Dropout spacing and wheel axles.

webhead said:

Currently I'm squeezing a 126mm rear wheel into a steel 130mm frame.
Works well, and from what I've gathered innocent and common.
The problem is that I see the derailleur dropout bend a few mm inwards
(obviously) and being somewhat uptight it ticks me off.

I'm having some problems getting the shifting exactly perfect and I
think it's an indexing thing but could the small bending of the
derailleur cause an issue?
Is it possible to swap the axle in the hub, add some spacers and make
it a 130mm wheel or is this simply not done 'cause I'm having trouble
locating loose axles.

You can probably just add a 4mm spacer to the left side, recentering
the axle with 2mm less on either side, then redishing the wheel (the
added tension on the non-drive side will make the wheel stronger, too
- bonus). When clamped into the dropouts, 3mm of axle on each side
works just as well as 5mm. Honestly, bottoming out on a too-long axle
is a bigger problem.

Hank Wirtz said:

webhead said:

Currently I'm squeezing a 126mm rear wheel into a steel 130mm frame.
Works well, and from what I've gathered innocent and common.
The problem is that I see the derailleur dropout bend a few mm inwards
(obviously) and being somewhat uptight it ticks me off.

Quoted message said:

I'm having some problems getting the shifting exactly perfect and I
think it's an indexing thing but could the small bending of the
derailleur cause an issue?
Is it possible to swap the axle in the hub, add some spacers and make
it a 130mm wheel or is this simply not done 'cause I'm having trouble
locating loose axles.

You can probably just add a 4mm spacer to the left side, recentering
the axle with 2mm less on either side, then redishing the wheel (the
added tension on the non-drive side will make the wheel stronger, too
- bonus). When clamped into the dropouts, 3mm of axle on each side
works just as well as 5mm. Honestly, bottoming out on a too-long axle
is a bigger problem.

Oh, but if you do need an axle, check http://biketoolsetc.com in the
"repair parts" section. You'll need to figure out beforehand what the
threading is on your current one. I think most modern ones are
M10x1mm, but others are 3/8"x26 or 24 tpi. M9x1mm is also used for
fronts.

quote='Hank Wirtz'On Dec 22 said:

Currently I'm squeezing a 126mm rear wheel into a steel 130mm frame.
Works well, and from what I've gathered innocent and common.
The problem is that I see the derailleur dropout bend a few mm inwards
(obviously) and being somewhat uptight it ticks me off.

I'm having some problems getting the shifting exactly perfect and I
think it's an indexing thing but could the small bending of the
derailleur cause an issue?
Is it possible to swap the axle in the hub, add some spacers and make
it a 130mm wheel or is this simply not done 'cause I'm having trouble
locating loose axles.

You can probably just add a 4mm spacer to the left side, recentering
the axle with 2mm less on either side, then redishing the wheel (the
added tension on the non-drive side will make the wheel stronger, too
- bonus). When clamped into the dropouts, 3mm of axle on each side
works just as well as 5mm. Honestly, bottoming out on a too-long axle
is a bigger problem.[/QUOTE]
+1 agreement with Hank. You also might want to check the derailer Hanger alignment.

parktool.comreadhowto.aspOpen ↗

Are your shifter, derailer, and chain all specified for 7 (or 6 as the case me be) speed?
Are your cable, housings, and cable ends all in good shape (including clean and well lubed guide under the bottom bracket)?

On Sat, 22 Dec 2007 09:16:28 -0800 (PST), webhead <[email hidden]>

may have said:

Currently I'm squeezing a 126mm rear wheel into a steel 130mm frame.
Works well, and from what I've gathered innocent and common.

Certainly not unusual, at least.

Quoted message said:

The problem is that I see the derailleur dropout bend a few mm inwards
(obviously) and being somewhat uptight it ticks me off.

I'm having some problems getting the shifting exactly perfect and I
think it's an indexing thing but could the small bending of the
derailleur cause an issue?

