Quarq Accuracy

I've ridden one stretch of road enough to try to see how repeatable the Quarq CinQo is. It's the stretch from the bottom of Montebello to the school. So, we can play some games with numbers. Let's assume that I didn't change wheels (I probably put a set on that weighs ~1/2 lb lighter for some runs) and that my body weight and clothes were constant. Here are the results:

time	average power	deviation	kJ
00:14:09	284	101.91%	241.1
00:15:39	250	100.24%	234.8
00:12:28	326	101.78%	243.8
00:12:39	314	99.83%	238.3
00:13:33	286	98.21%	232.5
00:13:03	302	99.40%	236.5
00:12:37	311	98.70%	235.4

So, the mean is 237.5 kJ, and I've tabulated the deviation from this. It looks like the Quarq is well within its +/-2% accuracy spec, but of course, this spans a lot of time and probably many variations in weight and equipment. Oh yeah, I'm neglecting the confidence in the mean and such things that probably matter. I'm basically impressed that a device as rugged as this can give such repeatable data day after day.

OK, enough geeking out for a day.

Coast down estimation of drag and rolling resistance - Part 1

So I promised some geekery here. The goal was to do a simple test and try to estimate rolling resistance and drag coefficients. The simplest thing anyone can do is a coast down: you accelerate to speed, stop pedaling, and coast to a halt (or close to it.) So, to do the analysis, you first need to solve the equation that describes the motion:



where:
ρ is the density of air
c_rr is the coefficient of rolling resistance
C_dA is the drag coefficient multiplied by the frontal area of bike and rider
m is the mass of rider and bike
g is the acceleration due to gravity
v is the velocity of rider and bike

You can use separation of variables to get a rather gnarly looking expression that describes the coast down behavior of a rider in a constant position:



where I've defined:



I went out and did several coast-down tests in two positions (straight arm in drops, hands on tops,) and covering the same course forward and backward. The reason for this is that and slope will look like a change in rolling resistance, so if you take the average rolling resistance derived from the two directions, that should cancel out any error due to slope. It does NOT cancel out wind, so I did this at midnight, which is typically fairly wind-free. I downloaded the data from the powertap and used the nonlinear fitting function in Excel (blah :() to find values for c_rr, C_dA and t₀. I then used R to see if there was a statistical difference in rolling resistance and drag between the two positions I used, and to estimate the error in those values. Next time, I'll show some data.

Teetering on the edge

One of the challenges of training is getting close to the edge, but not falling off. The human body has a strange negative feedback mechanism. Do too much physical work and you have problems sleeping, and you slow down, making you think you have to do more work to compensate. I've overtrained before, but this year I've been pretty good (so far) at walking up to that edge and not going over it. This weekend was pretty close to it for me; after riding ~5 hours in 105 degree weather with a bunch of climbs on Saturday and three times up Mt Diablo on Sunday, I'm due for some rest.

A Rarity

My wife came with me to the race. It's probably the only road race worth going to to watch the race, though there may be others in cool places to visit. She grabbed this photo of me:



So I don't just make up stories about riding...

University Road Race

Ah, University. As a simpleton racer, this is a race I can actually train for. It goes up, then it goes down. I usually like that kind of thing. Things started in earnest, with Menso de Jong rolling off the front repeatedly, and Chris marking him early on in the race. The pack reeled them in several times before Menso finally broke the elastic and rode away from everyone in true pro MTBer style. Chris followed after him, but got reeled back in one last time. Somehow, I managed to remember to drink without him there to remind me, but from now on I'm gonna have "god, do I have to mother you?" stuck in my head in Chris's voice.

Like I said, I'm simple racer, so I followed some simple rules for the rest of the race: coast up to the front on the descent, drift back on the climb, and never stand on the kicker unless absolutely necessary. I closed gaps where necessary as attrition really set in after 10 laps, but basically sat in pretty comfortably thanks to all the work Chris was doing off the front.

