Tested: Speedplay Zero Aero Pedals

Before we get started, let me make a confession to all of you. I’m a huge fan of Speedplay pedals. I’ve been using them on my bikes since their inception in 1992, and still use X Series pedals today. At ERO, it’s quite common to recommend Speedplay to our clients, though we don’t sell them (maybe we should!). I’ve been interested in testing the Speedplay Zero Aero pedal since it’s unveiling, but testing the aerodynamics of the foot/shoe/pedal interface is not an easy task. I’ll explain the challenge below, but if you really don’t care about such things, scroll down a few paragraphs to see the results of our testing.

In the eyes of the wind, the shoe, cleat, and pedal (let’s just call this the Pedal Interface) isn’t pretty. Most Pedal Interface combinations are bulky and present a significant frontal area that’s churning through the air as we pedal. There’s little doubt that substantial drag is likely created from this area. For instance, certain shoes test more aerodynamic than others, and proper shoe covers can have a positive effect on reducing drag, but not a lot has been done to smooth airflow underneath the shoes when it comes to the pedal interface; certainly nothing has stuck.

Testing the aerodynamics of the Pedal Interface with an actual rider is difficult. For instance, if you wish to test the difference in drag between two competing pedal systems, you’ve created quite a challenge for yourself. First of all, you’ll need to use the same shoes. Not just the same make and model of shoes, but the same shoes. Why? Because no two shoes are exactly alike and will, therefore, test differently from one another. Once you’ve decided to use the same pair of shoes, you need to insure the cleats place the pedal and, therefore, the foot in the exact same position. If you don’t, and you’re going to have a really hard time doing it, the foot will not likely pedal at the same angle which will, in turn, change the frontal area. Heck, tightening the buckles, laces, or boa’s differently can affect the frontal area of the shoe. Any change in the frontal area of the entire pedal interface and you’re no longer measuring the difference in drag between two pedal systems but, instead, the difference between two foot positions.

Speedplay, while asserting the Zero Aero does have an aerodynamic advantage, doesn’t actually claim what the reduction in drag may be. I like that. Maybe they don’t have the data, I know for a fact they understand how difficult it is to test, so instead of giving you pie-in-the-sky numbers, they prefer to make no specific claims. Okay, let’s get to what we found.

Test Riders:

  1. Rider #1 – David
    1. Bike: Specialized Shiv TT
    2. Shoes: Sidi Wire SP Carbon (Speedplay Specific)
    3. Pedals: Speedplay Zero vs Zero Aero
    4. Power Meter: PowerTap G3
    5. Weight = 79.4 kilos w/bike
  2. Rider #2 - Leo
    1. Bike: Fuji Track Elite
    2. Shoes: Specialized S-Works 6
    3. Pedals: Speedplay Zero vs Zero Aero
    4. Power Meter: Power2Max
    5. Weight = 85.5 kilos w/bike

Aero test technology: Alphamantis Track Aero System

Location: VELO Sports Center (LA Veldrome)

Protocol: Test riders completed multiple runs with both Zero and Zero Aero pedals. Each run consisted of at least 12 laps. CdA was an average of those laps discarding both highest and lowest recorded lap CdA’s (Click here for a definition of CdA). Non-walkable Zero cleats were used for the Zero pedals. Cleats were exchanged and placed as close as reasonably possible on the same shoes. All pedals had identical spindle lengths.

Speedplay did not provide the product for this testing, nor did they know the testing was taking place. They were informed of the test results prior to publishing this article and provided permission to use photos from their web site. Otherwise, this was a completely independent test.

Both of our test riders had worked with ERO previously and had quite a bit of experience aero testing on the velodrome. This helped produce consistent results for all runs. Each was able to reasonably repeat their drag numbers, which is key for credible results.

The Numbers:

Rider #1 - David

Run # Pedal System CdA
1 Zero .2441
2 Aero Zero .2387
3 Zero .2437
4 Zero .2458
5 Aero Zero .2381
6 Aero Zero .2394

Average CdA – Zero Pedal:                 .2445

Avergae CdA – Zero Aero Pedal:         .2387

Average watts saved Aero Zero vs. Zero: 4.8

Time saved Aero Zero vs. Zero:

Distance Average Watts Time Saved
40K 200 28.7 seconds
40K 250 26.6 seconds
Ironman 200 2.2 minutes
Ironman 250 2 minutes

 

Rider #2 - Leo

Run # Pedal System CdA
1 Aero Zero .2352
2 Zero .2389
3 Zero .2390
4 Aero Zero .2359

Average CdA – Zero Pedal:                 .2389

Average CdA – Zero Aero Pedal:         .2355

Avg Wattage Savings Aero Zero vs. Zero = 2.9 watts

Time Saved Aero Zero vs. Zero:

Distance Average Watts Time Saved
40K 200 17 seconds
40K 250 15.7 seconds
Ironman 200 1.27 minutes
Ironman 250 1.19 minutes

Discussion:

Both riders consistently experienced a reduction in drag from the Zero Aero pedals. David was near 5 watts, while Leo saw almost 3 watts. Why the difference in drag savings between the two? There are any number of variables involved, but I did note one interesting difference between the two riders. Their Retul data shows David has a flatter pedal stroke than Leo, who tends to point his toes a bit more. For those familiar with Retul, David’s maximum ankle angle (plantarflexion) is 88 degrees, while Leo’s is 96 degrees. We can reasonably assume, therefore, that David exposes the pedal interface’s frontal area more than Leo, who would expose it less and the top of his shoe more. Perhaps, then, David is taking better advantage of the pedal’s aero properties, or it’s simply exposing the top of the shoe more would be an increased frontal area for Leo no matter what pedal system is being used. Also note, David’s Sidi shoes are Speedplay-specific, so no base plate is necessary to install the cleats. Either way, both saw a clear and repeatable drag reduction.

David's foot position (left) vs Leo's (right). You can see the difference in angle and what part of the Pedal Interface they're presenting to the wind.

Conclusion:

Down and Dirty - the Speedplay Zero Aero looks to live up to its name. It saved our riders 3-5 watts, and about 1-2 minutes over the course of an Ironman distance race.

Look, I’m an unabashed fan of Speedplay pedals. I think, from a fit perspective, they make a lot of sense and solve many potential biomechanical issues for an athlete. That, combined with the dual-sided entry, and availability of multiple-length spindles, already make them a good choice for our clients. Now that we see an aero advantage to the Zero Aero pedals, I have yet another reason to recommend them.

Now, what we didn’t do was test the Speedplays against other pedal systems (i.e. Shimano or Look) because it’s difficult and time consuming to accomplish. Perhaps we will in the future, but I do know these tests have been done in the past, and the Speedplays have come out ahead of the others, it’s just not data I can share with all of you. I would note that Bradly Wiggins did extensive aero testing before his hour record last year, and he chose to use the Speedplay Zero Aero pedal.

It really shouldn’t be a surprise to anyone that these pedals are more aero. Richard Bryne, the founder and owner of Speedplay, was thinking aero long before many others were in the bike industry. In fact, he could likely be credited with developing the first aero bar as well as other aero innovations like the steep seat tube geometry we see in Tri bikes today (If you ever corner him, he’s got some great pictures from way back in the day). So, yeah, he’s not just about pedals, he just happened to see an area in the cycling market that needed an upgrade and, boom, Speedplay was born.

Questions? Comments? Let’s discuss.


 

We hope this information is helpful and instructive. That's really the whole point of conducting these tests for you. It's not free for us to test, so if you're so inclined, you can donate to the aero test fund below. Thanks for reading. Feel free to ask questions.

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