Conference noted::bicycle

    Caveat: I have no experience, but have just observed first & second
    hand.  Clearly, solid disk wheels eliminate the tiresome business
    of truing the wheel by adjusting spoke tension, and make one tool
    (the spoke wrench) superfluous.  For people like Rod MacFadyen who
    strap extra spokes to the frame, I don't know how to achieve an
    equivalent impact with the solid-disk wheel.
    
    Seriously,  the solid disk wheels seem to help a lot of people,
    at least psychologically, despite the funny noises they can make
    braking into a turn.  But they are a specialized component - they
    suffer in a crosswind.  Ummm... I guess you probably know all of
    this already.  :-)
    
    -john

    Solid disk wheels are not stronger, lighter, or safer than traditional
    spoked wheels.  They're designed for one purpose only -- cheating
    the wind on relatively flat time trials.  There's little reason
    to buy one today, since you can use a wheel cover on a spoked wheel
    to achieve nearly the same effect.
    
    (.1 brings up an interesting point: how do you true a solid disk wheel?)

    
    MATT

    During yesterday's coverage of the TdF, the listening audience was
    informed that front and back disk wheels can save a top rider 10
    seconds on the mile.  

    
       You Don't True a disk wheel. If it goes to far out of true you
    simply add it to the dead wheel collection or use it as a decoration.
    
    
            JOhn C.
    

    	A caution on wheel covers:  The typical aluminum tension ring,
    draw-string cover design (Air Uni, etc) keeps dirt off the spokes,
    interior or rim, and hub in most instances.  But watch out for loose
    sand!  A weekend ago at the LAW Nat. Rally, I rode to Assateague
    Island (to see the wild ponys) and forgot about my rear cover and
    pushed the bike thru the beach sand a ways (I had to take a wade
    in the Atlantic [the Rally was called "Beach to Bay"] just to say
    I had done it).  My rear wheel must have picked up a few ounces
    of sand, which, due to the fold-over pockets in the cover, were
    then trapped in the cover and very audible for the next bunch of
    miles (until I got going once off the bike path).  I don't want
    to think of the hub sitting in there in a self-contained sand storm.
    	so, watch the sand!  - Chris

    	The aero (tri-, penta-,) spoked wheels were developed primarily
    for front wheels.  A solid disk or wheel with a cover will try to
    steer the bike if hit by a cross-wind. An open (spoked) wheel will
    do so much less. Since the rear wheel runs in relatively 'dirty'
    air (in turbulence from all the stuff in front of it) it may not
    produce the benifit of the same wheel used in the front, running
    in 'clean' air.   The cheap covers provide almost exactly the same
    benifit as the disk and CF spoked wheels.  I can't see any reason
    to use the more expensive ones in the rear, either.  But, if you
    want to go full tilt, the CF spoked wheel in the front is the way
    to go. (Now, if I could get one in 16"...) - Chris

    I was keeping my extra spokes on my rear carrier (so they wouldn't
    get bent, as Rod warns).  Now that I have been shamed into removing
    the rear carrier, at least for the time being, I'm at a loss.  The
    frame sounds a good place, but why not the helmet - they might improve
    reception, and definitely would enhance the image of helmet-wearing
    bicyclists as Martians on patrol.  :-)
    
    -john

>< Note 1239.8 by SHALOT::ELLIS "John Lee Ellis - assembly required" >
>                            -< ahhh, which image? >-
>
>    I was keeping my extra spokes on my rear carrier (so they wouldn't
>    get bent, as Rod warns).  Now that I have been shamed into removing
>    the rear carrier, at least for the time being, I'm at a loss.  The
>    frame sounds a good place, but why not the helmet - they might improve
>    reception, and definitely would enhance the image of helmet-wearing
>    bicyclists as Martians on patrol.  :-)
>    
>    -john


My Fuji Saratoga, a loaded touring bike, has braze-ons on the 
left chainstay to hold two extra spokes. The bike came with 
two spares that match the ones on the wheels. 

