Frame alignment question

ron said:

I just repacked the rear hub on a bike, checked the truing (including
dish) of the wheel and mounted it - noticing that no matter how careful I
was to align it "straight," the rim could be seen to be slightly offset to
the drive side when viewed from the rear, relative to the center mounting
hole on the brake bridge. This is while the rim is well-centered relative
to the chain stays. I triple-checked the spacers, dish, etc., to make sure
everything on the wheel was symmetric, but kept getting the same result.
The spacing on the frame is the stock 126mm.

You might want to try the string test:
http://www.sheldonbrown.com/frame-spacing.html
(scroll down)

You might also want to have the rear dropout alignment checked at a
shop. They have the tools to check and correct this easily. Misaligned
dropouts put stress on the axle

Quoted message said:

I measured the offset vis-a-vis the left and right seat stays with a rule
(delta of distance of rim edge from each corresponding seat stay), and
found that the rim was off center left-to-right by about 2mm. This
prompted me to measure four other bikes. Turned out that all but one was
off by about 1-1.5mm in the same way. The one that was dead on and evenly
spaced happened to be a really nice CIOCC-built frame. The other bikes are
nice steel frames, but perhaps not as nice as the CIOCC.

All of these bikes seem to ride just fine - I never noticed any pull or
drift on any of them.

Misalignment of the forks would have more effect on handling.

Quoted message said:

What is considered a tolerable range for this measurement?

Good question. If the bikes ride well, I wouldn't worry too much. I
have heard that many classic bikes had less than perfect alignment.

Art Harris

ron said:

I just repacked the rear hub on a bike, checked the truing (including
dish) of the wheel and mounted it - noticing that no matter how careful I
was to align it "straight," the rim could be seen to be slightly offset to
the drive side when viewed from the rear, relative to the center mounting
hole on the brake bridge.

....

Quoted message said:

Ron Abramson

Ron,

You are way ahead of me in skill. Dishing wheels is pretty easily
understandable to do, but
what are you aligning the wheel rim to when dishing? Centering wheel on
axis between rear fork spacers?
Never quite understood going from 120 to 130 mm would require a 2"
shift in dish if so, and seems like would rub chain. Or are you
aligning wheel between the fork centers, which may be the same thing.

Thanks!!

ron said:

I just repacked the rear hub on a bike, checked the truing (including
dish) of the wheel and mounted it - noticing that no matter how careful I
was to align it "straight," the rim could be seen to be slightly offset to
the drive side when viewed from the rear, relative to the center mounting
hole on the brake bridge. This is while the rim is well-centered relative
to the chain stays. I triple-checked the spacers, dish, etc., to make sure
everything on the wheel was symmetric, but kept getting the same result.
The spacing on the frame is the stock 126mm.

I measured the offset vis-a-vis the left and right seat stays with a rule
(delta of distance of rim edge from each corresponding seat stay), and
found that the rim was off center left-to-right by about 2mm. This
prompted me to measure four other bikes. Turned out that all but one was
off by about 1-1.5mm in the same way. The one that was dead on and evenly
spaced happened to be a really nice CIOCC-built frame. The other bikes are
nice steel frames, but perhaps not as nice as the CIOCC.

All of these bikes seem to ride just fine - I never noticed any pull or
drift on any of them.

What is considered a tolerable range for this measurement?

Most frames we see are within 3mm left/right at the rear and forks are
almost all within 1mm left/right - which is tolerable for functionality.
Some riders gush at the improvement after alignment, others can't tell
either way. Most supplied-with-new-bike wheels are within 2mm left-right
which again can look funny but still work.

Since it is trivial to correct all of those things ( at least on steel
frames and wheels with 'normal' spokes!)to dead straight, I don't see
why not. Even if you cannot feel a difference in handling, it looks nice
and wheel changes are quicker. The expense is minimal.

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

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

Quoted message said:

I just repacked the rear hub on a bike, checked the truing (including
dish) of the wheel and mounted it - noticing that no matter how careful

I

Quoted message said:

was to align it "straight," the rim could be seen to be slightly offset

to

Quoted message said:

the drive side when viewed from the rear, relative to the center

mounting

Quoted message said:

hole on the brake bridge. This is while the rim is well-centered

relative

Quoted message said:

to the chain stays. I triple-checked the spacers, dish, etc., to make

sure

Quoted message said:

everything on the wheel was symmetric, but kept getting the same result.
The spacing on the frame is the stock 126mm.

