Cassette loose? Not normal, right?



D

dgk

Guest
I noticed that the cassette on my Trek 7100 hybrid (7 speed) is loose,
in that the individual pieces can move a bit. The locking thing is
tight; it's like the spacers aren't exactly right. I have no problem
with the alignment of the gears; the chain jumps correctly when
shifted.

I wouldn't have noticed except I was oiling the chain and just
happened to see that it wasn't tight. I took the wheel off to tighten
it (using the matching tool) and it was already tight.

Is this normal or a cause for concern?
 
N

Neil Brooks

Guest
On Mon, 16 Jul 2007 14:40:20 -0400, dgk <[email protected]> wrote:

>I noticed that the cassette on my Trek 7100 hybrid (7 speed) is loose,
>in that the individual pieces can move a bit. The locking thing is
>tight; it's like the spacers aren't exactly right. I have no problem
>with the alignment of the gears; the chain jumps correctly when
>shifted.
>
>I wouldn't have noticed except I was oiling the chain and just
>happened to see that it wasn't tight. I took the wheel off to tighten
>it (using the matching tool) and it was already tight.
>
>Is this normal or a cause for concern?


You may want to post this to rec.bicycles.TECH.

More wrenches per square kilobyte there than here, I'm thinking.
 
D

dgk

Guest
On Mon, 16 Jul 2007 12:28:49 -0700, Neil Brooks <[email protected]>
wrote:

>On Mon, 16 Jul 2007 14:40:20 -0400, dgk <[email protected]> wrote:
>
>>I noticed that the cassette on my Trek 7100 hybrid (7 speed) is loose,
>>in that the individual pieces can move a bit. The locking thing is
>>tight; it's like the spacers aren't exactly right. I have no problem
>>with the alignment of the gears; the chain jumps correctly when
>>shifted.
>>
>>I wouldn't have noticed except I was oiling the chain and just
>>happened to see that it wasn't tight. I took the wheel off to tighten
>>it (using the matching tool) and it was already tight.
>>
>>Is this normal or a cause for concern?

>
>You may want to post this to rec.bicycles.TECH.
>
>More wrenches per square kilobyte there than here, I'm thinking.


TOO LATE! Crossposting properly requires doing it at one time. If I
post it to rec.bicycles.tech now I might get dumped on. Someone here
will know, and if I don't find out, I'll try it at .tech.

It's probably been loose since I put on a new wheel a few months back
so another day or two won't kill me. I hope.
 
R

Robert Kercher

Guest
Lately, the godlike dgk wrote:
> I noticed that the cassette on my Trek 7100 hybrid (7 speed) is loose,
> in that the individual pieces can move a bit. The locking thing is
> tight; it's like the spacers aren't exactly right. I have no problem
> with the alignment of the gears; the chain jumps correctly when
> shifted.
>
> I wouldn't have noticed except I was oiling the chain and just
> happened to see that it wasn't tight. I took the wheel off to tighten
> it (using the matching tool) and it was already tight.
>
> Is this normal or a cause for concern?


The gears and spacers are held together by three riveted pins and the
whole setup has a little play, so nothing unusual here, as long as the
lockring is tight and the play is relatively little.
 
M

Mike Jacoubowsky

Guest
>>>I wouldn't have noticed except I was oiling the chain and just
>>>happened to see that it wasn't tight. I took the wheel off to tighten
>>>it (using the matching tool) and it was already tight.
>>>
>>>Is this normal or a cause for concern?

>>
>>You may want to post this to rec.bicycles.TECH.
>>
>>More wrenches per square kilobyte there than here, I'm thinking.

>
> TOO LATE! Crossposting properly requires doing it at one time. If I
> post it to rec.bicycles.tech now I might get dumped on. Someone here
> will know, and if I don't find out, I'll try it at .tech.
>
> It's probably been loose since I put on a new wheel a few months back
> so another day or two won't kill me. I hope.


