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A look into real world cycling aero gains – Part 3 on the Handlebars/Stem

With riders publishing their stats to Strava and Garmin Connect, among other places, it’s becoming easier than ever to understand the gains available to cyclists. And more importantly to this post, it affords us the ability to compare real world aerodynamic performance with the claims made via wind tunnel testing.

According to data released by FastFitness (who compile the publicly available stats) the following image is a breakdown of factors that cause aerodynamic drag and frictional resistance on the bike. Let’s take a look a the top four.

Body mass drag accounts for 18.8% of overall losses and Specialized claims it is 80% of the total drag. Which makes sense. Next up, the handlebars and stem accounts for a whopping 14% of cycling losses. Did you expect that? Finally, third runner up is clothing friction at 8.5% followed closely by frame drag at 8%.

Aerodynamic Drag Factors from FastFitness

So what is all this talk of drag?

Drag, or resistance, is created when an object “breaks” the wind or has voids that create turbulence. This is why aerodynamic designs are so sleek looking. Recent improvements in cycling technology have largely been about reducing the amount of drag created by the bicycle.

So, the single biggest culprit of bicycle drag isn’t the wheels or the frame. No it’s the handlebars and stem. Any aerodynamic improvements made to ones handlebars and stem setup will therefore have the greatest proportional impact. Which brings us to todays post.

How many watts can you save with an aero Handlebar/stem setup?

In part 1, we looked at the watt savings of loose fitting versus form fitting cycling apparel.

In part 2, we reviewed cycling body positions and the results of real world tests released by BikeRadar and GCN.

Today we’ll take a look at the Handlebar and Stem. And there are two options given to modern road cyclists to improve their aerodynamic performance.

  1. Slamming their stem.
  2. Aero drop bars

As it’s probably the most considered option, let’s begin with number 1.

To slam or not to slam?

slammed bicycle stemRiders everywhere are slamming their front ends. It’s gone global and it started with the pros switching to more aggressive frame setups. But is it the best option for you (or the pros)?

When comparing rider speed in different body positions at the same watts, BikeRadar uncovered something very interesting. While slamming a stem does make your bike more aerodynamic. It pulls your body down and forward, reducing the exposure of your chest to the wind. However, a more aero position may not be the fastest position.

The reason, is that it makes a rider uncomfortable. You may not notice it over a 5 minute test, but as the ride progresses so does ones fatigues. And there turns out to be perfectly simple explanation for this. We make micro movements to adjust our body when riding in an aggressively aero position. This movement creates drag. The results show it makes a surprisingly lot of it. And as we become increasingly fatigued in a position the number of adjustments we make also increases.

This doesn’t look comfortable

These minor movements are so inefficient that they do more to slow us down than the aero dynamic position would otherwise give. From my own testing, riding a slammed stem for more than a year, I’ve learned that the body does adjust. But there is a point where the reward is less than the effort given. And I have noticed the effect of fatigue that BikeRadar highlighted in their test. So I’ve relaxed my position slightly.

You will need to play around with the position of your stem to find what works best for you. Also, to increase your flexibility (and the position you can ride) try to hold a lower-than-normal position for 10 minutes. Simon, from GCN, was recommended to do this as well by a pro cyclist.

Conclusion: unless you are comfortable riding with a slammed stem, slamming it may actually slow you down. Instead marginally reduce the height of your stem until it’s just still comfortable.

Next up: Should I invest in drop handlebars or should I save my pennies for aero wheels instead?

I don’t know how it is for you, but a lot of the shop talk at my local club rides revolve around aero wheels. “Ron’s pulling strong. It’s gotta be those wheels.”

Is it possible to save more watts with an aero bar setup? Let’s be clear, I’m referring to aero drop bars, not the skinny aero bars used by triathletes or time-trialists.

Interestingly, I’ve never once spoken to anyone about aero drop bars. It just hasn’t come up. But this winter while bike shopping I’ve become increasingly convinced by the data that aero bars may be the key to unlocking the greatest aero improvements we’re seeing. And best of all… aero drop handlebars are available to every cyclist on every bike.

