OBRA: OBRA Chat: Shimano 10 speed life question

Mike Murray

2004-09-02

Rmsim-@cs.com wrote:

"What are the signs or indications that a cog needs to be replaced?"

They need to be replaced if they skip. If the chain is replaced frequently

enough it is nearly impossible to wear out a cog.

When the chain engages the cog there is pressure against the load bearing

portion of the tooth. This is the rear portion of the tooth about mid up

slope. The pressure will cause wear which will make the tooth slightly hook

shaped. As the chain is used the pins and rollers, or bushings if you are

stilling using a chain with bushings (most modern chains are bushingless),

will wear. This will increase the pitch of the chain. Pitch is the

distance between the teeth on the cog or the pins on the chain. With a new

chain the pitch of cog and chain are the same so force is spread over all

the engaging teeth. As the pitch of the chain lengthens with wear the force

gets transferred more to the last teeth to engage the cog on the back and

first to engage it on the front because the pitch of the chain will become

longer than the pitch of the tooth. Because of this the wear on the cog

does not progress in a linear fashion but will increase exponentially as the

chain wears since the same force is against the fewer loaded tooth, i.e.

increased force on those teeth. The pitch of the cog actually changes too

because the wear will lengthen it, however at a slower rate than the

increase in pitch of the chain. This is the reason that a worn cog and a

worn chain will work together but a new chain put on a worn cog will skip.

Skip is caused by the mismatch between the chain pitch and the cog pitch

which keeps the chain from adequately seating and engaging all the teeth.

This allows the chain to slide up the tooth and slip to the next space,

primarily under heavier load. If the chain is replaced frequently before

the chain pitch has elongated significantly the force against the cog tooth

remains fairly low and the cog will then only wear on the sides, becoming

progressively more narrow but remaining function, probably for more than a

riding lifetime. Wear is more noticeable on smaller cogs not only because

it happens faster since each tooth see the chain more frequently but also

because pitch mismatch is relatively larger compared to the radius of the

cog which makes the differential loading of the teeth a bigger deal and lets

the chain ride up over the tooth.

Mike Murray

Dan H

2004-09-02

I replace a lot of chains. I have 2 finishing nails in the wall at the same

height. I hang the old chain on one and the new chain on the other to

compare. I have seen chains "stretched" as much as 1&1/2 link plates over

the length of the chain.

BTW, chains don't really stretch. The lengthening is caused by bushing

wear.

Worn sprocket teeth develop wider than new "valleys" between the "peaks".

Also the theeth get pointier and in more extreme cases, develop a "hook".

Smaller cogs & sprockets always wear faster than larger ones given the same

hours of use because the load is distributed over a smaller area. I have

saved cassettes by simply repacing only the 11 or 12 tooth cog because the

larger cogs had lots of life left.

----- Original Message -----

From: ".David.Auker." <Dav-@Hevanet.com>

To: <Rmsim-@cs.com>; <chr-@thinairad.com>; <andyc-@hotmail.com>;

"obra" <ob-@topica.com>

Sent: Thursday, September 02, 2004 10:39 AM

Subject: Re: [OBRA Chat] Shimano 10 speed life question

What are the signs or indications that a cog needs to be replaced?

Worst case scenario: you replace your chain (too late) and find it

"skips."

The way I check chain-stretch: take it off the bike, hang next to a new

one.

Over the whole length, if the stretch is almost imperceptible, it's ok.

Much past that is good indication it needs to be replaced.

David

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Peter Murphy

2004-09-02

Old school chain cleaning...remove chain and put it in a container with

kerosene (or other stripper)and place on top of washing machine for 2 spin

cycles. You're chain will be nearly as clean as new.

Pete Murphy

From: Rmsim-@cs.com

Reply-To: Rmsim-@cs.com

To: chr-@thinairad.com, andyc-@hotmail.com, obra <ob-@topica.com>

Subject: RE: [OBRA Chat] Shimano 10 speed life question

Date: Thu, 02 Sep 2004 12:04:52 -0400

What are the signs or indications that a cog needs to be replaced?

Robbie

chr-@thinairad.com wrote:

Yes it is worth the effort. ?If you don?t maintain your chain well you

may

need to replace your cog. ?$200 for the cog is a lot of chains. ?(I

bought a

new cog this year after only one year of racing)

Chris

-----Original Message-----

From: Andrew Beehler [mailto:andyc-@hotmail.com]

Sent: Wednesday, September 01, 2004 11:29 PM

To: obra

Subject: Re: [OBRA Chat] Shimano 10 speed life question

I'm big on keeping my bike in good condition, but at what point is it no

longer worth your time to do soo much maintainance? Is 10 hours of extra

maintainance really worth the extra 1000 miles on the $30 Chain?

Andrew

----- Original Message -----

From: Dan H <mailto:br-@politesociety.com>

To: johnf-@msn.com <mailto:johnf-@msn.com> ?; dav-@bikecafe.net

<mailto:dav-@bikecafe.net> ?; ob-@topica.com <mailto:ob-@topica.com>

?;

murphy_-@hotmail.com <mailto:murphy_-@hotmail.com>

Sent: Wednesday, September 01, 2004 10:53 PM

Subject: Re: [OBRA Chat] Shimano 10 speed life question

"Recipe for a 3000 mile Campy chain. Use a master link specifically for

Campy 10, take the chain off every 100- 200 miles, clean well, lube with

Boe-shield, let dry for a couple of hours and re-install.

Clean your cassette often as well."

