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Aero wheels v aero helmet

Sorry if this has already been brought up, I was wondering if anybody has any info relating to how much of a time saving aero wheels give you in a 180km time trial and what the saving of an aero helmet is on the same ride. I already have the aero wheels on my road bike and now considering getting an aero helmet.


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    TTX PROTTX PRO Posts: 225
    I only use an aero helmet for when im racing otherwise you find there very unconfortable especialy in the summer when its very hot due to there being less air circulation.My advise is have one for racing but for anything else i recommend a Specialized S-WORKS 2D,lightest helmet on the market,very aero,confortable and becouse its so light you forget it even there.
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    feesfees Posts: 28
    A mate of mine imports Louis Garneau and he has a LG Rocket for me which I am thinking of buyig. I will only use it for racing and not to train with.
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    BopomofoBopomofo Posts: 980
    There's a table in the book 'Swim Bike Run' by Wes Hobson et al. that gives numbers for approximate time savings on a 40km bike ride.

    From memory it says 3 mins for aero bars, 1.5 mins for aero wheels and something like 30s for a streamlined hat (compared to a normal hat, rather than a bare head, of course).

    I think for those of us who are wildly inconsistent with our times it would probably be easier to understand a list of kit versus power required to maintain, say, 25mph on the flat. I've not yet found such a list, though.
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    Hi guys

    There's a great reasearch article that we've put a link to from our website http://www.shop.kinetic-one.co.uk/bike-fit--performance-knowledge-base-1-w.asp (Loads of people seem to claim its there research which is a bit odd - including Cevelo which gives it a bit of credibility too I guess!) It looks well researched.

    It attempts to scientifically quanitify the relative and absolute benefits of (1) good riding position, (2) aero wheels (3) aero frame - and basically concludes that the importance is in just that order. No mention of helmets from what I recall.

    What I can say from the limited experience I have on working in a wind tunnel with some boffin guys at Drag2Zero is that position does seem to be by far the most significant contributor with any thing up to 85% of the drag created being attributable to the rider rather than bike. As the helmet is one of the leading edges of the lump that is the rider - it must be significant on its own. Not sure how helpful this last bit is!
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    krazycalkrazycal Posts: 45
    I've been told it's around 1/2 second per mile for aero helmet

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    On the same theme. I need a set of aero bars to clip onto a Bianchi 928 C2C to have a stab at Ironman UK. I have FSA Pro carbon contoured so simple bolt on's don't look like they'll fit. I was thinking about a bar that attached to the stem.

    Was planning to reverse the seat post and add on the bars rather than the expense of a new tri bike. Is this a valid idea as i'm trying to strike the balance of comfort over 180k and not loosing 3mins per 40k by not being streamlined?

    Any help appreciated
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    aero blobaero blob Posts: 29
    Reversing seat posts to get a steeper angle is always an interesting one.

    On the plus: It can give you the tri-specific seat angle you are looking for - with all the accompanying muscle recruitment benefits and at the same time it enables a more appropriate angle between upper leg and torso when you're on the tri-bars compared to how it would be with the seatpost the right way round.

    However there's a pretty major downside. Your Bianchi is designed to be ridden as a road bike with relaxed geometry - roadie style. Reversing the seatpost will upset the geometry and change the centre of greavity and handling characteristics. If you were to try for a really agressive position on the aero-bars then this could potentially be dangerous on downhills and bends. As you're going for irnonman distances rthis is perhaps less likely than for sprints etc.

    Tri geometry bikes (78-80 degrees for example) are designed to have longer wheelbases and more generous fork rake angles to compensate for the steep angles and to put the centre of gravity further back.

    Hope this helps. We've seen a slow but steady rise in people coming to bike-fitting's over the last few years after they've had falls or near-misses due to this issue. Its also particularly critical that your bike is not too small for you as this would also serve to increase the tendency to push the centre of gravity forward.

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