Yes, just enough to be annoying, in my experience. It works, but with
some finicky action at one end of the range; one or two gear need a
little extra push to get the shift to happen, for instance.

Quoted message said:

Is it possible to swap the axle in the hub, add some spacers and make
it a 130mm wheel or is this simply not done 'cause I'm having trouble
locating loose axles.

As long as it's 10x1.0 thread, you can probably pick up a suitable
axle here:

www.loosescrews.com
www.biketoolsetc.com

Add a 2mm thick washer on each side, and you're set.

--
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.

Quoted message said:

Yes, just enough to be annoying, in my experience. It works, but with
some finicky action at one end of the range; one or two gear need a
little extra push to get the shift to happen, for instance.

Exactly ! I just don't seem get it fixed by indexing adjustment alone.
Not that it don't work but it gets on my nerves.

"webhead" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Currently I'm squeezing a 126mm rear wheel into a steel 130mm frame.
Works well, and from what I've gathered innocent and common.
The problem is that I see the derailleur dropout bend a few mm inwards
(obviously) and being somewhat uptight it ticks me off.

I'm having some problems getting the shifting exactly perfect and I
think it's an indexing thing but could the small bending of the
derailleur cause an issue?
Is it possible to swap the axle in the hub, add some spacers and make
it a 130mm wheel or is this simply not done 'cause I'm having trouble
locating loose axles.

Squeezing the dropouts like you are doing can cause them to be misaligned
putting undue pressure on the rear hub axle which can eventually cause it
to bend or break.

Many rear dropouts are misaligned to begin with. Offsetting them 4mm
(.157" or 5/32"😉 is enough to cause shifting problems with some
derailleurs.

You can easily check the alignment of your dropouts. This link shows you
how it's done with dropout tools:

http://www.parktool.com/repair/readhowto.asp?id=40

You can measure them the same way using two 10mm or 3/8" bolts and 4 nuts
to fit the bolts. Some flat washers will help insure that the bolts sit
correctly in the dropouts.

Here's another link with a lot of good info on frame alignment:

http://www.bcltechnologies.com/document/products/magellan/samples/sample.pdf

Chas.

Werehatrack said:

As long as it's 10x1.0 thread, you can probably pick up a suitable
axle here:

www.loosescrews.com
www.biketoolsetc.com

Add a 2mm thick washer on each side, and you're set.

Assuming the geometry of the bike works out. I'm thinking that adding
4mm to the left side is more likely to result in the cluster ending up
the original distance from the right stay. I don't think the original
130mm wheel would have had 2mm of extra space on that side. But,
depending on a lot of other variables, you might have to fool with the
spacing a bit to get the overall alignment correct.

still just me said:

On Sat, 22 Dec 2007 12:56:03 -0600, Werehatrack

Quoted message said:

As long as it's 10x1.0 thread, you can probably pick up a suitable
axle here:

Quoted message said:

www.loosescrews.com
www.biketoolsetc.com

Quoted message said:

Add a 2mm thick washer on each side, and you're set.

Assuming the geometry of the bike works out. I'm thinking that adding
4mm to the left side is more likely to result in the cluster ending up
the original distance from the right stay. I don't think the original
130mm wheel would have had 2mm of extra space on that side. But,
depending on a lot of other variables, you might have to fool with the
spacing a bit to get the overall alignment correct.

I just checked and I'm pretty sure adding washers alone will be
sufficient. Now, if I add 2mm to each side I think a 130mm wheel would
not have this extra space, like you said. But, if I add the 4mm to the
left that would mean redishing/trueing the wheel and I don't think I'm
up to that. Couldn't I adjust the 2mm offset with derailleur
adjustment ?

* * Chas said:

Squeezing the dropouts like you are doing can cause them to be misaligned
putting undue pressure on the rear hub axle which can eventually cause it
to bend or break.

Why would squeezing the dropouts closer together put any more strain
on the hub? Seems to me the only additional strain on the wheel would
be on the axle, and it would be entirely an axial strain with no
additional bending moments.

