Forum home› Road cycling forum› Road buying advice

Don't get aero road bikes

MaxwellBygravesMaxwellBygraves Posts: 1,353
edited July 2011 in Road buying advice
I don't get it!

They look very sexy, but to me whenever I see someone riding one with two bottles on the frame I think 'why'?

I don't doubt that slippery tubes might make the ride marginally faster, but surely by sticking two big and very un-aerodynamic water bottles on the frame you negate the benefits?

Or am I missing something?
"That's it! You people have stood in my way long enough. I'm going to clown college! " - Homer

Posts

  • HerbsmanHerbsman Posts: 2,029
    An aero frame with two bottles is more aero than a normal frame with two bottles. Get it now?
    CAPTAIN BUCKFAST'S CYCLING TIPS - GUARANTEED TO WORK! 1 OUT OF 10 RACING CYCLISTS AGREE!
  • what brakeswhat brakes Posts: 328
    Also whether your going at 10mph or 30mph its also still more aero and therefore less drag than a normal bike! so still save you energy.
  • Zoomer37Zoomer37 Posts: 725
    Perhaps their doing a long TT?

    I'd not think about it to much. Theres no point.
  • skyd0gskyd0g Posts: 2,540
    how does it rate in a cross-wind? :wink:
    Cycling weakly
  • PokerfacePokerface Posts: 7,960
    I ride a Cervelo S3. Massive aero tubes. It handles fine in all winds/conditions.

    As for whether it saves me any energy or not - who knows? I just like the way it looks and rides. But for me, if I can save even 1 watt over an hour of racing, it 'may' be worth it.
  • Slow DowncpSlow Downcp Posts: 3,041
    MaxwellBygraves wrote:
    I don't get it!

    They look very sexy, but to me whenever I see someone riding one with two bottles on the frame I think 'why'?

    I don't doubt that slippery tubes might make the ride marginally faster, but surely by sticking two big and very un-aerodynamic water bottles on the frame you negate the benefits?

    Or am I missing something?

    Answered your own question :wink:
    Carlsberg don't make cycle clothing, but if they did it would probably still not be as good as Assos
  • sub55sub55 Posts: 1,025
    and we wont mention Andy Wilkinson`s steed
    constantly reavalueating the situation and altering the perceived parameters accordingly
  • Monty DogMonty Dog Posts: 20,614
    If the marketing guys didn't have the opportunity to dream-up these concepts based on cod-science then the whole bike market would just dry up! (or alternatively, a few guys would be out of jobs and we'd carry on riding regardless).
    I do like the bit about the extended headtube being a 'feature' when in reality it's more to do with the amble girth of many riders preventing them from getting into a lower tuck - so there you have it, the new Cervelo strap line: "designed especially for fat people with thick wallets" Do you think the'd give me a job? :wink:
    Make mine an Italian, with Campagnolo on the side..
  • nferrarnferrar Posts: 2,511
    Yeah aero bikes can look nice so I can see why non-competitive riders by them (although I personally wouldn't trade comfort for looks so you need to be careful on models). Unless you are competing the drag reduction stuff is utter tosh - take a look in the mirror, that's what's dragging in the wind not the bike...
  • MichaelWMichaelW Posts: 2,164
    Monty Dog wrote:
    "designed especially for fat people with thick wallets" Do you think the'd give me a job?
    As long as you design lycra one-piece for the same market sector.
  • mowflowmowflow Posts: 212
    Aero bikes look sexy but if you are even slightly over weight you look ridiculous on one.
  • yayayaya Posts: 411
    edited July 2011
    It's a PR video but but it's also a VERY nice bike :)

    http://s5.cervelo.com/

    Better start saving :wink:
  • MrChuckMrChuck Posts: 1,663
    Monty Dog wrote:
    If the marketing guys didn't have the opportunity to dream-up these concepts based on cod-science

    I don't believe it's cod science. If the guys at Cervelo or wherever claim their new frame is x% stiffer, y% lighter and z% more aero then I will readily believe that all those things are true, and marketing doesn't come into it. I'll also happily believe that those things can add up to less watts needed for s given speed/distance.

    Whether that means that people should rush out and buy one is something else, and whether they'd notice much difference if they did (apart from a lighter wallet) is something else again. That's where the marketing guys come in and that's where you have to start taking it all with a pinch of salt. But as far as the engineering claims go I don't see why you'd doubt them.
  • zoidzoid Posts: 100
    What percentage does the bike play in the total overall aerodynamic drag figure, at a guess I reckon the rider would account for about 80% and the bike 20%, would that be about right?

