Saturday, May 1, 2010

The Nerd Report: Aero Wheels vs Regular Wheels

*disclaimer* The following data is NOT scientific and was not done in a controlled environment. I was subject to variable winds (which were NOT extreme) and gusts from passing trucks. This data is most likely meaningful to ME only, as my body shape, weight, bike, etc are different from YOU. However! I think this data is pretty consistent and does have some merit, in my non scientific opinion.

I tested out a pair of rented Zipp 808's this morning and compared them to a pair of regular set of wheels, a rear DT-Swiss RR1.2 and a front Fulcrum Race 7. Neither are very deep in rim depth. Both rear wheels have a PowerTap SL+ Hub, so I was able to use power to control my tests.

I started with 2 runs (~4 miles each) on the regular wheel set, followed by two runs on the Zipp's, then repeated, making a total of 4 runs each. The course I used was a 4 mile out and 4 mile back, somewhat rolling but mostly flat course.

I went easy on the way out, then held a wattage between 170 and 180 watts on the way back in. I wound up with 67.6 miles for the day! 32 of which were used in the testing at target wattage.

My findings? There was NO gain by using the Zipp 808's. ZERO! NADA! ZILCH!

I am really surprised! When I did the time trial vs road bike test back in early March, I found a noticeable difference (4-6% of energy savings!) that was consistent across the board. I was hoping for a noticeable difference in this test, whether it be as measly as 1 or 2%, but I got NOTHING! It was as if I was using the same pair of regular wheels in all 8 runs! I'm baffled!

Run #1 (Non aero on top, aero on bottom)

Run #2 (Non aero on top, aero on bottom)

Run #3 (Non aero on top, aero on bottom)

Run #4 (Non aero on top, aero on bottom)

Run #2 looked like I went a bit harder on the non aero wheels, pushing 9 more watts, which made me go faster, obviously. Run #3 looks like the wheels worked! But you compare that to runs #1 and #4, and there is really no conclusion. Perhaps more data needs to be collected? 67.6 miles for me was enough for the day....this is why I wrote the disclaimer above. I wish I could collect 10X the data on multiple riders, then maybe that would be enough to start making conclusions?

Another thing that I did not do was use heart rate. I don't train with it because I don't trust it because the heat, humidity, caffeine, amount of rest, diet, etc can muck with your heart rate sending it in any direction. Watts are watts. Either you are producing the watts or you aren't!

Like what I saw very clearly in my previous test, if I had gone the same speed, but used 5% less watts across the board, or gone the same wattage but gone 5% faster across the board, then yes, I would say these wheels made a difference. But I didn't see that.

Dangit! These wheels look sooooo cool! ;) I am glad that I plunked down only $235 to see that they are not for me instead of almost $3000 for some cool looking hardware that only looks cool.

My conclusion on getting faster? Tuning up the engine goes a long, long, looooooooooong way! ;)

Well at least I got some nice volume in to start May off in the right direction!

*final disclaimer* Take this report with a grain of salt. This is what happened to ME. The intensity and wattage that I went during these tests was the SAME intensity and wattage that I went during my half ironman in New Orleans. If I got these results today, I probably would have gotten the same results during the race. I hope that this report does NOT discourage you from trying or racing on aero wheels. If they make you faster, then awesome! I am glad that they work for you.


  1. WOW! First, nice freaking volume today Jon! Second, that is a lot of wheel changing .. so kudos to you for the preciseness if the trial. Third, gotta admit I am a little upset you didnt see any significant variance in your results. sorta blows because they look so damn cool!

    Now, before you write the Zipps off let ask a couple of questions: Was the ride with the aero wheels noticeably smoother? Do you think that the results would be different over a longer ride (like 25+ miles?)? If they are lighter and smoother than quite possibly over a greater distance the time savings may be realized? Or maybe not? Maybe you can find a used pair in the $1200 range on ebay or craigslist?

  2. That's pretty interesting, but I'm kind of with Jeff. I think I remember reading that aero wheels make the most difference over longer periods of time. So, you wouldn't really see a difference in a sprint tri, but you possibly would in a HIM. Just a thought.

  3. LOL @ disclaimer's! great review...I was actually starting to think wheels, though I have only owned a bike for a few months and only have a handful of rides on it. I should probably figure how to get air in the tires before looking at any upgrades!

  4. Good post.
    "Don't buy upgrades; ride up grades" - Eddy Merckx

  5. I do a 12 mile TT. I noticed the same think with my HED3's - nada.

    But I still race with them - they make me feel faster!

  6. I'm from the theory that if they look good and make me **feel** faster, then they are worth it! :) You're findings were definitely interesting though.

  7. Very good, if non scientific, report. And you not only saved me $3000, you saved me $235! ;)

    I blew a tire this weekend in my long ass 100 miler (happily my tube stayed intact). what tires are you using on your bikes?

    this was a good read, thanks for the blood, sweat and tears.

  8. Hey, if you don't want em, send them my way! LOL

  9. Ok I am shocked!!! Really shocked!! They claim 19 seconds saved on a 40k. You did it by the books, pulled the same watts on the ride, no spiking. Wow, sounds like a $3k rip off.

  10. Found your blog through Big Daddy Diesel, having just bought new wheels for my bike (not zipps, and because I drove over the front... obviously by mistake) :( I'm glad I didn't even look at them! Interesting!


Don't be shy! Leave me a comment!