wheelbuilding question

jabpn wrote:

I have recently begun the forray into wheel-building. I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?

Yes, for bikes with derailer gearing.
It seems to make sense that the rotor side
should have more tension now to provide proper wheel support. Any
info you can send me regarding your experience or knowledge would be
so helpful. All wheel-building websites and books I've found/read
just aren't updated enough to answer the questions about new
technologies in the bicycling industry.

That's 'cause there's nothing new to update. You'll only have one disc
rotor, which won't take up nearly as much lateral space as a cassette

Sheldon "No News Is Good News" Brown

(sorry, don't have my quotes collection on this $#!@*! Wintel box.)

Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com
Useful articles about bicyces and cycling
http://sheldonbrown.com

In article ,
jabpn wrote:
I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?

Spoke tension is a vector and the left/right components of the spokes
on both sides must add to 0 for the rim to remain stationary.

Where the spokes on one side are more angled than the other their tension
has a larger left/right component so the total tension must be lower on
that side.

Total tension on the two sides won't be equal unless the spokes approach
the rim at the same angle. While a disc wheel can have less difference
it's not going to be symetrical.
--
a href="http://www.poohsticks.org/drew/"Home Page/a
Life is a terminal sexually transmitted disease.

In article ,
jabpn wrote:
I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?

Spoke tension is a vector and the left/right components of the spokes
on both sides must add to 0 for the rim to remain stationary.

Where the spokes on one side are more angled than the other their tension
has a larger left/right component so the total tension must be lower on
that side.

Total tension on the two sides won't be equal unless the spokes approach
the rim at the same angle. While a disc wheel can have less difference
it's not going to be symetrical.
--
a href="http://www.poohsticks.org/drew/"Home Page/a
Life is a terminal sexually transmitted disease.

jabpn wrote:
I have recently begun the forray into wheel-building. I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?

yes.

It seems to make sense that the rotor side
should have more tension now to provide proper wheel support. Any
info you can send me regarding your experience or knowledge would be
so helpful.

the relative tensions are a function of the angles the spokes make with
the rim, which is in turn determined by flange spacing. if the flange
spacing on a disk hub is the same as a non-disk hub, the relative
tensions will be the same.

All wheel-building websites and books I've found/read
just aren't updated enough to answer the questions about new
technologies in the bicycling industry.

it's not new technology, but you're right, this is not covered in any
book i've seen. however, if you want to look at the math, it's in the
latest version of damon renard's spoke calculator spreadsheet.

jabpn wrote:
I have recently begun the forray into wheel-building. I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?

yes.

It seems to make sense that the rotor side
should have more tension now to provide proper wheel support. Any
info you can send me regarding your experience or knowledge would be
so helpful.

the relative tensions are a function of the angles the spokes make with
the rim, which is in turn determined by flange spacing. if the flange
spacing on a disk hub is the same as a non-disk hub, the relative
tensions will be the same.

All wheel-building websites and books I've found/read
just aren't updated enough to answer the questions about new
technologies in the bicycling industry.

it's not new technology, but you're right, this is not covered in any
book i've seen. however, if you want to look at the math, it's in the
latest version of damon renard's spoke calculator spreadsheet.

Jonesy wrote:
(jabpn) wrote in message . com...

I have recently begun the forray into wheel-building. I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?


Yes. The rotor mounting stuff moves that flange inboard a bit, but
not as much as the cassette.


It seems to make sense that the rotor side
should have more tension now to provide proper wheel support. Any
info you can send me regarding your experience or knowledge would be
so helpful.


That's true - the more tension you can bring to bear (before
destroying the rim) the better. Read "The Bicycle Wheel" by Jobst
Brandt.

i know that "high tension" recommendation is "in the book" and often
repeated here, but it's a fundamentally flawed piece of advice. the
closer a rim is operated to it's yield point, the less will be its
fatigue life, with the kind of results reported here yesterday:

http://mixednutsband.com/crack4.jpg

just because a rim doesn't fail with static load, doesn't mean it can
take the fatigue load. that's why there are so many reliability
complaints here on r.b.t.

in addition, as can be seen in damon rinard's experiments, increasing
spoke tension makes absolutely no difference to lateral strength. see:

http://www.sheldonbrown.com/rinard/wheel/tension.gif

original page:
http://www.sheldonbrown.com/rinard/wheel/index.htm

max spoke tension is determined by the rim's manufacturer. something
like a mavic open pro has a recommended max tension of 100-110 kgf.

Lots of good info on the "why" of wheelbuilding, and a nice
section of "how" as well. He does not specifically address disk
brakes, but from the info, you can determine how the spokes should be
to best support the loads.

