Chainline and pedal alignment for old Cannondale

https://www.google.com/#q=Cannondale...bottom+bracket

User Bp wrote:
My old Cannondale AA series bike needed a new drivetrain (rings,
cogs, chain and maybe derailers). There's nothing discernibly
wrong with the frame and other components, so it's worth fixing.

For the moment, I've installed some cheap rings, chain and cogs
supplied by an LBS, but the quality of the parts and the way they
fit make me yearn for parts that fit together somewhat better.

The most obvious sticking point is the bottom bracket: The new
chainrings/crank had the wrong offset until I turned the crank
spindle over and shimmed the fixed cup. Now it all works, but
the pedals are shifted a good half inch to the left and there's
only about one thread engaged on the lock ring..

The bottom bracket is British thread, anything that fits would
be of interest.

How do folks get chainlines and pedals to line up? A couple
millimeters in the seat make a noticeable difference, so I
suspect I'll care about getting the pedals correct left to right.
If it's unlikely to be true a warning would be appreciated.

Thanks for reading,

bob prohaska

I'm guessing that you will be wanting a new crankset with a new modern
cartridge bottom bracket and that you want to stick with a square taper
spindle. If you choose a Shimano crankset, Shimano tell you what length
bottom bracket you want in the instruction sheet that comes with the
crankset. The instruction sheets are online at
http://techdocs.shimano.com/techdocs/index.jsp

Say you choose the quite decent and fairly inexpensive square taper Shimana
Tiagra grade crankset, FC 4400 double or FC 4403 triple.
Dig down a bit in Shimano Techdocs and you find a .pdf of the FC 44xx
instructions.
http://techdocs.shimano.com/media/te...9830612377.pdf
Right there on the left hand side is a table that tells you that the double
wants a 110mm spindle length and the triple wants a 113mm spindle length.
Chainline for the double is 43.5mm from centreline of seat-tube to midway
between the two rings. Chainline for the triple is 45mm to the middle ring.

You could always plunge headlong into the 21st century and choose a two
piece crankset like the Shimano FC 4503. It is compatible with your British
threaded bottom bracket shell. The adaptor cups carrying the outboard
bearings screw straight in and the chainline is automatically correct for
either the common 68mm shell width or the rarer 73mm shell width. They
supply spacers to suit either width.
http://techdocs.shimano.com/media/te...9830614887.pdf

These are just examples of where to find Shimano bottom bracket information
.. You can go cheaper and dearer than Tiagra grade if you are buying
Shimano..

You could go for a very pretty Sugino brand crankset, available as
singleseed, triple or double and great value for money.
Here's the Sugino RD2 crankset page.
http://www.suginoltd.co.jp/english/p...er_english.htm
Sugino also tell you the bottom bracket width you want, in this case exactly
the same lengths as many Shimano doubles and triples.

So, in general I rely on the manufacturers published information to get the
right bottom bracket for the correct chainline.
If I'm building a derailleur equipped multispeed bike I invariably use
either Shimano or SRAM rear cassettes and aim for Shimano's recommended
chainline for triple or double cranksets. If I have some antique crankset I
want to use I take a guess as to which of my collection of different length
BB cartridges I will try. I measure the chainline when it's all assembled.
If it's way off I guessed wrong. If the chainline is fractionally too small
by a millimeter or two I can always shim the right hand end of the cartridge
with shims readily available in various thicknesses as small as half a
millimeter. If it is too large I will try the next bottom bracket length
down and shim if absolutely necessary.
PH

On Tuesday, November 26, 2013 8:37:08 AM UTC-5, Peter Howard wrote:
User Bp wrote:

My old Cannondale AA series bike needed a new drivetrain (rings,

cogs, chain and maybe derailers). There's nothing discernibly

wrong with the frame and other components, so it's worth fixing.



For the moment, I've installed some cheap rings, chain and cogs

supplied by an LBS, but the quality of the parts and the way they

fit make me yearn for parts that fit together somewhat better.



The most obvious sticking point is the bottom bracket: The new

chainrings/crank had the wrong offset until I turned the crank

spindle over and shimmed the fixed cup. Now it all works, but

the pedals are shifted a good half inch to the left and there's

only about one thread engaged on the lock ring..



The bottom bracket is British thread, anything that fits would

be of interest.



How do folks get chainlines and pedals to line up? A couple

millimeters in the seat make a noticeable difference, so I

suspect I'll care about getting the pedals correct left to right.

If it's unlikely to be true a warning would be appreciated.



