have good rolling resistance, and are comfortable. When I saw them for sale in Box Dog Bikes in San Francisco , that sealed the deal. Bicycle Quarte...

The happy group at the start of MDR. This past weekend I did the "Memorial Day Ride" ("MDR"), a supported bike tour between Los Gatos and Santa Barbara organized for the past 22 years by Janine Rood. The route alternates between the original "coastal route" and a newer "inland route". The coastal route, held on odd years, follows Highway 1 through Big Sur while the odd-yeared inland route tours the parched hills of Hillister, Pacines, Bitterwater, and King City on the way to Cabria and San Simenon. From San Simeon to Santa Barabara the two routes share the same final two days. 2011 being odd, this was a coastal route year, but the same landslides which diverted the Tour of California from its planned Big Sur passage did the same to MDR this year, so inland it was for the second consecutive year. So odd and even switch: next year will be coastal, Caltrans permitting. The inland route is 370 miles or so in four days: a long first day of 1...

Quick post today..... I estimated the power taken for Contador to do the climb to Nevegal, which took him 20:58 from the checkpoint at the base of the climb to the summit: 600 meters climbed in 7.30 km for an average grade of 8.2%. For direct comparison with Horner's Sierra Road climb I used the same numbers: 65 kg body mass, 6.8 kg bike, 1.5 kg of other stuff, 0.32 m² CdA. I reduced rolling resistance from 3% to 2.5% since Contador was on time trial tires. I still assumed 3% drivetrain loss. I used a power-speed model including inertia. I assumed he started the climb at 40 kph. The result: 6.24 W/kg. This is lower than the 6.56 W/kg I had for Horner on Sierra Rd. Horner's VAM was 1916 m/hr while Contador was 1750 m/hr. Of course it's not a fair comparison as Contador had finished two brutally tough stages immediately preceding the rest week the day before, and may not have fully recovered. It seems riders aren't having rest days as productive as the...

After much speculation and indirect guessing, I finally got a time for Chris Horner climbing Sierra Road during stage 4 of the 2011 Amgen Tour of California. Recovox News VeloNews posted Rory Sutherland's power data , with analysis, for the climb. Rory started the climb in Horner's group and finished 1:15 behind. According to the article, Sutherland's time was an impressive 18:02. However that puts Horner's time at an amazing 16:47. I'd put maybe 2-second error bars on that number. For example, if Sutherland hit the base of the climb one second after Horner, then Horner's time would be one second longer. But I'll stick with this estimate. Sierra Road climbs 536 meters according to my numbers. So plugging that into Chris Horner's 0.280 hour ride and you get a VAM of 1916. Generally in the Tour de France if you see a VAM in excess of 1700 that's extraordinary. 1916? But in addition to overcoming gravity when you climb (producing ...

This past Wednesday I took a "long lunch" to go watch the Tour of California stage of Sierra Road. As a consequence, I had to work late and didn't get home until after 9pm and had to skip my planned SF2G rides that week to still get a project done, but it was all worth it. I even went in for a bit on Saturday. But you can't take races like the Tour of California for granted in the United States. History has shown over and over that each year may well be the last. I rode with some SF2G buddies to just before the summit of Sierra Road. There the road was blocked for some reason, even though it was still an hour and a half to an anticipated finish. So I was denied the last 100 meters. The climb was fun: I was enthusiastic at the start, dodging other riders, caught up in the crowd, until I looked back and realized I was in my 34/21, a gear well beyond my present fitness for this hill. I backed off to the 34/23 and took it easier the rest of the way, even thoug...

Tomorrow is only the third summit finish in the history of the Tour of California, the first two being the San Francisco prologue from 2006-2007 which finished on the top of Nob Hill. Tomorrow's climb is a bit tougher... 2007 Low-Key Hillclimbs I first encountered Sierra Road in Grant Peterson's fantastic Roads to Ride South, a book of route profiles of Bay area climbs from the 1990-era. It became for me an obvious candidate for the Low-Key Hillclimb series which Kevin Winterfield and I organized for the first time in 1995 . And the series will revisit it this year, in week 2 . My next encounter was when I did the Devil Mountain Double in 2000. That was quite a different experience, as it came after having already climbed Mount Diablo, Morgan Territory Road, Patterson Pass, Mines Road, and San Antonio Valley Road. Post-bonk, with tired, legs, it was an exercise in survival. But I did, and finished the 200 miles, albeit after dark. The Tour of California had the br...

I'm really enjoying the recent series of VeloNews bike test articles. First it was aero mass-start road bikes ( April 2011 issue ) and now it's "endurance" bikes ( June 2011 ). This one is especially interesting because while there's already plenty of windtunnel data out there, vibraton data is less readily available. Wind tunnel tests are extremely trickly because the result depends so strongly on the size of the bike chosen, what's bolted on it, and the position of the rider. With vibration testing, we're getting closer to fundamental engineering, and I would hope the results would tend to be less dependent on assumptions. VeloNews isn't the first to do such tests, of course. I've already commented on Champoux's work in which he analyzied the spectral distribution of vibrations transmitted to a bike frame using a treadmill with a bump attached. Hastings did a study , also with a treadmill with a bump, at M.I.T. comparing old Cerve...