Becoming more aero, and faster

Road surface (and rolling resistance in general as per Anthony’s big ol’ gravel tyres) must play a huge factor. Most the roads around here are rough chip and 5-6hours at 30km/h used to be reasonably steady.

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Again, 200w, 18 mph, minimal wind. BUT, non-aero bike, 1L bottle, hands on hoods in endurance position (not trying to be aero), 35c tires @ 55 psi.

Not optimized, but very comfortable.

Sounds just like me

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Then there’s Chad…

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Was hoping to never see one of that guy’s attention loving posts again :disappointed:

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This thread has been very interesting and eye opening for a big guy like me!! I’m 6’5" and could stand to lose 40 lbs (working on that). It took 230W average/246W normalized just to maintain this speed over a short, relatively flat route. I’d probably need to sit over 250w average to have a 20 mph average speed.

This is with a Lynskey XL GR300, 130mm stem (not super low), 28mm GP5000 TL on 50mm Bontrager wheels, tight kit, and a Specialized Evade II helmet.

@brendanhousler is an interesting follow on Strava for tall dudes! He’s super fast but you can see he has to put out serious watts!!

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So, ignoring equipment, how much does height and weight (and flexibility) play a roll in aerodynamics?

Height must be alot (but I’m no expert!). I think Nate on one the the podcasts said in their TT positions he had to put out like 40W more than Jonathan just to maintain the same speed.

I think weight is relevant to some degree on flats but based on some models in Best Bike Split for me, getting more aero would be a better option on flatter courses.

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Coggan wrote up some estimates here:

Frontal area based estimate:

  • one estimate for frontalArea = 0.18964 x height (m) + 0.00215 x mass (kg) - 0.07861
  • CdA (0 degree yaw) = frontalArea x 0.707
  • example 90kg and 1.88m (6’ 2") = 0.333
  • example 100kg and 1.88m (6’ 2") = 0.348
  • example 110kg and 1.88m (6’ 2") = 0.364

Mass based estimate:

  • Cd (unitless) = 4.45 / mass (kg)^0.45
  • example 90kg = Cd of 33.7
  • example 100kg = Cd of 35.3
  • example 110kg = Cd of 36.9
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But does that take into account the aero benefits of my belly? :sweat_smile::rofl::joy::sweat_smile::rofl::joy:

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Out the door I targeted 200W today. Hands on hoods. Head up. 2021 Quarq PM on my road bike. Wind was light out of the southeast as the flags were mostly drooped but, the bottom was flirting a bit. The direction was a headwind while gaining what little altitude difference exists and a tail on the descent. Course was a loop. The little power spike was coming around a corner. I’m 177cm tall and around 75Kg. 200W in ERG with a huge gear on my Wahoo Kickr is about 18mph same PM…4mph seems crazy. Wonder what’s going on? I am not a good TTer either.

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Just curious…what’s the IF for this ride?

.70

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I think it’d be good to include elevation on these average speed comparisons. It can be a huge difference, even at very pedestrian altitudes. According to the BikeCalculator app with my settings (185lbs, 95% drivetrain efficiency. 0.96 rolling resistance, 1.10 aerodynamic resistance), 200w at 300ft elevation is 21.1mph on a flat road. At 3000ft, all else equal, it’s 21.8. So those are pretty huge differences, even at low altitudes. It’s definitely worth considering in the speed vs power conversation.

Take those 200w to the flat streets of Denver at ~5200ft, and I’d be be rolling 22.5mph, a full 1.4mph (a touch under 2.3kph) faster than at 300ft.

No intelligent point being made here. Just bored and felt like posting.

Both rides on the same loop same, bike, position…not scientific by any stretch as the day was different but, it always amazes me how much difference 30W can make in speed, RPE, IF, TSS etc…nothing is linear might be a takeaway I suppose.

I was targeting 230W and 200W respectively. One thing is for sure. I’m an underachiever! Cheers!


Rpm 81 is very low. To low i think.

Looks like 30W made you 1.5 mins faster on the same loop? Doesn’t sound that unreasonable to me, in a race that would be quite a big margin. For everyday life, I guess it shows that killing yourself to get somewhere faster makes very little difference, so you can just as well ride at a lower power/RPE :laughing:

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I hadn’t thought about it. I just self select and have never actively monitored cadence while riding. Over the decades for criteriums it’s usually between 0 and 130 with an average around 90-ish. In general on extended climbs as it gets steeper cadence drops. Shallow descents it’s much higher. Most importantly when fatigue really sets in cadence drops quickly. Rather than focus on the cadence side I focus on the fatigue side of the equation.

For this flat loop I tend to ride a larger gear to engage the glutes more. Seems to make constant power easier for me but, I’m just an average joe. I’ve made every mistake in the book. Twice. So, just in case I’m missing something new, where should it be?

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