With only Menso long gone off the front for the last few remaining laps, not too much was going on in the pack. I managed to drop my chain and had to do a pretty hard effort to chase back on, but even that was fairly uneventful. I repeated my simple plan and thought about what I was going to try to do on the last lap. Somehow, I got it in my head that it would be a fantastic idea to launch a sprint from the corner, about 2 minutes from the finish line. Unfortunately, a rider from Cyclepath had already cleared the group by the last corner when I wasn't paying attention, so it was a race for third. I attacked hard up the left side right after the corner, looked Chester from Platinum square in the eye and we were off. I led out for the last 1.5 min, then Chester came around me for 3rd near the line; I held my position for 4th. We almost caught the Cyclepath guy, so I can't say I made the wrong choice, just not the best. Glad I was able to hold on for so long given my early "sprint" start!

I stuck around to cheer on the 4/5 and women's fields, then had a great lunch in SC before heading home.

Legs are finally coming around, so I'm looking forward to at least Challenge and Everest later on this year.

Patterson Pass

Patterson Pass was my first race as a 3 last year. It's a hard man race, and I don't really belong to that category of rider. This year there was no wind so the climb was extremely selective. Being my first real race back in a long time, I hung in until the 3rd lap then got dropped as the heat and pace got to me. I soft pedaled to the top, caught a bunch of riders going back to the finish and slotted in at 12th. Nothing much else to report except that it was HOT. No water at the finish this year so I was parched by the time we stopped at the first gas station to BUY water. I'm not at all a believer in buying something that comes virtually for free from a tap, so it was a painful move for me to buy a liter of water and some V8 to replace all the salt that was all over my kit and face. Good stuff.

I got a new power meter. I have two sets of nice wheels, but since I'm a geek, I rarely use them so I can get power data from races. This, of course, being suboptimal, needed to stop, so when Quarq released their compact Cinqo, I jumped on it. I'd been saving the money since March, when I originally thought they were going to release it, so even though it's an expensive toy, it didn't hurt too badly. The first one broke on me during my crazy ride of the year (3x Diablo with Everest Challenge teammates) but Quarq's customer service came through in two big ways:

1) they answered email on a Saturday. They have this funny habit of apologizing for answering late, you know, because 2 hours is a long time to wait for help. I'm used to vendors taking forever, so I'm already impressed.
2) they overnighted a new crank to me. I barely missed using it. Awesome.

The Cinqo and powertap agree very well. I have Tukey mean-difference plots to prove it, but those who actually read this already know I'm a dork so I won't plot that here. I will, however, update you on how I measured my drag coefficient and rolling resistance in the next post.

Leesville

Yeah, so that was interesting. Woke up with a stiff back that didn't want to loosen up and beat it with a stiff carbon frame across some beautiful dirt roads in Northern California. Break a few parts, lose some water and finish on the most god-awfully boring roads I've ever seen and call it a day. Probably not doing this one again. Basically, after breaking my power meter and getting a rock in the knee, I sat up and rode it home.

Good to get out in a fast pack again, and the damage wasn't anything a soldering iron couldn't fix.

Long Time No Post

Been away from racing for a while. I'm nursing our bird Kang right now and don't really think I can get out to race. It's amazing how such a little bird can work his way into our family and be so important. I'm still riding, so come Cal Cup time, I'll bring a full summer's worth of training to the races.

Arthur

Our adopted budgie checking out the camera:

Berkeley Hills 2009

Arg. I started this race feeling like garbage again. Legs moved OK but my head was full of snot once again. I can't wait for summer so everything will just go and die. I wasn't having any problems sticking with the pack and started to think I actually had a chance when a crash separated me from the field. I turned around to check on my teammate who also went down and he told me to go for it. I tried, but my bike was skipping gears. I stopped and tried to straighten the wheel, but it turned out my derailleur hanger was bent. Unfortunately, this was at the top of the course, so I had to chase back on with a two minute gap.

I nailed the descent (why can I go faster on my own?) and drilled it down Camino Pablo, where I could finally see the field and all of the minor attacks rolling off the front. Head down, I cranked away. Finally, I got to a line of cars and used the draft to get myself back on. Now I was tired.

The last time up the main climb, I thought I should mitigate the damage and just go hard. That was a mistake - I should have gone all out. What's to lose? Anyway, finished up 20th or so of 60. I feel really good about getting back on with a flat/downhill TT (at <135 lbs, I don't go all that fast on the flats) but am disappointed with my mental performance where it really counted. Lessons learned.

For a change of pace, I think I'll do the Sonoma 100 km mountain bike race this weekend. I've been surprised at my ability to recover recently, so hopefully it won't impact Mt Hamilton.

