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Wheel disc's????????????????

TrisurferTrisurfer Posts: 228
in General Chat

Hello,



competed in my first sprint event back in september, I noticed some of the faster looking bikes in the transition area had rear discs. Upon this observation I thought they looked quite cool, and decided to see how much they were!!!! wow!! so expensive!!!



Can anyone tell me the real benefit you get from a disc??? (my bike already has two wheels so is this a wise investment??)(thinking cost per extra second gained!)



I also noticed you can get different wheel types for different cycle courses, ie. straight and flat or hilly and wyndy. is there a general rule of thumb for certain wheels for certain terrains.



cheers, quite a technical one this, thanks again!





Comments

  • transittransit Posts: 163
    The general rule with wheels is that if they are expensive then you must by them, even if they won't make you that much faster!! (especially carbon ones, it's the rules!!)



    Disc wheels don't allow air to pass through the centre of the wheel which can cause resistance. To save you time you need to travel at something like 23mph and over - not sure about the science but think that is the value. But...because the wind doesn't go through the wheel it can blow you off (cycling term?!?). That's why people on the road don't have a front disc too like on the track.



    The types of wheels people use often depend on wind and terrain. A deeper section rim will be more aero for the reasons detailed above however will be unstable and cos of the additional material may add more weight over a narrow rim wheel that might be better for hills. Like you said, a bit of a balance for each course.



    The actual amount of time saved could be quite significant over bottom spec wheels but as you said, it's a lot of money for maybe 5mins over 40km. I see alot of people with 50mm ish rims which seem a good compromise for all occasions.



    Hope that all makes sense, tried to whizz through it.
  • BopomofoBopomofo Posts: 980
    So.... what's to stop me making my fairly average wheels (Mavic Aksium race) into super fast ones by simply sticking a lightweight plastic disc over the spokes? In fact, isn't this how some 'fast' wheels are made; simply using a fairing to deepen the rim or make a disc? (Seem to recall HED do some wheels which are faired to make a deeper rim).



    And does somebody already make such disks? Can't believe I'm the first person to think of it. You could even make a pair of nice big carbon fairings with a red stripe on, for ultimate speed.



    Cheapskates could simply use cling film.



    Or have I gone mad? [&:]



  • BARNYBARNY Posts: 157
    nothing to stop you doing that in triathlon bofomofo! it does however comprimise normal biking rules.. I think your not supposed to have any non nesesacry bits added to the bike.... the get around that with the curent discs by saying they need the disc to support the wheel becasue it is not strong enough on its own...



    Unless youi are able to form a lightweight and strong materal to fot snuglly, secure and airtioght on your wheel is won't work and/ or cost you a fortune.... I recomend gaffa tape 2 rolls at £5 a roll and at least 70% of the benifits of a disc wheel..



    BY the way the aero benifit it the fact that the turbalance creating the wheel spinning acts a bit like an air brake where as the air slips by a disc... i.e. a block of wood is more aero than a broom head. lol
  • bennybenny Posts: 1,314
    Anyone know a decent brand with good price/quality?
  • GHarvGHarv Posts: 456
    Bopo,



    They already do the i'm affraid $60. Not seen them in the UK but i'm sure someone will have them.



    G



    http://www.excelsports.com/new.asp?page=8&description=Wheel+Cover&vendorCode=CHAERO&major=1&minor=24
  • treefrogtreefrog Posts: 1,242
    I question the value of a rear disc on a hilly or a very technical course. However a disc (under the legs of a good cyclist) on a flat couse is an advantage. Try the usual suspects Zipp Sub9, Corima disc
  • BopomofoBopomofo Posts: 980
    under the legs of a good cyclist


    Yep, that spoiled it for me [:D]

  • BARNYBARNY Posts: 157
    Some good makes are 3m, scotch....

  • TrisurferTrisurfer Posts: 228
    Thank you all for you're input!



    basically you need different wheel types for different conditions.





    This sounds very expensive think I'll stick with the spokes in the mean time till I got money to burn!!!



    thanks again
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