I measured the offset vis-a-vis the left and right seat stays with a

rule

Quoted message said:

(delta of distance of rim edge from each corresponding seat stay), and
found that the rim was off center left-to-right by about 2mm. This
prompted me to measure four other bikes. Turned out that all but one was
off by about 1-1.5mm in the same way. The one that was dead on and

evenly

Quoted message said:

spaced happened to be a really nice CIOCC-built frame. The other bikes

are

Quoted message said:

nice steel frames, but perhaps not as nice as the CIOCC.

All of these bikes seem to ride just fine - I never noticed any pull or
drift on any of them.

What is considered a tolerable range for this measurement?

Ron Abramson

Unless the frame tubes are really screwed up, you should be able to align
a frame to within 1 mm without too much problem. Closer alignment would be
better but less than .2 mm would probably be overkill.

This would include the seat tube 90° to the BB spindle, seat tube, head
tube and forks parallel, forks and rear triangle centered, wheels sitting
in line with the frame axis both horizontally and vertically, etc.

One problem with cold setting a frame is that you have to keep
re-measuring because after you have the main triangle aligned, it will go
out of whack again when you move the rear triangle and so on.

I put together a late 80s Colnago Technos last summer. I bought the frame
from a local frame builder. He had taken it in as a partial trade for a
custom frame. He had aligned the forks for the original owner who claimed
the bike always handled squirrelly.

While assembling the bike I noticed that the rear triangle was out of
alignment so I took it back to the frame builder's and we put it on his
layout table. The rear triangle was off 11mm to the left (from the rear),
the seat tube was angled off 18mm at the top and the head tube was off
12mm in the other direction. The frame looked new and probably came from
the factory that way.

In 10 minutes time we had it aligned to within .2 mm. It rides and handles
like a dream now. The way it came from the factory it would have never
tracked straight, hands off on it would have probably rode in circles.

I remember back in the 1970s having to file dropouts in order to get a
wheel to sit in straight. I saw a beautiful new Bob Jackson from that era
that had one chainstay 1/2" shorter than the other.... but the paint was
perfect.

Chas.

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

Quoted message said:

ron said:

I just repacked the rear hub on a bike, checked the truing (including
dish) of the wheel and mounted it - noticing that no matter how

careful I

Quoted message said:

Quoted message said:

was to align it "straight," the rim could be seen to be slightly

offset to

Quoted message said:

Quoted message said:

the drive side when viewed from the rear, relative to the center

mounting

Quoted message said:

Quoted message said:

hole on the brake bridge. This is while the rim is well-centered

relative

Quoted message said:

Quoted message said:

to the chain stays. I triple-checked the spacers, dish, etc., to make

sure

Quoted message said:

Quoted message said:

everything on the wheel was symmetric, but kept getting the same

result.

Quoted message said:

Quoted message said:

The spacing on the frame is the stock 126mm.

I measured the offset vis-a-vis the left and right seat stays with a

rule

Quoted message said:

Quoted message said:

(delta of distance of rim edge from each corresponding seat stay), and
found that the rim was off center left-to-right by about 2mm. This
prompted me to measure four other bikes. Turned out that all but one

was

Quoted message said:

Quoted message said:

off by about 1-1.5mm in the same way. The one that was dead on and

evenly

Quoted message said:

Quoted message said:

spaced happened to be a really nice CIOCC-built frame. The other bikes

are

Quoted message said:

Quoted message said:

nice steel frames, but perhaps not as nice as the CIOCC.

All of these bikes seem to ride just fine - I never noticed any pull

or

Quoted message said:

Quoted message said:

drift on any of them.

What is considered a tolerable range for this measurement?

Most frames we see are within 3mm left/right at the rear and forks are
almost all within 1mm left/right - which is tolerable for functionality.
Some riders gush at the improvement after alignment, others can't tell
either way. Most supplied-with-new-bike wheels are within 2mm left-right
which again can look funny but still work.

Since it is trivial to correct all of those things ( at least on steel
frames and wheels with 'normal' spokes!)to dead straight, I don't see
why not. Even if you cannot feel a difference in handling, it looks nice
and wheel changes are quicker. The expense is minimal.

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

Andy,

Are you talking about wheel adjustments or frame alignment too? I would
like to think that modern bikes come in with better frame and wheel
alignment than those of 20-30 years ago. Is that true?