Electrical Tape works great too.

So what the heck is wrong with rear carriers? Is that out of 
phase with the new "yuppie-bike" trends?  :-)

JC

    Re .9:
    
    Now that you mention it, the top-of-the-range Raleigh tourer, the Raleigh
    Randonneur, has braze-ons on the right chainstay to hold two spare
    spokes. They serve a dual purpose by also protecting the chainstay from
    damage to the paint caused by chain slap, which seems a pretty neat
    idea to me.
    
    
    Re .8:
    
    Yes, what's this about being "shamed into removing the rear rack"?
    Being shamed into removing mudguards I can understand, but the rear
    rack, I don't know...
    
    
    Rod

     Disk wheels on touring/hybrids?? Isn't that like putting a 
    spoiler on a M60 heavy tank???   :-)  ;-)
    
    Chip

    RE: .-2
    
    There were some comments about fearing for my skin if I got 
    within 10km of Milanino with baggage on this bike.  Of course,
    removing the rear carrier really didn't help.  I still have
    the Polar Expedition size handlebar pack.  Maybe with a disk
    rear wheel, people's attention would be diverted from the
    handlebars?  ;-)
    
    -john

    I had done some test 2 years ago as to the advantages of a wheel cover 
    vs. a spoked wheel. At normal speeds (ie. < 25mph) the cover gave no
    advantage over a spoked wheel. It was when I then moved to a steeper
    hill where I was hitting speeds in excess of 35 mph that I started to
    notice that the cover made a difference. 
    
    This spring I bought a HED disk only because I was made an offer on it
    that I couldn't refuse (actually I could have but I'ld never see that
    price on a disk again). I set a goal of getting under 25:00 in the
    Sudbury TT (9.2 miles) before I would use the disk. In May, on my third 
    time on the bike since I torn my ACL (knee) in a skiing accident, I did
    a 24:21 on a spoked wheel. From this I concluded that the loss of 20 lbs 
    will do much more for you tan a disk wheel ever will. I got my per week
    mileage up to ~120-150 and dropped another 5 lbs. In the middle of June
    I was down to 23:32. From this I concluded that working on the engine
    will help you more than a disk will. Over the next few weeks I cut my
    biking and worked more on swimming and running after some poor run and
    swim splits in a couple of triathlons. I finally put the disk on and I
    did a 23:16 after having finished a mile swim. This week  I hope to
    break 23:00.
    
    With the disk I find myself doing 2-3 mph more on flats and about the
    same on climbs. I haven't done any testing to compare it to a spoked
    wheel or cover but have made plans to with another noter as soon as we
    both have some free time. We will, of couse, enter the results.
    
    As far as strength I am at 190 lb and there doesn't seem to be much
    flex in the wheel, even in out of the saddle climbs. I saw am ad. for
    the Velbec disk (1600gm aluminum) that claimed 24,000km (thats ~15000
    miles) for a 160 lb rider. Since most people use them in races (TT,
    triathlons, etc.) that is a pretty long life.
    
    Paul

    How many people have PROVED to themselves that a diskcover (such
    as UNI) is faster than regular wheels? I convinced myself that the
    UNI made absolutely no difference by riding the weekly tt course
    ... one week with the UNI, next without ... for an entire season.
    The result was the same time with or without the covers.
    
    In the most recent edition of Velonews there was an article on aero
    wheels, comparing a regular 36x wheel to aero wheels, tri spoke
    composites, wheelcovers, and a HED disk. The results from the wind
    tunnel tests (at 30mph, over 25 miles) were that the wheelcovers
    provided NO additional time savings. The HED disk saved a lot of
    time (I forget the exact number of min&sec).
    
    The reason I suspect that wheelcovers provide no additional time
    savings over a standard non-aero wheel are:
    
    	1. The dishing of the wheel makes the air travel at unequal speeds 
    	   over the two sides of the wheelcovers - since one side of the
    	   wheel is dished more than the other.
    
