Racing In The Wind
Since I just experienced this, and since Coach R has just put in the wiki a "How-to" on biking in the wind, I thought I'd share a few thoughts I've had on this past past two days, and open a thread for others to chime in.
1. Over in John Withrow's report on his 112 mi TT @ Challenge Atlantic City, it was noted it seems harder to hold watts into a headwind compared to calm air. I've thought one reason for this is we are doing extra stabilizing work with our legs and core, just to keep from falling down, and to keep going in a straight line. This work is not reflected in watts at the pedals or hub, but is reflected in our RPE. Maybe thats why we find it hard to keep watts up going into the wind? This is more of a sidewind issue, it seems to me
2. Talking to Coach Rich about my race @ IM CDA, he pointed out something I hadn't truly appreciated before, concerning going up hill into a head wind. Received wisdom is that, going up hill @, say 8-12 mph, there is much less value in staying aero, compared to the ease of maintaining watts when sitting up. That might be true with no wind or a tail wind, or even a light headwind. Since aero effects increase geometrically with a linear increase in speed, the aero cost between, say, 20 and 22 mph is much greater than between 10 and 12 mph. BUT … and this is the important point … with a 15-20 mph wind in your face, even going 6 mph up hill presents you with the same aero difficulty as a calm day @ 16-21 mph. A Big Reason to stay aero (if the slope allows it) when going up hill into a stiff wind. IM CDA presented that opportunity as the hills were taking me 15 minutes to ascend, were only 5-6% steep, and were into a 15-20 mph wind.
3. Downhill with a tailwind is not an opportunity to coast, but an opportunity to pick up time on all those who passed me going up hill, burning matches while I chugged along @ 0.71 IF. When you're going 20 mph and feel no wind on your face, that's a clue that you're in a serious tailwind, and should take advantage of it not to rest, but to gain time on others who are resting after burring those matches. My low VI will trump their strong hill climbing when it comes to the run.
Comments
Yup...being on the moto at IMCDA this year really drove this home for me. It was clear that people were going to their default riding up a hill position (sitting up in the hoods) without regard to the 20+mph wind they were riding into. This got me thinking about airspeed vs ground speed, being aware of both, the terrain you're on, and making the correct decisions about body position in all terrain on a windy course.
Ref- Al's Comments.
1. Agree that your body is doing a lot of stabilizing work and its coming at a cost. Would like to add that on a windy day (flat, up , down doesn't matter) most riders will tend to over-grip their bike (don't underestimate the amount of energy leaving your body through your arms while biking). Get jostled by a few gusts and its only natural to over-grip , this is an overall energy suck , and there is not much to do about it except try to relax and be aware its happening.
2. I played around with this quite effectively while climbing the switchbacks on Mt. Lemmon. Aero into the wind , sit up down wind. You could really see and feel the differences. Easy to say but still hard to do!
3. Downhill or Tailwind is not the time to coast , its definitely when to make time you will be losing later.... But its a good time to stand, stretch , eat , and pee. So if you know the wind and the course , you can wait for these downhill or tailwind times to do those things at less of a time penalty.
@Rich... Airspeed vs. Groundspeed is an awesome analogy/explanation.... I have actually been in an airplane flying into a head wind (positive airspeed) and going backwards over the ground (negative groundspeed) ... Its all relative....
Its important to differentiate between training and racing.... In training we are programmed to hit those goal watts and most will do whatever is necessary to, and that is a good thing because we are trying to maximize the amount of work performed.... But in racing we have to remember or think its about getting from point A to point B as fast as we can... We all preach watching your watts on an NP autolap and NOT watching our speed, but at the same time we should be thinking am I doing everything possible to maximize my speed at the correct effort level of course at all times.... IOW sometimes its just more important to stay aero than it is to hit those target watts!
On the very slight chance the wind is actually greater than your forward speed, AND it is perfectly aligned (0/360 deg) with your direction of travel, that might actually work. But IMO, tri bikes are designed to be more stable, and more comfortable when ridden in aero position, so I just hunker down, whether my hands are on the bases or bull horns.