It was nothing to see a brand new bike from the 70s with vertical wheel
alignment off over 1/2" in different directions front and rear. It could
take 2-3 hours to assemble a bike properly.

Chas.

Chas,

Can you go into detail about where to locate such frame angles and what
was done in
2 minutes to fix all of those large deviations within 0.2mm?

Thanks!

* * Chas said:

While assembling the bike I noticed that the rear triangle was out of
alignment so I took it back to the frame builder's and we put it on his
layout table. The rear triangle was off 11mm to the left (from the rear),
the seat tube was angled off 18mm at the top and the head tube was off
12mm in the other direction. The frame looked new and probably came from
the factory that way.

In 10 minutes time we had it aligned to within .2 mm. It rides and handles
like a dream now. The way it came from the factory it would have never
tracked straight, hands off on it would have probably rode in circles.

Quoted message said:

Chas.

Quoted message said:

Quoted message said:

ron said:

I just repacked the rear hub on a bike, checked the truing (including
dish) of the wheel and mounted it - noticing that no matter how

careful I

Quoted message said:

Quoted message said:

was to align it "straight," the rim could be seen to be slightly

offset to

Quoted message said:

Quoted message said:

the drive side when viewed from the rear, relative to the center

mounting

Quoted message said:

Quoted message said:

hole on the brake bridge. This is while the rim is well-centered

relative

Quoted message said:

Quoted message said:

to the chain stays. I triple-checked the spacers, dish, etc., to make

sure

Quoted message said:

Quoted message said:

everything on the wheel was symmetric, but kept getting the same

result.

Quoted message said:

Quoted message said:

The spacing on the frame is the stock 126mm.

I measured the offset vis-a-vis the left and right seat stays with a

rule

Quoted message said:

Quoted message said:

(delta of distance of rim edge from each corresponding seat stay), and
found that the rim was off center left-to-right by about 2mm. This
prompted me to measure four other bikes. Turned out that all but one

was

Quoted message said:

Quoted message said:

off by about 1-1.5mm in the same way. The one that was dead on and

evenly

Quoted message said:

Quoted message said:

spaced happened to be a really nice CIOCC-built frame. The other bikes

are

Quoted message said:

Quoted message said:

nice steel frames, but perhaps not as nice as the CIOCC.

All of these bikes seem to ride just fine - I never noticed any pull

or

Quoted message said:

Quoted message said:

drift on any of them.

What is considered a tolerable range for this measurement?

Quoted message said:

I said:

Most frames we see are within 3mm left/right at the rear and forks are
almost all within 1mm left/right - which is tolerable for functionality.
Some riders gush at the improvement after alignment, others can't tell
either way. Most supplied-with-new-bike wheels are within 2mm left-right
which again can look funny but still work.

Since it is trivial to correct all of those things ( at least on steel
frames and wheels with 'normal' spokes!)to dead straight, I don't see
why not. Even if you cannot feel a difference in handling, it looks nice
and wheel changes are quicker. The expense is minimal.

* * Chas said:

Are you talking about wheel adjustments or frame alignment too? I would
like to think that modern bikes come in with better frame and wheel
alignment than those of 20-30 years ago. Is that true?

It was nothing to see a brand new bike from the 70s with vertical wheel
alignment off over 1/2" in different directions front and rear. It could
take 2-3 hours to assemble a bike properly.

You are correct. A modern frame off by 3mm is nothing like the twisted
wrecks we used to pull out of new bike cartons! Wheels, too, are
dramatically more uniform now that there isn't a unique axle spacing on
every factory shift!
--
Andrew Muzi
www.yellowjersey.org
Open every day since 1 April, 1971

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

Quoted message said:

Chas,

Can you go into detail about where to locate such frame angles and what
was done in
2 minutes to fix all of those large deviations within 0.2mm?

Thanks!

10 minutes, not 2 minutes. The frame builder has a large ground flat
tooling plate with an adjustable post for holding the frame by the bottom
bracket.

If the BB and fork have been previously removed, this operation can be
done in about 5 minutes if the frame isn't too tweaked or made of "tubo
del ferro di getto"- cast iron pipo. It could take a half an hour or more
with a badly tweaked frame made of heavy gage tubing.

Attach the frame to the plate, put a pair of Campy dropout alignment tools
into the rear dropouts and start checking tube height off of the table
with a height gage.

