Frame Alignment

rosco said:

I was looking at a road frame whose alignment seemed
questionable. When a properly built wheel was put in the
rear, the space between the rim and the chainstay is
considerably different between the left and the right
sides (estimate about 2.5mm difference). The chainstays
are non-exotic straight chainstays. The left/right spacing
of the rim at the seat stays does appear to be equal.

Would you consider this symptom to indicate something is
wrong, or is it within standard tolerances?

A wheel-independent test: run a piece of fine thread around
the head tube and the rear dropouts. Measure the distance
between the thread and the seat tube on both sides. Are
they the same?

If it's a steel frame it doesn't cost a vast amount to have
it cold-set properly by a framebuilder, provided there isn't
a bad fault like one of the stays being cut too short.

rosco said:

I was looking at a road frame whose alignment seemed
questionable. When a properly built wheel was put in the
rear, the space between the rim and the chainstay is
considerably different between the left and the right
sides (estimate about 2.5mm difference). The chainstays
are non-exotic straight chainstays. The left/right spacing
of the rim at the seat stays does appear to be equal.

Would you consider this symptom to indicate something is
wrong, or is it within standard tolerances?

flip the wheel over. in each case let the wheel fall into
the frame ends. If the same error shows both ways the
frame is off.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

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

Quoted message said:

rosco said:

I was looking at a road frame whose alignment seemed
questionable. When

a

Quoted message said:

Quoted message said:

properly built wheel was put in the rear, the space
between the rim and

the

Quoted message said:

Quoted message said:

chainstay is considerably different between the left and
the right sides (estimate about 2.5mm difference). The
chainstays are non-exotic

straight

Quoted message said:

Quoted message said:

chainstays. The left/right spacing of the rim at the
seat stays does

appear

Quoted message said:

Quoted message said:

to be equal.

Would you consider this symptom to indicate something is
wrong, or is it within standard tolerances?

flip the wheel over. in each case let the wheel fall into
the frame ends. If the same error shows both ways the
frame is off.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971

Both the flip the wheel test and the string test show the
frame is off between 1 to 1.5 mm. Is this within normal
tolerances? It's a high-end stock frame from a regular
manufacturer (not a boutique builder). Should you expect
better than this?

What frame manufacturer is it?

Quoted post said:

Originally posted by A Muzi

Brosco said:

I was looking at a road frame whose alignment seemed
questionable. When a properly built wheel was put in the
rear, the space between the rim and the chainstay is
considerably different between the left and the right
sides (estimate about 2.5mm difference). The chainstays
are non-exotic straight chainstays. The left/right spacing
of the rim at the seat stays does appear to be equal.

Would you consider this symptom to indicate something is
wrong, or is it within standard tolerances?

flip the wheel over. in each case let the wheel fall into
the frame ends. If the same error shows both ways the
frame is off.
--
Andrew Muzi www.yellowjersey.org Open every day since 1
April, 1971 [/B]

Dear Rosco and Andrew,

While I passionately favor symmetry and perfection,
it occurs to me that I have no idea what to expect
from this problem at this level.

What effect does a 1.5mm asymmetry between the
rim and the chainstay have, versus a 0.15mm failure
to meet the ideal?

More tire wear? Extra rolling resistance? A weakened
rear triangle? A tendency to pull to one side? Brake
pad mis-alignment? Chain-line and shifting difficulty?

How much would things flex during normal riding?
That is, how much would the rim waggle from side
to side while turning, bumping, braking, and struggling
up a steep hill?

Is this something practical that some riders can notice
while riding, or are we just having fun with calipers
and enjoying the warm glow of theoretical satisfaction?

I just examined my Fury Roadmaster. Its hind rim
cowers about 5mm further from one chainstay than
the other, but unbolting the axle and wiggling it in
the dropout slot might improve matters. I'm just
curious what matters I'd be improving.

Carl Fogel

Quoted message said:

Quoted message said:

Quoted message said:

>rosco wrote:
I was looking at a road frame whose alignment seemed
questionable. When a properly built wheel was put in
the rear, the space between the rim and the chainstay
is considerably different between the left and the
right sides (estimate about 2.5mm difference). The
chainstays are non-exotic straight chainstays. The
left/right spacing of the rim at the seat stays does
appear to be equal.

Quoted message said:

Quoted message said:

Quoted message said:

Would you consider this symptom to indicate something is
wrong, or is it within standard tolerances?

Quoted message said:

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

Quoted message said:

flip the wheel over. in each case let the wheel fall into
the frame ends. If the same error shows both ways the
frame is off.

rosco said:

Both the flip the wheel test and the string test show the
frame is off between 1 to 1.5 mm. Is this within normal
tolerances? It's a high-end stock frame from a regular
manufacturer (not a boutique builder). Should you expect
better than this?

Expect as you will but 2mm is common and frankly you can't
feel a 2mm rear end variance.

It is easy to fix on a steel frame and for one thing
will at least make changing wheels easier not to mention
peace of mind.

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

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

Quoted message said:

Quoted message said:

Expect as you will but 2mm is common and frankly you can't
feel a 2mm rear end variance.

It is easy to fix on a steel frame and for one thing will
at least make changing wheels easier not to mention peace
of mind.

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

Andrew,

Thank you. I really didn't know what you should expect. I'd
rather be a little extra careful upfront. It seems that the
actual error is even less as it should be 1/2 of the
difference that is measured.

A Muzi said:

Open every day since 1 April, 1971

By the way, CONGRATULATIONS!

Sergio Pisa

Ditto! 33 yrs. is quite an accomplishment. -tom

"Sergio SERVADIO" <[email hidden]> wrote in
message news:Pine.LNX.3.96.1040331105629.7259Q-
[email hidden]...

Quoted message said:

A Muzi said:

Open every day since 1 April, 1971

By the way, CONGRATULATIONS!

Sergio Pisa