Thanks for reading,



bob prohaska



I'm guessing that you will be wanting a new crankset with a new modern

cartridge bottom bracket and that you want to stick with a square taper

spindle. If you choose a Shimano crankset, Shimano tell you what length

bottom bracket you want in the instruction sheet that comes with the

crankset. The instruction sheets are online at

http://techdocs.shimano.com/techdocs/index.jsp



Say you choose the quite decent and fairly inexpensive square taper Shimana

Tiagra grade crankset, FC 4400 double or FC 4403 triple.

Dig down a bit in Shimano Techdocs and you find a .pdf of the FC 44xx

instructions.

http://techdocs.shimano.com/media/te...9830612377.pdf

Right there on the left hand side is a table that tells you that the double

wants a 110mm spindle length and the triple wants a 113mm spindle length.

Chainline for the double is 43.5mm from centreline of seat-tube to midway

between the two rings. Chainline for the triple is 45mm to the middle ring.



You could always plunge headlong into the 21st century and choose a two

piece crankset like the Shimano FC 4503. It is compatible with your British

threaded bottom bracket shell. The adaptor cups carrying the outboard

bearings screw straight in and the chainline is automatically correct for

either the common 68mm shell width or the rarer 73mm shell width. They

supply spacers to suit either width.

http://techdocs.shimano.com/media/te...9830614887.pdf



These are just examples of where to find Shimano bottom bracket information

. You can go cheaper and dearer than Tiagra grade if you are buying

Shimano..



You could go for a very pretty Sugino brand crankset, available as

singleseed, triple or double and great value for money.

Here's the Sugino RD2 crankset page.

http://www.suginoltd.co.jp/english/p...er_english.htm

Sugino also tell you the bottom bracket width you want, in this case exactly

the same lengths as many Shimano doubles and triples.



So, in general I rely on the manufacturers published information to get the

right bottom bracket for the correct chainline.

If I'm building a derailleur equipped multispeed bike I invariably use

either Shimano or SRAM rear cassettes and aim for Shimano's recommended

chainline for triple or double cranksets. If I have some antique crankset I

want to use I take a guess as to which of my collection of different length

BB cartridges I will try. I measure the chainline when it's all assembled..

If it's way off I guessed wrong. If the chainline is fractionally too small

by a millimeter or two I can always shim the right hand end of the cartridge

with shims readily available in various thicknesses as small as half a

millimeter. If it is too large I will try the next bottom bracket length

down and shim if absolutely necessary.

PH

uuuuuuuuuuuuuuuuuuuuuu


yeah basically Shim takes the pain out and deafinitly in their best interests butbutbut just tobe sure measure. Getting onto the measure mode is excellent practice, using the new and correct equippe, for when you believe the device is out of whack in alignment...usually at the deray hanger n cage...pipe wrench with vise grips

look for THE STRING...another Images search....BICYCLE CHAINLINE ALIGNMENT STRING....

https://www.google.com/search?site=i...58.hKzTRX4nqMU

On Tuesday, November 26, 2013 8:46:11 AM UTC-5, wrote:
On Tuesday, November 26, 2013 8:37:08 AM UTC-5, Peter Howard wrote:

User Bp wrote:



My old Cannondale AA series bike needed a new drivetrain (rings,



cogs, chain and maybe derailers). There's nothing discernibly



wrong with the frame and other components, so it's worth fixing.







For the moment, I've installed some cheap rings, chain and cogs



supplied by an LBS, but the quality of the parts and the way they



fit make me yearn for parts that fit together somewhat better.







The most obvious sticking point is the bottom bracket: The new



chainrings/crank had the wrong offset until I turned the crank



spindle over and shimmed the fixed cup. Now it all works, but



the pedals are shifted a good half inch to the left and there's



only about one thread engaged on the lock ring..







The bottom bracket is British thread, anything that fits would



be of interest.







How do folks get chainlines and pedals to line up? A couple



millimeters in the seat make a noticeable difference, so I



suspect I'll care about getting the pedals correct left to right.



If it's unlikely to be true a warning would be appreciated.







Thanks for reading,







bob prohaska







I'm guessing that you will be wanting a new crankset with a new modern



cartridge bottom bracket and that you want to stick with a square taper



spindle. If you choose a Shimano crankset, Shimano tell you what length



bottom bracket you want in the instruction sheet that comes with the



crankset. The instruction sheets are online at



http://techdocs.shimano.com/techdocs/index.jsp







Say you choose the quite decent and fairly inexpensive square taper Shimana



Tiagra grade crankset, FC 4400 double or FC 4403 triple.



Dig down a bit in Shimano Techdocs and you find a .pdf of the FC 44xx



instructions.



http://techdocs.shimano.com/media/te...9830612377.pdf



Right there on the left hand side is a table that tells you that the double



wants a 110mm spindle length and the triple wants a 113mm spindle length.



