Indexed shifting suddenly not working right

The bike is a Miyata One-Twelve, a decent 12 speed around 10 years old. I got it very slightly used
almost 5 years ago and it didn't have problems for a long time and I used it pretty lightly. Lately
(about the last 4 months) I'm using it heavily, taking 12 mile rides daily and climbing 1000 feet.

During one of these climbs a tooth broke on the freewheel and I wound up switching out the back
wheel for another used one I had which was in very good shape and also had a 6 sprocket freewheel,
although the largest sprocket has 30 teeth whereas the original had 28 teeth. I bought a new chain,
cleaned everything up and with a small turn of the high end screw adjustment on the rear Shimano
"Light Action" derailleur, the indexed shifting continued to work perfectly.

However, after around 4 to 6 weeks, the indexed shifting no longer worked OK. I started getting
kerchunks that were inexplicable. At first I thought that the chain was moving from one sprocket to
another, but I since realized that while that may be true at times, sometimes this happens when the
chain was already on the smallest rear sprocket. Of course, this is very disconcerting, especially
when you are climbing. My biggest fear when that happens is that I will break another freewheel
tooth and I know now that it's hard to find 6 sprocket freewheels.

Now I find that changing the shifter often doesn't accomplish what I expect, and today I spent a
couple of hours trying to adjust things. I failed. I have John Forester's "Effective Cycling", and
he has detailed instructions on how to make the adjustments, but it didn't work out for
me. Maybe I should try it again. Is it all that hard to make your own adjustments? Am I banging my
head against a wall - i.e. is there something wrong that I don't realize?

I realize that I can use the friction setting on the Shimano indexed shifters, but I've come to
really love indexed shifting, especially when riding in the hills. Thanks for any help.

Dan

Dan Musicant <musicant@spamnot.pacbell.net> wrote:
: However, after around 4 to 6 weeks, the indexed shifting no longer worked OK. I started getting
: kerchunks that were inexplicable. At first I thought that the chain was moving from one sprocket
: to another, but I since realized that while that may be true at times, sometimes this happens when
: the chain was already on the smallest rear sprocket. Of course, this is very disconcerting,
: especially when you are climbing. My biggest fear when that happens is that I will break another
: freewheel tooth and I know now that it's hard to find 6 sprocket freewheels.

: Now I find that changing the shifter often doesn't accomplish what I expect, and today I spent a
: couple of hours trying to adjust things. I failed. I have John Forester's "Effective Cycling", and
: he has detailed instructions on how to make the adjustments, but it didn't work out for
: me. Maybe I should try it again. Is it all that hard to make your own adjustments? Am I banging my
: head against a wall - i.e. is there something wrong that I don't realize?

: I realize that I can use the friction setting on the Shimano indexed shifters, but I've come to
: really love indexed shifting, especially when riding in the hills. Thanks for any help.

: Dan

Might just be gunked up cables and housings. They really should be changed every now and then.

6 speed Freewheels should still be available. Sheldon Brown's Harris Cyclery sells them pretty
cheap, I believe.

--------------------------------
Bob Masse' kh6zv9@PE.NET
--------------------------------

On Wed, 27 Aug 2003 04:10:10 -0000, kh6zv9@pe.net wrote:

an Musicant <musicant@spamnot.pacbell.net> wrote:
:: However, after around 4 to 6 weeks, the indexed shifting no longer worked OK. I started getting
:: kerchunks that were inexplicable. At first I thought that the chain was moving from one sprocket
:: to another, but I since realized that while that may be true at times, sometimes this happens
:: when the chain was already on the smallest rear sprocket. Of course, this is very disconcerting,
:: especially when you are climbing. My biggest fear when that happens is that I will break another
:: freewheel tooth and I know now that it's hard to find 6 sprocket freewheels.
:
:: Now I find that changing the shifter often doesn't accomplish what I expect, and today I spent a
:: couple of hours trying to adjust things. I failed. I have John Forester's "Effective Cycling",
:: and he has detailed instructions on how to make the adjustments, but it didn't work out for
:: me. Maybe I should try it again. Is it all that hard to make your own adjustments? Am I banging
:: my head against a wall - i.e. is there something wrong that I don't realize?
:
:: I realize that I can use the friction setting on the Shimano indexed shifters, but I've come to
:: really love indexed shifting, especially when riding in the hills. Thanks for any help.
:
:: Dan
:
:Might just be gunked up cables and housings. They really should be :changed every now and then.

I suppose this is definitely possible, especially considering my problem is with indexed shifting.
Wouldn't hurt to just replace that stuff now in any case. They're due. Thanks.

Dan

:
:6 speed Freewheels should still be available. Sheldon Brown's Harris
:Cyclery sells them pretty cheap, I believe.
:
: --------------------------------
: Bob Masse' kh6zv9@PE.NET
:--------------------------------
:
:
:
:

> :Might just be gunked up cables and housings. They really should be :changed every now and then.
>
> I suppose this is definitely possible, especially considering my problem is with indexed shifting.
> Wouldn't hurt to just replace that stuff now in any case. They're due. Thanks.

howbout something bent? like a derailleur or hanger? has it fallen on that side recently?

On Wed, 27 Aug 2003 21:15:11 GMT, "H. Guy" <HelpfulGuy@helpfulplace.org> wrote:

:
:> :Might just be gunked up cables and housings. They really should be :changed every now and then.
:>
:> I suppose this is definitely possible, especially considering my problem is with indexed
:> shifting. Wouldn't hurt to just replace that stuff now in any case. They're due. Thanks.
:
:howbout something bent? like a derailleur or hanger? has it fallen n that side recently?

No, I can't recall any kind of acident like that. However, it does seem to me that the cage is not
perpendicular to the plane of the freewheel. I've adjusted just about everything and I totally
regret that. I didn't research this as well as I should have before I started making adjustments. I
was very careful at first but by now I think I've readjusted every darn thing I could have and it's
still screwed up. I don't know if the cabling is the culprit. Actually, I have no reason to believe
it is except for the fact that I haven't tried replacing it. I feel no resistance when adjusting
the shifters.

I think I will give adjustments another try, while carefully consulting instructions. I printed out
the deraileur adjustment help at Sheldon Brown's website yesterday and think I'll give it another
try today. Yesterday I rode with friction shifting, but I'm determined to return my bike to top
calibre indexed shifting in the near future - hopefully within a day or two.