Thursday, September 30, 2010

Ghisallo to San Primo

Onward from Ghisallo....

After climbing to the church, spending plenty of time at the church and at the adjacent museum, then enjoying a delicious panini & frizzante lunch at the cafe, I was ready for more. Most riders consider the church to the the finish of the climbing, but really it's just the first course. A narrower, steeper, yet still excellently paved road continues upward, to San Primo. Just follow the sign...

start of climb

You can see the data from my ride on Strava. As of now, I'm the only one to have loaded data for the segment (which I defined) which extends from the junction at the Madonna to the Y-junction at San Primo. I initially continued from here left onto a dirt road, which led me to this sign:

junction @ top of Strava segment
Beyond here the road became too rough for comfort with my 23 mm tires. The profile to this point:

The dirt is just the final few hundred meters. Using the Low-Key hill ranking index, the full profile comes out at 103 on the Old La Honda = 100 point scale.

Go the other direction at the Y and the road is flatter, smooth gravel which leads to a parking lot. Along the way is this luxury villa:

San Primo villa
Great stuff, and my ride for the day had only really just begun.

As I said last time, the combo of the climb to Ghisallo and onward, without pause, to San Primo would be a really good one. Then save the church visit for the descent back from the summit. Hopefully someone will sign up for a Strava account and define it. With over an hour break between the two halves, I am unworthy.

Wednesday, September 29, 2010

Gazzetta dello Sport on Bola Del Mundo and Vuelta a España

After I'd reached Madonna del Ghisallo and visited the absolutely incredible church and museum, I saw some riders emerging from another building. Ah, that must be the bar and cafe, I realized, which was soon confirmed. What a difference between the US and Italy, that in any local snack bar you can get something as sublime as a delicious panini made with fresh bread, formaggio, lattuga, pomodori, and with Gazzetta dello Sport as a side:

Let's take a closer look at what Gazzetta highlighted in that article, on Mosquera's dramatic stage win at Bola Del Mundo in stage 19 of the Vuelta a España:

Wow -- a VAM of 1800 meters/hour for the final 3 km of a brutal climb three weeks into a stage race. But the roundness of that number immediately rang suspicious...

Consider first the quoted stats: 12% average for 3 km. That's 360 meters. So how long does it take to climb 360 meters at a VAM of 1800? Simple: 1/5 of an hour = 12 minutes. But it says it took 12:53, not 12:00. That's some really sloppy rounding, partner! 12:53 corresponds to a VAM of 1677 m/hr, well shy of 1800, and much closer to the stated average for the full climb of 1460 m/hr.

But maybe the problem is with the 12%, not the VAM itself. So I checked Climb by Bike, a fantastic resource for these things. It says the final 3 km, the steepest of the climb, interpolated from the plot, average 11.4%. Then I checked the profile from the Vuelta (see CyclingNews) which shows the final 3.3 km average 11.5%. I'll take the Vuelta number. Then we have 345 meters gained in that 12:53, a VAM of "only" 1609 m/hr. So the 12% is also a problem (but consistent with listed precision), but the problem is it's too high, not too low. Gazzetta is even further off.

Now a VAM of 1609 is simply amazing. But it's a long, long way from the 1800 number the article quoted. There's been a lot of discussion (see, for example, Science by Sport, along with their earlier post on Contador) on how VAMs in the climbs in grand tours have dropped with the recently increased scrutiny against blood boosting. So the data at the Vuelta, despite what the Gazzetta nominally shows, are consistent with this claim, especially considering how VAM tends to increase on steeper roads due to the decreased influence of rolling and wind resistance.

Still, lets not fret too much over the details. Here's a daily paper which even tries to provide VAM, every savvy climbing fan's favorite statistic. Panini and Gazzetta is rivaled only by fresh espresso and Gazzetta. Life was good in Italy.

As an aside, the article notes that Vuelta champion Nibali had a 36/29 for this climb, further evidence that even on steep stuff, the best way to be fast is to keep the legs spinning, rather than "power through" with a big gear. Another salvo against the bias that 110 mm BCD "compact" cranks are only for "recreational" riders.