This past weekend on my 56 mile RR, I was thinking about this because of the strong 15-25 mph head/cross winds while trying to stay on my target watts. My conclusion at the time was that a big part of the difficulty was due to the constant variation in pressure against my body and bike. Subtle changes in wind speed and direction meant my cadence, current gear, and peddle pressure were constantly out of sync. In open country like grassland or desert, the wind may be more straight line and consistent, but where I ride it is always gusty and variable.
A strong gust > drop a gear > spin-up > over watts > yaw change > lighter wind > under watts, etc. So from moment to moment, as wind pressure changes caused me to be over/under watts and making some sort of adjustment immediately to peddle pressure or gearing. Other times I didn't react expecting the change to be too short to matter and find myself in the wrong gear/cadence. For me it seems like I can never get the cadence right in windy conditions.
As pointed out by others about staying aero in the wind, I consciously worked at getting as small as I could when it was windiest. I could definitely feel the difference.
On a windy course/day, it is important to have a cleanly setup bike. Aero is even more important when you factor in this "effective" airspeed that you are traveling at. Because wind resistance is a function of your speed squared, this "coefficient of drag" that you are presenting (your bike and your body/head) becomes uber-important into the wind. So after having a nice aero setup on your bike, your mental focus needs to be "I'm riding into the wind, so I must stay glued to my aerobars". For me it was a bit of a game on the AC return leg. I knew I was being crushed by the headwind, but so was everyone else. So I could gain a small advantage on the competition by being "more areo" and keeping good head and back and arm position.
This thread helped me to think of doing the same on a hilly course if there is a headwind.
@Peter, It is rare that you will not be travelling faster than the tailwind. So it's not that sitting up will necessarily help you in these situations. It just won't hurt you nearly enough if you sit up or stretch here. Your strong pedaling legs san still make you go say 16mph (ground speed) into a 20mph headwind (36mph effective wind speed)... So that means you should be able to go 30+mph (gorund speed) with a 20mph tailwind. This still presents an effective forward "wind adjusted" speed if 10+ mph. And your drag at 10+ mph is still drag, but way way less than your drag at the 36mph (wind speed) into the headwind. [all that math was completely made up btw...]
http://members.endurancenation.us/Forums/tabid/57/aft/16073/Default.aspx
Rich, here you go:
Coach R's presentation (along with several windy rides I have had lately) on started me thinking about the effect that wind has on a ride. The question that I was considering was this: "What is the net effect that wind will have on my time to complete a course where part of it is head wind and part of it is tail wind?"
There is a cool calculator (Bike Calculator) that allowed me to setup and mode this. I made the following assumptions:
Pavg: 200 watts
Rider Weight: 160 lbs
Bike Weight: 20 lbs
Tires: Clinchers
Position: Aero
Grade 0%
Head Wind: -15 mph to +15 mph (I did calculations for each 1 mph between 0 and 15)
Distance: 56 miles (assuming an out and back course that gives 56 miles headwind / 56 miles tailwind)
Temp: 75º
Elevation: 100'
Trans Efficience: 95%
This is a little bit hoky, because the grade is 0%, the wind is constant, it assumes your position is the same all the time, etc, etc... but I thought it was still interesting.
In any case - I just wanted to share.
The chart is below...
Rich
@Peter - I have thought about sitting vs. aero in a tailwind... here is what I came up with:
When we are riding, the drag (wind resistance) that we feel is a force that slows us down. The force of the wind resistance is proportional to our surface area, to the square of our speed and to some other constants relating to the density of the air.
As long as we are riding faster than the wind, the effect of the "tailwind" is to reduce the "relative headwind". For example, if we are riding at 25 mph, and we have a 5 mph tailwind, that means our relative headwind is 25 - 5 = 20 mph. If we sit up, we will increase our surface area into that 20 mph headwind, and slow down more than if we stayed aero. So - unless the tail wind is faster than we can ride, it will always be best to stay aero because it will reduce the forward surface area.
