A Cycling & bikes forum. CycleBanter.com

Go Back   Home » CycleBanter.com forum » rec.bicycles » Techniques
Site Map Home Register Authors List Search Today's Posts Mark Forums Read Web Partners

butted spokes (?)



 
 
Thread Tools Display Modes
  #11  
Old September 4th 05, 05:31 PM
jim beam
external usenet poster
 
Posts: n/a
Default butted spokes (?)

Phil, Squid-in-Training wrote:
methods. some are indeed swaged, but some others are drawn and yet
others are ground & polished.



Does Wheelsmith do the last one? I've noticed that...

yup.

Ads
  #12  
Old September 4th 05, 06:22 PM
external usenet poster
 
Posts: n/a
Default butted spokes (?)


Use 14/15/14 gauge spokes(2mm/1.8mm/2mm), and lace them inside pulling
for a disc wheel.


Could you explain what does it mean exactly? Any scheme etc.?


  #14  
Old September 5th 05, 12:39 AM
Ron Ruff
external usenet poster
 
Posts: n/a
Default butted spokes (?)


jim beam wrote:

3) what spokes would you reccomend (thickness) and why ?


2mm/1.8mm/2mm. best trade-off between fatigue strength and stiffness.
stiffness is important for lateral stability.


Rinard found that lateral stiffness of a wheel changed much less than
the difference in spoke stiffness (look for #7 at the bottom):

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

A 90% increase in spoke siffness (1.45mm dia to 2mm dia) produced only
an 11% increase in lateral wheel stiffness.

  #15  
Old September 5th 05, 01:01 AM
Ron Ruff
external usenet poster
 
Posts: n/a
Default butted spokes (?)


jim beam wrote:
go to sapim.be and dig about for their fatigue strength tables.

http://www.sapim.be/index.php?st=pro...=fatiguetes t

If I calculated correctly their "fatigue test" results seem a little
odd. 1,000,000 wheel revolutions is only 1,340 miles
(27*pi/12/5280*1,000,000). Even the CX-rays with 3,500,000 revolutions
only get 4,690 miles.

I would be nice to know more about that testing...

  #16  
Old September 5th 05, 01:22 AM
jim beam
external usenet poster
 
Posts: n/a
Default butted spokes (?)

Ron Ruff wrote:
jim beam wrote:

go to sapim.be and dig about for their fatigue strength tables.


http://www.sapim.be/index.php?st=pro...=fatiguetes t

If I calculated correctly their "fatigue test" results seem a little
odd. 1,000,000 wheel revolutions is only 1,340 miles
(27*pi/12/5280*1,000,000). Even the CX-rays with 3,500,000 revolutions
only get 4,690 miles.

I would be nice to know more about that testing...

all i've discovered is that it was done by cycling from 90kgf to zero.
that's much higher than most wheels see in service. being as fatigue
life is usually regarded as having a logarithmic relation to stress, you
can see that your mileage will quickly increase with decreasing stress
cycle.

  #17  
Old September 5th 05, 01:23 AM
jim beam
external usenet poster
 
Posts: n/a
Default butted spokes (?)

Ron Ruff wrote:
jim beam wrote:

3) what spokes would you reccomend (thickness) and why ?


2mm/1.8mm/2mm. best trade-off between fatigue strength and stiffness.
stiffness is important for lateral stability.



Rinard found that lateral stiffness of a wheel changed much less than
the difference in spoke stiffness (look for #7 at the bottom):

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

A 90% increase in spoke siffness (1.45mm dia to 2mm dia) produced only
an 11% increase in lateral wheel stiffness.

sure, so why don't you include damon's comment about the rim
contributing to wheel stiffness as well?

  #18  
Old September 5th 05, 01:39 AM
Ron Ruff
external usenet poster
 
Posts: n/a
Default butted spokes (?)


jim beam wrote:

sure, so why don't you include damon's comment about the rim
contributing to wheel stiffness as well?


