Durability Of Velocity Aerohead Rims In 20/24 Hole Drillings.

On Nov 17, 10:32*am, Phil W Lee wrote:

I learned to say "passing on your left" fairly quickly when I was
riding the hike/bike path regularly.

It isn't how fast you can say it, it's how fast they can hear and
understand it, and work out what they need to do as a consequence.
PING!!! needs very little interpretation

Word order. I quickly learned, etc. as a matter of survival and
politeness.

But yes, sometimes even with a careful "passing on your left, please",
people would jump left, even though I'm afraid they were used to being
buzzed by faster users passing on the left, usually.

Again, it was amazing to see the rude behavior. Especially when the
bike path encouraged out-and-back rides. You tended to not loop on
city streets even in the nicer neighborhoods in this area of Houston
if you were riding by yourself-- IOW, without a witness.

- Occasionally one of the above-mentioned would get irate
* and yell something like "And do does yer momma!"

Well, even on the bike path, some people don't want to see you out
there g. Plus, many cyclists take obvious delight in "shaving" and
scaring people, so there is "baggage". So it goes.

Timing the "ding" goes a long way. * *I try to do it far enough
back that people can react well before I'm close and I try to do
it from the position in which I'll be passing - so most people
can locate the sound and realize nobody's bearing down on them.

Same with vocal. Yes, you gotta negotiate the difficulties.

The bell is very directional, and screams "bicycle" like nothing else.

I think this discussion leads to one obvious conclusion-- "use both".
Wow-- old dog, new trick!
--D-y

On Nov 19, 11:39*am, Michael Press wrote:
In article ,
*"Tom Sherman °_° --" wrote:



[...]

Polite company do not yawn in public.

Give the poor ol' fella a break. He must be very tired, yawning all
over the place as he is.

JS.

On Nov 19, 12:39*am, Michael Press wrote:
In article ,
*"Tom Sherman °_° --" wrote:



[...]

Polite company do not yawn in public.

--
Michael Press

it is lower case and bracketed.

"JimmyMac" wrote in message
...
On Nov 17, 1:55 am, "Edward Dolan" wrote:
[...]
My contempt for mountain bikers who ride their
bikes on hiking trails knows no bounds. They are scofflaws and they border
on being violent when opposed and confronted. Mr. Vandeman is a hero for
standing up to them.

Conan the Librarian, a hero is one who lays down their life for
another ... not one who threatens someone with a saw.

Mr. Vandman verbally confronts mountain bikers. It takes courage to do that
since all mountain bikers, as is well known, are criminal thugs.

Regards,

Ed Dolan the Great - Minnesota
aka
Saint Edward the Great - Order of the Perpetual Sorrows - Minnesota

On Nov 18, 9:40*pm, "Edward Dolan" wrote:
Durability Of Velocity Aerohead Rims

On Nov 4, 5:37*pm, Steve Sr. wrote:
Hello,

I am considering rebuilding a set of wheels that had Alex 20/24 hole
rims. They went about 5K miles before the spokes started to pull
thorough the rims.

I am considering using these hubs and Velocity Aerohead and Aerohead
O/C rims but am wondering about the durability because of my previous
experience with the Alex rims.

I currently have a set of these Velocity rims but in 32 hole
configuration that have been flawless for the past 10K miles.

BTW, I only weigh about 160 pounds.

Thanks,

Steve

OP, I think a more vertically compliant rim section will distribute
the tension load more evenly among the spokes. Kind of like the way a
miss sized O-ring can break steel fittings...

If you think of the rim as a container of spokes as if they are an
incompressible liquid, if the container is perfectly stiff the
pressure of the liquid is constant, as the volume does not change. If
you draw the free body diagram around the hub, the only force acting
to change the tension balance in the spokes is the hub itself with the
weight of the rider on it.

If the road causes the rim to deform, the tension in all the spokes
away from that deformation goes up. Now when you draw the free body
diagram around the hub, the differential tension of the spokes away
from the deformation (those spokes on the top side of the hub) will be
greater. This will reduce the amount of cyclic loading at the base of
the nipples on the under-spoked wheel.

This is consistent with Josh's less than favorable experience with
tall sections.

A23

On 11/19/2010 6:47 AM, Ed wrote:
On Nov 4, 5:37 pm, Steve wrote:
Hello,

I am considering rebuilding a set of wheels that had Alex 20/24 hole
rims. They went about 5K miles before the spokes started to pull
thorough the rims.

I am considering using these hubs and Velocity Aerohead and Aerohead
O/C rims but am wondering about the durability because of my previous
experience with the Alex rims.

I currently have a set of these Velocity rims but in 32 hole
configuration that have been flawless for the past 10K miles.

BTW, I only weigh about 160 pounds.

Thanks,

Steve

OP, I think a more vertically compliant rim section will distribute
the tension load more evenly among the spokes. Kind of like the way a
miss sized O-ring can break steel fittings...