R

"RicodJour" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

* * Chas said:

Squeezing the dropouts like you are doing can cause them to be

misaligned

Quoted message said:

Quoted message said:

putting undue pressure on the rear hub axle which can eventually cause

it

Quoted message said:

Quoted message said:

to bend or break.

Why would squeezing the dropouts closer together put any more strain
on the hub? Seems to me the only additional strain on the wheel would
be on the axle, and it would be entirely an axial strain with no
additional bending moments.

R

Because squeezing or spreading the dropouts can change the parallelism
between them and this can put uneven pressure on the axle end flanges.

For a lot of different reasons many bikes have dropouts and forkends that
are out of alignment.

The bearings on most cassette style hubs are located near the outboard
ends of the axles and are less likely to have problems with misaligned
dropouts. The right side bearings on the axles in freewheel style hubs are
further inboard leaving a long section of unsupported axle hanging out
which is susceptible to bending and breakage.

Chas.

RicodJour said:

* * Chas said:

Squeezing the dropouts like you are doing can cause them to be misaligned
putting undue pressure on the rear hub axle which can eventually cause it
to bend or break.

Quoted message said:

Why would squeezing the dropouts closer together put any more strain
on the hub? Seems to me the only additional strain on the wheel would
be on the axle, and it would be entirely an axial strain with no
additional bending moments.

When the stays are bent inwards, the dropout faces don't remain
parallel. Now when you clamp in (or bolt in) your wheel there is indeed
a bending moment, which can and does cause the axle to fail in some
circumstances.

Yes, the bending moment is small. I will leave the calculations to
someone else. However the axle is not designed for that loading; best
to avoid it by adding spacers as necessary, or by cold-setting the frame
so that the spacing is correct for the hub and the dropout faces are
parallel.

--
Ted Bennett

Ted Bennett said:

RicodJour said:

"* * Chas" <[email hidden]> wrote:

Quoted message said:

Quoted message said:

Squeezing the dropouts like you are doing can cause them to be misaligned
putting undue pressure on the rear hub axle which can eventually cause it
to bend or break.

Why would squeezing the dropouts closer together put any more strain
on the hub? Seems to me the only additional strain on the wheel would
be on the axle, and it would be entirely an axial strain with no
additional bending moments.

When the stays are bent inwards, the dropout faces don't remain
parallel. Now when you clamp in (or bolt in) your wheel there is indeed
a bending moment, which can and does cause the axle to fail in some
circumstances.

Yes, the bending moment is small. I will leave the calculations to
someone else. However the axle is not designed for that loading; best
to avoid it by adding spacers as necessary, or by cold-setting the frame
so that the spacing is correct for the hub and the dropout faces are
parallel.

But the clamping action of the skewer (I said axle in my first post
when I meant skewer) will tend to pull the dropouts against the
essentially immovable, parallel axle lock nuts. I just don't see an
appreciable difference in. Once it's clamped down, the force is all
axial. Put it this way, there's no more twisting force on the
dropouts, and probably far less, than when the wheel experiences a
sideways load while riding.

R

On Sun, 23 Dec 2007 10:18:50 -0800 (PST), webhead <[email hidden]>

may have said:

still just me said:

On Sat, 22 Dec 2007 12:56:03 -0600, Werehatrack

Quoted message said:

As long as it's 10x1.0 thread, you can probably pick up a suitable
axle here:

Quoted message said:

www.loosescrews.com
www.biketoolsetc.com

Quoted message said:

Add a 2mm thick washer on each side, and you're set.

Assuming the geometry of the bike works out. I'm thinking that adding
4mm to the left side is more likely to result in the cluster ending up
the original distance from the right stay. I don't think the original
130mm wheel would have had 2mm of extra space on that side. But,
depending on a lot of other variables, you might have to fool with the
spacing a bit to get the overall alignment correct.

