rear derailleur cable loop - conflicting advice

If you've read the Park Tool website advice on cutting cable housing,
you may have noticed that Park recommends a longer "loop" at the rear
derailleur than most bikes come with from the factory. This longer
loop achieves a straight cable entry into the derailleur, which helps
provide smoother shifting. So I set my bike up that way, and it works
fine.

On the other hand, the mechanic at the LBS saw my bike and said that my
derailleur cable was "much too long." He said that the longer cable
loop could get "sucked into the rear wheel" by which I assume he meant
it could get forced into the spokes if another rider's wheel pushed
into it. I noticed that all the bikes at the shop, like the majority
of bikes you see, had really short cable loops at the derailleur, and
that, consequently, the cables did not insert into the derailleurs in a
nice, straight line. But does it matter?

Does anybody have an opinion on this? Is the Park advice just overly
compulsive?

The Park advice is plenty sensible, do it their way to annoy the bike
shop weenies.

On 26 May 2006 09:04:08 -0700, "Josh Hassol" wrote:

Does anybody have an opinion on this? Is the Park advice just overly
compulsive?

IMO and IME, Park has it right. The longer loop makes for more
reliable shifting, and I've never yet had such a cable get fouled in
the spokes. The tech at the nearest lbs agrees; he also sets them up
with a longer loop.
--
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Werehatrack wrote:
On 26 May 2006 09:04:08 -0700, "Josh Hassol" wrote:

Does anybody have an opinion on this? Is the Park advice just overly
compulsive?

IMO and IME, Park has it right. The longer loop makes for more
reliable shifting, and I've never yet had such a cable get fouled in
the spokes. The tech at the nearest lbs agrees; he also sets them up
with a longer loop.

I use generous loops and have never had a problem with cable-in-spokes,
I can't even imagine how that could happen. FWIW, you can also use brake
cable housing on that loop.

"Josh Hassol" wrote in news:1148659448.006660.283680
@i40g2000cwc.googlegroups.com:

If you've read the Park Tool website advice on cutting cable housing,
you may have noticed that Park recommends a longer "loop" at the rear
derailleur than most bikes come with from the factory. This longer
loop achieves a straight cable entry into the derailleur, which helps
provide smoother shifting. So I set my bike up that way, and it works
fine.


Barnett's gives a process that has two basic concepts:

1. Insert the cable housing normally into the derailleur and do all your
cutting of the cable housing at the shifter end of the piece.

2. With the parallelogram of the shifter roughly parallel to a line from
the axel center to the bottom bracket center, size the loop from the
shifter end to ensure the cable housing enters the derailleur adjusting
barrel squarely, letting the forces in the housing do the aligning.

They also note that mechanics seem to be used to seeing loops that are too
short, as you've noted.

Get an Avid Rollamig and then you can shorten up the loop as well as have
smoother, more reliable shifting.

http://www.sram.com/en/avid/cablesystems/rollamajig/


"Werehatrack" wrote in message
...
On 26 May 2006 09:04:08 -0700, "Josh Hassol" wrote:

Does anybody have an opinion on this? Is the Park advice just overly
compulsive?

IMO and IME, Park has it right. The longer loop makes for more
reliable shifting, and I've never yet had such a cable get fouled in
the spokes. The tech at the nearest lbs agrees; he also sets them up
with a longer loop.
--
Typoes are a feature, not a bug.
Some gardening required to reply via email.
Words processed in a facility that contains nuts.

wvantwiller wrote:

Barnett's gives a process that has two basic concepts:

1. Insert the cable housing normally into the derailleur and do all your
cutting of the cable housing at the shifter end of the piece.

2. With the parallelogram of the shifter roughly parallel to a line from
the axel center to the bottom bracket center, size the loop from the
shifter end to ensure the cable housing enters the derailleur adjusting
barrel squarely, letting the forces in the housing do the aligning.

They also note that mechanics seem to be used to seeing loops that are too
short, as you've noted.

This is good advice. Thanks

"TonyKiz" wrote:

Get an Avid Rollamig and then you can shorten up the loop as well as have
smoother, more reliable shifting.

Those do work well (and I've used 'em on various bikes of my own).
Another cheaper, lighter, cleaner solution is to use one of the metal
"noodles" that come with V-brakes (the more "U-shaped", the better).
They give you a short-radius bend with low friction (I suspect about
as low as a Rollamajig). And they're essentially free (if you've
saved the extra ones that you didn't use).

Mark Hickey
Habanero Cycles
http://www.habcycles.com
Home of the $795 ti frame