Aero road drop handlebar

The world’s leading aero bikes such as the S-Works Venge, S-Works Tarmac, Cervelo S5, or Pinerallo Dogma F10 all come with aero drop bars (stock). In fact you can’t order any other kind of bar for the S-Works. They also all claim incredible watt saving statistics. Yet their frames haven’t changed that much in the past 3 years. So where are they getting their extra savings? Maybe it’s the wheels and bars.

In 2014 Bike Rumour published that the Cervelo aero bar saved 4.4watts over the rounded bar. Since then Zipp have released even better bars that report 7.5 watt savings at 40km/hr. Their research showed that a traditional round bar creates 0.74 Newtons of drag, whereas their SL-70 aero bar creates just 0.11 Newtons of drag.

If one were to combine an aero bar with an aero stem, similar to the canyon Aeroad in the picture below, the aerodynamic improvements would likely increase further.

Canyon Aeroad CF SLX-014

“For reference, a bike [creates] 70–100w [of resistance] at 45kph using the same weighted yaw sweep. And, of course, you, the rider, contribute about 75 percent of the total drag.” [BikeRadar] Therefore, a savings of 7.5 watts is a significant amount. Also, unlike aero wheels where the amount of drag created by the wheel can increase depending on the direction of the wind, aero bars are more uni-directional as they are the first part of the bike to cut directly into the wind and do not create the “sail effect” as wheels do.

Given mild wind conditions, however, wheels will save you more watts. In comparison, Elite Custom did a test comparing Enve aero wheels with standard Mavic “training” wheels. They found that Enve SES 4.5 aero wheels saved 14.4 watts compared with standard Mavic Ksyrium Elite wheels at 40km/hr [Elite Custom].

Conclusion

So should you go for an aerodynamic wheel that could save you 14+ watts or an aerodynamic handlebar/stem combo that could also save you 7+ watts?

The handlebar and stem may be the next aerodynamic frontier. It creates the most drag on the bicycle, so clearly there is a big opportunity to improve it. That said, wheel designs are further ahead than aero drop bars.

A new set of aero wheels start at around $2000 and go up from there. Whereas a new handlebar may only cost a few hundred dollars. If you’re in the market for aero components consider starting with the bar. You may be pleasantly surprised at the outcome.

P.S. Have you done any watt testing of your own? I would love to hear about it and publish it here. Please let me know in the comments.

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On Bicycles Resource

A look into real world cycling aero gains – Part 2 on Body Position

Welcome to part 2 of how cycling aerodynamics effects the real world. This article will look at body position, training and most importantly how these translate into real results for you.

Introduction – Why I’m posting on this.

Part 1 – Aero gains for clothing

Let’s begin. The Perfect Body Position for Aero Savings

Aerodynamic savings on bicycles can cost a small fortune. What I love about getting gains from body position is that it is 100% free.

It seems pretty intuitive that lowering your body will reduce drag as you are making yourself a smaller object. But, which position is really the most efficient? And does fatigue impact aerodynamics? And when does vascular restriction outweigh the benefits from an aero position?

It turns out these all play important factors, and it’s not as simple as slamming a stem or using the drop bars to get gains. (I’ve tried both of these options).

What does David Miller have to say?

David Millar is a Scottish former professional road racing cyclist. He’s no saint, having admitted to using EPO, but he was the first British rider to have won the leaders jersey in all three Grand Tours. He was also the British Time Trial and Nation champion and has worn of all Tour de France Jerseys.

And, most importantly, he’s the most winningest time trialist that I know of who has shared his training techniques.

David Miller Time Trialist

A1 coaching did a series of videos with David Miller. And he’s surprising forthright of his experiences with aero testing. He shared that he’s learned, that, “You can acquire as much data as you would like, be it from a home trainer or a wind tunnel, but when it comes down to it, it’s that course on a road where you will be able to gauge [the benefits of position] most consistently.”

He tells a story of working on his aero position with coach Peter Keen who did a lot of research and testing using wind tunnels and science. David thought that he also needed to do a lot of science to get his position right. But Keen said, “You look fast David, pretty much that’s what we’ve learnt. If you look fast, generally you are fast, and you can’t do much more about it.”

