large jump between adjacent cogs on custom Hyperglide cassette



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B

Bill Bushnell

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How large a jump between adjacent cogs can one design into a Shimano Hyperglide cassette and expect
reliable shifts?

For example: I'm planning to put together a custom Shimano cassette that involves adjacent 17t and a
32t cogs to be shifted with a Shimano M960 med cage derailer. I don't need a particularly smooth
shift, but I want it to work reliably.

If this is too big a jump I could consider 17-28, 20-32, or 20-28. Will any of these
combinations work?

Thanks.

--
Bill Bushnell
 
M

Mark Wolfe

Guest
Sounds like you've got the parts. That's a pretty good jump. If I had the parts, I'd just put it
together and try it then ask why it didn't work later. :)

Bill Bushnell wrote:

> How large a jump between adjacent cogs can one design into a Shimano Hyperglide cassette and
> expect reliable shifts?
>
> For example: I'm planning to put together a custom Shimano cassette that involves adjacent 17t and
> a 32t cogs to be shifted with a Shimano M960 med cage derailer. I don't need a particularly smooth
> shift, but I want it to work reliably.
>
> If this is too big a jump I could consider 17-28, 20-32, or 20-28. Will any of these
> combinations work?
>
> Thanks.
>

--
Mark Wolfe http://www.wolfenet.org gpg fingerprint = 42B6 EFEB 5414 AA18 01B7 64AC EF46 F7E6 82F6
8C71 "Dogs believe they are human. Cats believe they are God."
 
M

M Gagnon

Guest
> Bill Bushnell wrote:
>
> > How large a jump between adjacent cogs can one design into a Shimano Hyperglide cassette and
> > expect reliable shifts?
> >
> > For example: I'm planning to put together a custom Shimano cassette that involves adjacent 17t
> > and a 32t cogs to be shifted with a Shimano M960 med cage derailer.
I
> > don't need a particularly smooth shift, but I want it to work reliably.
> >
> > If this is too big a jump I could consider 17-28, 20-32, or 20-28. Will any of these
> > combinations work?
> >
> > Thanks.
> >
>

I use custom cassettes. My touring bike has 12-14-15-16-17-19-21-25-32, with a Shimano LX
derailleur, and I shift in friction with bar-end shifters.

No problem ! However, I don't put any pressure on the pedals while I upshift.That seems natural to
me, because I have been used to do that on my older bikes (1970-1980).

Regards,

--
Michel Gagnon -- Montréal (Québec, Canada) mailto:[email protected]
 
J

Jeff Wills

Guest
Bill Bushnell <[email protected]> wrote in message news:<[email protected]>...
> How large a jump between adjacent cogs can one design into a Shimano Hyperglide cassette and
> expect reliable shifts?
>
> For example: I'm planning to put together a custom Shimano cassette that involves adjacent 17t and
> a 32t cogs to be shifted with a Shimano M960 med cage derailer. I don't need a particularly smooth
> shift, but I want it to work reliably.
>
> If this is too big a jump I could consider 17-28, 20-32, or 20-28. Will any of these
> combinations work?
>
> Thanks.

I suspect that you may run the upper pulley of the derailleur into the larger cog before
accomplishing the shift. If it's possible, I consider going with an intermediate cog:
x-x-x-x-x-17-24-32. The middle cog would just be a "transfer" cog- the chain wouldn't have to run on
there for long.

Jeff
 
S

Steve Palincsar

Guest
On Sun, 09 Mar 2003 20:02:56 -0500, Bill Bushnell wrote:

> How large a jump between adjacent cogs can one design into a Shimano Hyperglide cassette and
> expect reliable shifts?
>
> For example: I'm planning to put together a custom Shimano cassette that involves adjacent 17t and
> a 32t cogs to be shifted with a Shimano M960 med cage derailer. I don't need a particularly smooth
> shift, but I want it to work reliably.
>
> If this is too big a jump I could consider 17-28, 20-32, or 20-28. Will any of these
> combinations work?

Shimano has a 10T jump on its "Megarange" freewheel, 24 to 34T. Sheldon Brown says of this, "At
first glance, many people look at the sprocket numbers 11-13-15-18-21-24-34 and wonder what
Shimano's engineers were smoking when they came up with that setup, with a 10 tooth jump between the
bottom two sprockets! In practice, this is actually a very nice arrangement, because the big jump to
the 34 allows the jumps in the cruising range to be much more reasonable. If the jumps were evenly
spaced, the user would often find that one gear was too low for cruising, while the next one up was
too high. This type of freewheel, sometimes known as an "alpine" design, is intended to provide
comfortable cruising, with the super-low gear for the tough hills. It works a lot better on the road
than it looks on paper!"
 
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