I just checked and I'm pretty sure adding washers alone will be
sufficient. Now, if I add 2mm to each side I think a 130mm wheel would
not have this extra space, like you said. But, if I add the 4mm to the
left that would mean redishing/trueing the wheel and I don't think I'm
up to that. Couldn't I adjust the 2mm offset with derailleur
adjustment ?

Maybe. Sometimes there's enough throw in the der, sometimes there's
not. It can't hurt to try, if you have the spacers available.

--
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.

Werehatrack said:

Quoted message said:

I just checked and I'm pretty sure adding washers alone will be
sufficient. Now, if I add 2mm to each side I think a 130mm wheel would
not have this extra space, like you said. But, if I add the 4mm to the
left that would mean redishing/trueing the wheel and I don't think I'm
up to that. Couldn't I adjust the 2mm offset with derailleur
adjustment ?

Maybe. Sometimes there's enough throw in the der, sometimes there's
not. It can't hurt to try, if you have the spacers available.

Yep, give it a try first.

Another possible issue is the overall alinement of the rear triangle
to the BB. 2m is not much. There's also the displacement of the
chainwheels to consider. Sometimes 2mm causes an issue, sometimes it
doesn't matter. But, as with the derailleur, it depends whether or not
something is at the limit or marginal in the current setup.

Also, keep in mind that you're assuming the wheel is currently dished
accurately. If it's off even 1mm in a good direction for you then
adding 2mm would just bring it 1mm in the other direction. Of course,
if it's off 1mm the wrong way, 2mm would make it off 3mm... that
you're going to see.

Lots of variables. Give it a shot. See what happens.

still just me said:

On Mon, 24 Dec 2007 01:27:29 -0600, Werehatrack

Quoted message said:

Quoted message said:

I just checked and I'm pretty sure adding washers alone will be
sufficient. Now, if I add 2mm to each side I think a 130mm wheel would
not have this extra space, like you said. But, if I add the 4mm to the
left that would mean redishing/trueing the wheel and I don't think I'm
up to that. Couldn't I adjust the 2mm offset with derailleur
adjustment ?

Quoted message said:

Maybe. Sometimes there's enough throw in the der, sometimes there's
not. It can't hurt to try, if you have the spacers available.

Yep, give it a try first.

Another possible issue is the overall alinement of the rear triangle
to the BB. 2m is not much. There's also the displacement of the
chainwheels to consider. Sometimes 2mm causes an issue, sometimes it
doesn't matter. But, as with the derailleur, it depends whether or not
something is at the limit or marginal in the current setup.

Also, keep in mind that you're assuming the wheel is currently dished
accurately. If it's off even 1mm in a good direction for you then
adding 2mm would just bring it 1mm in the other direction. Of course,
if it's off 1mm the wrong way, 2mm would make it off 3mm... that
you're going to see.

Lots of variables. Give it a shot. See what happens.

I've realigned the minor difference in the dropouts and added the
washers to the wheel. It seems like the derailleur is well capable of
bridging that amount. At the moment I can't visually find anything
wrong but the shifting still is off, either it shifts properly on the
first 3-4 cogs or on the last (bigest) 3-4 cogs, depending on how I
adjust the indexing. It does shift but there's some chain rattle due
to bad derailleur alignment.
Maybe it still needs a little tweaking but it annoys me. Maybe it's my
old shifters but those seem to shift the cable just fine.
Ofcourse when I take it out to the field and it collects mud it picks
up some additional noise but still...

In article
<[email hidden]
groups.com>,

RicodJour said:

Ted Bennett said:

RicodJour said:

"* * Chas" <[email hidden]> wrote:

Quoted message said:

> Squeezing the dropouts like you are doing can cause them to be misaligned
> putting undue pressure on the rear hub axle which can eventually cause it
> to bend or break.
Why would squeezing the dropouts closer together put any more strain
on the hub? Seems to me the only additional strain on the wheel would
be on the axle, and it would be entirely an axial strain with no
additional bending moments.