BikeRadar’s testing confirmed this line of reasoning. They showed that even though Ben Delaney could ride for a short time in a more aero position, he was actually losing aero performance (from lateral movement and constant adjustments) because his body wasn’t relaxed in that position.

So before we get into which position is most efficient. Here’s what David says are the five things he focused on to improve his position and performance.

Number 1: Get a course, so that tests are repeatable outdoors.

Number 2: Focus on your current position on your current equipment to get a benchmark.

Number 3: Apply training around the course you are trying to improve your time on.

Number 4: Make sure you have all the equipment that suites the course and temperature you are riding in.

Number 5: Race strategy. Your pre-race should be the same for every race.

Using David’s system in the real world

As a result of David’s interview I focused my training around my position. I dropped my stem to a position where I was just comfortable and began adding drop-position sessions into my weekly training.

Here’s what I learned. It’s hard to sustain the same effort in a more compact position. The reason was that my heart rate was higher at the same effort/pace with my body in a more compact aero position. With training I was able to increase high effort segments from 1 minute to 8 minutes on the handle bar drops. 12 minutes short of my 20 minute goal at my desired effort.

Was the training worth it?

Yes … and no.

Yes it was worth it for position training. One year on and I am much more comfortable in that new position. However, the performance gains I did experience from this kind of training did not translate into performance gains for century type rides. My original goal was to improve my functional threshold power FTP as well as my aero position. Instead I improved my anaerobic lactate threshold and my aero position.

As you will see below, it may have made more sense to focus on a less aggressive position.

Both GCN and BikeRadar have posted interesting studies on which body position on the bike is the most aero. However they took different approaches.

GCN did a test where they held the same watts over time and then tested for time savings. Whereas BikeRadar tested various positions and tested for watt savings. I think they are both equally interesting.

GCN’s Body Position Test & Results

GCN tested riding with straight arms on the tops of the bars (non-aero position) versus riding with bent arms with hands on the drops. They saw a significant savings between the two.

Non-Aero Position:

  • 200W – 30.2KPH
  • 300W – 36.1KPH
  • 400W – 39.9KPH

Aero Position

  • 200W – 33.4KPH
  • 300W – 40.1KPH
  • 400W – 43.6KPH

Clearly, riding with your hands on the drops is much faster than riding with your hands on the top bars. But is it the most efficient position? BikeRadar helps answer that question below.

GCN non-aero position vs aero position test results

BikeRadar did another test in which they tested 4 positions.

Position 1: Straight arms with hands on the tops.

Baseline

Position 2: Bent arms with hands on the tops.

It lowered his back angle significantly and took his arm angle out of the wind.

Saved an average of 94 Watts which translates to 362 seconds over 40KM at 250 Watt average.

Position 3: Straight arms with hands on drops.

Saved an average of 67 Watts which translates to 214.85 seconds over 40KM at 250 Watt average.

Position 4: Bent arms with hands on the drops.

Saved an average of 112 Watts which translates to 442 seconds over 40KM at 250 Watt average.

However, even though it saved him wattage, he was moving around a lot and it was clear he wasn’t going to be able to stay in that position over 40KMs.

The overall winner?

It turns out that the most efficient position for Ben was Position 2. It saved him slightly less time than position 4, but because it was more sustainable and comfortable, overall his body would be significantly less fatigued holding it over the course of 40 km’s and would give him the greatest gain.

 

Here’s both BikeRadar and GCN’s videos:

BikeRadar – Finding the perfect cycling position

GCN – Aero challenge. How much time can you save?

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A look into real world cycling aero gains – Intro and Part 1 on Clothing

The study of aerodynamics is a science, but when it comes to cycling it can be a bit of a black art. Go to any bike shop and you will see options from aero frames, aero helmets, aero bars, aero wheels, aero clothes, and the list goes on. But it’s unclear which of these offers the greatest benefit to the modern cyclist – and how much of an impact they will have in real world settings.

