Sunday, May 31, 2009

Power vs Penetrating the Wind

A few days ago I wrote about power, penetrating the wind (aerodynamics) and pacing. Getting the balance right between these is critical to success in time trialing and the bike leg in multisport. Seeing lessons on such topics play out in real life helps to drive home the point.

Remember this? In the 1989 Tour de France Greg LeMond beat Laurent Fignon by 38 seconds in the final time trial stage to win the overall title. That day LeMond opted for better aerodynamics by using the new "triathlete bars," as Phil Liggett called them on the TV coverage that day. Fignon decided not to use aero bars and instead relied on his power to win. He lost.

Today's final stage of the Giro provided another good lesson on this same topic. Race leader Dennis Menchov used aero bars and a very low position. Danilo Di Luca, in second place and only 20 seconds back at the start of the day, went the Fignon route. Menchov crashed on the rain-soaked cobbles inside of the final 1km and stll beat Di Luca by 21 seconds on the day to win the Giro. I doubt if Di Luca will make that same decision again.

To time trial well you need balance between power and aerodynamics. They are trade offs. If you opt for more power you will need to make position changes that increase drag and thus sacrifice aerodymanics. If you want to go for the most aero-possible position you'll give up some power. You need to balance these. And the balance is somewhat dependent on the course you are racing. The hillier or more technical the course, the more you need power. And the opposite is also true: The flatter and less technical the course the more you should shift the balance toward aerodynamics.


At June 1, 2009 6:11 AM , Blogger Gary said...

Joe, terrific stuff! Here's my question: If you have a target goal of say 280 watts for a 40K tt, have your clients already done that in training? In other words, is training -- even if via intervals -- harder than the actual race? For example, are they doing 300 watt 2x20s in practice? Or do they expect to do better in the race than they've done in practice? Thanks, Gary

At June 1, 2009 6:34 AM , Blogger Mark Liversedge said...

of course di luca, who is noted as a supreme bike handler, chose to ride with a normal road bike, fitted with stub aero bars because of the rainy conditions on an extremely technical course.

Menchov didn't and crashed. If it weren't for the unbelievably swift response of the Rabobank mechanic then you might, instead, be blogging about the importance of bike handling today.

At June 1, 2009 10:25 AM , Anonymous wkinch said...

Agreed, but Menchov would have to crash several times to loose to DiLuca on any TT course except (maybe) a hill climb. Lemond/Fignon is a much better comparison. Both excelent TT'rs.

At June 1, 2009 11:41 AM , Blogger gewilli said...

I may be saying this from a naive point of view, but I was under the impression that DiLuca picked his road bike for better handling.

Much like the insanely long and twisty stage earlier in the Giro.

Traditional road bikes give you better handling over an aero bike and that, on a twisty wet course, may trump both power and aero. Menchov would have beaten DiLuca no matter what bike he was riding IMHO.

At June 1, 2009 12:45 PM , Anonymous Anonymous said...

On the Cinque Terra TT we saw every possible setup. Di Luca was on a road bike with a road helmet; Menchov and Leipheimer were on road bikes with clip-on aero bars and road helmets; Lovkvist was on a road bike with clip-ons and a TT helmet; Sastre was on a TT bike with road bars and a TT helmet. It was wild to see pros all opt for something unique on that stage. It appeared that the Menchov/Lepheimer setup was the right choice for the stage since those two went 1-2 on the day.

BTW, Di Luca always seems a step behind the curve. No aero bars at Cinque Terra and then only a road bike with aero bars in Rome. Maybe his power suffers so much in the aero position that it's worth it for him to go with the standard set up.

At June 1, 2009 2:32 PM , Blogger Bahzob said...

Great post and very interesting. If I had to choose though I would say penetration rules over power, which I think is a bit of a shame as you can buy the former but the latter needs hard work (and good genes).

I've come to TTing late in life, past couple of years I've done these on a road bike, turning 50 I decided needed a bit of help so treated myself to a TT bike with all the trappings.

When riding a "normal" bike I used to think sustained periods of 25mph+ were for the pros. However last weekend rode first 100TT with full TT setup in 4:06. What surprised me was how "not hard" this was. Just needed a steady average around 230-240W. OK but nothing special. Conditions were not perfect and going under 4 hours seems straightforward, something I never dreamed I could imagine thinking when on my previous bike.

So spending a lot of money bought me what all my hard training couldn't. Seems like cheating somehow...

Anyway, having ridden with and without modern aero aids my respect goes out to the times achieved by those on pre-aero rigs. e.g. occasion someone rode a 30mile TT under the hour. Difficult to compare performances like these with today's rides. Interestingly over here in UK an "old school" TT series has started up, regulating equipment to restrict aero benefit and focus on rider. Typically a 10 for same rider will be at least 2 minutes slower.

PS on this. I've just started swimming again. Just had a conversation about suits there that make you go a lot faster but cost several hundred pounds and only last for a few swims. Again, not sure this is progress. Maybe I am getting old.

At June 1, 2009 7:25 PM , Blogger Joe Friel said...

Gary--You should be able to do half of the race distance at race goal power in a workout when you are fresh.

At June 2, 2009 7:17 AM , Anonymous Anonymous said...

So based on this, if you are not a very good time trialer (Di Luca) and you go aero, you should be able to beat someone who is a strong time trialer who is going aero? The logic is not there.

At March 8, 2010 2:35 PM , Blogger Thomas said...

Lemond beat Fignon by 58 and not 38 seconds in the last timetrial in the 1989 Tour de France.


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