If you think of the rim as a container of spokes as if they are an
incompressible liquid, if the container is perfectly stiff the
pressure of the liquid is constant, as the volume does not change. If
you draw the free body diagram around the hub, the only force acting
to change the tension balance in the spokes is the hub itself with the
weight of the rider on it.

If the road causes the rim to deform, the tension in all the spokes
away from that deformation goes up. Now when you draw the free body
diagram around the hub, the differential tension of the spokes away
from the deformation (those spokes on the top side of the hub) will be
greater. This will reduce the amount of cyclic loading at the base of
the nipples on the under-spoked wheel.

This is consistent with Josh's less than favorable experience with
tall sections.

A23


What you really need to understand this is a finite element analysis.
"The Bicycle Wheel" has tabular results of one, there are other analyses
on-line.

Ed wrote:

OP, *I think a more vertically compliant rim section will distribute
the tension load more evenly among the spokes.

It's the opposite. The more flexible the rim, the more loads are
transferred among just the spokes over the contact patch. If the rim
has high beam stiffness, the same applied load is shared among more
spokes and the magnitude of tension fluctuations is less.

Chalo

On Nov 19, 6:03*pm, Chalo wrote:
Ed wrote:

OP, *I think a more vertically compliant rim section will distribute
the tension load more evenly among the spokes.

It's the opposite. *The more flexible the rim, the more loads are
transferred among just the spokes over the contact patch. *If the rim
has high beam stiffness, the same applied load is shared among more
spokes and the magnitude of tension fluctuations is less.

Chalo

Keep going Chalo and you will end up with a disc wheel, with all its
weight and no springing. There is an ideal and a whole range of
acceptable rim compliance depending on the exact conditions of
service. Along with this goes the quality of the spoke assembly.

You only 'need' ultra rigid rims if your spoke assembly is poor.
Make good spoke assemblies which by their construction also engage the
forward and rearward spokes for wheel stabilty and the wheel comes
alive, aiding the rider through controlled springing. For 28 spokes
it doesn't matter and the lightest rims, as would be used for 36
spokes can be used, but when thinking of 20 and 24, the rim does
require a little more strength and inherent stiffness because it is
not possible to make a spoke assembly with the same amount of control
as for 28 or more. There is not a lot of difference and going from a
10oz to a 12oz rim should adequately compensate, but make the wheel
heavier by at least an ounce, more if heavier gauge spokes are also
thought necessary.

The way the spokes carry the load depends on the detail of the spoke
assembly. A 'stiffer' assembly will help distribute the load to the
front and rear of the wheel. Poor assemblies such as the woven
factory assembly are not appropriate for the lightest rims and will
not result in reliable and pleasant wheels.

On Nov 19, 6:23*am, Peter Cole wrote:
On 11/19/2010 6:47 AM, Ed wrote:





On Nov 4, 5:37 pm, Steve *wrote:
Hello,

I am considering rebuilding a set of wheels that had Alex 20/24 hole
rims. They went about 5K miles before the spokes started to pull
thorough the rims.

I am considering using these hubs and Velocity Aerohead and Aerohead
O/C rims but am wondering about the durability because of my previous
experience with the Alex rims.

I currently have a set of these Velocity rims but in 32 hole
configuration that have been flawless for the past 10K miles.

BTW, I only weigh about 160 pounds.

Thanks,

Steve

OP, *I think a more vertically compliant rim section will distribute
the tension load more evenly among the spokes. Kind of like the way a
miss sized O-ring can break steel fittings...

If you think of the rim as a container of spokes as if they are an
incompressible liquid, if the container is perfectly stiff the
pressure of the liquid is constant, as the volume does not change. *If
you draw the free body diagram around the hub, the only force acting
to change the tension balance in the spokes is the hub itself with the
weight of the rider on it.

If the road causes the rim to deform, the tension in all the spokes
away from that deformation goes up. *Now when you draw the free body
diagram around the hub, the differential tension of the spokes away
from the deformation (those spokes on the top side of the hub) will be
greater. *This will reduce the amount of cyclic loading at the base of
the nipples on the under-spoked wheel.

This is consistent with Josh's less than favorable experience with
tall sections.

A23

What you really need to understand this is a finite element analysis.
"The Bicycle Wheel" has tabular results of one, there are other analyses
on-line.

I think this is true if considering anything other than a radially
spoked wheel.

With a radially spoked wheel it should be straight forward:

1) A perfectly stiff rim that holds its circular section perfectly
will not redistribute tension loads in the spokes beyond what the hub
weight bearing forces apply to the spokes.

2) A rim that does not hold its circular section, but acts as an
incompressible line around its circumference must increase in distance
from the hub everywhere away from the contact deformation just below
the hub. This redistribution of spoke loads/strain caused by the
deformation of the rim results in a differential force upward on the
hub. This remapping of spoke tension reduces the peak loading on any
individual spoke that is required to support the weight on/of the hub
observed in case 1.

I guess I am saying that if it cannot be understood with free body
diagrams there is a chance it is not modeled correctly in the FEA.