Losing one spoke in an 18 spoke wheel... effect on lateral true.

[Ron Ruff]

On Feb 24, 6:39 pm, "[email protected]" <[email protected]>
wrote:
> For a given distance, and for a given aero improvement (wheel, helmet,
> whatever), the time saved is *less* when you go faster. The slower
> riders save *more* time than the fast guys (for a given distance).
> They're out there collecting the time savings longer.

And if you go slow enough, the time savings can be almost infinite...

If you are going slow, then the time savings is sort of unimportant
(and that would include me). If an equipment upgrade would turn you
into a champion, then an upgrade is completely sensible. Otherwise,
you might as well ride whatever you want, and enjoy knowing that your
"competitors" will ascribe a higher handicap to your low-tech
equipment than there really is.

 

[Mike Jacoubowsky]

>> A little brake rub would just slow me down. If the wheel warped much
>> more though, the tire would start rubbing on the forks as well...
>>
>
> Yes, like this guy.....
>
> http://www.samoht.com/wiki/wiki.pl?action=browse&id=why_i'll_never_shop_at_wheatridge_again
>
> Phil H

There's something a bit screwy in that story. We sold a ton of bikes with
the wheels he had issues with (Rolf Vector Comps), and spoke failures were
extremely rare. The Vector Pro was more likely to have issues, since it had
fewer spokes and was built a bit closer to the "edge" (lots of tension on
small number of spokes). And, according to his wiki, it was the spoke
nipples that broke. Again, strange. And then, after the shop built him a new
pair of conventional wheels, he had yet another spoke failure. Eventually he
ended up with the wheels rebuilt by a reputable shop (that posts here
frequently)... wonder how those wheels are doing?

But I'm also surprised at the sentiments regarding the particular shop in
question. I know at least one person high up in their organization who, if
this were brought to his attention, would be quite dismayed and make sure
things were dealt with appropriately.

--Mike-- Chain Reaction Bicycles
www.ChainReactionBicycles.com

 

[Stephen Greenwood]

On Feb 24, 10:57 am, "Phil Holman" <piholmanc@yourservice> wrote:

> "Ron Ruff" <[email protected]> wrote in message
> > A little brake rub would just slow me down. If the wheel warped much
> > more though, the tire would start rubbing on the forks as well...
>
> Yes, like this guy.....
>
> http://www.samoht.com/wiki/wiki.pl?action=browse&id=why_i'll_never_sh...

And like me, when a rear spoke broke on the Shimano WH-R535 wheels
that were original equipment on my first road bike:

<http://groups.google.com/group/rec.bicycles.tech/msg/
5fe5ee912959ff41>

The wheel rubbed on the chainstay after breaking one spoke. The rim
depth was 28mm, comparable to Ron's. I didn't measure the deflection,
but I'm pretty sure it was over 5mm. Of course it didn't lock up the
wheel with me on the bicycle at normal speed, but it was severe enough
that after I dismounted and tried to walk it, the wheel dragged along
the ground rather than rolling. I can't say how it affected the
handling because I stopped immediately, reflexively responding to the
frightful noise made by the broken spoke whacking against the frame.

Stephen Greenwood

 

[daveornee]

On Feb 24, 4:16 pm, daveornee <daveornee.2mj...@no-
mx.forums.cyclingforums.com> wrote:
> Antti Salonen Wrote:
>
>
>
> > daveornee <[email protected]> wrote:
>
> > > 18 spoke wheels are certainly not a great choice for recreational
> > > riding or training. If you are racing, they may be a good choice,
> > > when the spoke breaks what happens to you in the race?
>
> > In amateur racing I would guess that's usually it for the race if the
> > wheel is not rideable. However, low-spoke-count wheels with
> > high-profile
> > rims do have a real, measurable performance benefit in road cycling.
> > It's a deal you make, and while most do it for fashion if you look at
> > the data, it makes sense.
>
> > Besides, how likely are you to break a spoke in a race? With good
> > wheels
> > it's something that happens less than once per 10,000 kilometres.
> > Probably way less.
>
> > -as
>
> I agree, "It's a deal you make". Your point is well taken.
> Lower spoke count increases the dynamic load per spoke; thus shortening
> the fatigue life.
> Spacing spokes fruther apart also has impact on how the rim is
> supported. The greater spacing also has another potential risk that
> something like a stick (squirrel, dog nose, plastic bag, etc.) will get
> wedged in between and not brushed away.
> The real and measurable differences are there, no doubt.
> A real world example might mean finishing a Century Ride (100 miles ..
> not a metric century) in 5 hours instead of 5 hours and 5 minutes.
> The faster you ride the bigger the delta is for each aerodynamic
> feature you add.
> Of course, if you break a spoke in that Century Ride, your time to
> finish is not much of an issure any longer.
> I look at the data and see what people are riding... and how they are
> riding it. I try to make sense of the "deal you make".
> Aero helmets and improved rider position make real and measurable
> differences too.
>
> --
> daveornee- Hide quoted text -
>
> - Show quoted text -