Start at the seat tube / BB junction, then measure the seat tube at the
top tube lug connection. Next check the alignment of the rear triangle.
Make adjustments and re-measure the seat tube to make sure that it hasn't
moved.

Next check the head tube top and bottom. If the seat tube and head tube
are aligned there's no need to check the top tube or down tube unless you
suspect that one is bent. Re-check everything again and voila.

The next step is to check the forks in a fork jig. Another 5 minutes if
you are lucky and they are not too far out of alignment.

I've spent up to an hour aligning a really badly tweaked frame and fork
made of heavy gage tubing. Smaller frames are a little harder to align.

Chas.

Quoted message said:

I remember back in the 1970s having to file dropouts in order to get a
wheel to sit in straight. I saw a beautiful new Bob Jackson from that
era that had one chainstay 1/2" shorter than the other.... but the
paint was perfect.

1/2"? I'm guessing a wheel couldn't be inserted in to that one, huh?

--
Phil

My Schwinn Paramount P-15 came with the rim offset by almost 1/2" to
one side. Can't change it. Otherwise the bike wouldn't be stock !!
Actually, Schwinn/Waterford severely damaged their own reputation by
shipping a lot of wheels in the mid 70's which were not dished.

The main problem with a wheel that's not centered is that most brakes
like to self-center when you brake - unless they are tightened
extraordinarily tight - and this means you have to leave more slack in
the cables if your wheel isn't centered.

Ride your bikes no handed. If you can detect no discernable pull to
one side or the other, then I think the bike is fine. I doubt you'll
be able to detect any pull with just 1-2mm of offset error.

- Don Gillies
San Diego, CA

Thanks Chas!

So I need a frame builder's services.

I appreciate your experience. Sounds like a worthwhile investment for
a big guy (me).

* * Chas said:

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

Quoted message said:

Chas,

Can you go into detail about where to locate such frame angles and what
was done in
2 minutes to fix all of those large deviations within 0.2mm?

Thanks!

10 minutes, not 2 minutes. The frame builder has a large ground flat
tooling plate with an adjustable post for holding the frame by the bottom
bracket.

If the BB and fork have been previously removed, this operation can be
done in about 5 minutes if the frame isn't too tweaked or made of "tubo
del ferro di getto"- cast iron pipo. It could take a half an hour or more
with a badly tweaked frame made of heavy gage tubing.

Attach the frame to the plate, put a pair of Campy dropout alignment tools
into the rear dropouts and start checking tube height off of the table
with a height gage.

Start at the seat tube / BB junction, then measure the seat tube at the
top tube lug connection. Next check the alignment of the rear triangle.
Make adjustments and re-measure the seat tube to make sure that it hasn't
moved.

Next check the head tube top and bottom. If the seat tube and head tube
are aligned there's no need to check the top tube or down tube unless you
suspect that one is bent. Re-check everything again and voila.

The next step is to check the forks in a fork jig. Another 5 minutes if
you are lucky and they are not too far out of alignment.

I've spent up to an hour aligning a really badly tweaked frame and fork
made of heavy gage tubing. Smaller frames are a little harder to align.

Chas.

"Phil, Non-Squid" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

Quoted message said:

I remember back in the 1970s having to file dropouts in order to get a
wheel to sit in straight. I saw a beautiful new Bob Jackson from that
era that had one chainstay 1/2" shorter than the other.... but the
paint was perfect.

1/2"? I'm guessing a wheel couldn't be inserted in to that one, huh?

--
Phil

There was a MO house in the '70s BikeBarn > Bikeology in Youngstown, OH. I
think they became Nashbar.

In the late '70s they imported large numbers of frames from Colnago, Bob
Jackson, Mercian and others.

The frames looked beautiful but some of them were real junk. A customer
brought in this particular Bob Jackson and complained that it wanted to
ride in a circle. I took it around the block and it didn't track for
@#$^&.

I put it up on the stand, checked the forks and removed the rear wheel. At
that point it was obvious that one chainstay was 1/2" shorter than the
other. Someone had bent the dropouts so that a wheel would go in and out
easier but it came that way from the factory.

I showed the customer the problem and recommended he return it to where he
bought it. There was a minor inference about saving a few bucks buying
through a MO house and how we would have inspected the frame way before he
received it but those words fell on deaf ears.