For example, Specialized claim that their latest Venge bike can save you a whopping 5 minutes over 40km’s. But what is that primarily due to? The frame, the bars, the wheels, or the riders body position? And what are they comparing it to? It’s hard to know and Specialized doesn’t release that information.

Furthermore, most cycling conditions are anything but what are offered in wind tunnels. Terrain is often undulating and intermixed with steep hills, rolling descents, rain, crosswinds, potholes, traffic lights, rough surfaces, and bare tarmac.

It it faster riding a lighter bike? Or is it better to invest in a more aero one?

Throw in group rides, drafting and tight cornering in crits… and one wonders if all the “science” is truly relevant to the real world.

I’ve ridden a 2005 Trek 2100 for the past 12 years. It lacks a lot of the features found in modern bike design. Yet, during group and solo rides alike, my times are very similar to riders with much more aero setups. Which has got me wondering, what are the real advantages to aero? And is there a clear cost/aero equation one could use to ensure they really are getting the best bang for their buck?

See that sweet lookin’ classic Trek ride on the far left

Intro

Welcome to part 1 of a multi-part series on aero dynamics where I will be sharing what I’m learning through the tests of others and personal experiences. This will be an attempt to reconcile industry tests/results with the real world.

I will be starting with the cheapest options for aero savings (clothing and body position) and working my way eventually to what I’ve learned about aero frames.

Specialized and recently GCN (Global Cycling Network) have released tests on loose fitting cycling apparel versus form fitting ones. And the results… are interesting.

Using a wind tunnel Mark Cote and Chris Yu of Specialized ran their tests at 50k/hr. And tested both winter gear and warm weather kits. According to their findings, there was a difference of 83 seconds over 40 kms for the cold weather clothing. For the warm weather gear the difference was 91 seconds between a size M club fit jersey and a size S form fit jersey.

“We’re talking about a difference that’s more than race wheels.” Chris Yu. Specialized R&D

But how does it compare to the real world? Well that’s where GCN’s test comes in.

Click here to scroll down to see GCN’s results on cycling aero performance savings with regards to loose fitting versus form fitting clothing.

When did aero first become important to me?

Watch World Tour cycling and it’s perfectly obvious why aerodynamics is important when race leaders are separated by seconds and time trials can split the field.

But what about the recreational racer?

In 2016 I road what was to be my second last event of the year. The morning started as many epic autumn rides do; with light sprinkles of rain and the threat of more to come. I put on a blue Sugoi cycling jacket gifted by my parents. It’s a great design (or so I thought). The arms and back are held together by magnets and literally peal away if needed to reveal a vest.  It’s perfect for layering.

A Wet Salmon Arm Bike For Your Life Century Ride

The peloton split early. I joined the front group as we attacked the first climb. I’m a climber, I don’t have a specialty per se, but if I did it would be climbing. I noticed immediately that the ride was feeling tougher than usual. I took note that my legs weren’t as recovered as I thought they would be. Slowly I lost touch of the riders. Dropping back about 200ft.

We hit the flats and I felt confident that I would find my rhythm and catch them. It was an out of town event, but a strong rider that I knew had also lost the front group, so I intended to catch his wheel and then catch the front group again.

Salmon Arm Bike For Your Life Century Ride Route

Unfortunately neither of those scenarios panned out. Riding on a relatively flat section I was easily 3km/hr slower than I would normally ride and was feeling frustrated at my apparently tired legs.

The leading pack was long gone and soon I was caught by a strong chasing group. To make matters worse my father was in it (he’s a very fit father *cough). By now the rain was beginning to open up and soon it was pouring down. I joined the second group. And by the latter leg of the race my pace was closer to normal.

Looking at the times at the end of the day it turned out that my father and I finished just 4 minutes behind the race leaders. How could this be? I thought, clearly the front group had been riding much stronger.

The reason should have been obvious, but I didn’t know what I didn’t know. Later some of the riders came up to me and joked about my parachute. Unbeknownst to me, the clever 2 part design of my jacket had caught the wind and converted the top layer into a perfect parachute.

It wasn’t until the rain started pouring that the jacket was soaked enough to stay compact.

