D
dkahn400
Guest
Martin Wilson wrote:
> On Mon, 13 Dec 2004 20:36:20 +0900, James Annan
> <[email protected]> wrote:
> >Personally I think you're not firing on all cyclinders if you
> >prefer to make up some feeble straw man rather than just read
> >what I said, which was neither ambiguous nor inaccurate.
>
> Make up some straw man? Never heard of this before and frankly don't
> know what your talking about.
James is suggesting, I think, that the argument you refuted was not the
one he was putting forward but rather a superficially similar one you
set up just so you could knock it down. That's my understanding of a
"straw man". Whether that's what you were actually doing I'll leave for
the two of you to sort out.
> The OP has high levels of wear on the sprocket most used that has
> the most load applied. The wear on the other sprockets is much,
> much lighter and from the sound of it almost non existant. I assume
> the same grit and dirt moves with the chain and goes round all the
> sprockets and not just the smallest. I don't know the percentage of
> how much the smallest rear sprocket is used compared to the other
> gears. I suspect quite high but theres possibly more chain/teeth
> contact in the lower gears at any one time. Obviously cadence is
> factor too. Surely though if load wasn't a factor the wear and tear
> of the chain and sprocket teeth would be more general across the
> whole range of cassette gears.
In the OP's case the wear is greatest on the smallest sprocket because
that's the one he uses most of the time. First the chain wears causing
it to "stretch". Once it has stretched sprocket wear begins to
accelerate. The more stretched the chain, the faster the sprocket
wears. The sprockets that wear most are the ones that are used most.
I've personally worn out 2 and 3 in a 6 sprocket cluster by continuing
to use a stretched chain. 4 was less worn and 1 (the largest) and 5 and
6 (the smallest) were hardly worn at all.
I believe distance covered is far more significant in this than either
load or cadence. No matter what gear you are in each tooth of the
engaged sprocket meshes with a chain link once per wheel revolution.
The point about the larger sprockets having more teeth in contact with
the chain is misleading, I think, because the stretched chain no longer
meshes properly with the teeth; the load is concentrated on the top
teeth until the sprocket has worn sufficiently to conform to the
stretched chain.
--
Dave...
> On Mon, 13 Dec 2004 20:36:20 +0900, James Annan
> <[email protected]> wrote:
> >Personally I think you're not firing on all cyclinders if you
> >prefer to make up some feeble straw man rather than just read
> >what I said, which was neither ambiguous nor inaccurate.
>
> Make up some straw man? Never heard of this before and frankly don't
> know what your talking about.
James is suggesting, I think, that the argument you refuted was not the
one he was putting forward but rather a superficially similar one you
set up just so you could knock it down. That's my understanding of a
"straw man". Whether that's what you were actually doing I'll leave for
the two of you to sort out.
> The OP has high levels of wear on the sprocket most used that has
> the most load applied. The wear on the other sprockets is much,
> much lighter and from the sound of it almost non existant. I assume
> the same grit and dirt moves with the chain and goes round all the
> sprockets and not just the smallest. I don't know the percentage of
> how much the smallest rear sprocket is used compared to the other
> gears. I suspect quite high but theres possibly more chain/teeth
> contact in the lower gears at any one time. Obviously cadence is
> factor too. Surely though if load wasn't a factor the wear and tear
> of the chain and sprocket teeth would be more general across the
> whole range of cassette gears.
In the OP's case the wear is greatest on the smallest sprocket because
that's the one he uses most of the time. First the chain wears causing
it to "stretch". Once it has stretched sprocket wear begins to
accelerate. The more stretched the chain, the faster the sprocket
wears. The sprockets that wear most are the ones that are used most.
I've personally worn out 2 and 3 in a 6 sprocket cluster by continuing
to use a stretched chain. 4 was less worn and 1 (the largest) and 5 and
6 (the smallest) were hardly worn at all.
I believe distance covered is far more significant in this than either
load or cadence. No matter what gear you are in each tooth of the
engaged sprocket meshes with a chain link once per wheel revolution.
The point about the larger sprockets having more teeth in contact with
the chain is misleading, I think, because the stretched chain no longer
meshes properly with the teeth; the load is concentrated on the top
teeth until the sprocket has worn sufficiently to conform to the
stretched chain.
--
Dave...