You buys your tickets and you takes your chances.

Chas.

Phil said:

Quoted message said:

I remember back in the 1970s having to file dropouts in order to get a
wheel to sit in straight. I saw a beautiful new Bob Jackson from that
era that had one chainstay 1/2" shorter than the other.... but the
paint was perfect.

1/2"? I'm guessing a wheel couldn't be inserted in to that one, huh?

Those old horizontal dropouts covers a mulitude of sins.....

Quoted message said:

--
Phil

* * Chas said:

There was a MO house in the '70s BikeBarn > Bikeology in Youngstown, OH. I
think they became Nashbar.

For the record, the original name was Bike Warehouse.

Arni Nashbar changed it to Bike Nashbar when the company's lawyer told
him the original name was too generic to defend from copyright
infringement.

- Frank Krygowski

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

Quoted message said:

Thanks Chas!

So I need a frame builder's services.

I appreciate your experience. Sounds like a worthwhile investment for
a big guy (me).

You can do some basic checks to see how well your frame is aligned without
having a lot of equipment.

Sheldon Brown's suggestions are a good start:

http://www.sheldonbrown.com/frame-spacing.html

If you find that your frame is really out of whack then a frame builder or
qualified LBS may be an easier way to go.

A well aligned bike will track properly and in some ways it may be easier
to ride on a long haul because you can ride 1 handed or no hands for brief
periods.

Good luck,

Chas.

"Donald Gillies" <[email hidden]> wrote in message
news:[email hidden]...
<snip>

Quoted message said:

Ride your bikes no handed. If you can detect no discernable pull to
one side or the other, then I think the bike is fine. I doubt you'll
be able to detect any pull with just 1-2mm of offset error.

- Don Gillies
San Diego, CA

True. I figure that if I have access to the equipment to straighten a
frame and forks then it's only a little more effort to get them aligned as
closely as I can without going overkill as in knowing when to quit while
I'm ahead.

Some frames become a tar baby. You get the main triangle true and the rear
triangle is off and so on and so on...

What you said about the wheel alignment between the brakes is often
overlooked. We used to fix that problem with a round file when all else
failed.

Chas.

* * Chas said:

"ddog" <[email hidden]> wrote in message
You can do some basic checks to see how well your frame is aligned without
having a lot of equipment.

Sheldon Brown's suggestions are a good start:

http://www.sheldonbrown.com/frame-spacing.html

Chas.

Chas,

I knew about the single rear fork adjustment from Sheldon. I was more
interested in
measuring and adjusting all the other angles you were talking about.
Suppose you need a frame fixture per specific type frame since a
universal frame adjustment
machine seems unrealistic.

Thanks,
Phil Bailey

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

Quoted message said:

* * Chas said:

"ddog" <[email hidden]> wrote in message
You can do some basic checks to see how well your frame is aligned

without

Quoted message said:

Quoted message said:

having a lot of equipment.

Sheldon Brown's suggestions are a good start:

http://www.sheldonbrown.com/frame-spacing.html

Chas.

Chas,

I knew about the single rear fork adjustment from Sheldon. I was more
interested in
measuring and adjusting all the other angles you were talking about.
Suppose you need a frame fixture per specific type frame since a
universal frame adjustment
machine seems unrealistic.

Thanks,
Phil Bailey

Never tried changing frame angles by bending, too difficult.

I was suggesting "cold setting" which is bending the various tubes
slightly so that they are properly aligned close to the original frame
geometry.

Chas.

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

Quoted message said:

* * Chas said:

There was a MO house in the '70s BikeBarn > Bikeology in Youngstown,

OH. I

Quoted message said:

Quoted message said:

think they became Nashbar.

For the record, the original name was Bike Warehouse.

Arni Nashbar changed it to Bike Nashbar when the company's lawyer told
him the original name was too generic to defend from copyright
infringement.

- Frank Krygowski

Thanks for the info. I knew it was something like that. Bike Warehouse was
a pretty good place to deal with. I used to anticipate getting their
catalog. Even though we had a pro bike shop, there were lots of things
that we couldn't readily get and a quick call to Bike Warehouse did the
trick.

There was another MO house down in Santa Monica??? that also put out
regular catalogs. They were the ones that flooded the market with
previously hard to get European frames of sometimes questionable quality -
they looked great though.

Palo Alto was another good MO house.

Chas.