Tuesday, September 28, 2010

adventures in Italy: Madonna del Ghisallo

I was in Italy for a bit over a week and brought my trusty Ritchey Breakaway. I really love that bike, steel frame and all. It's relatively bomb-proof, packs nicely into its near-regulation-sized travel case, and rides really well. It's no weenie @ 17.5 lb or so with clinchers and first-generation SRAM Rival, but then again 17.5 lb ain't so bad either. I wouldn't use it for a hillclimb time trial, but it's certainly a race-worthy bike.

So my first target was the legendary Ghisallo climb from Bellagio on Lake Como. The Ghisallo ends at the Madonna del Ghisallo, the internationally famous church dedicated to cyclists.

The climbing actually begins deep in the center of Bellagio. However, here's where I consider the true climb to start, at the 9 km to go sign at the traffic circle (below this traffic is too heavy):

the start of the climb
the start of the climb proper

From this point, here's the route profile, riding along the main road as opposed to the alternate back-road ascent:

Ghisallo route profile
Not quite 9 km by my GPS, but close enough. The climb rates 113% on the Low-Key Hillclimbs rating scale, where Old La Honda is by definition 100%. Note the substantial descent along the way: as a result the rating is almost as large just riding the first portion. But to do that would be to miss some of the best climbing. Traditionally it's said to be 14% maximum grade, but you can see from the profile any 14% grade isn't sustained for long.

But wow -- what an amazing experience! I passed three Italian randonneurs on the way, the only cyclists I encountered during my climb on that Tuesday morning, but later on my ride (after stopping at the church and the associated museum) I was humbled by an extremely fit looking guy with an SRM: an obvious racer.

summiting Ghisallo (staged)
staged shot of summiting the climb (I put my camera on timer and then recrossed the line, slowly)

Here's the segment on Strava. My goal had been to set the KOM on this legendary climb and I succeeded. However, Strava hasn't yet caught on in Italy, but when it does my time won't last long. Still, it's really nice to have reached my goal on what's a super-legendary climb.

Merckx's Merckx
Merckx's Merckx with an honored position inside the church

So all you riders in Italy: sign up for Strava and start posting that GPS data! I want to see some real numbers for this one. It's an absolutely fantastic climb: steep sections, gorgeous scenery, easily accessible by train and ferry, smooth pavement, and what a reward when you get to the top: the church and the museum are almost worth a trip to Italy on their own.

Afterwards I climbed further to San Prima. This is also a rewarding climb, and in combination with the climb to the church makes for a nice combination. But how can one not stop to admire the church? But I'm sure someone will soon enough post a Strava segment for the two together.

Monday, September 13, 2010

letter to the editor of Palo Alto Post

Every once in awhile I get fiesty and feel the impulse to fire off a letter to the editor of a local paper.

Back in the day, this required actually printing (or before that, typing or writing) an email, finding an envelope and stamp, and deliberately mailing it. These days, however, it's click-click-click,CLICK, and you've fired off your reactionary diatribe to take its place in the ever-increasing annuls of journalism.

Anyway, returning from the Fremont Peak Hillclimb yesterday, my ride made an unfortunate choice of taking 101 north, and I forgot to check 511 for traffic conditions. Due to a horrific accident on the road 7 hours prior, traffic was appalling, and we sat in walking-pace congestion for at least 45 minutes. This partially inspired my response to the Palo Alto Daily Post's latest editorial blasting high speed rail.

Here's my letter:

Palo Alto Daily PostThe 13 September Post editorial, Take a Stand, warned against how high speed rail could "devastate the city and others along the Peninsula". Indeed there has been a focused local opposition bordering on hysteria against the high speed rail project due to its impact on local residents.

Given this, I'd fully expect the paper to additionally support the closure of 101 and 280. Rail can't come close to the destruction and horror of a highway: just the day before two people were brutally killed on southbound 101 (CHP car drives over body after accident on 101, also 13 Sep). These freeways cut two massive swaths, denuded zones of death, down the entire peninsula.

Virtually any attempt at transportation infrastructure expansion faces opposition. Even something as innocuous as a bike path can result in an empassioned debate which goes on for years. However, as long as we as a society value the freedom of travel, hard decisions need to be made. For some reason we accept it as given that auto infrastructure is worth the terrible cost it imposes in finances, noise, pollution, congestion, and death. Yet rail is held up to such a standard that any serious commitment is called "devastating". It's time to reconsider our priorities and expose the car to the same scrutiny we expose other transportation modes.