Chainline for the double is 43.5mm from centreline of seat-tube to midway



between the two rings. Chainline for the triple is 45mm to the middle ring.







You could always plunge headlong into the 21st century and choose a two



piece crankset like the Shimano FC 4503. It is compatible with your British



threaded bottom bracket shell. The adaptor cups carrying the outboard



bearings screw straight in and the chainline is automatically correct for



either the common 68mm shell width or the rarer 73mm shell width. They



supply spacers to suit either width.



http://techdocs.shimano.com/media/te...9830614887.pdf







These are just examples of where to find Shimano bottom bracket information



. You can go cheaper and dearer than Tiagra grade if you are buying



Shimano..







You could go for a very pretty Sugino brand crankset, available as



singleseed, triple or double and great value for money.



Here's the Sugino RD2 crankset page.



http://www.suginoltd.co.jp/english/p...er_english.htm



Sugino also tell you the bottom bracket width you want, in this case exactly



the same lengths as many Shimano doubles and triples.







So, in general I rely on the manufacturers published information to get the



right bottom bracket for the correct chainline.



If I'm building a derailleur equipped multispeed bike I invariably use



either Shimano or SRAM rear cassettes and aim for Shimano's recommended



chainline for triple or double cranksets. If I have some antique crankset I



want to use I take a guess as to which of my collection of different length



BB cartridges I will try. I measure the chainline when it's all assembled.



If it's way off I guessed wrong. If the chainline is fractionally too small



by a millimeter or two I can always shim the right hand end of the cartridge



with shims readily available in various thicknesses as small as half a



millimeter. If it is too large I will try the next bottom bracket length



down and shim if absolutely necessary.



PH



uuuuuuuuuuuuuuuuuuuuuu





yeah basically Shim takes the pain out and deafinitly in their best interests butbutbut just tobe sure measure. Getting onto the measure mode is excellent practice, using the new and correct equippe, for when you believe the device is out of whack in alignment...usually at the deray hanger n cage....pipe wrench with vise grips



look for THE STRING...another Images search....BICYCLE CHAINLINE ALIGNMENT STRING....



https://www.google.com/search?site=i...58.hKzTRX4nqMU

======================

here's a SHELDON BROWN halfway down the page

http://sheldonbrown.com/images/check-BB_IMG_5381.JPG

On 11/25/2013 9:58 PM, User Bp wrote:
Andre Jute wrote:
Bob: What you need is a bottom bracket with an axle long enough to give you the correct chain line. The correct chain line is determined by the width of the hub/cluster on the back wheel. The correct axle width in the bottom bracket to give you that chain line is determined by the design of the crank. So you have to obtain two numbers. What is the best chain line for the cluster, and what is the chain line with some nominal bottom bracket axle length on your particular cranks, a number which you can then use to calculate (apply here again, because it isn't obvious how you do it) the required bottom bracket axle length. -- Andre Jute

What are the standard reference surfaces on the crank and spindle?
One can measure things like the face of the fixed cup, the end of
the spindle and the edge or centerline of the chainrings. It's hard
to estimate how far the spindle will enter the crank. If there's a
rule of thumb that says the inner face of the crank boss is always
"X" millimeters from the end of the crank spindle that would be a
huge help. Better yet if there's a "Y" from bottom bracket to inner
chainring. I've not seen anything of the kind published.

Thanks for reading,

bob prohaska

On Monday, November 25, 2013 3:17:43 AM UTC, User Bp wrote:
My old Cannondale AA series bike needed a new drivetrain (rings,

cogs, chain and maybe derailers). There's nothing discernibly

wrong with the frame and other components, so it's worth fixing.



For the moment, I've installed some cheap rings, chain and cogs

supplied by an LBS, but the quality of the parts and the way they

fit make me yearn for parts that fit together somewhat better.



The most obvious sticking point is the bottom bracket: The new

chainrings/crank had the wrong offset until I turned the crank

spindle over and shimmed the fixed cup. Now it all works, but

the pedals are shifted a good half inch to the left and there's

only about one thread engaged on the lock ring..



The bottom bracket is British thread, anything that fits would

be of interest.



How do folks get chainlines and pedals to line up? A couple

millimeters in the seat make a noticeable difference, so I

suspect I'll care about getting the pedals correct left to right.

If it's unlikely to be true a warning would be appreciated.



