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Home » Cycling » Cycling: The Noob’s Guide to Aero – What You Need to Know. And Ignore.

Cycling: The Noob’s Guide to Aero – What You Need to Know. And Ignore.

June 2014
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Cycling all on its own is hard enough. Picking the right road bike for you?  A veritable mine field of choices.  Then you hear guys talking about aero this and aero that, you’ve got time trial helmets and now even aero road bike specific helmets.  You’ve got wheels and handlebars, forks and entire bikes that are now billed as aero.  And all of it is expensive.  The bike?  $3,000, minimum.  Wheels?  Another $2,000.  Helmet?  $250.  Handlebar?  $220, and you have to install it and wrap the bars for that cost.

To make things extra fun, you’ve got people running around claiming “it’s all about the legs” at first, suggesting all of that aero stuff makes little difference.

So who is right?  Everybody.  Technically.

The common misperception is that aero equipment will make anyone faster.  This simply isn’t the case, and there’s a very good explanation that wraps all of this into a tidy little bow:  You have to be able to ride fast enough for the stuff to work in the first place.  That’s why it’s all about the legs at first.  I’ve seen, and passed, on several occasions, women cruising along on a $3,000+ Time Trial (or Triathlon) bike, down on the aero bars, nicely tucked and “aero”, cruising along at about 16 mph.  I shoot by, hands on the bar tops, at 20 on my road bike…  For someone who rides 16 mph, a TT bike is an utter waste of money for one simple reason:  You’re not fast enough to gain the advantage of having a tri-bike in the first place.  As we ride, we are forced to cut into the air.  Taking wind out of the equation, you’re not pushing enough air at 16 mph for the benefit to be worth the cost.  You’d be able to ride just as fast with a microscopic amount of additional effort on a plain old road bike.  However, as one picks up speed, say to my aforementioned 20 mph, the force required to cut through the air increases dramatically.  Up to 25 mph and you’re talking about some serious wattage (the amount of force required to the pedals to turn the crank arms).  20+ mph is where “aero” makes a decent difference and 25 mph is where it’s a huge advantage…  How much?  If you went whole hog with aero, bike, 50 mm deep rims, aero helmet, tight fitting clothing…  At 25 mph, over one hour you’d save three minutes (that’s more than a mile folks, it’s significant) – at least according to this article that was written after checking the differences in Specialized’s wind tunnel.  Special thanks to Cranky’s Corner for sending me the link btw (thanks brother).

There’s a problem with that article though…  It tries to put an answer to these questions:  “But what if anything do those numbers really mean to the average cyclist? Is that a difference that actually matters – that you can feel?

Do you see the conundrum they’ve presented?  The average cyclist can’t ride 25 mph for an hour.  Heck, the average cyclist can’t ride a mile at that speed without a tailwind.  And therein lies the rub.  If I were to hazard a guess, and I will, they picked 25 mph because that’s the speed where the aero equipment really shows a stark advantage.

That said, I can say, with utter certainty, there is a decent advantage at a 20 mph average (which translates to a cruising speed of 21-22 mph to account for stopping for traffic signals and such)…and I’ve only got the painted on clothing and aero road bike – I don’t have the helmet or the deep rims (I’ve got 28 mm deep aluminum clinchers with aero spokes and a mid-high-end Specialized Propero II helmet).  I know there is a difference because I spent my most of my first 8,000 miles on a Trek 5200 with standard round composite tubes and cheaper, loosely fitting clothing while my new bike, a Specialized Venge is entirely aero race bike (the very bike they used to test the differences in the linked article above, though a lower-end model) and I now have pro jerseys and shorts.  There’s one other place an aero bike (not a Time Trial bike, an aero road bike) helps a lot:  In a group.  If you’ve ridden a lot in a group, at high speeds (22+ mph average) you know that getting a decent draft can be the difference between staying with the pack or falling off of the back, right?  Well the bulk of the draft works around the cyclist, not so much their bike so having an aero bike in a group does offer a slight advantage where it matters – down low, beneath the draft.

