Double-butted spokes translate into softer ride?
Phil, Squid-in-Training
first pair of wheels, and upon his first test ride he said that he could
feel how the ride was so much softer than his old wheels because of the new
2.0/1.8/2.0 spokes compared to straight-gauge 2.0. I was very inclined to
disagree, but I said nothing due to my lack of evidence.
Any empirical data to support this? Upon closer inspection, his spokes were
just barely butted... these DTs were more like 2.0/1.9/2.0, pretty much
out-of-spec on the 1.8 slot of the Wheelsmith spoke measuring ruler.
--
Phil, Squid-in-Training
carl...@comcast.net
Squid-in-Training" <phil_leeIHEA...@hotmail.com>
wrote:
Dear Phil,
We are awfully good at convincing ourselves that we can
detect impossibly small differences.
Depending on the strength of your friendship, you might ask
him if he notices tire pressure changes of 1 psi.
Cheers,
Carl Fogel
Qui si parla Campagnolo
Phil, Squid-in-Training wrote:
> Do thinner spokes result in a more compliant wheel?
No, a more durable wheel but not 'softer'. Is the tension
correct?...all tension on spokes should be the same in kg of force, the
amount of force to deflect the spoke a certain amount.
jobst....@stanfordalumni.org
> Do thinner spokes result in a more compliant wheel? A coworker
> built his first pair of wheels, and upon his first test ride he said
> that he could feel how the ride was so much softer than his old
> wheels because of the new 2.0/1.8/2.0 spokes compared to
> straight-gauge 2.0. I was very inclined to disagree, but I said
> nothing due to my lack of evidence.
Yes they are more compliant, but not for the rider, only for the
spokes and rim. Load is distributes over more spokes. To visualize
this, imagine using spokes several times thicker and the resulting
elastic response. I'm sure you have seen load distribution graphs
here on wreck.bike.
> Any empirical data to support this? Upon closer inspection, his
> spokes were just barely butted... these DTs were more like
> 2.0/1.9/2.0, pretty much out-of-spec on the 1.8 slot of the
> Wheelsmith spoke measuring ruler.
The difference is at most that of riding over a sheet of copier paper
lying on the road, something you cannot feel... but the rim does.
Jobst Brandt
Werehatrack
<phil_leeIHEA...@hotmail.com> wrote:
I'm with you on this; I think the rider had new-toy syndrome, possibly
abetted by a tire that may not have been inflated as much as usual.
Tire pressure has a lot more to do with ride smoothness than anything
that can be done with spoke elasticity in a wheel that's useful.
--
Typoes are a feature, not a bug.
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Ozark Bicycle
carl...@comcast.net wrote:
<snipped>
-on mind over matter-
>
> We are awfully good at convincing ourselves that we can
> detect impossibly small differences.
>
That's what makes it possible to sell things like Bzzkillers, Zertz and
all those gram-saving, vibration damping CF bits.....
Phil, Squid-in-Training
"Qui si parla Campagnolo" <pe...@vecchios.com> wrote in message
news:1145452021....@i40g2000cwc.googlegroups.com...
>
> Phil, Squid-in-Training wrote:
>> Do thinner spokes result in a more compliant wheel?
>
> No, a more durable wheel but not 'softer'. Is the tension
> correct?...all tension on spokes should be the same in kg of force, the
> amount of force to deflect the spoke a certain amount.
Yes: 100kgf using a tensiometer. He's a heavy guy (230lb) and the spokes
were slightly oversize, so the Park chart would have set him off on the
over-tensioned side by a little bit.
His previous CXP22 pulled some nipples through the rim. He replaced with
Open Pros.
--
Phil, Squid-in-Training
Paul Kopit
<phil_leeIHEA...@hotmail.com> wrote:
>Do thinner spokes result in a more compliant wheel? A coworker built his
>first pair of wheels, and upon his first test ride he said that he could
>feel how the ride was so much softer than his old wheels because of the new
>2.0/1.8/2.0 spokes compared to straight-gauge 2.0. I was very inclined to
>disagree, but I said nothing due to my lack of evidence.
