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11T compatible with 1996 Trek road bike?



 
 
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  #11  
Old July 2nd 05, 02:44 PM
CraigNJ
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Default 11T compatible with 1996 Trek road bike?

PS -- unlike the photos at http://sheldonbrown.com/k7.html#hyperdrivec
my hub body has threads on the outside of the hub body running through
the top quarter inch or so of the splines' lengths, although the
splines run all the way to the top. (I didn't notice if there were
any on the inside.) Maybe that makes a difference to whether
modification is needed? At least it helps you understand what I meant
when I suggested I might grind off the top one or two threads.

Craig in NJ

On Sat, 02 Jul 2005 09:36:03 -0400, CraigNJ
wrote:

That's sort of what the mechanic did -- he had the entire old 8-speed
cassette on but with the 12t replaced by an 11t, and then the lock
ring. He said it looked like he could get the lock ring to tighten.
Could he be right that there's no need for additional spacers or
grinding down the top lip of the splines to accomodate the 11t
securely? Or maybe there's something we can't see that makes it
mechanically unsufficient without grinding down the splines a little?

I'm thinking that just to be safe, I'll want to do the grinding down
anyway. I'm not quite sure how much, though, or at what angle. I'm
guessing the best would be straight/flat, not angled, grinding off of
the splines down by a distance that is exactly the thickness of the
part of the 11t that is not cut through for the splines, e.g., maybe
0.5mm or so. Is that right? That might be just one or two threads,
right? That sounds pretty easy to do, and maybe not too dangerous to
sacrifice one or two threads.

Craig in NJ

On 1 Jul 2005 22:50:43 -0700, "JeffWills" wrote:

CraigNJ wrote:
The local bike shop helped me get a good look -- it's the non-compact
body. It sounds like I'll need to grind off a little of the splines
at the top, but ...

But the mechanic there dropped an 11t cog on top in place of the 12
and seemed able to screw it all together, so he's thinking it won't be
necessary to modify the body. Could that be true, or maybe we're just
fooling ourselves because we didn't try it with a whole new cassette?


The 11-tooth cog will slip on, but you might not be able to get the
entire cassette clamped on properly. Put all the cogs and spacers on,
including the 11-tooth, and then the lock ring. Make sure all the cogs
are tight once you're cranked down on the lock ring. If they're not
tight, put a thin spacer on the cassette body before installing the
cassette- there's a Shimano spacer that's 0.3mm thick that should do
the trick.

If nothing wiggles with the lock ring in place, you're good to go.

Jeff


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  #12  
Old July 2nd 05, 06:36 PM
JeffWills
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Default 11T compatible with 1996 Trek road bike?

CraigNJ wrote:
PS -- unlike the photos at http://sheldonbrown.com/k7.html#hyperdrivec
my hub body has threads on the outside of the hub body running through
the top quarter inch or so of the splines' lengths, although the
splines run all the way to the top. (I didn't notice if there were
any on the inside.) Maybe that makes a difference to whether
modification is needed? At least it helps you understand what I meant
when I suggested I might grind off the top one or two threads.

Craig in NJ


Yes, that makes sense. You have an original Hyperglide cassette body.
The external threads were put on in order to make the body
backwards-compatible with the earlier Uniglide cassettes. When the
11-tooth cogs came out, Shimano extended the solid splines all the way
to the end of the body, with a relief to allow the 11-tooth cog a
little more strength.

As I said, if the cassette fits on the body with the lock ring nice and
tight and the larger cogs don't move around, you should be OK. If not,
grinding down the first thread or two OR putting a thin shim under the
cassette should give you enough room to clamp the cassette properly.

Ain't bike-mechanicing fun?

Jeff

  #13  
Old July 2nd 05, 11:05 PM
Sheldon Brown
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Default 11T compatible with 1996 Trek road bike?

JeffWills Wrote:

The 11-tooth cog will slip on, but you might not be able to get the
entire cassette clamped on properly. Put all the cogs and spacers on,
including the 11-tooth, and then the lock ring. Make sure all the cogs
are tight once you're cranked down on the lock ring. If they're not
tight, put a thin spacer on the cassette body before installing the
cassette- there's a Shimano spacer that's 0.3mm thick that should do
the trick.

