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



I remember him saying “it depends” a lot, but at one point I think in reference to the selling of products they said they like to deal in absolutes like “a skin suit will always be faster than a jersey” but “it depends” how much of a difference. That als when they said “it depends” on long sleeved skin suits vs short sleeved because of the wrinkles at the elbow.

That’s also why they promote dimples or texture vs trip strips in products so that it’s more universal.


I was always under the impreseion that long sleeve skin suit always faster than short sleeve so interesting to hear it’s not (however I have NO intention of shaving my arms so maybe better off long sleeve). Shaved legs interesting but been told 100% by she who must be obeyed that shaved legs are a no no…so trip socks for TT it is then!!!


This is true for sure. Before I spend $500 for a skin suit like the Evade, however, I’d like to know what the benefit might be for me riding at MTB-like speeds.






I think the terrain you ride would play a big roll in this choice. Here in Florida Aero is king, while in the hills you’re better off going super light.


That is likely only true on the steeper (guessing over 5%) and longer (10+ minutes) climbs, and particularly if you end with a climb.

If you end up with up AND down, you will likely be better with an aero focus in that situation.


Just watched your saddle pressure vid @mcneese.chad and couldn’t help but notice all those wrinkles in the trainerroad jersey. I fear I shall now always look for wrinkles and poor cable management. :wink:


LOL, I didn’t bother to do any stretching for position. I have a shorter torso and long legs. Leads to wrinkles in just about every kit I own. This fits super comfortable, despite the wrinkles. Funny thing is this is a Small / Slim jersey too. And I am 5’ 10", 145 lbs.


I am speechless.

Soon to be hairless.

This must win the cheapest speed contest.


Free speed :stuck_out_tongue:

Funny when this info is widely available, and yet I still see hairy legs, even in road events.


I’m going to pick up one of the Velotec suits based on this:

(hat tip to @Landis for mentioning it above)

Tough to beat for 100EUR:


That Velotec suit is a great deal.

I was a little surprised by the article, showing reasonable small differences between skin suit and jersey/shorts.


Sweet! I have the long sleeve Pro aero speedsuit (no pockets) size medium. I’m 5’10" and 75Kg and I don’t have too much trouble getting in/out. But, feel like I’m between a small and medium. Sleeves definitely run long but, that’s easily fixable. Otherwise super happy with the fit and quality!


Im getting lost with some of the abbreviations and terms, but am keen to learn notwithsanding im in my mid 50s and coming into my prime.

What is crr? Cd



Rolling resistance coefficient: Crr

Drag coefficient: Cd

For an individual rider we usually talk about CdA (which is to say, their frontal area multiplied by the drag coefficient), but if you are talking more generally about riders of different sizes you might ignore the A and focus just on the drag coefficient of their shape.


I went ahead and ordered the Velotec skin suit along with some socks. I’ll report back once it arrives with height/weight/fit/pics.


As promised here’s the table with Crr added.

I’ve chosen a 70 kg rider and Vittoria Corsa Speed with a Crr of 0.00231 (fast as).

Back calculating Velocity from power wasn’t as straight forward as I thought once you have two velocity terms, one of which is cubed… Wolfram Alpha to the rescue along with a bottle of Auchentoshan American Oak.


v = velocity, A = drag constant, B = rolling resistance constant, and P = power

Even taking into account the rolling resistance the drop in time saved is much lower than the drop in power saving, so I still think it’s more relevant to state time gains as a percentage of overall time.



Great analysis. Not sure at my advanced age I’d be able to figure out formulas like that anymore :grin:

Looks like % time saved is probably the best metric, followed by % power saved.

Savings expressed as absolute watts is not very helpful.

For your next assignment, what about adding in % grade :stuck_out_tongue_winking_eye:

Really helpful to see the analysis like this. Helps inform if it’s worth spending a lot of $ on aero gear.


I wrote down P = A x v^3 + B x v scratched my head and then promptly typed it into Wolfram Alpha…

Took a while to type it into excel. Again, numbers match the online calculator.

I agree with you assessment of the numbers.



So if I buy a skin suit that saves 20watts at 45kph, and ride at an average of 20kph on a MTB, I’ll save about 1.75% in time. So for 9 hrs on the bike at 20kph, I’d save 9.5 minutes with the skin suit. That a correct takeaway from your numbers?