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

new chain, slack



 
 
Thread Tools Display Modes
  #41  
Old December 26th 17, 06:35 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default new chain, slack

On 12/26/2017 8:42 AM, Emanuel Berg wrote:
Frank Krygowski wrote:

If there were nothing to bend the links (as
when they wrap or unwrap around the
sprockets), then applying and releasing
tension would cause essentially no wear at
all. To get wear you need relative motion
between the parts, as well as some
contact pressure.


"Relative motion between the parts", yes
of course.

What do you mean by "contact pressure"?


Contact pressure is the force applied between two mechanical pieces
divided by the area of contact.

For now, I'll postpone discussing the internal geometry of the chain.
Let's just look at two steel bars, dimensions 10 mm x 10 mm x 1 m. Place
one horizontally on your workbench. Place the second bar on top of the
first and perpendicular to it. If you apply any downward force to the
bar on top, that force generates pressure on the square centimeter of
area in contact. Force divided by area gives you the magnitude of the
pressure.


E.g., if you have a chain attached to a heavy
boulder and drag it back and forth, starting
and stopping, isn't there wear when the slack
chain turns stiff and pulls the boulder into
motion, after which load balances out over all
the links and the boulder moves forward in part
by its own momentum?


If the chain moves (from hanging slack to being nearly straight under
tension) and tension is applied, there will be some opportunity for it
to wear, although I think the wear would be negligible in this case. If
the chain were supported so that it was horizontal and did not move as
tension were applied, there would be essentially zero wear.

It's easier to visualize a chain hanging vertically and having a load
applied and removed. (If you want to do it right, test a length of chain
in a Universal Testing Machine. See
http://www.instron.us/en-us/products...esting-systems
) Done this way there will be no motion during the application and
removal of load, and essentially no wear even if the forces are large.

--
- Frank Krygowski
Ads
  #42  
Old December 26th 17, 06:45 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default new chain, slack

Frank Krygowski wrote:

Contact pressure is the force applied between
two mechanical pieces divided by the area
of contact.


OK, good.

So where is the pressure area? The rollers and
the inside/front of the sprocket and
chainring teeth?

And pressure from pedaling and driving the bike
forward?

I take it wear is reduced to a huge extent by
the sprocket and chainring rotating in the same
direction as the pull?

Or rather the required pressure is reduced?

If the chain moves (from hanging slack to
being nearly straight under tension) and
tension is applied, there will be some
opportunity for it to wear, although I think
the wear would be negligible in this case.
If the chain were supported so that it was
horizontal and did not move as tension were
applied, there would be essentially
zero wear.

It's easier to visualize a chain hanging
vertically and having a load applied and
removed. (If you want to do it right, test
a length of chain in a Universal Testing
Machine.
See
http://www.instron.us/en-us/products...esting-systems
) Done this way there will be no motion
during the application and removal of load,
and essentially no wear even if the forces
are large.


OK, cool.

--
underground experts united
http://user.it.uu.se/~embe8573
  #43  
Old December 26th 17, 08:13 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default new chain, slack

Contact pressure is the force applied
between two mechanical pieces divided by the
area of contact.


OK, good.

So where is the pressure area? The rollers
and the inside/front of the sprocket and
chainring teeth?


Wait, if the preassure area and wear happens at
the same place, this doesn't make any sense...

If wear happens inside the chain between to
links, when does this happen on the chain
cycle? When one link is on a teeth pulling the
load and another (the link next to it) is
"free" pulling the tangled link? Because the
chain or pair of two links aren't in a stright
line at that point?

--
underground experts united
http://user.it.uu.se/~embe8573
  #44  
Old December 26th 17, 08:27 PM posted to rec.bicycles.tech
[email protected]
external usenet poster
 
Posts: 824
Default new chain, slack

On Tuesday, December 26, 2017 at 8:13:38 PM UTC+1, Emanuel Berg wrote:
Contact pressure is the force applied
between two mechanical pieces divided by the
area of contact.


OK, good.

So where is the pressure area? The rollers
and the inside/front of the sprocket and
chainring teeth?


Wait, if the preassure area and wear happens at
the same place, this doesn't make any sense...

If wear happens inside the chain between to
links, when does this happen on the chain
cycle? When one link is on a teeth pulling the
load and another (the link next to it) is
"free" pulling the tangled link? Because the
chain or pair of two links aren't in a stright
line at that point?

--
underground experts united
http://user.it.uu.se/~embe8573


Jesus Christ... The wear happens at the moment a link leaves the sprocket and when it enters the chainring. At that moment you have a relative movement and tension between the parts that wear. You can push your handpalm on a piece of sandpaper. That doesn't hurts. It hurts when you aren pushing and moving over the sandpaper. Tip; take a chain/link apart and figure out how it works.

Lou
  #45  
Old December 26th 17, 09:06 PM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default new chain, slack

Lou wrote:

Jesus Christ... The wear happens at the
moment a link leaves the sprocket and when it
enters the chainring. At that moment you have
a relative movement and tension between the
parts that wear.