I thought that was obvious... at any rate it was the same rim in both
tests... and I suspect that on an MTB wheel the rim stiffness would
contribute even more, making the effect of spoke stiffness even less.

  #19  
Old September 5th 05, 02:04 AM
Ron Ruff
external usenet poster
 
Posts: n/a
Default butted spokes (?)


jim beam wrote:
Ron Ruff wrote:

If I calculated correctly their "fatigue test" results seem a little
odd. 1,000,000 wheel revolutions is only 1,340 miles
(27*pi/12/5280*1,000,000). Even the CX-rays with 3,500,000 revolutions
only get 4,690 miles.

I would be nice to know more about that testing...

all i've discovered is that it was done by cycling from 90kgf to zero.
that's much higher than most wheels see in service. being as fatigue
life is usually regarded as having a logarithmic relation to stress, you
can see that your mileage will quickly increase with decreasing stress
cycle.


So, they stressed the spokes in an unusual way to get them to break
sooner... fairly standard, I guess. Still, it seems odd that they would
have presented it as "wheel revolutions" when it really isn't... and it
makes their spokes look bad.

Also, that 200lb cycle is roughly only 20% of the tensile strength that
they list elsewhere... a huge difference between fatigue and static
strength.

Do you know of any other (hopefully better) online data regarding spoke
fatique and strength?

  #20  
Old September 5th 05, 02:27 AM
jim beam
external usenet poster
 
Posts: n/a
Default butted spokes (?)

Ron Ruff wrote:
jim beam wrote:

Ron Ruff wrote:

If I calculated correctly their "fatigue test" results seem a little
odd. 1,000,000 wheel revolutions is only 1,340 miles
(27*pi/12/5280*1,000,000). Even the CX-rays with 3,500,000 revolutions
only get 4,690 miles.

I would be nice to know more about that testing...


all i've discovered is that it was done by cycling from 90kgf to zero.
that's much higher than most wheels see in service. being as fatigue
life is usually regarded as having a logarithmic relation to stress, you
can see that your mileage will quickly increase with decreasing stress
cycle.



So, they stressed the spokes in an unusual way to get them to break
sooner... fairly standard, I guess.


yup.

Still, it seems odd that they would
have presented it as "wheel revolutions" when it really isn't...


a translation thing?

and it
makes their spokes look bad.


don't think so. as a relative measure between sapim's different spokes,
it's tells you what you need to know. as an absolute measure between
brands, i think it interesting that none of the other manufacturers have
the minerals to publish any fatigue info at all!


Also, that 200lb cycle is roughly only 20% of the tensile strength that
they list elsewhere... a huge difference between fatigue and static
strength.


sure, there's a spoke elbow on the bottom of this spoke bending back &
forth on each stress cycle. that'll raise the stress in the skin of the
bend considerably. you'll never see that reflected in static loading.


Do you know of any other (hopefully better) online data regarding spoke
fatique and strength?

carl fogel posted a pdf by someone named prof. gavin a while back. istr
that it contained fatigue testing. other than that, your googling is as
good as mine.

 




Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Threads
Thread Thread Starter Forum Replies Last Post
Snaping Spokes [email protected] Techniques 82 March 8th 05 05:34 PM
Rec.Bicycles Frequently Asked Questions Posting Part 1/5 Mike Iglesias General 4 October 29th 04 07:11 AM
Wheel building questions big Pete Techniques 18 October 16th 04 03:14 AM
Wheel Rebuilding TheObieOne3226 Unicycling 16 January 1st 04 11:55 AM
(Un)even spoke tension Ted Bennett Techniques 2 July 17th 03 12:33 PM


All times are GMT +1. The time now is 08:56 PM.


Powered by vBulletin® Version 3.6.4
Copyright ©2000 - 2024, Jelsoft Enterprises Ltd.
Copyright ©2004-2024 CycleBanter.com.
The comments are property of their posters.