When the stays are bent inwards, the dropout faces don't remain
parallel. Now when you clamp in (or bolt in) your wheel there is indeed
a bending moment, which can and does cause the axle to fail in some
circumstances.

Yes, the bending moment is small. I will leave the calculations to
someone else. However the axle is not designed for that loading; best
to avoid it by adding spacers as necessary, or by cold-setting the frame
so that the spacing is correct for the hub and the dropout faces are
parallel.

But the clamping action of the skewer (I said axle in my first post
when I meant skewer) will tend to pull the dropouts against the

Assumption: For particular values of tend.

Quoted message said:

essentially immovable, parallel axle lock nuts. I just don't see an

Assumption: for some value of essentially immovable.
None of this stuff is essentially immovable. It is all elastic.

Quoted message said:

appreciable difference in. Once it's clamped down, the force is all
axial.

No, the bending moment remains non-zero.

It is an Euler strut unevenly loaded with a non-zero
bending moment, and therefore further toward the edge
of its buckling regime than with even loading. That it
has not buckled does not prove the condition benign.

Look up `imperfection sensitivity' in a text on structures.

Quoted message said:

Put it this way, there's no more twisting force on the
dropouts, and probably far less, than when the wheel experiences a
sideways load while riding.

Assumption: `probably'. And the forces are additive.

That failures have not been attributed to out of parallel
drop outs does not prove that the condition is benign.
Look up `imperfection sensitivity' in a text on structures.

--
Michael Press

"webhead" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

still just me said:

On Mon, 24 Dec 2007 01:27:29 -0600, Werehatrack

Quoted message said:

>I just checked and I'm pretty sure adding washers alone will be
>sufficient. Now, if I add 2mm to each side I think a 130mm wheel

would

Quoted message said:

Quoted message said:

Quoted message said:

>not have this extra space, like you said. But, if I add the 4mm to

the

Quoted message said:

Quoted message said:

Quoted message said:

>left that would mean redishing/trueing the wheel and I don't think

I'm

Quoted message said:

Quoted message said:

Quoted message said:

>up to that. Couldn't I adjust the 2mm offset with derailleur
>adjustment ?

Quoted message said:

Maybe. Sometimes there's enough throw in the der, sometimes there's
not. It can't hurt to try, if you have the spacers available.

Yep, give it a try first.

Another possible issue is the overall alinement of the rear triangle
to the BB. 2m is not much. There's also the displacement of the
chainwheels to consider. Sometimes 2mm causes an issue, sometimes it
doesn't matter. But, as with the derailleur, it depends whether or not
something is at the limit or marginal in the current setup.

Also, keep in mind that you're assuming the wheel is currently dished
accurately. If it's off even 1mm in a good direction for you then
adding 2mm would just bring it 1mm in the other direction. Of course,
if it's off 1mm the wrong way, 2mm would make it off 3mm... that
you're going to see.

Lots of variables. Give it a shot. See what happens.

I've realigned the minor difference in the dropouts and added the
washers to the wheel. It seems like the derailleur is well capable of
bridging that amount. At the moment I can't visually find anything
wrong but the shifting still is off, either it shifts properly on the
first 3-4 cogs or on the last (bigest) 3-4 cogs, depending on how I
adjust the indexing. It does shift but there's some chain rattle due
to bad derailleur alignment.
Maybe it still needs a little tweaking but it annoys me. Maybe it's my
old shifters but those seem to shift the cable just fine.
Ofcourse when I take it out to the field and it collects mud it picks
up some additional noise but still...

Two other things to consider:

1. The derailleur hanger could be misaligned. The derailleur needs to be
parallel to the wheel axis on 2 plains - front to back and top to bottom.
If the derailleur is angled on either plain then it can cause some
shifting problems.

2. The top jockey wheel in the derailleur could be worn out. The wheel
should move freely side to side but have no angular slop.

Chas.

