Aerodynamics / Aerodynamic Cost / Aero parts

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  • Is there any aero advantage to them? Or are they purely aesthetic?

  • Is there any aero advantage to them?

    See caveat here

  • Very late to this party. I've always used a regular cycling cap to stop the sweat gathering. (the assos ones being nice and thin)

    Will give one of these a try, any merits to getting this vs the headband version?

  • Will give one of these a try, any merits to getting this vs the headband version?

    I've got the headband version too, the full cap seems more effective.

  • Following from the hour attempt discussion, given dimpled surfaces help round objects' laminar flow not to detach, would it make sense having frame tubes dimpled? At least the vertical ones? And does that mean slick tyres are less aero efficient than lightly sculpted ones?

  • http://www.racecar-engineering.com/artic­les/technology/can-dimpled-aerodynamic-s­urfaces-reduce-drag/

    http://www.aerospaceweb.org/question/aer­odynamics/q0215.shtml

    "The reason we do not see dimples on other shapes, like wings, is that these particular forms of boundary layer trips only work well on a blunt body like a sphere or a cylinder. The most dominant form of drag on these kinds of shapes is caused by pressure, as we have seen throughout this discussion. More streamlined shapes like the airfoils used on wings are dominated by a different kind of drag called skin friction drag."

  • And does that mean slick tyres are less aero efficient than lightly sculpted ones?

    Probably, the Conti GP4000S always seems to come out of aero tests well

  • Thanks, what I had in mind was cylindrical objects like seatposts and tyres but I guess a small fairing behind them like in aero seatposts and high profile wheels solves the problem much more efficiently. What about dimpled brake cables though? ;)

    Dimpled legs anyone?

  • continental 4000s tires are apparently pretty low drag because of their side markings:

    http://flocycling.blogspot.dk/2013/04/fl­o-cycling-flo-30-wind-tunnel-results.htm­l

    edit: tester was faster...

  • Dimples need a certain size/speed to work (just under the critical spot where drag changes dramatically)

    I put cinelli bumpy tape on my road bars and tried to calculate if it helps :) With 2mm bumps on a 3cm cylinder going 20-40km/h they are just outside the range that actually works.

  • Yes, I imagine that would be a pretty small advantage anyway.
    Isn't there a valid case for an irregular/dimpled surface full body suit then, though? I could really see that work. Sorry if already been discussed.

  • Interesting. Ok, I ll'start to putting holes in my tyres and will report back.
    Anyone got a hammer and a screwdriver?

  • That is why the top end skinsuits have different fabrics in different places - ie the Castelli mesh and the BioRacer ribs on the arms.

  • I've always wondered what effect tyres/tubulars with glued on tread like VF Records has on aerodynamics. Faster due to some sort of trip effect, or slower?

    Steve Irwin has always run Supersonics, but switched to Records this season and that won't be for an untested reason.

  • Makes sense, tnx

  • Google for the aero test of the Spesh Turbo Cotton - they warble on about the tread attachment so it might cover your question. #margarinegains

  • I'm always dubious of manufacturers claims.

  • Who said anything about manufacturer claims? It was a third party that had tested them and were commenting on the tread attachment. I can't remember if they thought it was making it faster or slower.

  • Oh yeah, fair enough.

    Only a big difference over 5 degrees of yaw, which if you believe some people isn't particularly significant for reasonably decent time triallists.

  • Turbo Cotton doesn't come in anything smaller than 24c though, so useless for Hed3. I might try TC 24c rear with a 20c VF Record front later in the season.

  • I think they score well for rolling resistance too but they're too fast for me so I really can't remember much about them :)

  • Indeed: http://www.cyclingpowerlab.com/Yaw.aspx

    At 48kph (just under 30mph) with a 10kph (~6mph) cross wind - the max Yaw you would see (90deg cross wind) is just under 7degrees.

  • The 26mm must be worth investigating for the 24hr? Must be more than a few watts of rolling resistance available, even if any aero benefit turns out to be negligible.

  • I'm not sure I knew they did a 26mm TC. Seen them for sale anywhere?

    Thing is, one p_nct_re and any Crr or CdA advantage goes bye bye.

  • Sigmasport. How long does it take you to fix a puncture? Depends how much there is to gain from RR, could still end up faster.

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Aerodynamics / Aerodynamic Cost / Aero parts

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