An interesting thought would be to sail (remember - sails work by lift created when air passes over them, not by being pushed by the wind)... could we get some wing-shaped bike frames that create lift in cross winds... :-)
As the amount of time we were out there on the return trip to town on the Challenge AC bike course, I noticed that as I stayed down and as aero as I could the entire way back and so many people were sitting up it made a bigger and bigger difference as time (distance) went on. The further and further along (or closer to the finish I got) it seemed to have a greater and greater impact on how everyone else seemed to be slowing down.
Perhaps to compound the increase in RPE ..The wind in your face helps evaporate the sweat, perhaps it is more difficult to notice how much fluid you are loosing??
The actually temperature increase when were out on the highway was about 10 to 15 degrees warmer than it had been up to that point, and no shade at all. To have that at the end of the ride was a great test (I did not like it at the time but glad I did it). I had poured water on myself to try to stay cool, but at the finish area from the Aquabike almost everyone I saw had salty sweat stains all over their clothes...more than I had ever seen before.
You touch on something I see every year at IMAZ, the course with the most potential for wind to be acting on you from one direction for a long time, as you do the 9mi out and back on the Beeline: athletes ride to hard on the first lap of the bike and into the second. They get tired and begin to sit up on the bike later in the day...right when the winds pick up. The net is that a LOT of people are sitting up on the bike on the second and third laps, and they go dramatically slower than the athletes who paced themselves well the first lap and therefore able to stay aero in the windiest parts of the day.
IMAZ is an example of poor pacing early on the bike compromising pace AND riding position later in the day = they go even slower because their out of aero because they screwed up their pacing early on the bike leg.
I find at least for me staying aero for hours is a drag, some pun intended, it really is ,for me, a challenge to stay in that position for a long time. I find my HR is a bit higher too. I put my road bike up 6 weeks before a Oly to acclimate to my Tri bike. Perhaps my HR was higher as I hammered myself.
Anyway not to get off topic here, if we are to be/stay in this position for hours and be comfortable, how long is it taking for you in training to just stay in that position?
You can always have a plan to get out of the aero position at regular intervals and/or at times when your speed is lower. Stand up, sensibly, on a climb, sit up for a few seconds going into and out of an aid station, etc. Stuff like that.
I usually sit up for 40-50 pedal revs every 15 minutes, to drink. Also, half way between those breaks, I stand and slow pedal for 15-20 revs, for an additional break. Trying to stay aero every second for six hours is both mentally taxing, as well as risking problems on the run.
I ride 80% of my miles year round now on my TT bike. used to do less when I was mtn biking, bike commuting, tandeming with my wife. I just feel more comfortable in the bars than any other position these days. I don't even have a real road bike, rather a 20 yr old steel double diamond with touring geometry.
I agree with Al, and think that the benefits that you get in terms of comfort, confidence, flexibility, strength and experience in the aero position by training this way and figuring out what fits your body is well worth it.
These bikes cost so much that I want to be able to eek every minute out of them on race day; the data suggests that you have to be aero to do that.
I've put another chart together comparing Aero vs Drops for 112 miles (one way this time - not an out and back). Rider parameters are (160#, bike 20#, power 200w, distance 112 miles) and I varied the windspeed from -5 mph (tailwind) to +5 mph (headwind) and plotted the difference between riding in the Hoods vs riding Aero....
Awesome thread.
One thing I noticed when training for CAC was mentioned in one of the comments below. Pacing all day is critical to being able to say aero in the wind, as the winds picked up as time went by on each and every training ride for the race. The days I started out too fast (in particular the last ride before the race), I really wound up regretting it later in the day from a number of standpoints.
I also wonder about the RPE comment; as a newbie on a tri bike, the wind really caused me to feel like I needed to "tense up" to keep the bike upright and not kiss the pavement. I wonder if playing around with how to "stay loose" in the wind would help.
Thanks all!
Staying loose, slightly adjusting saddle position into the wind and keeping your focus "down the road" generally lets the bike correct itself much more gracefully than trying to fight it... that is the right answer from my perspective.