It could be either missing a thin spacer between one of the smaller cogs, or
the 1st cog is offset from where it should be (there's a wider spline that
needs to line up properly, but it's possible to put it on incorrectly, which
keeps it from sitting in as far as it should).

--Mike Jacoubowsky
Chain Reaction Bicycles
www.ChainReaction.com
Redwood City & Los Altos, CA USA


"dgk" <[email protected]> wrote in message
news:r8in9[email protected]
> On Mon, 16 Jul 2007 12:28:49 -0700, Neil Brooks <[email protected]>
> wrote:
>
>>On Mon, 16 Jul 2007 14:40:20 -0400, dgk <[email protected]> wrote:
>>
>>>I noticed that the cassette on my Trek 7100 hybrid (7 speed) is loose,
>>>in that the individual pieces can move a bit. The locking thing is
>>>tight; it's like the spacers aren't exactly right. I have no problem
>>>with the alignment of the gears; the chain jumps correctly when
>>>shifted.
>>>
>>>I wouldn't have noticed except I was oiling the chain and just
>>>happened to see that it wasn't tight. I took the wheel off to tighten
>>>it (using the matching tool) and it was already tight.
>>>
>>>Is this normal or a cause for concern?

>>
>>You may want to post this to rec.bicycles.TECH.
>>
>>More wrenches per square kilobyte there than here, I'm thinking.

>
> TOO LATE! Crossposting properly requires doing it at one time. If I
> post it to rec.bicycles.tech now I might get dumped on. Someone here
> will know, and if I don't find out, I'll try it at .tech.
>
> It's probably been loose since I put on a new wheel a few months back
> so another day or two won't kill me. I hope.
 
D

Dart70ca

Guest
I recently dismantled a Shimano cassette that was held together not
by rivets but by small bolts. They were all loose and the cassette was
a lot tighter after I cinched them up a little.



Keith
 
D

dgk

Guest
On Mon, 16 Jul 2007 20:39:18 -0700, Dart70ca <[email protected]> wrote:

> I recently dismantled a Shimano cassette that was held together not
>by rivets but by small bolts. They were all loose and the cassette was
>a lot tighter after I cinched them up a little.
>
>
>
>Keith


Now I'm going to have to look closer. As I recall, five of the gears
were one piece and the other two were detached. I think all of them
are moving. I'll try to take off the whole thing.
 
R

Robert Kercher

Guest
> I recently dismantled a Shimano cassette that was held together not
> by rivets but by small bolts. They were all loose and the cassette was
> a lot tighter after I cinched them up a little.
>
>
>
> Keith
>

I don't know how common the bolts are, but they are very useful for
recycling the riveted cassettes. Just grind away head of the rivet and
recycle the useable gears with the bolts plus the smallest gear from the
bolted cassette (which is the one with the thread for the bolts).

My guess is that Shimano went for the rivets because

a) they are cheaper

b) it makes reusing good gears of cassettes more difficult

Somebody please contradict me. I also would like to know why Shimano
went from regular grooves for cassettes which enable me to turn the
gear by 180 degrees, thus doubling its service life to an irregular
pattern which prevents this. Why do I sense the evil monopoly here?

Sigh. If economy would only be ruled by engineers and not marketing
people....

Robert
 
P

Paul O

Guest
Robert Kercher wrote, On 7/17/2007 11:54 AM:
>> I recently dismantled a Shimano cassette that was held together not
>> by rivets but by small bolts. They were all loose and the cassette was
>> a lot tighter after I cinched them up a little.
>>
>>
>>
>> Keith
>>

> I don't know how common the bolts are, but they are very useful for
> recycling the riveted cassettes. Just grind away head of the rivet and
> recycle the useable gears with the bolts plus the smallest gear from the
> bolted cassette (which is the one with the thread for the bolts).
>
> My guess is that Shimano went for the rivets because
>
> a) they are cheaper
>
> b) it makes reusing good gears of cassettes more difficult
>
> Somebody please contradict me. I also would like to know why Shimano
> went from regular grooves for cassettes which enable me to turn the
> gear by 180 degrees, thus doubling its service life to an irregular
> pattern which prevents this. Why do I sense the evil monopoly here?
>
> Sigh. If economy would only be ruled by engineers and not marketing
> people....
>
> Robert