Wente RR, 2009

I had to miss this race last year due to injury, and was really looking forward to a large-field tough race. Mark, Eliot and Bernhard provided some really valuable pre-race recon as I had no idea what to expect. I decided to remove all the distractions I could from my race: I raced with a simple bike computer and don't think I looked at it once. I also tried my new wheels - after racing on open pros and powertaps for so long, my 2 lbs lighter bike seemed like a brand new ride.

I lined up congested (allergies?) and feeling generally lousy (they need more lazy afternoon start times for us recovering mountain bikers,) but luckily it wasn't too hard up the climb the first two times. Brad was extremely active at the front while I basically sat in trying to clear the snot out of my head. On the fourth time up, a break of twelve had made it up the road, so Grant from Pen Velo and I drilled it on the climb and caught them by the finish. My head was finally clearing so I started to think about doing something beyond just finishing.

The last lap was aggressive and fast, and another Pen Velo guy made it up the road and away while the moto ref neutralized what was left of the field. Oh well, racing for 2nd now. I made my way near the front coming up to the turn up the climb and hit it hard when we made the turn, first chasing down a few riders, then making a newbie mistake by sprinting for the first tent I saw. Luckily, I didn't let up too much and kept going when I realized it wasn't the finish- and that sprint put me well off the front, or so I thought. I turned the corner for the real finish and saw one other guy from my field that I couldn't catch, nor had I seen him roll off the front, for third place. Still working on that race awareness.

Here's a picture of my bike in race garb:


I have to say gluing your tires on is a unique experience. The wheels are pretty nice, but I think I might need to drill out a bit more for the valve stems.

This weekend in Berkeley Hills, then I think I'm going to do the So No Mas 100 because I haven't had enough instant weight loss this year. And I haven't ridden my MTB in over a month, so I figure 8 hours in one shot should make up for that.

Copperopolis 2009

Arg. This race is hard. Someday I'll do it right. This time I forgot to eat. I was on the bike for four hours and only drank one bottle and had 2 gels. That's somewhere around 300 calories, or what I should be consuming per hour.

The race started somewhat fast on the climb, but it's the rough lead-in that gets me. I fell back to the back of the pack and hung in for three laps of crappy pavement. The weather was good at least. My teammate went up the road for two solid laps; he's going to have a great season of Master's racing. By the fourth lap, I was barely hanging on in the crosswind section and actually got dropped on the climb. That's how gone I was. I rolled in for ~25th, glad to have finished. My old man back thanked me for stopping.

Sonora races 2009

A few weekends ago I did a double header up in Sonora. Ward's ferry was up first. Classic rough velopromo pavement mixed with a punchy climbs, this course had everything except a flat road. I was loving it until my front tire went flat at 38mph. I rolled safely to a stop, got a tube from a teammate and a pump from Robert and was back on my way, only 35 minutes after flatting. I pulled out, sadly.

The next day was Warnerville, a new race for the Norcal calendar, featuring some gently rolling terrain, a 1 mile rough dirt section and the winds from hell. At the starting line, we were under a wind advisory, and it only picked up from there. The field split in the dirt when someone lost control, and unfortunately I got caught behind the split. I chased like crazy, dragging around the winner from Ward's ferry, so the pack wasn't going to let me get anywhere near them. During the fourth lap, my hips started to hurt (I'm old, I guess) so I had to back off a bit from the pace. I ended up 8th out of 18 or so, which is pretty good for me in a flat race. I felt absolutely destroyed and couldn't even eat all of my burrito on the way home. Good stuff.

Due to work, I've done a drop-dead taper for Copperopolis this weekend. It's a C race for me - meaning I just want to survive and am not planning on peaking for it. A bunch of heavy hitters from the international and domestic scene will be racing the P12 race, so it should make for some entertaining racing from someone's point of view.

In other news, we're keeping Kang in an aquarium right now. He doesn't like it, but we think he ate something that's not agreeing with him and the vet recommended this treatment. He's already looking more chipper, but looks really strange pecking at the plastic and in general seems confused. Birds are expensive: his vet bills have totaled over $400 just for diagnostic work (blood, stool samples) so if you're eyeing a parakeet as a cheap pet, think more about getting a cat or something. The upfront cost may be low for a bird, but vet care is really pricey (although talented if you go to the right people.)

