Bent hanger -- Bent frame? ... shifting problems

[58 cm Rivendell Ramboulliet -- steel frame, Dura Ace bar ends]

Days ago I had a clipless newbie style slow-speed side crash which
bent the derailleur hanger and the Ultegra rd-6500gs triple der. My
LBS straightened the hanger and replaced the bent der with a Dura Ace
rd-7700GS.

The new der shifted fine on the stand -- but on the road I
experienced problems, particularly when downshifting from 15 to 14
teeth cogs (Ultegra 12-27, 9 sp cassette). The prob seems to be
erratic, not yielding to any amount of adjustment.

Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Generally, how frequently is a bent hanger accompanied by a bent
frame? Tough question, I know. My immediate concern is whether I need
to find a shop that is equipped for frame checking and alignment.

I've read Sheldon and others regarding bent hangers and I've not seen
bent frames being mentioned as an associated issue, though the
possibility is obvious.
Dave

DaveH wrote:
Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Try the "string test" to check frame alignment:

http://sheldonbrown.com/frame-spacing.html
(scroll down near the bottom)

Also make sure the shift wire is anchored at the correct place on the
derailleur.

Art Harris

On Thu, 04 Oct 2007 17:51:02 GMT, still me
wrote:

On Thu, 04 Oct 2007 16:22:48 -0700, M-gineering
wrote:

Bent frame isn't very likely with just toppling over. If you can ride
the frame no handed without the frame veering left or right it's fine.
I'd investigate free movement of the shiftercable first. Is the cable
properly located underneath the bracket? Last bit of outer cable not to
short, kinked, badly cut. missing ferrule etc? And another good one:
cable properly clamped in the groove on the derailleur body?

Not to mention, bent frames are more likely to affect the movement at
the limits, not in the middle of the cog. It's possible, but I would
think the bend would have to be severe for that to happen.

How good a job did they do on the hanger straightening? Any chance
they left it "non flat" ?

Marten and Still,
I did the string test for rear triangle displacement at:
http://www.faqs.org/faqs/bicycles-fa...ection-50.html

The test indicates the seat tube deviates to the right by 1/16". This
suggests the rear tri is displaced 1/32" to the left. This doesn't
sound like much; but indeed, I just did some extensive no-hands riding
and there is a mild but distinct tendency to veer to the right.

I thought something didn't feel right about the ride feel before a
bent frame even occurred to me but it was a bit vague and assumed it
was my imagination.

Still, you would not think this would be enough to effect shifting,
especially in the middle cogs as noted. I talked to Rivendell and they
agree with this.

Regarding hanger straightening: The LBS appeared to take his time with
what is obviously a special tool. I must assume at this point that
it's ok.

Regarding cable issues Marten: Everything's ok, as far as I can tell.
Not sure what to do. I'm tempted to put an Ultegra derailleur back on
it.

I live in the sticks and this LBS is not equipped to straighten
frames. The FAQ page suggests manual straightening. Not crazy about
that idea. I'll figure it all out.
Dave

On Thu, 04 Oct 2007 11:23:49 -0700, Art Harris
wrote:

DaveH wrote:
Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Try the "string test" to check frame alignment:

http://sheldonbrown.com/frame-spacing.html
(scroll down near the bottom)

Also make sure the shift wire is anchored at the correct place on the
derailleur.

Art Harris
Art,
Please see my latest post in the original thread.
Thanks -- Dave

DaveH wrote:
[58 cm Rivendell Ramboulliet -- steel frame, Dura Ace bar ends]

Days ago I had a clipless newbie style slow-speed side crash which
bent the derailleur hanger and the Ultegra rd-6500gs triple der. My
LBS straightened the hanger and replaced the bent der with a Dura Ace
rd-7700GS.

The new der shifted fine on the stand -- but on the road I
experienced problems, particularly when downshifting from 15 to 14
teeth cogs (Ultegra 12-27, 9 sp cassette). The prob seems to be
erratic, not yielding to any amount of adjustment.

Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Generally, how frequently is a bent hanger accompanied by a bent
frame? Tough question, I know. My immediate concern is whether I need
to find a shop that is equipped for frame checking and alignment.

I've read Sheldon and others regarding bent hangers and I've not seen
bent frames being mentioned as an associated issue, though the
possibility is obvious.

Much more likely to be a simple error/oversight; derailleur
alignment/adjustment/cable problem. You should be able to return to the
shop which 'upgraded' your gear system and watch the Campagnolo "R" tool
alignment then a full frame alignment gauge. If the rear end were off to
one side enough to give shifting problems, you'd likely have noticed a
difference when riding no hands.
p.s. if there are plastic ferrules on your casing, have them replaced
with real ones.

--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

DaveH wrote:
[58 cm Rivendell Ramboulliet -- steel frame, Dura Ace bar ends]

Days ago I had a clipless newbie style slow-speed side crash which
bent the derailleur hanger and the Ultegra rd-6500gs triple der. My
LBS straightened the hanger and replaced the bent der with a Dura Ace
rd-7700GS.

The new der shifted fine on the stand -- but on the road I
experienced problems, particularly when downshifting from 15 to 14
teeth cogs (Ultegra 12-27, 9 sp cassette). The prob seems to be
erratic, not yielding to any amount of adjustment.

Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Generally, how frequently is a bent hanger accompanied by a bent
frame? Tough question, I know. My immediate concern is whether I need
to find a shop that is equipped for frame checking and alignment.

I've read Sheldon and others regarding bent hangers and I've not seen
bent frames being mentioned as an associated issue, though the
possibility is obvious.
Dave

Bent frame isn't very likely with just toppling over. If you can ride
the frame no handed without the frame veering left or right it's fine.
I'd investigate free movement of the shiftercable first. Is the cable
properly located underneath the bracket? Last bit of outer cable not to
short, kinked, badly cut. missing ferrule etc? And another good one:
cable properly clamped in the groove on the derailleur body?

--
/Marten

info(apestaartje)m-gineering(punt)nl

On Thu, 04 Oct 2007 15:57:48 -0500, A Muzi
wrote:

DaveH wrote:
[58 cm Rivendell Ramboulliet -- steel frame, Dura Ace bar ends]

Days ago I had a clipless newbie style slow-speed side crash which
bent the derailleur hanger and the Ultegra rd-6500gs triple der. My
LBS straightened the hanger and replaced the bent der with a Dura Ace
rd-7700GS.

The new der shifted fine on the stand -- but on the road I
experienced problems, particularly when downshifting from 15 to 14
teeth cogs (Ultegra 12-27, 9 sp cassette). The prob seems to be
erratic, not yielding to any amount of adjustment.

Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Generally, how frequently is a bent hanger accompanied by a bent
frame? Tough question, I know. My immediate concern is whether I need
to find a shop that is equipped for frame checking and alignment.

I've read Sheldon and others regarding bent hangers and I've not seen
bent frames being mentioned as an associated issue, though the
possibility is obvious.

Much more likely to be a simple error/oversight; derailleur
alignment/adjustment/cable problem. You should be able to return to the
shop which 'upgraded' your gear system and watch the Campagnolo "R" tool
alignment then a full frame alignment gauge. If the rear end were off to
one side enough to give shifting problems, you'd likely have noticed a
difference when riding no hands.
p.s. if there are plastic ferrules on your casing, have them replaced
with real ones.

I wonder if the Dura Ace 7700gs triple rear derailleur is incompatible
with my Sugino XD-2 48/36/36 crank since the problem is worst on the
largest chainring, though I know that can be typical.

DaveH wrote:
On Thu, 04 Oct 2007 15:57:48 -0500, A Muzi
wrote:

DaveH wrote:
[58 cm Rivendell Ramboulliet -- steel frame, Dura Ace bar ends]

Days ago I had a clipless newbie style slow-speed side crash which
bent the derailleur hanger and the Ultegra rd-6500gs triple der. My
LBS straightened the hanger and replaced the bent der with a Dura Ace
rd-7700GS.

