Aero Deep Dive in The Specialized Win Tunnel – Ask a Cycling a Coach 188


Guess I’m that +3cm/kg guy…so you think M would fit me?
At most I’m concerned about the height chart which is almost 10cm low but that problem seemed to be the same for you and you say it has worked out…so?
Rest should be ok so I’m just about to buy…


I think you should go for the medium, specifically due to the height.

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I’m just guessing here, but I think a Small would be good for someone in the 5’9 to 5’11 range at between 145-160lbs.

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Was thinking L or M. But if you have no problem with S even if your height is 10cm more than recommend for S, then I could go by M I guess (want a good fit, no flapping around).


Those are some seriously low pressure recommendations! If I’m reading the chart right, I’m inflating my 25mm tire to 66psi and the 23mm tire to 68 psi?! Is this for mountain biking or road?


I have a medium LS skinsuit. At 181-2cm and 75Kg it fits pretty good north to south but, I wish it were a little tighter around. If I could do it again I’d buy a small.


Dave, what are your thoughts on bike computer mounts that hang in front of the handlebars. Are they really bad for aerodynamics? Is it better to put the computer on top of the stem?


How do we determine when it’s time for an aero frame? Lets say I have a CAAD12 with 20cm of spacers under the stem, is it worth buying a skinsuit and 50mm wheels or a total waste of time to go racing on that bike? There is an ocean in between affordable bikes like a $1000 CAAD12 and an aero bike that I would ruin with a higher than average stack height, which would also dishonor the bike and bring embarrassment upon me.


yikes - you think 25.3 MPH is far from elite for a 70.3?


Yes. I am reasonably competitive on the bike, but there are many people who can crush me. Then, when I show up at proper TT or even a crit, the proper cyclists kick my behind even more


How do you find the LS skinsuit in terms of cooling?
Would it be too hot for the italian summer?
Should i go for the SS (or for the yellow LS one?)




@sciuste I have the LS with out a pocket and use it for time trials of 1 hour or less only. It feels like most others I’ve had as far as cooling and I think if on a sunny day with temperatures pushing past 21-23 C I’d want the short sleeve.

If you’re going to choose one for everyday road riding/racing I’d buy the SS with pockets.

Lastly, I have the normal thigh length version. Again it runs about the same as every other piece of clothing as far as length goes. I do not know how much longer the “long thigh” version is. FYI…I’m 181-182cm tall and 75Kg and went with the medium but, should have bought the small.


Thanks a lot!
I would use it for short time trials within 20km.
But here in Italy summers are pretty warm and humid…
Should I go for the SS one?


Yes I think that’s a very wise choice. Your forearms will be parallel to the relative wind (more or less). So not a lot of area causing drag enough to offset staying cooler in my opinion.


@KennyC yes, in short. They are bad. While there have been efforts to clean up the mounts by some computer brands like Wahoo and stem brands like 3T’s Integra there’s no ignoring the square-ish shape and poor leading edge. Keeping the computer inline with the front of the stem and faceplate so you don’t also add FA would be my recommendation; not on top of the stem.

Maybe in the future we can just wrap the screen over the surface of the bar/stem

or you can consider one of the heads-up units like Gaimon promotes.

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Thanks for the insight Dave


I might’ve missed it, but is there any checklist of what to do for the most return? Kinda a pre-race checklist of wax your chain, order a size down skinsuit, get an aero helmet, etc.? And maybe what they offer in wattage savings?

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There is not, but that would be awesome for someone to build!

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Being the change I want to see in the world:

From Episode 188: Listed from most to least impact.

  • Hoods-to-Drops Position: 20-50w depending on baseline position
  • Skinsuit vs. Tight Race-Fit Kit: 20w or more
  • Shaved Legs: 20w or more
  • Shifting Head (1-2cm drop): 10-20w
  • Aero vs. Non-Aero Road Helmet: ~10w
  • Aero Handlebar vs. Round Handlebar: 5w (and only put bar tape where you need it)
  • Trip socks: “A couple of watts”

From Chris Yu, via Strava: Listed from most to least impact.

  • Water Bottles & Cages: 5w (penalty)
  • Bottle Cages Only: 2.5w (penalty)

From Episode 188: Unknown or no impact.

  • Handlebar Width: Too complicated to estimate. Narrow doesn’t always equal faster.
  • Side-to-side shifting without changing your “front face/area”: No impact.
  • Beard: Intuition is if it’s wider than your face, it’ll matter. Otherwise, no impact.
  • Arm Hair: Shave if you’re Chewbacca. Otherwise, no impact.

From Ceramic Speed: Listed from most to least impact.

  • “Good” Chain Lube: 6w
  • Replacing Stock Bearing Grease: 5w
  • Clean & Lube Chain: 4w
  • Oversized Pulley System: 3w
  • Use Big Ring until ~8th cog, then use Small Ring: 3w
  • Replaced Old/Worn Chain: 2w
  • Upgrade to Top-End Bottom Bracket: ~2w
  • Upgraded 11T pulley: ~1w each
  • Break-In a New Chain in for at least 1 hour: 1w

So my take-aways are:
Ride/Race preparation: Listed from most to least impact.

  • Wear a tight, race-fit jersey if not a skinsuit
  • Shave your legs
  • Buy an aero road helmet
  • Clean your drivetrain
  • Lube your drivetrain
  • Make sure your bearings have an appropriate amount of grease

During the ride/race: Listed from most to least impact.

  • Stay in your drops
  • Keep your head tucked as SAFELY as you can
  • Avoid cross-chaining

^ top 7 list, starting with biggest savings

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