Thanks for reading,



bob prohaska

Well, sorta.
Crank designers have a great latitude in design and the
placement of the chainrings in relation to the spindle is
highly variable. Your SR Apex shipped with a 3-S (122mm
asymmetric) spindle. That crank (typical of its era) has a
flat outside face from pedal to spindle. Modern cranks use a
curved outside face with something like 102mm symmetric
spindle to get the rings in the same place.

Short answer = Buy the matching spindle or crank bearing
unit for the crank you intend to use.

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

Peter Howard wrote:
http://techdocs.shimano.com/media/te...9830612377.pdf
Right there on the left hand side is a table that tells you that the double
wants a 110mm spindle length and the triple wants a 113mm spindle length.
Chainline for the double is 43.5mm from centreline of seat-tube to midway
between the two rings. Chainline for the triple is 45mm to the middle ring.

Ok, makes sense, but the issue for the old Cannondale is clearing the
fat(ish) chainstays. Getting the rings centered on the middle cog is
nice, but it won't help if the frame gets in the way 8-)

The tubes on the old AA are only a little larger than is commonplace.
Truly fat-tubed frames (old Kleins come to mind) present a much more
obvious problem. How did folks solve it?

Thanks for reading,

bob prohaska

AMuzi wrote:

Well, sorta.
Crank designers have a great latitude in design and the
placement of the chainrings in relation to the spindle is
highly variable. Your SR Apex shipped with a 3-S (122mm
asymmetric) spindle. That crank (typical of its era) has a
flat outside face from pedal to spindle. Modern cranks use a
curved outside face with something like 102mm symmetric
spindle to get the rings in the same place.

Where is the 122 mm measured from? How is it related to fixed
cup position? Inner chainring position?

Short answer = Buy the matching spindle or crank bearing
unit for the crank you intend to use.

The only easy things to measure are bottom bracket width, chainstay
width at various distances and freewheel offset from centerline. It
looks like the chainstay width is my problem right now. If the inner
ring scuffs it's trouble. Having the rings too far from the
frame puts them out of front derailer range.

Thanks for reading,

bob prohaska

On Wednesday, November 27, 2013 5:08:43 AM UTC, User Bp wrote:
Peter Howard wrote:

http://techdocs.shimano.com/media/te...9830612377.pdf

Right there on the left hand side is a table that tells you that the double

wants a 110mm spindle length and the triple wants a 113mm spindle length.

Chainline for the double is 43.5mm from centreline of seat-tube to midway

between the two rings. Chainline for the triple is 45mm to the middle ring.



Ok, makes sense, but the issue for the old Cannondale is clearing the

fat(ish) chainstays. Getting the rings centered on the middle cog is

nice, but it won't help if the frame gets in the way 8-)



The tubes on the old AA are only a little larger than is commonplace.

Truly fat-tubed frames (old Kleins come to mind) present a much more

obvious problem. How did folks solve it?



Thanks for reading,



bob prohaska

Bob, you're pushing yourself deeper and deeper into the quicksand. These guys are used to fitting bottom brackets to bikes that use standard components, either 110 or 113mm. If the bike isn't standard, the rule of thumb doesn't run. Here, again, is the decision tree which delivers the correct answer..

1. Decide on the hub and rear cluster. They determine the chain line required. This :chain line" is a distance from the centre of the bike, usually from the centre of the seat tube. This is a fixed number, recommended by the maker of the components. Everything else proceeds from it. You don't know what it is until you decide on your hub and cluster.

2. At the chainring end you next decide whether you will fit one, two or three chainrings. If one chainring, you want the chain line to run down the centre of the chainring, if two precisely between the two chainrings, if three precisely through the centre of the centre chainring. Once more, the chain line is a distance from the centre of the seat tube.

3. Achieving the desired chain line is arranged by choosing the axle length of your bottom bracket correctly.

4. The width of the bottom bracket shell is irrelevant, as long as you get the correct width for your bike, usually 68mm: measure the shell when the bottom bracket is out. This measurement has nothing to do with the chain line.

5. Not all cranks have the same outward angle from their attachment to the bottom bracket axle towards the pedal attachment. You should choose cranks angled to clear your chain stays.

6. Not all cranks attach the chainrings the same distance from their mounting on the bottom bracket axle. This affects your chain line. Manufacturers of cranks thus tell you something like, "With a 110mm bottom bracket axle, the chain line will be 43.5mm," which just happens to suit the bikes of a whole lot of roadies who don't need to calculate because like lemmings they all fitted the same standard components (just as well, as some of the specimens on RBT are too thick to calculate).

7. If your bike doesn't fit these near-standard parameters, you nonetheless already have all the information required to calculate what length of bottom bracket axle will give you the desired chain line.

