Why is my chainline off?
#26
car dodger
Thread Starter
yes and yes, but neither would affect the front chainline measurement.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#28
car dodger
Thread Starter
Drive side:
Non drive side:
both spindle ends are the same depth from the crank face, 12mm
Non drive side:
both spindle ends are the same depth from the crank face, 12mm
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#30
looking at the drive side spindle taper, how far inside the hole is the end of the spindle, from being flush with the crank face on the drive side? You need to remove the plastic cover and crank bolt in order to check.
#31
car dodger
Thread Starter
12mm, same as the other side.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#32
Senior Member
It's not clear exactly how you're measuring chainline. In the last picture in your post (the one with the metal ruler), the ruler is clearly not at the centerline of the tube. Chainline on a 2x crank is measured from the center of the seat tube (where the point of the lug is) to the midpoint between the two chainrings. It can be tricky to measure accurately, but I use the same type of metal ruler. If you have digital calipers those work too. There are diagrams and other useful information here: All About Bicycle Chainline
Can you confirm how you measured it?
Can you confirm how you measured it?
#33
car dodger
Thread Starter
I took the photo that way to show how far off from center the chainline is. It was hard for me to get a clear photo of the steel ruler in the gap between the two rings. I also measured the chainline from the edge of the seat tube to the center of each ring and worked out the same result as the direct measurement.
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#34
I'm talking about the outer end of the spindle, the one inside the crank. The top red line is the face of the crank arm, the bottom red line is the end of the spindle. If the spindle doesn't stop where it's supposed to, your measurement will be off by a few mm. This is an asymmetric spindle, it's not necessarily supposed to look symmetric once fitted.
#35
Passista
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Looks like both cranks should be a bit more inward, like 3mm (to my eye). That should give a chainline of about 45mm, not too far off. Maybe the crank/spindle tapers are not matched?
#36
car dodger
Thread Starter
I'm talking about the outer end of the spindle, the one inside the crank. The top red line is the face of the crank arm, the bottom red line is the end of the spindle. If the spindle doesn't stop where it's supposed to, your measurement will be off by a few mm. This is an asymmetric spindle, it's not necessarily supposed to look symmetric once fitted.
about 4.5mm on the drive side.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#37
car dodger
Thread Starter
well the reason I sourced a dura ace 7400 bottom bracket for the 7402 crank was to insure a matched fit.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#38
car dodger
Thread Starter
your photo shows that more clearly than I was able to view, but from what I could tell my crank lined up about 1 cog too far outboard. Tomorrow I will check wheel dish and frame alignment but I'm sure I checked all that a few years ago.
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#40
#41
car dodger
Thread Starter
ah dang I don't think I can measure taper!
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#43
The Wheezing Geezer
Join Date: Oct 2021
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iirc, a Phil Wood can be installed in a 5mm range, up to 2.5mm off-center. When I put my triplizer in, I had about 2mm of clearance from the new chainring to my (un-indented) chainstay, and that has been sufficient in my application - no need to adjust my Phil Wood off from center.
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Beneath the valley of the underbikers.
Beneath the valley of the underbikers.
#44
car dodger
Thread Starter
" If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length."
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
Likes For norskagent:
#45
Junior Member
For what it's worth, I have just measured my Moser with the BB-7400 and FC-7402 combo and got 10mm on the drive side and 9mm on the non drive, crank to chainstay.
Measuring from the back of the crank arm to the 28.6mm seat tube, 44.5mm drive, 43.5mm non drive. Have a measure of those on yours and see how they compare.
The amount of square taper visible on each side in the pictures above looks correct, when compared to what I have here.
The chainline I have measured just now is 45.3mm
For those doubting the spindle, 113mm with 1mm offset, longer on the drive side, is correct.
Measuring from the back of the crank arm to the 28.6mm seat tube, 44.5mm drive, 43.5mm non drive. Have a measure of those on yours and see how they compare.
The amount of square taper visible on each side in the pictures above looks correct, when compared to what I have here.
The chainline I have measured just now is 45.3mm
For those doubting the spindle, 113mm with 1mm offset, longer on the drive side, is correct.
Last edited by Seanaus; 10-23-23 at 06:47 AM.
#46
car dodger
Thread Starter
For what it's worth, I have just measured my Moser with the BB-7400 and FC-7402 combo and got 10mm on the drive side and 9mm on the non drive, crank to chainstay.
Measuring from the back of the crank arm to the 28.6mm seat tube, 44.5mm drive, 43.5mm non drive. Have a measure of those on yours and see how they compare.
The amount of square taper visible on each side
Measuring from the back of the crank arm to the 28.6mm seat tube, 44.5mm drive, 43.5mm non drive. Have a measure of those on yours and see how they compare.
The amount of square taper visible on each side
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
#47
Senior Member
Try adding a 2.5mm anti-matter spacer under the drive-side cup. I think Problem Solvers has them.
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"Progress might have been all right once, but it has gone on too long."
--Ogden Nash
#48
okay then here is a theory - since "low profile JIS" is similar to ISO (or so I have read), and my crank is (I guess) low profile JIS, my spindle may be "regular" JIS, which would situate the crank further outboard, according to St. Sheldon:
" If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length."
" If you install an ISO crank on a J.I.S. spindle, it will sit about 4.5 mm farther out than it would on an ISO spindle of the same length."
This is part of a chart that I copied a while back. It is still floating around web. Don't know the original source so can't confirm if it is 100% accurate, so FWIW.
Don't know if there's a better source to get the Q info for your crank.
#49
seņor miembro
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#50
car dodger
Thread Starter
__________________
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"
1989 Schwinn Paramount OS
1980 Mclean/Silk Hope Sport Touring
1983 Bianchi pista
1976 Fuji Feather track
1979 raleigh track
"I've consulted my sources and I'm pretty sure your derailleur does not exist"