In retrospect I realize this is a rehash of my previous letter on the same subject, that time to the Daily News. It shows how little the debate has progressed, I suppose.

Wednesday, September 8, 2010

Fremont Peak Hillclimb this Sunday

Sunday is the second annual Fremont Peak Hillclimb.

Last year I couldn't make it for some silly reason, then Mt Tam was canceled, so no Mt Tam for me. This year Mt Tam is back, but I'll be traveling with family in Italy, so will miss out there. But I will be at Fremont Peak

Last year I posted a route profile for the climb, which is intriguing:

Fremont Peak from San Juan Baptista (Motionbased:mooseman)

Here's the grade extracted from that profile, which I've convolved with a Gaussian of standard deviation 100 meters, to keep the numbers significant:

Fremont Peak from San Juan Baptista (Motionbased:mooseman)

So it pokes its nose above 10% for a bit, but nothing super-steep here. I find the suffering really kicks in over 12% if I'm over-geared, over 15% pretty much whatever my gear.

It should be fun.

As an aside, normally I don't bring any metrology with me on hillclimbs except perhaps a wristwatch to judge pacing. But this time I'm bringing the Edge 500: here's the Strava segment. Even if I have little chance to win my race, at least I hope to post a decent Strava time.

Sunday, September 5, 2010

Hardtails, Dual Suspension, and 29'ers

French mountain bike cross-country racer Julian Absalon had the amazing ability to deliver the goods when it counted most. He won the 2004 Olympic mountain bike cross-country race in Athens, Greece, an amazing four consecutive world championships from 2004 to 2007, then repeated as Olympic champion in 2008 in Beijing, China. Each of these wins was on a 26-inch hard-tail mountain bike.

But at the World Championships in 2008, there was what appeared to be a breakthrough. Swiss Christophe Sauser won the cross-country worlds on a pre-production 2009 Specialized Epic dual-suspension bike. It seemed perhaps the dual-suspension bike had finally come of age: a new era of dominance was about to begin.
Sauser wins in 2008 on Specialized Epic dual-suspension 26 incher

Indeed, in 2009 Matt Pochacha, then of VeloNews, claimed "The 26-inch wheeled hardtail mountain bike is, indeed, dead," where he tested a 26-inch wheeled hardtail, a 29-inch wheeled hardtail, and a 26-inch wheeled full-suspension bike over a test course and declared the 26-inch hardtail to be substantially slower, despite a weight advantage of at least a full pound over each of the other two bikes.

So what happened? Here's the winners of the UCI World Mountain Bike championship since 2008, men and women, in action on their big day. All photos are hijacked from CyclingNews:

2008 women: Margarita Fullana wins on a 26-inch hardtail.
CyclingNews photo

2009 women: Irina Kalentieva wins on a 26-inch hardtail.
CyclingNews photo

2009 men: Nino Schurter wins on a 26-inch hardtail.
CyclingNews photo

2010 women: Maja Wloszczowska wins on a 26-inch hardtail.
CyclingNews photo

2010 men: Jose Antonio Hermida wins on a 26-inch hardtail.
CyclingNews photo

Now, this is hardly all scientific. But I'll just say that I hardly feel that were I to try my hand at mountain bike racing, I wouldn't feel like I was crippling myself too profoundly by sticking with my tried-and-true Gary Fisher 26er hardtail.

Friday, September 3, 2010

Cross-winds and trail and Bicycle Quarterly, part 3

Last two times, I discussed an article in Bicycle Quarterly which described how low-trail bikes should perform better in cross-winds. I showed that this is true for two effects from the sidewind, one that a bike leaning into a side-wind will tend to steer into the wind if it has positive trail, and the other that a sudden gust will cause a reaction force on the front wheel that will tend to rotate the wheel. Actually, these two effects are really the same, one the steady-state effect, the other a short-term effect. But what the article missed was that the sudden gust is also going to tend to blow the bike over in the direction of the wind, so an effect which causes the bike to suddenly steer away from the wind can compensate for this.

But there's another effect. Everyone knows that a deep-dish rim is often less stable than a shallow rim, or even that bladed spokes may be less stable than round ones. This is due to the direct force of the wind on the front wheel, although there are also contributions from the effects already discussed.