The new der shifted fine on the stand -- but on the road I
experienced problems, particularly when downshifting from 15 to 14
teeth cogs (Ultegra 12-27, 9 sp cassette). The prob seems to be
erratic, not yielding to any amount of adjustment.

Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.

Generally, how frequently is a bent hanger accompanied by a bent
frame? Tough question, I know. My immediate concern is whether I need
to find a shop that is equipped for frame checking and alignment.

I've read Sheldon and others regarding bent hangers and I've not seen
bent frames being mentioned as an associated issue, though the
possibility is obvious.
Much more likely to be a simple error/oversight; derailleur
alignment/adjustment/cable problem. You should be able to return to the
shop which 'upgraded' your gear system and watch the Campagnolo "R" tool
alignment then a full frame alignment gauge. If the rear end were off to
one side enough to give shifting problems, you'd likely have noticed a
difference when riding no hands.
p.s. if there are plastic ferrules on your casing, have them replaced
with real ones.

I wonder if the Dura Ace 7700gs triple rear derailleur is incompatible
with my Sugino XD-2 48/36/36 crank since the problem is worst on the
largest chainring, though I know that can be typical.


Doesn't sound likely. Does the DA rear have a weaker spring than the
original? Sluggish shifting to smaller sprockets is usually because the
spring is too light for the friction in the path.

DaveH wrote:
[58 cm Rivendell Ramboulliet -- steel frame, Dura Ace bar ends]
Days ago I had a clipless newbie style slow-speed side crash which
bent the derailleur hanger and the Ultegra rd-6500gs triple der. My
LBS straightened the hanger and replaced the bent der with a Dura Ace
rd-7700GS.
The new der shifted fine on the stand -- but on the road I
experienced problems, particularly when downshifting from 15 to 14
teeth cogs (Ultegra 12-27, 9 sp cassette). The prob seems to be
erratic, not yielding to any amount of adjustment.
Rivendell suggested the frame may have been bent in the crash --
triangle pushed to the left. It looked like the hanger was bent
something on the order of 2-3 degrees -- wild visual guess.
Generally, how frequently is a bent hanger accompanied by a bent
frame? Tough question, I know. My immediate concern is whether I need
to find a shop that is equipped for frame checking and alignment.
I've read Sheldon and others regarding bent hangers and I've not seen
bent frames being mentioned as an associated issue, though the
possibility is obvious.

A Muzi wrote:
Much more likely to be a simple error/oversight; derailleur
alignment/adjustment/cable problem. You should be able to return to the
shop which 'upgraded' your gear system and watch the Campagnolo "R" tool
alignment then a full frame alignment gauge. If the rear end were off to
one side enough to give shifting problems, you'd likely have noticed a
difference when riding no hands.
p.s. if there are plastic ferrules on your casing, have them replaced
with real ones.

DaveH wrote:
I wonder if the Dura Ace 7700gs triple rear derailleur is incompatible
with my Sugino XD-2 48/36/36 crank since the problem is worst on the
largest chainring, though I know that can be typical.

Crank's not the problem.
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

DaveH wrote:
I wonder if the Dura Ace 7700gs triple rear derailleur is incompatible
with my Sugino XD-2 48/36/36 crank since the problem is worst on the
largest chainring, though I know that can be typical.

Crank's not the problem.

I replaced the DA 7700gs rear derailleur with a new Ultegra 6500gs.
It now shifts perfectly. Smoother, more incisive -- it is a mystery.

Now I must solve the bent frame problem. No hands it veers right,
requiring a slight left body lean to maintain a straight line. I had
an experienced friend confirm this. Mild, not terminal, but
psychologically intolerable.

I'm guessing I can find a frame man near Wash DC, 2 hours away.
It is tempting to try the FAQ's manual straightening method. I think
the rear-end needs to be pulled to the right ~1/16".
Dave