How many flanges are on your hub?

Miscellaneous 4 10

I have been meaning to say something about these FSA RD-600 wheels for a long time, but it is one of the many topics that I just never got around to posting about. You see, I like FSA and I think they make really good products. I have an FSA crankset on my cross bike and I am very happy with it. Still, when I first saw these wheels with triple flange hubs and spokes in the center, I was a bit skeptical. We all know that spoked wheels work under tension. Basically, spokes from one side of the hub pull the rim to oppose the force from the spokes on the opposite side. So what are these spokes in the middle really doing? I don’t see how they really can contribute to the lateral structural integrity of the wheel. FSA claims that, by tucking a third of the spokes in line with the rim, they are sheltered from airflow and create a more aerodynamic wheel. I don’t doubt that, but is there a trade off? I guess my real question is this; is this concept a true innovation or just a marketing gimmick to differentiate FSA’s product from the masses of road wheels on the market?

Recently, I saw someone with a set of these wheels on a ride, so I asked how he liked them. His response was not favorable. Among other things, he said that the wheels do not stay true. Of course, that is just one person’s opinion. I have not ridden these wheels myself so I cannot speak first hand as to how they work. I do think that FSA has a well-deserved good reputation, so I do not believe that they would release a product that doesn’t work well. As I said before, I am skeptical, but curious about these wheels. If any of you have ridden or currently ride these wheels, let me know what you think about them.

Photo from Cycling News

4 Comments

  1. Anonymous September 20, 2006 at 11:20 pm -  Reply

    They look similar to the Rolf Prima design w/o the dual spoke configuration. I’ve also heard that they have issues with staying true due to higher spoke tension (I’m not sure if that’s applicable to this wheel).
    Nice site btw.

  2. Olivier Blanchard September 20, 2006 at 11:29 pm -  Reply

    A friend of mine has them, and he’s moderately happy with them (read: he doesn’t want to admit that they were kind of a waste of money). I’d wager that he’ll be riding some kind of Mavic or Bontrager wheel again inside of three months.

  3. Anonymous September 29, 2006 at 1:32 pm -  Reply

    Radial load decreases spoke tension where the wheel presses on the road. As spoke tension goes down, so does lateral support, and the easier ywheel is able to warp. The worse the spoke bracing angles, the less there is to hold the wheel against warp.

    Mavic used to make front hubs with close-spaced hub flanges and the claim (reduced aerodynamic profile) and the effect (weaker wheel that loses true more easily) were the same.

    Before that, Roger Saunders of Aerolite Pedals made tri-flange wheels. Then he stopped.

    I recommend “The Bicycle Wheel” by Jobst Brandt. It’s no substitute for an ME degree, but it’s good. Keep re-reading it, there’s more information every time.

  4. James September 29, 2006 at 3:21 pm -  Reply

    Good comment. Thanks for confirming my suspicion about the vertical middle spokes.

    It has been a while since I read “The Bicycle Wheel”. We had a copy in the bike shop where I worked in the early nineties (back when bike shops actually still built wheels), and I did read it a couple of times. After 15 years, I am probably due for a reread so I should get my hands on a copy.

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