I thought long and hard about the results of that ride and have since learned that clothes can make a significant difference to aero performance. As we’ve learned from Specialized’s wind tunnel test.

Real world aero apparel test by GCN

GCN also posted an excellent video evaluating the speed difference between a loose fitting cycling jersey (say 1 size too big) versus a snug one at the same watts. The results were equally surprising.

This was a real world test held at 3 different intervals of power.

GCN results on aero clothing for cycling
GCN results on aero clothing for cycling

As you can see by this picture. At just 200W average a rider has a 0.8km/hr advantage with a tight shirt versus one with a relaxed fitting shirt. This goes up to 1.8km/hr at 400W.

When one considers the times they are pulling at the front of a group, closing down on a leading peloton or attacking solo, these numbers suddenly become much more important.

“The bottom line is whether it’s summer or winter if you just pay a little attention to how well the stuff fits your looking at a couple minutes over a medium to a long ride. So it really does matter.”
Chris Yu, Specialized

What have your experiences been with aero? Have you noticed a major performance advantage or disadvantage? Cycling is as much about science as it about personal stories, please share yours in the comments below.

Watch the full video here.

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The Wilier Triestina Zero.9

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The 2014 U.S. National Road Cycling Championship was a lively race, full of unexpected twists, attacks and breaks. When Eric Marcotte crossed the finish line and won the title, he was riding his trusty stead the Wilier Zero Nine.

The field was strong. He was racing against favourites like Taylor Phinney, Ben King, Phil Gaimon and Alex Howes.

It was an exciting finish. After a gruelling final climb which stretched the already tired front group Zwizanski attacked. Semper grabbed his wheel and Jones and McCabe joined.

2014 US National Road Cycling Championship
What’s left of the field nears the top of the last climb of the 2014 US National Road Cycling Championship

Jones attacked again with just 2km to go. But the chasing group wasn’t far behind.

Finally, in the last corner the attackers were caught by the chasing group.  With Jones, Wren, Stemper, Kyer, Marcotte, Howes, Zwizanski, Rathe, McCabe, Miller, Butler, Reijnen and Busche coming together, it came down to a sprint finish.

2014 US National Road Championships
Eric Marcotte sprints to the win on the left

It was a fitting end to the season for both Marcotte and the Wilier Zero 9. By the end of the year they had seen numerous podium finishes. Something race journalists may not have expected for the Wilier Zero.9 – the Cinderella in the family of Wilier pro bikes.

Wilier Zero.9 Part of the Wilier Triestina Racing Division

In 2015 Outside Magazine ranked the Wilier Zero.9 2nd after the Specialized Tarmac and above the Trek Emonda. Dramis wrote, “It seems like every year Wilier sends a bike to the Test is another year a Wilier makes it into the Top 3. Every Wilier I’ve ever tested has been a standout, from the Cento 1 to the incredible Zero.7, they’ve all been winners. The Zero.9 continues that tradition.”

Unlike its two racing siblings (The Zero.7 and the Cento Uno) the Zero.9 had been largely missed by journalists, due in part to their enthusiasm for the Zero.7, and by some pro-racers as they moved towards specialization.

The reason, you ask? It was partly because of marketing and partly because of its name Zero.9.

The Zero.7 is an excellent climbing bike weighing in under 790 grams and less, hence the name Zero.7. While the Cento Uno is an aero bike weighing just under 1300 grams.

Because the Zero.9’s frame weight was also under 1000grams, it was given the same Zero. naming style. With a size M weighing in at 940 grams.

But the name created confusion in the market place. With many people assuming that Zero.9 simply meant it was a heavier version of the Zero.7. Much like the Trek Emonda SL is a heavier variant of the Trek Emonda SLR.

But Wilier had built a very different bike. They tried to describe it in their marketing by comparing it to both the Cento 1 and the Zero.7.  It was a bike for climbing, like the Zero.7, but it’s stiffness wasn’t limited by the hill climber’s 790 gram limit. And unlike the Cento Uno, it wasn’t an outright aero bike either.