I think that 'compliant' is a word that Shimano began using for their
own brand wheelset. I don't know what it means. If you think that
the rim is bending, or flexing more because of thinner spokes, it's
not such a great wheel.
daveornee
difference is extremely small, but it is measurable.
Look at the data on:
http://www.sheldonbrown.com/rinard/wheel/data.htm
Wheel numbers 39 & 40 can be contrasted with # 47 & 48.
The geometry of the spoke angles is the same, same rims, but different
spoke guage.
I know the chart talks about lateral deflection, but it also works for
radial deflection.
The differences are very minute. At the same time we are talking about
increments of .01 mm on the rim, I think the tire would mask the effect
by having increments of delflection ~100 - 1,000 times more.
--
daveornee
carl...@comcast.net
Dear Dave,
Thanks for finding a link to some actual numbers.
Browsing around, I found actual radial stiffness numbers
nearby, with what looks like a wildly mistaken conclusion:
http://www.sheldonbrown.com/rinard/wheel/grignon.htm
The table near the bottom shows radial stiffness for various
wheels ranging from 8,400 to 20,200 lbs/inch, which I assume
was accurately calculated, but then draws the strange
conclusion that "soft wheels provide a more comfortable
ride."
While the stiffness range from 8,400 to 20,200 lbs/inch
looks impressive at first, I expect that the actual loads
are only around 200 lbs.
This suggests the actual difference between the very best
and the very worst wheels tested was the ridiculously small
difference between 0.0238 to 0.010 inches (200/8400 and
200/20200), which is about 0.014 inches.
And that's for a wide range of different rims and spokes.
For the same rim with butted versus unbutted spokes, the
difference would obviously drop down to the thickness of
Jobst's sheet of paper, which is around 0.005 inches.
Normal road surfaces vary far more than this, and a typical
tire is hardly uniform to this degree. The tire, seat, bar
tape, gloves, pants, and shoes of the rider will compress
far more than these tiny amounts under the same load.
Cheers,
Carl Fogel
Paul Kopit
<daveorne...@no-mx.forums.cyclingforums.com> wrote:
>> I think that 'compliant' is a word that Shimano began using for their
>> own brand wheelset. I don't know what it means. If you think that
>> the rim is bending, or flexing more because of thinner spokes, it's
>> not such a great wheel.
>Oh, but they are bending/flexing more due to thinner spokes. The
>difference is extremely small, but it is measurable.
>Look at the data on:
>http://www.sheldonbrown.com/rinard/wheel/data.htm
>Wheel numbers 39 & 40 can be contrasted with # 47 & 48.
>The geometry of the spoke angles is the same, same rims, but different
>spoke guage.
>I know the chart talks about lateral deflection, but it also works for
>radial deflection.
>The differences are very minute. At the same time we are talking about
>increments of .01 mm on the rim, I think the tire would mask the effect
>by having increments of delflection ~100 - 1,000 times more.
>
>
>--
>daveornee
Thank you for the well made point. After reading the chart and your
astitute comment, I'm more convinced that the old fashioned wheels
that we can build are still a most viable choice. I have not kept up
with new designed wheels and thought I might be missing something.
Alex Rodriguez
phil_leeIHEA...@hotmail.com says...
The amount of flex in a tire is huge compared to the tiny stretch in a spoke,
so I doubt it was the spokes he was feeling.
--------------
Alex
David L. Johnson
> The amount of flex in a tire is huge compared to the tiny stretch in a spoke,
> so I doubt it was the spokes he was feeling.
We can point this out until we're blue in the face, but no one listens.
On a ride yesterday, a guy was saying that his new wheels were "beating
him up" compared to his previous wheels. I didn't say anything; I've
given up with most riders.
We're dealing with a culture that believes the position of the planets
when we were born controls our destiny.
--
David L. Johnson
__o | Arguing with an engineer is like mud wrestling with a pig... You
_`\(,_ | soon find out the pig likes it!
(_)/ (_) |