chain ring replacement: cost effective?

[G.Daniels]

the l980's SR chainrings are wearing small ring first. Is replacing the small ring cost effective
given the different wear and thus chain stretch between large and small,now new, rings? or does the
larger diameters of the chain rings as opposed to the more rapid wear over the smaller rear gear
cluster cancel the two different chain stretchs out uh somewhat? So I'm seeing 3000+ miles from a
cluster and chain with the different unreplaced wear patterns. Do the new inner and worn outer rings
give a reduction in that 3000 mile useage?

 

[David Kunz]

g.daniels wrote:
> the l980's SR chainrings are wearing small ring first. Is replacing the small ring cost effective
> given the different wear and thus chain stretch between large and small,now new, rings? or does
> the larger diameters of the chain rings as opposed to the more rapid wear over the smaller rear
> gear cluster cancel the two different chain stretchs out uh somewhat? So I'm seeing 3000+ miles
> from a cluster and chain with the different unreplaced wear patterns. Do the new inner and worn
> outer rings give a reduction in that 3000 mile useage?

I replace CRs as they wear -- when the skip under load with a new chain. The middle wears the
fastest for me (usually 3 or 4 chains), then the small, and I've never replaced a big one from
riding wear (dang those rocks ).

David

 

[Paul Kopit]

On 5 Mar 2003 09:27:26 -0800, [email protected] (g.daniels) wrote:

>the l980's SR chainrings are wearing small ring first. Is replacing the small ring cost effective
>given the different wear and thus chain stretch between large and small,now new, rings? or does the
>larger diameters of the chain rings as opposed to the more rapid wear over the smaller rear gear
>cluster cancel the two different chain stretchs out uh somewhat? So I'm seeing 3000+ miles from a
>cluster and chain with the different unreplaced wear patterns. Do the new inner and worn outer
>rings give a reduction in that 3000 mile useage?

Your chain wear is directly related to how and when you clean the chain. 3,000 miles is good for a
chain and poor for the cogset. I'd only guess that the chain needs replacing before the 3,000 miles.

If the small ring is worn, evidenced by being very noisy or skipping, then you can replace that
ring. The noise can sound almost like front derailleur rub or grinding. You might also just turn the
ring over and mount it again. Smaller rings wear faster. On a triple, the middle ring frequently
wears first because it gets used most often.

 

[Bruce]

g.daniels wrote:
> the l980's SR chainrings are wearing small ring first. Is replacing the small ring cost effective
> given the different wear and thus chain

There is no need to replace a chainring unless the chain is jumping, or you have trouble shifting
etc. While a worn chain will cause increased gear-wheel wear, due to uneven loading, the reverse is
not true. The larger ring will wear more slowly, and tolerate more wear before it starts to jump.

> stretch between large and small,now new, rings? or does the larger diameters of the chain rings as
> opposed to the more rapid wear over the smaller rear gear cluster cancel the two different chain
> stretchs out uh somewhat?

I dont think you are making any sense there. Have a read of Sheldon Brown's page on so-called
"chain-stretch".

> So I'm seeing 3000+ miles from a cluster and chain with the different unreplaced wear patterns. Do
> the new inner and worn outer rings give a reduction in that 3000 mile useage?

No, not according to my understanding or experience. But I'll bet someone disagrees. If so, I'd like
to hear the explanation.

 

[Ron Hardin]

Bruce wrote:
> The larger ring will wear more slowly, and tolerate more wear before it starts to jump.

The difference is that the chainring takes on links under load and the freewheel cogs do not. The
tip of any would-be hook is what is worn off on the chainrings, but not the cogs.
--
Ron Hardin [email protected]

On the internet, nobody knows you're a jerk.

 

[Peter Cole]

"Ron Hardin" <[email protected]> wrote in message news:[email protected]...
> Bruce wrote:
> > The larger ring will wear more slowly, and tolerate more wear before it starts to jump.
>
> The difference is that the chainring takes on links under load and the freewheel cogs do not. The
> tip of any would-be hook is what is worn off on the chainrings, but not the cogs.

A more obvious difference is that chainrings are much larger.

Chainring hooking is common, it causes chain suck.