Lastly, I want to look at clothing.  Cycling with speed is vastly easier with clothing that fits tightly.  In fact, I would argue that a snug fitting jersey and proper shorts offers a cyclist one of the greatest aerodynamic advantages over baggier clothes that will have a slight “parachute” affect.  Fortunately I’ve been at this fitness thing long enough to have developed a pretty decent body so I don’t have any extra fat around my gut and my arms don’t look like funky sausages when I don my jersey.  There are, absolutely, body issues that have to be dealt with prior to purchasing tight clothes.  To test this theory, once you’ve made peace with your physique of course, go for a short five or ten mile ride wearing a loose, baggy tee shirt and some cargo shorts…  Then try the same ride wearing a skin-tight jersey and a decent pair of shorts.  You will feel a difference.

Now, before I close this post, I want to address one other hugely important aspect of cycling aerodynamically:  The cyclist.  Position on the bike is everything.  It’s more than an aero bike, aero wheels, painted on clothes and a decent helmet:  Fixing it is free too (or close to it, you may have to buy a new stem and have your fork cut down to lower your handlebar).  I am currently about as low as I can go (comfortably) on my Venge (my saddle is 5″ higher than the top of my handlebar).  This is by design and I actually have worked to become flexible enough to be comfortable riding with my back parallel to the ground.  In fact, I ride in about the same position as the guy in the article linked above…a little lower even.  Cycling with a flat back, rather than in an upright position where the cyclist resembles a sail atop his or her bike, will add as much as two miles per hour to your speed.  As suggested in the linked article and modifying it, try this on your way home from work today to understand the difference…  Lower your window and stick your arm out the window parallel to the ground with your fingers creating the leading edge that’s cutting into the wind.  Then bend your wrist keeping your hand flat so that your hand is at about a 45 degree angle to the ground.  That’s all the need be done to understand (in fact, you don’t even have to bother with the exercise if you’re nodding your head right now).  To train to ride low I simply lowered my stem a little bit every few weeks and made sure to spend at least one of my training rides in the drops the whole time.  Eventually, with work, I got used to it.
specialized-bg-fit

Often, people in the know will often suggest that riding low is less comfortable but I disagree completely.  In fact, I used to have severe lower back pain that required a couple of Aleve to knock out on a regular basis (once or twice a week).  I’m down to one, once every month or two, so I don’t know what they’re talking about when they recommend that upright posture.  Cycling low has clearly been good for my back.

So, after all of that, the thing to remember about “aero” in cycling is that you have to be able to ride fast enough to make it work.  This is why you often hear “work on your legs first”.  Until you’re fast enough to make “aero” work for you, the gain isn’t drastic enough to be worth it.  Once you are fast enough, “aero” is worth every penny you can throw at it.


6 Comments

  1. ” For someone who rides 16 mph, a TT bike is an utter waste of money for one simple reason: You’re not fast enough to gain the advantage of having a tri-bike in the first place.”

    some good points made here… I’m not sure I agree with the above, however.

    it’s all about power vs wind resistance

    • bgddyjim says:

      Perhaps I should have rephrased the “utter waste of money” part, I thought long and hard on that. The truth is, though, at 16 mph, you can ride just as fast on a comparably set up road bike, no aero bars, and the road bike is vastly more versatile (you can ride in groups etc.). Perhaps it would have been wiser to just stick with that statement.

  2. Agree about the back comment. I’ve had back problems most of my adult life off & on (working in the Outdoor Education sector didn’t help much either, especially before good manual handling practise became the norm). I find that a ride on the drops seems to ease things. Not too bothered about the extra speed, though that is a good by-product as long as I’m not looking for views.

  3. chrislocke90 says:

    This is a great guide to what’s not actually necessary! Makes me feel better about not riding a TT bike in triathlon too!

    • bgddyjim says:

      Chris, you’re right. However, and this is very important, there is a place for a TT bike. I know a few guys who have them, one guy is a nationally ranked time trialist and the other is a triathlete. They both use the bike in the manner for which it was intended. The third guy is the problem… He’s one of those dopes who only cares about riding the fastest possible equipment, safety (and the fact that he flats twice a week because the flat protected 23 mm tires “aren’t as aero as 20 mm racing tires”.

      This is a guide to hopefully convince a few people not to be that guy.

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