It's easy to be lured into the idea of riding faster by spending money on "fast" cycling gear. There are three ways to ride faster:
- Develop a stronger "engine" (basically, your muscles and your lungs).
- Make yourself and your bike lighter (this is most beneficial on hills).
- Make yourself and your bike more aerodynamic. This is most beneficial on the flats, when speeds are over 18 mph.
This post focuses on aerodynamics; the time saved versus the cost of the gear.
Why is Aero Important?
On a flat course, at speeds between 20 and 25 mph, 75% to 80% of your power goes toward overcoming air resistance (5% is for mechanical resistance (bearings, chain, etc.) and the rest is the friction of your tires against the road). The more slippery you and your bike are, the faster you'll go. Of this aerodynamic drag, approximately 2/3 comes from you (your position on the bike and what you're wearing) and 1/3 comes from the bike itself. Of the drag that comes from you, almost all of it is related to your position on the bike. A small amount comes from your clothing.
Standard Aero Gear and Costs
Triathletes seem to go through a standard procession of buying aero gear:
- Adding clip-on aero bars and forward seat post to a road bike. $150-$250, plus $100 - $200 for a professional to set them up so you fit properly.
- Time Trial bike $2,000 - $5,000
- Aero helmet $75 - $150
- Disc and tri-spoke wheelset $1500 - $2500
How Much Faster Are They?
I'm summarizing a lot of detailed information from two excellent articles here and here.
If you're considering buying any of this gear, I'd encourage you to study those. But I'll cover the basics of what they found from wind-tunnel testing.
The baseline is a standard road bike (ridden with hands in the drops), standard road helmet, and standard road wheels. The time saved is based on a 25 mile, flat course (there would be less time difference on hills, because at lower speeds aerodynamics have less influence).
Clip on bars for a road bike 2.5 to 3 minutes
Time Trial bike 5 to 6 minutes (or 2.5 to 3 minutes over a road bike with clip ons)
Aero helmet 1 to 1.5 minutes
Disc and tri-spoke wheelset 1 to 3 minutes
All of this gear put together could, in theory, save you five to ten minutes over 25 miles. But it would cost you $500 to $7,000.
Real World Considerations
Clip-on bars for a road bike. If you're currently riding a road bike, adding clip-on bars is the easiest, cheapest thing you can do to get faster. But they need to be set up properly--not only to only get a good aero benefit, but also to make sure you don't change your position so that you're actually generating less power. Things to consider:
- You'll have a hard time doing the setup by yourself--I recommend that you hire a professional (spend $100 - $200 at a high-end bike shop).
- You'll likely need a different seatpost that moves your whole body forward on the bike.
- Riding a road bike on a time trial setup can be annoying and uncomfortable for anything but racing.
- Once you're set up properly, measure the seat height and the bar configuration so you can switch back and forth between your standard road setup.
Time Trial bike. They sure are beautiful, and they even look fast. We can all think of a dozen reasons to buy one. Here are a few on the flip side:
- Do you have room to store it?
- It's one more piece of equipment to maintain.
- If you train and race with a power meter on your road bike, you'll either need a second power meter (if you use a crank-based system) or need to switch your rear wheel back and forth.
- You likely won't ride it nearly as much as your road bike. Will your non-triathlete spouse be okay with you spending $4000 on a bike you'll use maybe 20 times a year?
Aero Helmet. These are a quick, cheap way to shave time. But the downsides:
- Aero helmets have much less venting than standard road helmets, and get very hot on a warm day or during a long race.
- If your setup isn't ideal, you won't get much benefit.
- Unfortunately, some triathletes make a habit of criticizing other people's gear choices, saying that some "aren't as good as their gear." These snarky comments usually come in the form of, "Losing 20 pounds would help him go faster than that $5000 bike would." For some reason, aero helmets seem to draw the most of these goofy criticisms. While I certainly don't condone the practice, you should be aware that you might hear them. If you'll be distracted by these comments and become self-conscience on race day, that lack of focus might not help your time. Then again, if it makes you mad, you just might go faster...
Disc and tri-spoke wheelset. Again, these not only look fast, they also sound fast. But are they for you? Some things to consider:
- If you race and train with a Powertap powermeter, you'll need a second one for your disc wheel.
- On a race with a lot of hills, the extra weight might slow you down more than any aero advantage you'll gain on the flats.
- Strong crosswinds can make a bike with a disc wheel hard to control.
How to Decide?
How we each choose to spend our money is obviously a very personal decision, and is based on all sorts of factors. My opinion is that it's your money; spend it (or not) as you please.
Truly Free Time Savings
Here's a fun game that costs nothing and has none of the disadvantages discussed above. Look at the potential time savings for any aero gear you're considering buying. Subtract that time off of your last Olympic-distance race. Regardless of if that savings would have earned you a podium spot or not, think about how you would have felt with that as your official time. Then decide how much money that feeling is worth, and purchase accordingly.
A Closing Thought
I race with clip-on aero bars on my road bike. Considering my goals in racing, the costs of a time trial bike and other aero gear are too expensive for me. But the joy of passing of passing someone who's on a $5,000 time trial bike with a disc wheel and aero helmet? That, my friends, is priceless.
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