With a race geometry, an oversized bottom bracket, and the same carbon construction as the Cento Uno, Wilier seemed unsure of where to place it in an increasingly specialized field.

Wilier Zero 9 geometry
Wilier Zero 9 geometry

But the Zero.9 has yet another surprise. It’s an incredibly good road bike.

Road.cc wrote, “The Wilier Zero 9 is a performance orientated road bike … for people who want to get around the course as fast as possible.”

In 2015 Outside Magazine ranked it 2nd after the Specialized Tarmac and above the Trek Emonda. Dramis wrote, “It seems like every year Wilier sends a bike to the Test is another year a Wilier makes it into the Top 3. Every Wilier I’ve ever tested has been a standout, from the Cento 1 to the incredible Zero.7, they’ve all been winners. The Zero.9 continues that tradition.”

Bicycling Magazine concluded, “If you want a bike to toe the start line and be a contender at the finish—just add your pedals and bottle cages, and the Zero.9 is ready to go.”

So what made the Zero.9 so good? Wilier, an Italian Bicycle company since 1906, is known for producing top-end road bikes. They take what they learn from each model and improve the next. In recent years they invented the asymmetrical chain stay to improve power transfer from the chain to the rear cassette and the 386 bottom bracket to reduce the flex from the pedal to the bottom bracket.

When they made the Zero.9 they continued in this tradition. The Zero.9 geometry and the Zero.7’s are virtually identical. Also, like both the Zero.7 and the Cento Uno, the Zero.9 uses the high-modulus 60-ton carbon fibre in its construction. Making it a very strong, lightweight, and responsive machine.

2015 Wilier Zero 9
Wilier Zero 7 Geometry
2015 Wilier Zero 7

But they also improved the Zero.9 where they could. With a spec at just around 960grams, they had room to improve stiffness with the addition of carbon layups where it was most needed. And they kept the 386 bottom bracket. The outcome was a balanced bike that rides confidently in descents and sprint finishes.

Wilier Zero.9 386 Wide Bottom Bracket

While the Zero.7 was heralded as one of the world’s best climbing bikes, due to the fact that it is one of the most balanced lightweight frames in the peloton, it did have one flaw – a bit too much flex.

The Zero.9 fixes that problem. Brad Ford of Bicycling magazine remarked, “Through turns and on descents, I could pilot the Zero.9 with confidence.” And the power transfer of the 386 bottom bracket with the Asymmetrical chain stays makes it incredibly light and responsive when attacking.

Wilier Zero.9 Asymmetrical Rear Arm Top View

But one of the best surprises of the Zero.9 is the comfort. For a bicycle designed to be stiff and lightweight, the geometry and carbon do an excellent job of providing a comfortable ride. This was one of the things I noticed during rides.

Eric Marcotte shared with Bike Radar that if he were to have the opportunity to ride the Zero.9 again he would. “Haven ridden and trained on this frameset for a year now, I’d choose it myself. Super responsive, great position and comfort for me on the bike, good positioning over the bottom bracket for cornering, stiffness in the bottom bracket, and sharp front end.”

Eric Marcotte’s Zero.9 special paint after winning the U.S. National Championship Road Race

In the Dutch magazine Bike & Trekking, the Zero.9 was also well received. They wrote that out of the 3 Italian race bikes they reviewed Bianci Intenso, Olympia Ikon and the Wilier Zero.9, it was “the Zero.9 that would have a permanent place in my shed.”

Conclusion

In an age where manufacturers are searching for marginal gains and aggressive frame redesigns the Zero.9 continues in the tradition of the pure race bike. Wilier has taken great bicycles and improved on them year over year. The result? An Italian bicycle that evokes emotions with a design that places emphasis on form, function and history.

While the Zero.7 and Cento Uno find themselves neatly in the categories of Climbing and Aero frames, the Zero.9 defines its own. It is uncompromising in its power transfer, comfortable over diverse terrain, and light enough to crest any climb at the head of the pack. It is a Racer’s bike.

I’ve found this bike to be perfect for the hilly countryside of my area. And as a bike that is on the rarer side, if you do have an opportunity to ride it, I would highly recommend you take it.