    Obviously this figure would vary depending on the bike geometry, i.e. race, sportive, & TT and of course the position of the rider.
  • cougiecougie Posts: 22,512
    I doubt its 20% even.

    Take a photo of yourself head on and shade cut out the background. Now shade out your body. There wont be a lot of bike left ?

    I do think so much of cycling development is down to marketing. If you look at races - its not one frame that dominates - its the rider. If he swaps bikes - he still wins. Cancellara for example.

    Buy them if you want, but dont believe they will transform your performance.
  • PokerfacePokerface Posts: 7,960
    My math may be completely off on this, but if the bike only accounts for 10% of drag - does that mean I can lose up to 10% of my overall power output through poor frame design then?

    So, 300w ± 10% = 30w? That would be a LOT.
  • pianomanpianoman Posts: 706
    I would have thought that there'd be a sizeable difference, given that the "weight weenie" revolution when it comes to consumer bikes has long since dissipated and you see companies like Felt and Scott coming up with "aero road bikes". Then again, doesn't it largely depend on how aero your front wheel is? My wheels are Zondas..........with a hideous wide box-section rim :evil:

    So does that mean my S1 would benefit more than a round-tubed frame from sticking some aero wheels on, e.g. Cosmic Carbone's? The airflow would stay streamlined from wheel rim to downtube then.
  • simon_esimon_e Posts: 1,697
    Pokerface wrote:
    My math may be completely off on this, but if the bike only accounts for 10% of drag - does that mean I can lose up to 10% of my overall power output through poor frame design then?

    So, 300w ± 10% = 30w? That would be a LOT.
    No, the frame contributes 10% of the total estimated drag, you are the other 90%. If total drag is 300w only an invisible frame could save you 30w. If Brand X says their all-new aero frame reduces the drag by 20% that is 20% (a fifth) of the 10%. A fifth of 30w = 6w. That may be significant if you're at the sharp end of competition but not for the rest of us and the money may be better spent elsewhere. From what I've read wheels are a considerably more significant factor in aerodynamics and should be the first place to spend money on hardware (particularly for time trialling) - that's after you've made yourself as aerodynamic as possible.

    Marketing isn't lies but it isn't the whole truth either.
    Aspire not to have more, but to be more.
  • pianomanpianoman Posts: 706
    From what I've read wheels are a considerably more significant factor in aerodynamics

    Interesting you mention that; I've seen a fair few pictures of triathletes using traditional drop bar road bikes that aren't even "aero" yet they use Cosmic Carbones, Planet X 50's etc. So the next purchase will have to be a set of deep carbon wheels. No weight weenie posts from me of course :P

    As for "the rider being the other 90%", why do so many tri-bars have their arm rests raised slightly above the base bars/handlebars? I notice this on my Tranz-X clip-ons and while I've been told the slight raise helps with pumping out power, surely it's not the fastest way to cut through a headwind?
  • lifeformlifeform Posts: 126
    Simon E wrote:
    Pokerface wrote:
    My math may be completely off on this, but if the bike only accounts for 10% of drag - does that mean I can lose up to 10% of my overall power output through poor frame design then?

    So, 300w ± 10% = 30w? That would be a LOT.
    No, the frame contributes 10% of the total estimated drag, you are the other 90%. If total drag is 300w only an invisible frame could save you 30w. If Brand X says their all-new aero frame reduces the drag by 20% that is 20% (a fifth) of the 10%. A fifth of 30w = 6w. That may be significant if you're at the sharp end of competition but not for the rest of us and the money may be better spent elsewhere. From what I've read wheels are a considerably more significant factor in aerodynamics and should be the first place to spend money on hardware (particularly for time trialling) - that's after you've made yourself as aerodynamic as possible.

    Marketing isn't lies but it isn't the whole truth either.

    For real Friday night fun and japes read up about Coefficient of Drag (Cd).

    http://en.wikipedia.org/wiki/Drag_coefficient

    The difference in Cd between a circular tube and an oval one is enormous, but it's against a relative backdrop of things like the rider, as Simon E says.

    Wheels are the biggest drag on any motive device because they rotate - which plays havoc with laminar airflow. Jaguar cottoned on to this in the 90s and threw out the XJR-12 with faired in rear wheels - immediate 15mph top end, and 10% better fuel economy.


    http://www.flickr.com/photos/si558/3251368172/

    So it got banned.
Sign In or Register to comment.