    	2. The surface of the cover, when stretched tightly over the
    	   spokes, is not nearly as aero as a disk ... there a lots of 
    	   ridges from the spokes.
    
    	3. Mounting the covers creates a nonaero junction between the rim 
    	   and cover. The Wind tunnel tests also mention that it is
    	   extremely important for the tire width to match the rim (HED
    	   disk with 19mm tire saves 40 sec or so, but with a 22mm tire
    	   it saves only 4 sec!), so the bulge created by the aluminum
    	   hoop must have an adverse aero effect.
    
    So don't kid yourself ... wheelcovers don't come close to providing
    the aero edge that a solid disk will. I wanted to believe that the
    UNI's were almost as good as disks, but after a season of experimenting
    in time trials, the recent wind tunnel tests, and my current experience
    with a HED disk ... I'm glad I bought the HED disk, and glad I sold
    the UNI wheelcovers.
    
    Mark

    
       One thing that the wind tunnel tests do not show is the reduction
    of drag the spokes add to your riding.  When a wheel turns the spokes
    have to cut through the air within the stucture of the wheel creating
    the eggbeater effect. One of the main benefits (at least as I see_it)
    of a disk wheel is that there are no spokes at all and therefore
    there is no more resistance from the spokes having to cut throught
    the air as the wheel spins.  The wind tunnel will only show the
    results of a the air being pushed aside by the bicycle-rider
    combination and since the bike is stationary it misses part of the
    big advantage of a disk wheel
    
    
                                   JOhn C.
    

    Given the shape of the human body, isn't worrying about drag created by
    a spoke a little too much?  

    I am definitely less knowledgeable about cycling than some this conferences 
    experts and I know I have a lot to learn.  I would love someone to explain 
    to me how spokes could add more resistance than a little bit of shirt 
    hanging out of your shorts.  I'm not trying to instigate or be a wise ass, I
    simply can't fathom the fact that spokes make significant improvements in 
    drag coefficients.  


    -ken  

    p.s. Granted some bodies are more aerodynamic than others.

    When you're moving forward at 30 mph, the spokes at the top of your
    wheels are moving forward at 60 mph.  Since they're spaced fairly
    regularly, and alternate side-to-side, they create quite a bit of
    turbulence.  Though you're right that the human body is still the
    biggest non-aero part on a bike, getting rid of the spokes gives
    a significant advantage (and is much less painful than cutting off
    body parts!).
    
    Still, the biggest advantage that most people could reap is to 
    choose a more aero position.  Messing with spokes and stuff is
    a relatively small optimization.  Unfortunately, most people
    see technology as their savior, and try to buy speed.  They ignore
    the simple, free things that would get them the best results.
    
    
    MATT

    
       You hit that one right on the head Matt.  The best comparison
    that I can think of to demonstrate the difference would be to put
    I bike up on a repair stand, Put the bike into its biggest gear
    and then turn the crank with your hand up to about 30 MPH. Doing
    this with a normal spoked wheel and then with a disk wheel will
    show just how much difference eliminating the drag of the spokes
    can make. 
    
                                 
                                      JOhn C.
    

< Note 1239.15 by SVCRUS::CRANE >
                    -< there a little more to it than that >-

>    
>       One thing that the wind tunnel tests do not show is the reduction
>    of drag the spokes add to your riding.  When a wheel turns the spokes
>    have to cut through the air within the stucture of the wheel creating
>    the eggbeater effect. One of the main benefits (at least as I see_it)
>    of a disk wheel is that there are no spokes at all and therefore
>    there is no more resistance from the spokes having to cut throught
>    the air as the wheel spins.  The wind tunnel will only show the
>    results of a the air being pushed aside by the bicycle-rider
>    combination and since the bike is stationary it misses part of the
>    big advantage of a disk wheel

I'd guess that the wind tunnel tests were done with a rider on the bike riding
rollers or some other training device, not just with a bike sitting in the 
tunnel.  One thing that those tests didn't take into consideration is the 
extra weight and resulting fatigue, especially on non-flat courses.