Shimano's engineers would point out to everyone that their Hyperglide
sprockets are specially designed so that that the chain will to engage
two adjacent sprockets simultaneously during shifting. Shimano shapes
each of their sprocket with a set of ramps and modified teeth that
allows the chain to mesh with the new sprocket before it has disengaged
from the old one. This system provides much smoother shifting than older
designs. But it also means that each sprocket must be oriented so that
the "take-off teeth" on one sprocket lines up with the "landing teeth"
on the next sprocket. Flipping a sprocket 180 degrees "to double its
service life" would upset this geometry and probably result in a
cassette that would be very difficult to shift. So all Hyperglide
sprockets have a special spline to ensure that they can only go one one way.

It seems like a reasonable engineering trade off - better shifting
performance verses somewhat reduced servicability.

See:
http://sheldonbrown.com/gloss_ho-z.html#hyperglide

http://sheldonbrown.com/k7.html

--

Paul D Oosterhout
I work for SAIC (but I don't speak for SAIC)
 
On Jul 17, 11:54 am, Robert Kercher <[email protected]> wrote:
> > I recently dismantled a Shimano cassette that was held together not
> > by rivets but by small bolts. They were all loose and the cassette was
> > a lot tighter after I cinched them up a little.

>
> > Keith

>
> I don't know how common the bolts are, but they are very useful for
> recycling the riveted cassettes. Just grind away head of the rivet and
> recycle the useable gears with the bolts plus the smallest gear from the
> bolted cassette (which is the one with the thread for the bolts).
>
> My guess is that Shimano went for the rivets because
>
> a) they are cheaper
>
> b) it makes reusing good gears of cassettes more difficult
>
> Somebody please contradict me. I also would like to know why Shimano
> went from regular grooves for cassettes which enable me to turn the
> gear by 180 degrees, thus doubling its service life to an irregular
> pattern which prevents this. Why do I sense the evil monopoly here?
>
> Sigh. If economy would only be ruled by engineers and not marketing
> people....
>
> Robert


Bolts/rivets are only there to hold the cassette together in the box.
If the lock ring is finger tight, and the cogs are still moving,
something
is missing, or dirt/corrosion is preventing the lock ring from
screwing in
far enough.
 
D

dgk

Guest
On Mon, 16 Jul 2007 21:08:41 GMT, "Mike Jacoubowsky"
<[email protected]> wrote:

>>>>I wouldn't have noticed except I was oiling the chain and just
>>>>happened to see that it wasn't tight. I took the wheel off to tighten
>>>>it (using the matching tool) and it was already tight.
>>>>
>>>>Is this normal or a cause for concern?
>>>
>>>You may want to post this to rec.bicycles.TECH.
>>>
>>>More wrenches per square kilobyte there than here, I'm thinking.

>>
>> TOO LATE! Crossposting properly requires doing it at one time. If I
>> post it to rec.bicycles.tech now I might get dumped on. Someone here
>> will know, and if I don't find out, I'll try it at .tech.
>>
>> It's probably been loose since I put on a new wheel a few months back
>> so another day or two won't kill me. I hope.

>
>It could be either missing a thin spacer between one of the smaller cogs, or
>the 1st cog is offset from where it should be (there's a wider spline that
>needs to line up properly, but it's possible to put it on incorrectly, which
>keeps it from sitting in as far as it should).
>
>--Mike Jacoubowsky
>Chain Reaction Bicycles
>www.ChainReaction.com
>Redwood City & Los Altos, CA USA
>


I did have some problem lining it up when I changed the wheel. The
spacer I got from (nashbar or performance) didn't line up correctly
but the one from the old cassette did so I used that. I'm going to
have to give it a good look this weekend.