For a given distance, and for a given aero improvement (wheel, helmet,
whatever), the time saved is *less* when you go faster. The slower
riders save *more* time than the fast guys (for a given distance).
They're out there collecting the time savings longer.

Reference: http://www.cervelo.com/content.aspx?m=Engineering&i=Aerodynamics#5

I guess I learned something there.
Thank you for sharing that reference.
Somehow I had a refence in mind that said the faster you ride the more power is consumed by aerodynamic drag. I guess I made a leap of (mis-)understanding that aerodynamic improvements would increase their "watts saved" values as speed increased.
I guess I can take some pleasure in knowing that my improvements in aerodynamics are still worth it as I age more and ride even slower. :}...
and if I eat that extra slice of pizza or carry a few more onces of water in my water bottles I won't worry about the weight gain as long as it doesn't hurt my aerodynamic position.

 

[Ben C]

On 2007-02-25, daveornee <[email protected]> wrote:
>
> [email protected] Wrote:
[...]
>> For a given distance, and for a given aero improvement (wheel, helmet,
>> whatever), the time saved is *less* when you go faster. The slower
>> riders save *more* time than the fast guys (for a given distance).
>> They're out there collecting the time savings longer.
>>
>> Reference:
>> http://www.cervelo.com/content.aspx?m=Engineering&i=Aerodynamics#5
> I guess I learned something there.
> Thank you for sharing that reference.
> Somehow I had a refence in mind that said the faster you ride the more
> power is consumed by aerodynamic drag.

I'm fairly certain that's true.

> I guess I made a leap of (mis-)understanding that aerodynamic
> improvements would increase their "watts saved" values as speed
> increased.

It should do. It may be the leap from there to predicted time to
complete the 40k course that's counter-intuitive.

Suppose you're riding along at a speed where rider power = drag power.
Then you reduce drag power by P watts improving your position. Rider
power remains constant so you increase your speed by S kph until you
reach a new equilibrium speed where drag power equals rider power again.
What's S for a given P? You'd expect it to be bigger for a slower
rider-- it will take a bigger increase in speed to achieve a given drag
power at a lower speed. So even though P is bigger for the larger rider,
S for a given P will be smaller. Not sure how it all works out.

 

[Marcus Coles]

Stephen Greenwood wrote:
> I can't say how it affected the
> handling because I stopped immediately, reflexively responding to the
> frightful noise made by the broken spoke whacking against the frame.
>

Sounds like a case for tying and soldering ;-)

Marcus

 

[Ron Ruff]

On Feb 24, 9:44 pm, daveornee <daveornee.2mj...@no-
mx.forums.cyclingforums.com> wrote:
> Somehow I had a refence in mind that said the faster you ride the more
> power is consumed by aerodynamic drag. I guess I made a leap of
> (mis-)understanding that aerodynamic improvements would increase their
> "watts saved" values as speed increased.

These assumptions are correct. The slower rider will save a little
more *time* though, because it takes them longer. For anyone going at
a fairly high speed the aerodynamic drag is by far the greatest
resistance to overcome, so aero improvements will help anyone.

> and if I eat that extra slice of pizza or carry a few more onces of
> water in my water bottles I won't worry about the weight gain as long
> as it doesn't hurt my aerodynamic position.

That might be tougher than you think! As the mass increases, so does
the volume and area... plus I don't think a "spare tire" is very
aero...

By the way, I'm pretty happy with how the CX-Rays look in the built
wheel. They could be a hair closer to the flange, but the gap is very
small.

 

[daveornee]

On Feb 24, 9:44 pm, daveornee <daveornee.2mj...@no-
mx.forums.cyclingforums.com> wrote:
> Somehow I had a refence in mind that said the faster you ride the more
> power is consumed by aerodynamic drag. I guess I made a leap of
> (mis-)understanding that aerodynamic improvements would increase their
> "watts saved" values as speed increased.