Anyone notice that Pedro Delgado used 2 disks in the TdF TT's while Lemond 
only used one?  Even on the mountain TT.  Delgado had faster early splits, but 
Lemond ended up winning (Lemond also used aero bars!).  I wonder if Delgado 
tired and slowed at the end due to the extra weight of his two disks?  I think
that if it was the aero bars that allowd Lemond to win, he would have been 
faster thruout, tho still probably faster at the end due to less energy 
expended early.  Of course, equipment might not have had anything to do with 
it.

Any comments?

Kevin

    re: .19
    
    I think Lemond is a better TimeTrialer than Delgado.

    RE. 19, I also think Lemond is just an outstanding time trialist.  I
    was curious, though, why those guys were using disk wheels?  I mean,
    aren't those things a b*tch when you're climbing ?  I've never used
    them but I understand they're great once you get them rolling, which is
    difficult on climbs.

    Only about 35% of the uphill TT in the TdF was an out-of-the-saddle
    climb.  A disk definitely would help on the other parts.  With the
    really high-end composite wheels these guys are using, the extra
    weight is probably less than a kilo, so it's very difficult to say
    whether it was a plus, minus, or washout to use them.
    
    MATT
    
    PS - I don't remember Lemond having ANY disk wheel when he rode
         by, but since it happened so fast, I'm not certain.  The
         tri bars were the clip-on variety, not Scotts or anything like
         that.

     Attempts to determine the exact influence disk wheels had on 
    individual performances are impossible due to the myriad of
    variables not to mention opinion.
    
     I agree that LeMond is probably the superior TT man over Delgado.
    As far as double-disks vs. a single disk... more being better is
    an age old question. 
    
     Don't the efficiencies of a disk kick in around 15mph? If so, there
    was something to be had most of the stage.
    
      Chip

>    Don't the efficiencies of a disk kick in around 15mph? If so, there
>    was something to be had most of the stage.

    Rooks' AVERAGE speed was over 20 mph for the stage.
    
    MATT

    
       Lemond did not use a disk wheel in the Uphill Time trial.  At
    least not that I remember.  I will have to go and recheck the video
    tape of the stage.  Delgado did use a disk wheel for the Stage wich
    kind of suprised me but then again Hampsten also used a disk.  I
    believe that when it come to a time trial where some of the course
    is Hilly and a fair amount is flat its a matter of personal preference
    of the Rider.  Also because of the difference in riding and climbing
    styles one way or the other can make a big difference for one rider
    and less for another.
    
    
             JOhn C.

    Re .23   Rooks didn't use a disk wheel at all. In fact the first
    three home didn't use disk wheels, but I thought the Lemond did.
    Like -.1 I will have to confirm all of the above with a quick spin
    of the tape.
    
    John

Re .22 Wind tunnel tests by Steve Hed

The article didn't even mention that the wheels were mounted on a bicycle.  
Previous testing had all been done on stationary wheels, the recent tests 
spun the wheels at 20,25 and 30 mph.  The wheels were exposed to winds of
various angles (or yaws) to simulate the effects of crosswinds. As the winds 
were blown across the wheels, the wheels were rotated at the same speed as 
the wind "to simulate actual forward motion" .  He also took energy measurements
which determined how much energy is required to turn each wheel.  Steve HED's
interpretation of the results was that an 18 spoke radially laced front wheel
(with a drag coefficient  better than some 3-4-5-spokes) and a disc in back are
the best combo.  [He also claims he's not biased because he makes all kinds of 
wheels himself].

re TdF disc wheel usage

Aren't these guys riding the Campy Fluid Dynamic (or Ghibli?) disc that much 
lighter than the run of the mill 1000gm+ disc or even the high end HED @ 850g?
For $2450 it should be.