...And don't ride hills, stick to the flats and use large sprocket

combinations to distribute load ;-)

----- Original Message -----

From: John Forbes <mailto:johnf-@msn.com>

To: br-@politesociety.com <mailto:br-@politesociety.com> ?;

dav-@bikecafe.net <mailto:dav-@bikecafe.net> ?; ob-@topica.com

<mailto:ob-@topica.com> ?; murphy_-@hotmail.com

<mailto:murphy_-@hotmail.com>

Sent: Wednesday, September 01, 2004 10:23 PM

Subject: Re: [OBRA Chat] Shimano 10 speed life question

Recipe for a 3000 mile Campy chain. Use a master link specifically for

Campy

10, take the chain off every 100- 200 miles, clean well, lube with

Boe-shield, let dry for a couple of hours and re-install.

Clean your cassette often as well.

John Forbes

2126 NE 12th Ave.

Portland, OR 97212

503-331-6658

----- Original Message -----

From: Dan H <mailto:br-@politesociety.com>

To: dav-@bikecafe.net <mailto:dav-@bikecafe.net> ?; ob-@topica.com

<mailto:ob-@topica.com> ?; murphy_-@hotmail.com

<mailto:murphy_-@hotmail.com>

Sent: Wednesday, September 01, 2004 9:16 PM

Subject: Re: [OBRA Chat] Shimano 10 speed life question

"There are some good tools to help measure the wear of chains."

Have you ever used one of those tools to measure a new chain out of the

box?

I have tried several and they all indicate the new chain needs replacing

or

is more than half worn. ?I think they are nothing more than a tool to

sell

chains! Bunk!

I put the chain on the large sprocket in front and pull the chain toward

the

front of the bike. ?If you can see daylight under the chain, you should

have

replaced it already. ?Of course this depends on your sprocket being in

good

shape, too. Keeping a fresh chain on your bike will extend the life of

everything it touches, prevent skipping and promote clean shifts.

I can't speak for Shimano 10's but Campys won't last more than 1000 miles

unless you are very light and keep a clean bike.

----- Original Message -----

From: < dav-@bikecafe.net <mailto:dav-@bikecafe.net> >

To: < ob-@topica.com <mailto:ob-@topica.com> >; <

murphy_-@hotmail.com <mailto:murphy_-@hotmail.com> >

Sent: Wednesday, September 01, 2004 4:31 PM

Subject: RE: [OBRA Chat] Shimano 10 speed life question

There are some good tools to help measure the wear of chains. Some are

produced by Park Tool which has some good information regarding wear and

replacement, www.parktool.com <http://www.parktool.com>

Manufacturers recommend replacement between 0.75% and 1% wear.

David

David Visintainer

Owner, BikeCafe

www.bikecafe.net <http://www.bikecafe.net>

---------- Original Message ----------------------------------

From: Peter Murphy < murphy_-@hotmail.com

<mailto:murphy_-@hotmail.com> >

Reply-To: murphy_-@hotmail.com

<mailto:murphy_-@hotmail.com>

Date: ?Wed, 01 Sep 2004 16:25:56 -0700

Pat,

I believe all you need is a ruler. Line the beginning of a ruler at

the

center of a pin and another pin center should hit the 12 inch mark. If

the

the pin center is long by more than 1/8" the chain should be replaced.

At

least that is what I've heard/read.

Pete Murphy

From: Pat Sagers < pat.s-@alldata.net

<mailto:pat.s-@alldata.net> >

Reply-To: pat.s-@alldata.net <mailto:pat.s-@alldata.net>

To: " 'ob-@topica.com' <mailto:'ob-@topica.com'> " <

ob-@topica.com

<mailto:ob-@topica.com> >

Subject: RE: [OBRA Chat] Shimano 10 speed life question

Date: Wed, 1 Sep 2004 18:14:04 -0500

I read that once a chain is stretched to a certain point it will

begin

to

rapidly wear the cogs down on the rear cassette and eventually ruin

it.

I

can't remember off the top of my head what formula you use to

determine

the

stretch, but it seemed pretty easy to check out. ?However, I've

ridden

on

chains for at least 3000+ miles without any noticeable problems.

?Maybe

I

don't peddle with enough force to stretch the chain that fast.

Pat

-----Original Message-----

From: John Schader [mailto:voya-@yahoo.com]

Sent: Wednesday, September 01, 2004 4:08 PM

To: kj_f-@yahoo.com <mailto:kj_f-@yahoo.com> ;

Steve-@clark.wa.gov <mailto:Steve-@clark.wa.gov> ;

ob-@topica.com

<mailto:ob-@topica.com>

Subject: Re: [OBRA Chat] Shimano 10 speed life question

I don't know about Shimano 10 speed chains either, but I kept my

Campy

10

speed chain on for more than 6800 miles. I know that according to the

experts I should have retired the old chain a long time ago. I bought

a

Wipperman stainless steel chain to replace it, even though I have not

had

any problems at all with the old chain.

Ken Finch < kj_f-@yahoo.com <mailto:kj_f-@yahoo.com> > wrote:

Steve,

I don't know about Shimano 10 spd's but I started

riding a Campy 10 spd set up last year and I only got

about 800 miles out of my first chain. I bought a

11-21 cassette for it and noticed it skipped and

jumped in the 11 cog. (Not that I ever really need

that cog) and a new chain fixed the problem.

Ken Finch

--- Steve-@clark.wa.gov <mailto:Steve-@clark.wa.gov> ?wrote:

I realize this is a bit off topic for the

current threads, but,

I was wondering what kind of life you are

getting out there for your shimano 10 speed chains

and

cassetts.

I can get 3000-4000 miles out of my current 9

speed set up for a chain, and I haven't worn out a

dura ace 9 speed cassette

in

quite some time.

I had hear! d that

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