The key here is that the wind exerts force around the full perimeter of the wheel, which for simplification purposes might be considered axially symmetric. One can integrate force about the rim, but the simpler approach is to assume all the force is applied to the hub, which is the wheel's symmetry axis. So there will be an effective force on the hub proportional to the net force on the rim + spokes + hub + tire: the whole wheel.

Here's a diagram again of the hypothetical zero-trail Guru Photon:

zero-trail bikeZero-trail bike

Indicated in the plot is a moment arm between the steering axis and the hub. Even with zero trail, there will be a torque applied to the wheel proportional to this distance, which is equal to the rake of the fork.

For a given head tube angle, rake decreases trail. So if you decrease trail by increasing rake, you increase the steering moment applied by the wind when it hits the wheel, even though you might be decreasing some of the effects previously described.

Back in the glory days of epic racing, long-rake forks were in style, presumably because the long curve smoothed out road vibrations:

CyclingNews photo
Blog posts are always improved by a photo of Fausto Coppi

I don't think Fausto would want to clamp Zipp 1080's on that puppy.

Anyway, cross-winds aren't a simple matter, clearly. And I don't even address the lateral aerodynamic lift that deep carbon winds generate in cross-winds.

Thursday, September 2, 2010

Cross-winds and trail and Bicycle Quarterly, part 2

The description I gave last time was only part of the story described in Bicycle Quarterly and Tony Foale.

Suppose I'm riding along when a cross-wind strikes. It will apply a force to the rider, to the frame, to the rear wheel, and to the front wheel. The last time I dealt with the force as a whole, which causes the bike to lean, and the lean induces the front wheel to turn proportionate to the lean. But there's an additional factor. Okay, several, but there's only space to describe two of them in this post.

In the last analysis, I assumed a steady wind. But assume instead the wind strikes suddenly from the side. In this case, the bike is starting vertical: not leaned over. But the wind hits and suddenly it's pushing against the rider + bike. Without friction, the bike would accelerate sideways in response to this force, wheels and all. But there is friction: the tires grip the road, the and consistent with Newton's Third, the ground pushes back against the tire.

Now focus only on this reaction force. There's a lot of mass on the frame: it has a lot of inertia. The wheel, on the other hand, is relatively lighter. So as a first approximation we can consider the effect of this reaction force on the wheel orientation by assuming the frame position is fixed.

zero-trail bikeZero-trail bike

Here I show a bike with zero trail: a hypothetical Guru Photon built with enough fork rake to put the contact point of the tire against the ground directly in line with the steering axis. It's easy to imagine that as the ground pushes against this contact patch it is unable to rotate the wheel. So the wind hits the rider exerting a force, that force is transferred to the ground, the ground pushes back, but that reaction force is unable to rotate the wheel and the bike generally continues pointing in the same direction.

zero-rake bikeZero-rake bike

Now consider another extreme case: a bike with zero rake. Here the hub, not the contact point, is in line with the steering axis. As a result the contact patch falls well ahead of the steering axis. As the road pushes against the wheel, the wheel will rotate: wind flowing into the photo will tend to turn the wheel left (looking down). This will eventually cause the bike to fall into the wind.

But obviously this isn't all. A stationary bike balancing on two tires, hit with a gust of wind from the right, will fall to the left. The Bicycle Quarterly article doesn't discuss this component. The wind pushes the bike left, the tires provide a reaction force to the right (but lower down), and the resulting torque rotates the bike. This is the opposite of the effect from the wheel rotation.

So to cancel these two effects, so that the gust from the right pushes the bike to fall left but then the handlebars rotates to move the bike upright again, requires some trail. Zero trail and the bike would continue in a straight line but would tend to get blown over with the wind. Too much trail and the bike will change course too strongly when hit with the gust. So it's not a simple story of less trail is better in a cross-wind. The right amount of trail is needed, the optimum depending, among other factors, on the weight of the bike + rider and the height of the center-of-mass above the ground.

If the wind persists, however, and the rider needs to lean into the wind to compensate for the wind's force, then modest trail is probably desirable to reduce the force which must be maintained on the handlebars to keep the bike moving forward. Neither my Ritchey Breakaway nor my Fuji SL/1 is "low trail". The Ritchey is probably closer to the optimum for me if my perception that it handles better is valid.

Next time I'll look at the effect of the wind blowing against the wheel itself, another effect not described in the article.