Derailleur cage width question

Bruce W.1 said:

I'm about to upgrade my road bike derailleurs. I
have 7 gears on the back and will have three on
the front.

A bike shop guy was telling me that chains made for
5 to 7 sprocket rear freewheels will not fit thru the
cage on some derailleurs made for 9 and 10 sprockets.
Is this true? Which derailleurs would fit this
description?

Thanks for your help.

That is right. Your chain is about 8mm wide, but some 10 speed rear
derailleurs are only about 8.5mm wide. Rear derailleurs used to be 11mm
or more. The width of front derailleurs hasn't changed much -- they are
in the neighborhood of 11mm wide, but I wouldn't count on good shifting.

--
Bob Wheeler --- http://www.bobwheeler.com/
ECHIP, Inc. ---
Randomness comes in bunches.

Bruce W.1 said:

I'm about to upgrade my road bike derailleurs. I
have 7 gears on the back and will have three on
the front.

A bike shop guy was telling me that chains made for
5 to 7 sprocket rear freewheels will not fit thru the
cage on some derailleurs made for 9 and 10 sprockets.
Is this true? Which derailleurs would fit this
description?

This might be an issue with ancient chains from the 10-speed era. These
had rivets protruding out the sides of the plates.

I have never found this to be a problem with any reasonably modern chain.

I generally recommend Sram PC58 chains for systems with fewer than 9
rear sprockets.

These work fine in derailers marketed as "9-speed." I haven't had
occasion to try the PC58 with a so-called "10-speed" derailer, but I
doubt it would be a problem there either.

If such a problem were to arise, it could easily be fixed by installing
thin washers on either side of the pulleys.

Sheldon "Don't Borrow Trouble" Brown
+-----------------------------------------------------------+
| A pessimist sees the difficulty in every opportunity; |
| an optimist sees the opportunity in every difficulty. |
| -- Sir Winston Churchill |
+-----------------------------------------------------------+
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

Bruce W.1 said:

I'm about to upgrade my road bike derailleurs. I
have 7 gears on the back and will have three on
the front.

A bike shop guy was telling me that chains made for
5 to 7 sprocket rear freewheels will not fit thru the
cage on some derailleurs made for 9 and 10 sprockets.
Is this true? Which derailleurs would fit this
description?

I can tell you that the current XT 9-speed rear mech is fine on a
7-speed setup using a SRAM PC-59 chain (the chain is intended for 7 or 8
speed). Extrapolating, I would be extremely surprised if any 9-speed
Shimano mech was incompatible with a 7/8 speed chain. Given that you
can run these chains on 5-speed bikes - they're all 3/32" between inner
plates - there should be no problem. I don't know about 10 speed mechs,
but you wouldn't want to pay the premium anyway.

On Sun, 23 Jan 2005 01:16:48 GMT, "Bruce W.1"

may have said:

I'm about to upgrade my road bike derailleurs. I
have 7 gears on the back and will have three on
the front.

A bike shop guy was telling me that chains made for
5 to 7 sprocket rear freewheels will not fit thru the
cage on some derailleurs made for 9 and 10 sprockets.
Is this true? Which derailleurs would fit this
description?

Find a bike shop that employs people who are either well informed or
more honest. The difference in width of the chains is miniscule; all
derailleurs have adequate clearance for a 7/8sp chain, including the
latest and most expensive of the exotics.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

On Sun, 23 Jan 2005 18:45:33 +0000, Zog The Undeniable

may have said:

I don't know about 10 speed mechs,
but you wouldn't want to pay the premium anyway.

One local shop guy that I trust reported that he'd checked 10/9/8
backward compatibility already on the assumption that as the market
eventually shifts toward more 10s rear setups, there would be some
aftermarket cross-breeding going on. He found no problem with using a
10s-labeled Shimano der on an 8s setup with a PC48 chain. He also
said that it shifted no better than the 105 that the bike came with.

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

On Sat, 22 Jan 2005 22:07:44 -0500, Bob Wheeler <[email hidden]>

may have said:

Bruce W.1 said:

I'm about to upgrade my road bike derailleurs. I
have 7 gears on the back and will have three on
the front.

A bike shop guy was telling me that chains made for
5 to 7 sprocket rear freewheels will not fit thru the
cage on some derailleurs made for 9 and 10 sprockets.
Is this true? Which derailleurs would fit this
description?

Thanks for your help.

That is right. Your chain is about 8mm wide, but some 10 speed rear
derailleurs are only about 8.5mm wide. Rear derailleurs used to be 11mm
or more. The width of front derailleurs hasn't changed much -- they are
in the neighborhood of 11mm wide, but I wouldn't count on good shifting.

9s chains are typically about 6.6mm wide, 7s and 8s are usually around
7.3mm and 7.1mm respectively. They all clear just fine in 9s, and in
the 10s ders that I've heard were tried.

This same question arose when the 9s ders first hit the market, but
experience has been that the 9s ders run on 6/7/8 setups as well. The
10s chain (and reportedly the typical cage) is narrower, but
apparently not so much that it's beyond the range of what will work.
There is, however, no rational reason to pay the exorbitant prices for
10s bits if you're not building a 10s setup. As 10s prices and
selections become more attractive, I fully expect to see the number of
available 8/9 selections fall off unless some significant backward
compatibility issues eventually crop up. (There may be some with
Campy that I'm ignorant of; the only retrofits that I know of were
Shimano.)

--
My email address is antispammed; pull WEEDS if replying via e-mail.
Typoes are not a bug, they're a feature.
Words processed in a facility that contains nuts.

<< That is right. Your chain is about 8mm wide, but some 10 speed rear

Quoted message said:

derailleurs are only about 8.5mm wide. >><BR><BR>

Bollocks, Chains are about 7mm and they work fine in a '10s' rear der.

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

Bruce W.1 said:

I'm about to upgrade my road bike derailleurs. I
have 7 gears on the back and will have three on
the front.

A bike shop guy was telling me that chains made for
5 to 7 sprocket rear freewheels will not fit thru the
cage on some derailleurs made for 9 and 10 sprockets.
Is this true? Which derailleurs would fit this
description?

I am currently running a Shimano HG50 chain designed for 7/8 speeds
according to the box on a 9 speed Shimano Deore rear derailleur with a
7 speed cassette. No problems.

The HG50 chain is $13 at Nashbar. Chains are cheap. The Deore rear
derailleur is $33. Also fairly cheap.

And if running 7 speed chain/cogs with a 9 speed rear derailleur still
concerns you, then just buy a Shimano Sora or Alivio rear derailleur
for $20 from Nashbar. They are listed as 8 speed derailleurs. I doubt
your bike shop guy will say 8 speed derailleurs can't handle 7 speed
chain.