These assumptions are correct. The slower rider will save a little
more *time* though, because it takes them longer. For anyone going at
a fairly high speed the aerodynamic drag is by far the greatest
resistance to overcome, so aero improvements will help anyone.

> and if I eat that extra slice of pizza or carry a few more onces of
> water in my water bottles I won't worry about the weight gain as long
> as it doesn't hurt my aerodynamic position.

That might be tougher than you think! As the mass increases, so does
the volume and area... plus I don't think a "spare tire" is very
aero...

By the way, I'm pretty happy with how the CX-Rays look in the built
wheel. They could be a hair closer to the flange, but the gap is very
small.

Saving more time is understood now. I should have looked more closely at the equation and been more clear in my statement of what "more" is saved by aerodynamic upgrades.
OK on the mass and volume part of the equation. I was mentally justifying my lack of fitness and the extra slice of pizza I was eating at the time.

You mentioned your rear wheel is 14 and 7. Can you explain more about the spoke configuration?..... and also how the spoke tensions came out at least in a relative fashion.
I will also be interested to hear how you like your new wheels after a season's worth of riding and racing.

Another poster made comment about tying a soldering... very tough to do on radial spokes.... but maybe that is why he put a smily face after his "suggestion"

 

[Marcus Coles]

daveornee wrote:

> Another poster made comment about tying a soldering... very tough to do
> on radial spokes.... but maybe that is why he put a smily face after his
> "suggestion"
>
It was as you surmised a feeble attempt at humor, but funnily enough
might work with wheels such as the Shimano WH-R535, the subject of the
post to which I was responding. In that particular wheelset the spokes
cross laterally.

Marcus

 

[A Muzi]

>>> A little brake rub would just slow me down. If the wheel warped much
>>> more though, the tire would start rubbing on the forks as well...
>> Yes, like this guy.....
>> http://www.samoht.com/wiki/wiki.pl?action=browse&id=why_i'll_never_shop_at_wheatridge_again

Mike Jacoubowsky wrote:
> There's something a bit screwy in that story. We sold a ton of bikes with
> the wheels he had issues with (Rolf Vector Comps), and spoke failures were
> extremely rare. The Vector Pro was more likely to have issues, since it had
> fewer spokes and was built a bit closer to the "edge" (lots of tension on
> small number of spokes). And, according to his wiki, it was the spoke
> nipples that broke. Again, strange. And then, after the shop built him a new
> pair of conventional wheels, he had yet another spoke failure. Eventually he
> ended up with the wheels rebuilt by a reputable shop (that posts here
> frequently)... wonder how those wheels are doing?
>
> But I'm also surprised at the sentiments regarding the particular shop in
> question. I know at least one person high up in their organization who, if
> this were brought to his attention, would be quite dismayed and make sure
> things were dealt with appropriately.

I read that and cringed even though I sell none of those products. Nor
similar.
It's every business owner's nightmare that a customer with a beef,
legitimate or not, will get the brush from an employee and we hear about
it only after the situation is lost. . .
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

 

[Ron Ruff]

On Feb 25, 12:23 pm, daveornee <daveornee.2mk...@no-
mx.forums.cyclingforums.com> wrote:
> You mentioned your rear wheel is 14 and 7. Can you explain more about
> the spoke configuration?

14 3x DS, 7 radial heads in NDS, DA 7700 hub. Here is a picture:

http://123pichosting.com/images/11814-7_rear3_feb07.jpg

> ..... and also how the spoke tensions came out

Both sides nearly identical... the NDS is low 120s kg, the DS is high
120s. That is the nice thing about this kind of pattern. Both lateral
and radial loads are less likely to make the spokes go slack. A more
popular method is to use a 32h hub and a 24h rim... that way you don't
have to skip holes in the rim. You can also cross spokes on the NDS if
you have an even number. I would have liked to do that with the DA
hub, but with 7 spokes it isn't posible... or does anyone have a
clever method to do that? It didn't seem possible to me at least, but
I didn't spend a lot of time thinking about it. Maybe you could mix
different angles and still come up with a torsionally neutral
configuration.

> I will also be interested to hear how you like your new wheels after a
> season's worth of riding and racing.

Me too! I rode them 40 miles today, and the tension and true didn't
change... but I didn't do any stomping low gear sprints either...
maybe tomorrow.