If nothing wiggles with the lock ring in place, you're good to go.

Someone suggested.

What about slipping the 11T on with one of the remaining sprockets
removed?


No, this would make the problem _worse_, not better.

Shimano 11 tooth sprockets don't have the spline grooves running all the
way through (they'd be too weak if they did.) Thus, the 11 can only fit
partway onto a Freehub body. If that body doesn't have the truncated
splines, the 11 won't go on far enough to clamp the rest of the
sprockets and spacers.

This is explained in detail (with photos) at http://sheldonbrown.com/k7

Sheldon "3 Minutes With A Bench Grinder" Brown
+------------------------------------+
| Immigrants are not our burden, |
| They are our wealth --Jane Adams |
+------------------------------------+
Harris Cyclery, West Newton, Massachusetts
Phone 617-244-9772 FAX 617-244-1041
http://harriscyclery.com
Hard-to-find parts shipped Worldwide
http://captainbike.com http://sheldonbrown.com

  #14  
Old July 12th 05, 02:13 AM
CraigNJ
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Posts: n/a
Default 11T compatible with 1996 Trek road bike?

To follow up on this alteration to my 1996 Trek 2300 road bike to take
an XT 11-30 casette:

I used my Dremel on the hub body to grind off the splines' top outside
threads, and was then able to get a Shimano XT 11-30 cogset on &
locked down tight.

My local bike shop will finish the work with a new XT derailer and
appropriate adjustments, etc., so the bike will soon have the wide
range I've long wanted. The biggest jumps may take some getting used
to, but I'm sure I'll love my new 11T cruising gear and will
appreciate the new 30 at least briefly on most rides around here.

A couple of discoveries:

It was possible to get by without any grinding by putting a very thin
spacer ring on before the casette, and then screwing down the lockring
tight enough to bend down the top outer treads on the splines. (My
local bike shop did that -- I wouldn't have dared try that much
force.) I didn't feel comfortable with that (even though it was
already done) and proceeded with grinding off the top threads.

In retrospect, I should've ground down only the first thread (1mm or
less?) on each spline. It didn't need more, and by grinding down two
threads (1.5mm or 2mm?) I no longer had the option of using a spacer
(e.g., in case I needed to for some other reason) since that would
lift the 11T almost above the trimmed-down splines. (Unfortunately,
once the top threads were bent down during the attempt with the
spacer, it wasn't easy to tell the difference between the 1st two
threads.) Anyway, I think there's still enough spline left for the
11T for the swift cruising I'll do with it.

A Dremel with cutting disk worked very well. (I didn't need to resort
to my big RotoZip with diamond cutting disk.)

I had to get rid of the bike's spoke protector in order to accomodate
protrusions on the back of the XT's cassette. Otherwise, they would
have clamped down against that plastic disk and stopped the wheel from
turning. Without the plastic protector there is just barely enough
room for those protrusions to clear the spokes. (Using the thin
spacer was not enough to get the cassette to clear the spoke
protector, if I even wanted to use the spacer approach.)

Thank you all for your help & advice. It seems to be working out
fine.

Craig in NJ

On 2 Jul 2005 10:36:13 -0700, "JeffWills" wrote:

CraigNJ wrote:
PS -- unlike the photos at http://sheldonbrown.com/k7.html#hyperdrivec
my hub body has threads on the outside of the hub body running through
the top quarter inch or so of the splines' lengths, although the
splines run all the way to the top. (I didn't notice if there were
any on the inside.) Maybe that makes a difference to whether
modification is needed? At least it helps you understand what I meant
when I suggested I might grind off the top one or two threads.

Craig in NJ


Yes, that makes sense. You have an original Hyperglide cassette body.
The external threads were put on in order to make the body
backwards-compatible with the earlier Uniglide cassettes. When the
11-tooth cogs came out, Shimano extended the solid splines all the way
to the end of the body, with a relief to allow the 11-tooth cog a
little more strength.

As I said, if the cassette fits on the body with the lock ring nice and
tight and the larger cogs don't move around, you should be OK. If not,
grinding down the first thread or two OR putting a thin shim under the
cassette should give you enough room to clamp the cassette properly.

Ain't bike-mechanicing fun?

Jeff


 




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