Orosi 2009

Orosi is a tough, beautiful race. I haven't really put the training time in to do 90 mile races yet. I knew going in that this would hurt, but the scenery and course make up for the pain. We staged with only 8 guys, a result of some big race down south and the challenging terrain.

The first lap was pretty mellow; we set up a good tempo up the main climb and stopped for a nature break on the way down, and didn't get passed by the E4 pack until the smooth highway, which was a lot later than last year. Some attacks went off right after feed zone, and I zoned out and kind of followed, never in much difficulty, but got left in no man's land, which is where I stayed until the turn back onto Boyd when I got caught by some chasers. My brakes a-squealin' I kept up with my two  companions on the fast descent, now chasing the three up the road.

On the last climb, we swept up one of the guys off the front, and dropped one of the guys that had caught me on the highway section, so we were racing for third. My companion asked me to take it easy on him on the climbs, so we could work together on the flatish sections of the course.  I sat up and towed him in most of the way, enjoying a few minutes of draft on the highway. I actually felt pretty good, aside from hunger and a sore back. I rolled away from him ( he said he wouldn't contest a sprint anyway) on the approach to the finish and took third. For my longest ride by 20 miles and first race this year, I'm pretty happy with that result even though it means next to nothing for upgrade points.

SoCal

I really needed a break from science for a couple of days, so I took a trip to Southern California to visit old friends from college. I awoke on Thursday feeling under the weather from allergies, and having the day off, I decided to just sleep in and do a ride locally before heading to Los Angeles. The drive was uneventful and boring as ever. It actually made a great race drive preview, as I passed towns like Madera and Coalinga. I crashed at Chris and Lydia's place, after dining on some really great pasta. Their cats seem to like playing on me, but eventually I got to sleep.

Chris and I rode up highway 39 with the intention of hooking up to highway 2, taking that back to Pasadena. Overall, I think that would have been a fairly long ride and would have rivalled many of the big climbs in Bishop for elevation gain in one shot. I really wish I had brought a camera on this ride. The road snakes in and out of steep canyons that have been scarred and reborn from fires, and best of all, it's closed to traffic due to poor conditions at the top. We did encounter a few Caltrans trucks bombing down the hill, but they were few and far between. The climb starts in the desert and slowly transitions to pine forest, finally dumping you into high alpine territory. We started passing snow above Crystal lake. At some point, a snow blower had come along to clean up the huge drifts, but the steepness of the hillsides must have made that difficult. Finally, near the top, we were stopped by a huge drift that even Caltrans couldn't handle. We had to scrap our plans and did the Glendora Mountain Road loop instead, making for an equally good ride. I did get to witness some kids getting busted for pot before heading back down the hill.

The next day I rode with Jim and his tri buddies. OK, I think aerobars are dorky, but the company was worth breaking some important rules (actually, some of the TT bikes there made me drool.) We hammered around San Diego for about four hours. Got to hang out with Tony and some of his friends and really experience a M3 on one exit ramp before heading out for a midnight ride in one of San Diego's many canyons. That was eye-opening for me. Here in the Bay Area, it's impossible to go night riding without breaking some kind of law (on trails) and they use radar guns on the trails to ticket speeders. I've never heard of such a thing, and I think it really indicates something's wrong with the type of people that congregate here, which I guess includes me now.

Monday I had an epic drive in front of me, so after fixing my AC, I hit the road. I got in an hour on the bike up Old San Marcos in Santa Barbara before arriving home at 1 am, ready for work the next day. All in all, a very satisfying trip. This weekend is Orosi, the first RR for the year for me, and I hope all this rain riding and long rides pay some dividends.

Spring Races

I've got to admit, one of the hardest parts about racing is registering, after driving to the race. I think my heartrate goes to LT immediately upon taking a glance at the NCNCA website. I finally pulled the trigger and registered for four whole races. No crits yet, but eventually I'll get that bad taste out of my mouth and go for it (I like sprinting, even if I'm not good at it.) Most of the races I've entered so far are longer road races and many will have small fields, so maybe I'll even get an upgrade point or two. My fitness is looking pretty good. I think I'm at the same level I was last June (at least that's what my whiz-bang hub says) which was definitely my peak for '08. I hope to not get hit by cars, crash on my MTB, and mostly not get sick for the coming weeks. The spring season will all be new for me except for a few races, so I'm looking forward to it.