"Zinn and the Art of Mountain Bike Maintenance" by Lenard Zinn has a
section on wheelbuilding that has a nice how-to that directly
addresses disk brake wheels.


All wheel-building websites and books I've found/read
just aren't updated enough to answer the questions about new
technologies in the bicycling industry.


The Zinn book is nice - it has other stuff that's useful, like an
appendix containing a decent torque table.

If you are interested in reading some long-winded drivel I have
written recently, find the thread in this group titled "Wheelbuilding
Question(s)". One of the things that shocked me was that for my rim
and hub choice, the difference between the length of the longest and
shortest spokes and was 1.3mm. IOW, one length to do all of the
spoking. Sort of counter-intuitive, but the front wheel built up just
fine, and I suspect that the rear will build up equally well.

Good luck, and tell us how things work out.

Jonesy wrote:
(jabpn) wrote in message . com...

I have recently begun the forray into wheel-building. I have read a
lot of subject matter that states, for rear wheels, that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true?


Yes. The rotor mounting stuff moves that flange inboard a bit, but
not as much as the cassette.


It seems to make sense that the rotor side
should have more tension now to provide proper wheel support. Any
info you can send me regarding your experience or knowledge would be
so helpful.


That's true - the more tension you can bring to bear (before
destroying the rim) the better. Read "The Bicycle Wheel" by Jobst
Brandt.

i know that "high tension" recommendation is "in the book" and often
repeated here, but it's a fundamentally flawed piece of advice. the
closer a rim is operated to it's yield point, the less will be its
fatigue life, with the kind of results reported here yesterday:

http://mixednutsband.com/crack4.jpg

just because a rim doesn't fail with static load, doesn't mean it can
take the fatigue load. that's why there are so many reliability
complaints here on r.b.t.

in addition, as can be seen in damon rinard's experiments, increasing
spoke tension makes absolutely no difference to lateral strength. see:

http://www.sheldonbrown.com/rinard/wheel/tension.gif

original page:
http://www.sheldonbrown.com/rinard/wheel/index.htm

max spoke tension is determined by the rim's manufacturer. something
like a mavic open pro has a recommended max tension of 100-110 kgf.

Lots of good info on the "why" of wheelbuilding, and a nice
section of "how" as well. He does not specifically address disk
brakes, but from the info, you can determine how the spokes should be
to best support the loads.

"Zinn and the Art of Mountain Bike Maintenance" by Lenard Zinn has a
section on wheelbuilding that has a nice how-to that directly
addresses disk brake wheels.


All wheel-building websites and books I've found/read
just aren't updated enough to answer the questions about new
technologies in the bicycling industry.


The Zinn book is nice - it has other stuff that's useful, like an
appendix containing a decent torque table.

If you are interested in reading some long-winded drivel I have
written recently, find the thread in this group titled "Wheelbuilding
Question(s)". One of the things that shocked me was that for my rim
and hub choice, the difference between the length of the longest and
shortest spokes and was 1.3mm. IOW, one length to do all of the
spoking. Sort of counter-intuitive, but the front wheel built up just
fine, and I suspect that the rear will build up equally well.

Good luck, and tell us how things work out.

jab- that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true? BRBR

Yes but with hub flange placement, the tension between left and right is closer
to the same.



Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

jab- that the
non-freewheel side of the wheel will not be as highly tensioned as the
freewheel side. With disc brakes becoming more and more popular, does
this still hold true? BRBR

Yes but with hub flange placement, the tension between left and right is closer
to the same.



Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

On Fri, 09 Jul 2004 22:09:48 -0700, jim beam
wrote:

in addition, as can be seen in damon rinard's experiments, increasing
spoke tension makes absolutely no difference to lateral strength. see:

http://www.sheldonbrown.com/rinard/wheel/tension.gif

original page:
http://www.sheldonbrown.com/rinard/wheel/index.htm

Careful; the info on that page may not have much to do with a wheel's
lateral strength. Here's a quote from that link:

"It must be emphasized that wheel stiffness is not wheel strength, and
in fact may be unrelated to it. I am measuring stiffness, not
strength."

Also, and this statement doesn't appear to be backed up with any
measurements on that page, but he also says (under question #1):

"A wheel whose spokes become slack while riding is a weak wheel,
because slack spokes cannot support the rim. This can be avoided to a
large extent by building wheels with tighter spokes."

However, I wonder if Jobst's "slight taco" method is only one
potential upper limit on spoke tension. Rims cracking in fatigue,
nipples rounding, hub flanges breaking, etc. may be some others.

But I think we agree in practice. Without lots of experimentation,
it's difficult for me to predict the fatigue stuff before I build the
wheel, so I generally follow the manufacturer's specifications when
available.