 

[Bruce]

Ron Hardin wrote:
> Bruce wrote:
>
>> The larger ring will wear more slowly, and tolerate more wear before it starts to jump.

I was comparing the two chainrings there, but guess it applies to comparison with the cogs too.

> The difference is that the chainring takes on links under load and the freewheel cogs do not.

But the cogs "take off" the links under load. Wouldn't that have the same effect? How does wearing
differ? The loading on the links & teeth is symmetric. Wear is caused by friction under load, and
the direction of movement wouldnt matter. Its the size of the rings that makes the difference IMHO.

> The tip of any would-be hook is what is worn off on the chainrings, but not the cogs.

You reckon? I find that hard to believe. Havn't observed it, but then I lack your experience.

 

[Paul Kopit]

On Sat, 08 Mar 2003 10:55:10 +0800, Bruce <[email protected]> wrote:

> The loading on the links & teeth is symmetric.

Logical but not true. Charings wear more at the 1 o'clock position where you start the bicycle and
few riders apply even pressure all around. You can rotate a ring that is skipping a couple of holes
and find that the skip it gone or lessened.

Chainrings can be worn and not skip at all. I used a set of rings on the timing side of my tandem. I
turned them over 180 degrees to maximize use. The engagement of the teeth was not perfect and never
skipped but the rings were noisy. I replaced those 2 rings and happened to use one of the worn rings
on a single. There was zero skipping but the noise of engagement sounded almost like grinding.

 

[G.Daniels]

OK! the premise was that the chain as NEW and the rings as NEW----- MATCH then the rings wear(slowly
thanks) you wanna hear grinding noises think of CR's wearing like gear clusters. so the CR's wear
and wear and then one day you clean them and say holy ...... batman we need a new inner CR(cause the
'83 SR belonged to a woman and the sea breeze is a 50% grade so stop snickering) HOWEVER, the
thought occurs that the total wear on the CR's now exceeds the cost effective replacement when mated
to a new chain/gear cluster in other words wear with a tight inner and a loose outer CR-that is
asking the chain to pull at one new dimension then pull on one worn dimension wears the chain much
more than the almost equally worn inner and outer now on the frame. whew! the ratio of wear on
everything new vs the ratio of wear on everything worn but with a new chain und cluster vs the ratio
of a new inner CR, new chain/cluster, old outer CR. whew! the question is not moot as SR's are good
CR's and go maybe 10,000 miles with care while I'm not so sure that's the situation with lesser CR's
and i have two sets(with more used around here at terminus somewhere) so getting a new inner and
swapping back to the next set is cool( and the sugino's-check the site!-are dear i'm told). i assume
as no sentinent life form rose up to say "THIS IS A unghfoil L;OUSY IDEA" then the new inner will
run.no tooth grinding can anyone here give an engineering explaination/description of bearing
retainers at the headset?

 

[G.Daniels]

maybe the new ring shud be broken in with a half used, at less than 1/16", chain?

 

[G.Daniels]

further mulling! if itwernt cost effective down at the wagon factory, the replacement ring wudbe cut
or ground more to the worn large rings spec., no? gives rise to the idea, if this is an idea I'm not
sure... anyway the measure of a new tooth top vs the measure of the worn rings top vs the measure of
the large rings top shud yield an averge that rationally produces cost effectiveness in not
streeeectctching the chain unduly- that is to say without going to the trouble of actually looking
at the chain ring tooth tops as a continuing maintenance function (is this boring?)maybe the worn
ring shud be replaced before the tooth tops are worn to a point My first wonderings about this were
answered by bikemags photo of the longrangeHoffman holding up worn chain ring number 37 and LO! the
teeth wear worn to points.In fact,given the fleeting nature of most bike mechanic's contact with
specific bikes and the unlikely natute of having 37 worn rings pass through maybe Hoffman's mechanic
is one of the few people on this side of the planet with empirical knowledge? SOURCE!when I noticed
tooth wear approaching terminal velocity, Harris Cyclery was dialed up and Harris's ring scroll much
like that from Sparticus or GTW brought a healthy laugh 'cause there they are!Amazing. If you
enjoyed redaing this try DIY bike/cable luber's new headset installment!