Scales of Set... Right, that's what I said.
Except for the chainring which is the analogue
situation on the other end. One would think
there would be marginally less wear there as
there is less "relative movement" due to the
larger size, right?

--
underground experts united
http://user.it.uu.se/~embe8573
  #46  
Old December 28th 17, 04:20 AM posted to rec.bicycles.tech
JBeattie
external usenet poster
 
Posts: 5,870
Default new chain, slack

On Sunday, December 24, 2017 at 1:21:47 PM UTC-8, AMuzi wrote:
On 12/24/2017 12:50 PM, Emanuel Berg wrote:
Frank Krygowski wrote:

OK, but is there a reason why you bring this
up in such detail?

Yes. I brought it up because you asked.


OK, thank you in that case.


Your average guy imagines that the chain wears against the
teeth. This is not so. The chain roller doesn't turn or wear
against the tooth, chain wear is inside the chain.


Although I've broken and crushed rollers on a Sedis chain -- super low gear climbing pulling a kid in a trailer.

-- Jay Beattie.
  #47  
Old December 28th 17, 04:27 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default new chain, slack

jbeattie wrote:

Although I've broken and crushed rollers on
a Sedis chain -- super low gear climbing
pulling a kid in a trailer.


I've broken chains as well but that was before
I had this interest, so I didn't examine what
piece in particular broke. Darn

It was while standing up, climbing, with
additional stuff loaded on the bike as well.

I suppose this puts extra tention on the chain
and it prolongs the situation where wear is the
most intense for an individual link or pair of
links, because of the surplus load, and
"subplus" speed, right?

--
underground experts united
http://user.it.uu.se/~embe8573
  #48  
Old December 28th 17, 09:16 PM posted to rec.bicycles.tech
Frank Krygowski[_4_]
external usenet poster
 
Posts: 10,538
Default new chain, slack

On 12/27/2017 10:20 PM, jbeattie wrote:
On Sunday, December 24, 2017 at 1:21:47 PM UTC-8, AMuzi wrote:
On 12/24/2017 12:50 PM, Emanuel Berg wrote:
Frank Krygowski wrote:

OK, but is there a reason why you bring this
up in such detail?

Yes. I brought it up because you asked.

OK, thank you in that case.


Your average guy imagines that the chain wears against the
teeth. This is not so. The chain roller doesn't turn or wear
against the tooth, chain wear is inside the chain.


Although I've broken and crushed rollers on a Sedis chain -- super low gear climbing pulling a kid in a trailer.


Whoa! You're manlier than Joerg!


--
- Frank Krygowski
  #49  
Old December 29th 17, 06:59 PM posted to rec.bicycles.tech
JBeattie
external usenet poster
 
Posts: 5,870
Default new chain, slack

On Thursday, December 28, 2017 at 12:16:43 PM UTC-8, Frank Krygowski wrote:
On 12/27/2017 10:20 PM, jbeattie wrote:
On Sunday, December 24, 2017 at 1:21:47 PM UTC-8, AMuzi wrote:
On 12/24/2017 12:50 PM, Emanuel Berg wrote:
Frank Krygowski wrote:

OK, but is there a reason why you bring this
up in such detail?

Yes. I brought it up because you asked.

OK, thank you in that case.


Your average guy imagines that the chain wears against the
teeth. This is not so. The chain roller doesn't turn or wear
against the tooth, chain wear is inside the chain.


Although I've broken and crushed rollers on a Sedis chain -- super low gear climbing pulling a kid in a trailer.


Whoa! You're manlier than Joerg!


Or I got a crappy chain. I think Sedis had a problem with QC for a period of time. I think this was pre-SRAM, but it might have been at that cross-over point. I prefer Shimano (except the lack of a master link) and KMC chains.

-- Jay Beattie.
  #50  
Old January 2nd 18, 05:45 AM posted to rec.bicycles.tech
Emanuel Berg[_2_]
external usenet poster
 
Posts: 1,035
Default new chain, slack

AMuzi wrote:

Overly tight chain will destroy hub and crank
bearings before significant chain wear.


Today or if it was yesterday I tried this and
for sure there was a terrible noise and
a totally obnoxious pedaling experience.

I hope I didn't take the experiment too far so
the bearings will have to be replaced :-$

--
underground experts united
http://user.it.uu.se/~embe8573
 




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
OBree uses a slack chain someone Techniques 68 September 16th 09 02:19 AM
OBree uses a slack chain Fred Fredburger[_6_] Racing 0 September 15th 09 08:09 PM
Advice On Slack In Kh-schlumpf? Paulo Unicycling 4 May 18th 08 07:57 PM
Chain side slack Pat and Bob Chambers UK 1 September 8th 05 11:37 AM
Chain Side Slack Pat and Bob Chambers Australia 1 September 8th 05 09:23 AM


All times are GMT +1. The time now is 11:38 AM.


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.