I’m considering buying a dimpled skinsuit for my time trial races this year. I already own two regular skinsuits and am wondering if the special “speedsuit,” made from a dimpled fabric, is worth the extra money. It would be about $160. Just FYI - I think I’ve made most of the other major aero savings already - wind tunnel testing, cervelo p3carbon with Zipp disc and Zipp 1080 in the front, Spiuk Kronos helmet. I can TT at about 27 mph for longer efforts and probably faster for shorter efforts. Anyway, I just added those background details to illustrate that I’m pretty serious and think that it would be worth my while to try to gain additional aero advantages if possible. So, let me know what you think about the suit.
Wow your fast! Sorry I dont have an answer to your question, but I saw your thread and thought maybe you could help me! DO you know where I can find just a long sleeve skin top? I know its better to have no seems, but i just want a very tight long sleeve top to keep me warm (but also be fast) in colder tris.
thanks!
You might want to look at the Championsystem site. They make our team clothing. I’m not sure whether they make a top only. You could buy a long sleeve skinsuit though.
Or you can try PBK: http://www.probikekit.com/display.php?code=C0578 for a skinsuit.
IIRC, only Nike made a dimpled skinsuit when Lance was on either US Postal or Discovery teams.
I believe that dimples are only effective on spinning objects moving at very high speeds (some say in excess of 60mph I believe) so not much use on a skinsuit…
However…Sorry to hijack, but does anyone know wher to get a fairly plain, longsleeved skinsuit? The Assos one would be perfect…if it were half the price!!!
You are correct.
From Dassault Aircraft manufacturers:
“It is at the critical speed of about 55 mph that the nonspinning, dimpled golf ball passes the critical “Reynolds number”(aerodynamic jargon for “force barrier”), reducing the drag force significantly. The smooth ball goes through a similar force barrier, but at a critical speed of about 300 mph, and at this speed has less drag than the dimpled ball. It is at these critical speeds that the drag tail (turbulence behind the ball) suddenly decreases in size. The separation point of air causing the turbulent tail or wake rapidly moves from a point about 80 degrees from the air flow direction to about 110 degrees around the back of the ball.”
So unless your cycling between 55 and 300 mph, dimples don’t appear to be helpful.
Except they are also used on projectiles. Such as subsonic firearms: http://www.patentstorm.us/patents/7127996/claims.html and http://accurateshooter.wordpress.com/2009/04/01/us-army-team-tests-radical-new-dimpled-bullet/
Y’all must have missed the mythbusters episode…they PROVED that it doesn’t have to be a spinning object
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So unless your cycling between 55 and 300 mph, dimples don’t appear to be helpful.
Except, is the Reynolds number for a golf ball the same as for a bicycle wheel?
I think where you’re going for this is that dimples work on a bike wheel. Zipp found this to be true. But they take into account, not just translational drag but also rotational. So it didn’t state this explicitly but I suspect that the surface of a rotating bike wheel is traveling through air at speeds in excess of 55 mph and most definitely faster than a cyclists forward speed.
As for bullets… I don’t know. Fluids behave differently at different speeds and since a cyclist is not moving as fast a bullet, perhaps that is why it work on bullets but not on cyclists…?
I doubt Champ-Sys has any data about difference from their regular suit. That makes “worth it” impossible to measure in a $/second improvement.
Our team uses Champ-Sys also, I have the long sleeve version currently. The sleeves are VERY long (as in 2" too long in a size medium) and the material is impossible to get smooth, without large wrinkles in the arms. I considered the dimpled suit this last season but for double the price, opted to not get it. 2 team mates did. The fabric does fit better than the standard suit and but uses the same fit with very long sleeves (they both complained as well).
If you can afford it, you certainly won’t go backwards. How much forward, who knows?
This has been recently discussed on the John Cobb windtunnel thread. I was stunned by the difference in skinsuits in the summary data. See http://www.cyclingtechblog.com/2009/11/ . Who’da thunk
yeah, you can see it on the old episodes.
Kraig Willet has an article on skinsuits and boundary layers here:
http://biketechreview.com/aerodynamics/skinsuit_boundary.htm
Very techy but informational.
This is the response to the article from the design team of the Nike Swift Skinsuit:
http://biketechreview.com/aerodynamics/images/brownlie_kyle_macdonald.pdf
Note the last 2 paragraphs regarding fit and potential time savings. How much this translates to Champ-Sys’s suit is unknown.
yeah, you can see it on the old episodes.
http://digg.com/autos/Mythbusters_test_golf_ball_dimpling_effect_on_fuel_economy?t=28966543
or
Easton talked about dimples comparing there wheels to Zipps. It is on the Forum here, worth the read.
Lance uses it so it may be worth it
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So unless your cycling between 55 and 300 mph, dimples don’t appear to be helpful.
Except, is the Reynolds number for a golf ball the same as for a bicycle wheel?
I would suggest that many many cyclists and even 1/2 of the triathletes here have their wheel velocity regularly above 55mph.
Almost all of the time trials I’ve ever been to have been won with these speed ranges for the winners’ wheels.
-SD
Really? I might be missing something in the equation, but it would to me that the linear velocity of a wheel at the outside edge would always be equal the speed of the bike. Ie, the wheel is moving ‘backwards’ where the rubber meets the road at the same speed that the bicycle is moving forwards. I could certainly be wrong about the the actual dimension you’re talking about, but if a wheel’s edge is moving linearly at 60mph, it would seem necessary that the object it’s moving would have an equal speed, with linear velocity actually decreasing you move inwards. On the other hand, of a wheel is moving through space at 55 mph and then spinning forwards (like at part opposite the road contact point) then perhaps it’s ‘seeing’ wind at 110 mph.
I think I may have confused myself. And it’s kind of a non-argument for me anyway, I’m sponsored by HED! But surely I’m not the only one who might be looking for a little clarification…
By the way, SD, have been riding my F35 for years now and the thing is absolutely killer, comfortable and bombproof!
When you are riding your bike and look at the top of the front wheel is the top of the tire not moving away from you? (ie, going faster than the bike?)
Styrrell