8. Here's a worked example. These are the givens: The manufacturer of your cluster tells you the chain line on your hub should be, say, 54mm. You choose a crank that is cranked (sorry!) enough to clear your chain stays, and the manufacturer says that with 113mm axle in the bottom bracket the chain line will be 51mm.

9. From there you can calculate that, to get a 54mm chain line with that crankset, you need a bottom bracket axle of 113+(2*(54-51))=119. You add twice the difference because the bottom bracket is measured across its whole length while the chain line is measured across half of the bike's width. This presumes that you will fit the bottom bracket symmetrically.

10. Once you have all the parts torqued up, you can measure to confirm that you have done the job right. You measure in two stages. First, put calipers on the seat tube, Divide its diameter in two. Measure from the side of the seat tube to the chain line and add half the seat tube diameter. If you're measuring to empty air between two chainrings, measure to a hard point and then add or subtract half the measured space between two hard points, as you did for the seat tube.

11. If necessary you can shim the bottom bracket to bring the chain line to within half a mil or a millimeter of perfection, whatever your taste in precision is.

12. This is very simple once you grasp how the thighbone is connected to the shinbone via the knee, and give up trying to do it by street corner whispers. (Notice in the link I gave you that quite a few very experienced cyclists and bike constructors made a proper meal of calculating the bottom bracket axle for my new cranks, and that for a while I was as confused as you are, until I sat down and calmly thought it through from the one hard number I had, the maker of my hub and sprocket's very definite demand for a chain line to within one mm of a stated number. After that it was a breeze.)

Many cyclists with big junk boxes find the prospect of calculating so bothersome that they just fit one bottom bracket after another until they find one that gives an approximately right chain line...

Andre Jute

On Wed, 27 Nov 2013 05:24:09 +0000 (UTC), User Bp
wrote:

AMuzi wrote:

Well, sorta.
Crank designers have a great latitude in design and the
placement of the chainrings in relation to the spindle is
highly variable. Your SR Apex shipped with a 3-S (122mm
asymmetric) spindle. That crank (typical of its era) has a
flat outside face from pedal to spindle. Modern cranks use a
curved outside face with something like 102mm symmetric
spindle to get the rings in the same place.

Where is the 122 mm measured from? How is it related to fixed
cup position? Inner chainring position?

Short answer = Buy the matching spindle or crank bearing
unit for the crank you intend to use.

The only easy things to measure are bottom bracket width, chainstay
width at various distances and freewheel offset from centerline. It
looks like the chainstay width is my problem right now. If the inner
ring scuffs it's trouble. Having the rings too far from the
frame puts them out of front derailer range.

Thanks for reading,

bob prohaska

It really isn't as complicated as it seems. Firstly, the chain line is
only perfectly straight in one gear, any shifting and things are out
of line. If you have, for example, a 3 chain ring front set and you
very accurately align things so the middle chain ring is perfectly
aligned with the 5th cog, assuming a 9 speed cassette and you than
shift either the front or rear derailer and immediately your chain
line is crooked.

So, at best, a chain line is an approximate thing, or perhaps "the
best we can do" :-)

As for chain stays, often times the right side chain stay is flattened
a bit where the chain wheel is (I'm not recommending that you whack it
with a hammer ).

If you are using the same R.H. crank and sprockets than you can
probably measure the length of your existing bottom bracket axle and
buy the same length to replace it, or if you know that the chain line
is, say one cog crooked, you can add or subtract to come up with the
correct length. The center to center spacing of a 9 speed cassette is
4.55mm for Shimano or SRAM - the Italians are different :-)

As for how important a perfect chain line is, well, I installed a
Shimano outboard bearing bottom bracket on an old road bike and read
the instructions wrong and put the shims under the wrong side. Rode
the bike for about 6 months glorying in my slick 27 speed bike until
one day I was cleaning the bike and the chain happened to be on the
center chain wheel and the middle cassette cog.... and it was out of
line. As far as I can tell there was no undue chain wear, it shifted
as slick as can be, and the hills seemed to be about as high as they
ever had been. :-)
--
Cheers,

John B.

right. bring a string forward to a fixed - not bike -cleat ahead of the front wheel.

adjust string parallel as the future chainline or perpendicular to the future BB

by sighting the string flush, touching ( a tight nylon cord is best, no hairy strings Dude) the flat face of rear cog....get down behind the cog n sight thru.

fix the front string buttend to cleat ( moveable) move cleat to flush.

then measure that crankside.

like in the photo....

I gotta go....mention the 122 prob....there's a solution formula prob in Sheldon Brown Harris under crank measurement.

this works as I picked a crank out of a list and verified using the method with an unknown brand frame