It's been raining, a lot. I now have neoprene booties and one of those little Euro caps. Much more comfortable out. And on days where work is especially difficult, I find myself looking out into the storm outside wishing I was just hammering away into the wind. Cheesy, I know.

To get out of the rain, I'm going to make a trip to see some old friends down in SoCal in a week and a half. I'm going to load up the wagon with two bikes and all my riding gear and hope to get a bunch of quality visiting and saddle time in. That takes care of difficult work and rain at once!

Rain

It has been raining a fair amount here in Northern California - a realization that any viewer of the Tour of California has probably come to by now. I got a ride in the showers on Saturday, but rode the trainer Sunday after watching Mancebo take the win. Today, I couldn't take it anymore. I've come to the realization that trainer riding is fine when it's the only option, but today I just needed to man up and get outside. I've been testing some new gloves, and that really enabled the day, because it absolutely poured on me for most of the ride.

Last year I attempted a similar ride, and by the time I got home I couldn't even open the front door; my hands were completely frozen. I was absolutely miserable. I think I stripped and sat in front of our ubiquitous wall heater unit for a good 15 minutes before attempting to take a shower. After that, I looked like a boiled lobster (who knew water could be painful?) This year, I was bundled up and fairly comfortable. I think I need on of those caps, because I couldn't really see, and I'd love to get some warmer socks, though the wool ones I used worked alright. Really, fenders were the biggest thing I added to enjoy the ride. So, here's to riding in the rain.

The season is ramping up here, and I've got to decide what to do. I want to go out an support my team in all the road races I can, but I also want to see what kind of mark I can make in marathon MTB racing. Most of the MTB races around here don't suit my strength - climbing - except for the ultra-long ones. That probably means sacrificing some high-end for endurance, but it should be a fun season of racing once it gets rolling.

Espresso

Everyone knows that a true cyclist consumes espresso in quantity. Over this holiday break from work, I set out to make myself an affordable espresso setup. I've been using an Aeropress for quite some time, but it's definitely not the same thing. It produces very good espresso-like coffee, but throws away a lot of acid. This might be a good thing for certain drinks, but it kind of makes most coffees taste the same. There are a lot of very expensive machines out there, but I wanted to keep it as cheap as possible, preferably under $300, which is still a lot for a coffee maker. I'll try to document my setup here.

For the espresso maker, I bought a Saeco Via Venezia at Costco for $150. It has a pressurized portafilter (the part that holds the coffee) which means it's forgiving of tamp and grind, but on the other hand, doesn't let you diagnose those important attributes, either. You can remove the pressure mechanism (which also seems to make a fake crema) but I found that the gasket needs to remain in place. Here's a picture:



Everything pops apart, and with pressure control removed, it's easy to find deficiencies in technique. I found my cheapo grinder wasn't getting fine enough, so I got a Capresso Infinity grinder that works much better.

Temperature is very important in brewing, and you can find lots of information on adding PID control to the machine. I might do this some time with my Arduino, but for now I measured the temperature profile at the boiler and at the brew head. When the heater kicks off, peak temperature reaches about 100 C just at the mid point of the boiler, and about 105 C where the thermostats are. Just before the heater kicks in, the temperature drops to 80 and 85 C, respectively. I measured the brew temperature below the group by removing the portafilter and using a thermocouple in a styrofoam cup to probe the water temperature. Just after the boiler kicks off, the water is at 90 C, which is just passable for brewing espresso. For now, I brew right after the boiler kicks off. Eventually, the Arduino controlled unit could have forward looking adjustment and hotter temperatures for different roasts.

Tamping and grind control the pace of brewing. With my old grinder, the 'espresso' looked weak, tasted weak, and took only 11 s to brew. You can find a lot of information about tamping and most sites will say use about 30 lbs of force. The Saeco has a 53 mm portafilter, while commercial makers have 58 mm portafilters, so for this maker I settled on 25 lbs as a tamping force. I varied the grind fineness to get 20-25 s for a double shot pull and found that I need to use the finest setting on the grinder.

Two shots pulled using cheap Trader Joe's espresso blend. Tastes much better with good beans...