Michael Press said:

RicodJour said:

Ted Bennett said:

RicodJour <[email hidden]> wrote:
> "* * Chas" <[email hidden]> wrote:

Quoted message said:

Quoted message said:

> > Squeezing the dropouts like you are doing can cause them to be misaligned
> > putting undue pressure on the rear hub axle which can eventually cause it
> > to bend or break.

Quoted message said:

Quoted message said:

> Why would squeezing the dropouts closer together put any more strain
> on the hub? Seems to me the only additional strain on the wheel would
> be on the axle, and it would be entirely an axial strain with no
> additional bending moments.

Quoted message said:

Quoted message said:

When the stays are bent inwards, the dropout faces don't remain
parallel. Now when you clamp in (or bolt in) your wheel there is indeed
a bending moment, which can and does cause the axle to fail in some
circumstances.

Quoted message said:

Quoted message said:

Yes, the bending moment is small. I will leave the calculations to
someone else. However the axle is not designed for that loading; best
to avoid it by adding spacers as necessary, or by cold-setting the frame
so that the spacing is correct for the hub and the dropout faces are
parallel.

Quoted message said:

But the clamping action of the skewer (I said axle in my first post
when I meant skewer) will tend to pull the dropouts against the

Assumption: For particular values of tend.

Oh, God, here we go...

Quoted message said:

Quoted message said:

essentially immovable, parallel axle lock nuts. I just don't see an

Assumption: for some value of essentially immovable.
None of this stuff is essentially immovable. It is all elastic.

Quoted message said:

appreciable difference in. Once it's clamped down, the force is all
axial.

No, the bending moment remains non-zero.

It is an Euler strut unevenly loaded with a non-zero
bending moment, and therefore further toward the edge
of its buckling regime than with even loading. That it
has not buckled does not prove the condition benign.

Look up `imperfection sensitivity' in a text on structures.

Quoted message said:

Put it this way, there's no more twisting force on the
dropouts, and probably far less, than when the wheel experiences a
sideways load while riding.

Assumption: `probably'. And the forces are additive.

That failures have not been attributed to out of parallel
drop outs does not prove that the condition is benign.
Look up `imperfection sensitivity' in a text on structures.

While I'm at it should I look up 'how many angels can dance on the
head of a pin?' Exactly how sensitive is the imperfection to the
[censored]' 1/3 of 1 degree out of parallel condition?

My comments were in reply to Chas:

Quoted message said:

"webhead" <[email hidden]> wrote in message

Squeezing the dropouts like you are doing can cause them to be misaligned
putting undue pressure on the rear hub axle which can eventually cause it
to bend or break.

Squeezing the dropouts is not uncommon. How is it different than
spreading them to fit a wider hub? That's way more common and I've
never heard of a broken or bent axle in either situation where the
difference in hub widths was 4 mm. A 10 mm discrepancy is another
matter and could cause a problem, but so can crashing the bike or
running into a curb.

In any event, the OP shimmed the sucker and it's a done deal, but
thanks for the engineering refresher. I haven't been so lulled by
droning since Prof. Oral Buyozkuturk way back when. 🙂~

R

Quoted message said:

1. The derailleur hanger could be misaligned. The derailleur needs to be
parallel to the wheel axis on 2 plains - front to back and top to bottom.
If the derailleur is angled on either plain then it can cause some
shifting problems.

Could be but how do I check this? I've aligned the dropouts by
screwing something in it resembling that parktool thing for aligning
them. I sort of used a DIY version of the parktool model.
I'm somewhat scared of taking the deraileur out again because the
first mm of thread in somewhat damaged so it's difficult to screw it
in. I need to get my hands on an M10x1 tap for restoring that but I've
only got an M10x1.5 lying around, anyhow that's not the cause of the
misalignment.
If the derailleur hanger is out of alignment, can this be checked
somehow ?

Quoted message said:

2. The top jockey wheel in the derailleur could be worn out. The wheel
should move freely side to side but have no angular slop.

It's brand new actually. How much lateral movement are we talking
about ?