Can't find 42mm chainline crankset in UK
08-22-19, 03:13 AM
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Can't find 42mm chainline crankset in UK
Hi
I have an old English frame with 120mm rear dropouts (widened from 110mm)
The distance from the rear sprocket to the right-hand dropout 18mm, so I have a chainline of 42mm.
I have a bottom bracket 68mm x 103mm JIS.
Problem is I cannot find a low-cost 42mm chainline crankset in the UK. The only thing I can find is an Origin8 crankset from the USA.
Any ideas?
I have an old English frame with 120mm rear dropouts (widened from 110mm)
The distance from the rear sprocket to the right-hand dropout 18mm, so I have a chainline of 42mm.
I have a bottom bracket 68mm x 103mm JIS.
Problem is I cannot find a low-cost 42mm chainline crankset in the UK. The only thing I can find is an Origin8 crankset from the USA.
Any ideas?
Last edited by howieleem; 08-22-19 at 03:24 AM. Reason: mistake
08-22-19, 09:13 AM
#2
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Get a bottom bracket with an appropriate length spindle to match your chainline with whatever square taper crankset and/or shim out the chainring with spacers. Done.
08-22-19, 09:32 AM
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Make your chainline 51 mm with spacers at the rear
You mean, shim out the cogs in the back though, don't you. Here's why:
With the current setup, simple math says that a 42 mm chainline is only 8 mm wider than your BB shell, and the small spindle (Dura-Ace?) you're using is overshooting the chainline by 9mm. You can't change the crankset or chainrings, they have to sit against the taper firmly. Therefore, move your cassette or freewheel or single cog right 9 mm, since you have 18mm there.
Last edited by Unca_Sam; 08-22-19 at 09:47 AM.
08-22-19, 09:37 AM
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In UK search for Chainset instead of Crankset.
They don't sell them by the chainline.... that's up to you, the installer.
They don't sell them by the chainline.... that's up to you, the installer.
08-22-19, 09:57 AM
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Blast from the past
https://www.bikeforums.net/singlespe...-crankset.html
This thread from a decade ago seems to have dealt with similar issues. Please confirm if you're using a SS or Fixed setup.
https://www.bikeforums.net/singlespe...t-s-point.html
An older one proposes additional solutions. I agree with trying to respace the cog. I realize that your front chainline is likely less than 51.5mm, but you'd have to provide that info.
This thread from a decade ago seems to have dealt with similar issues. Please confirm if you're using a SS or Fixed setup.
https://www.bikeforums.net/singlespe...t-s-point.html
An older one proposes additional solutions. I agree with trying to respace the cog. I realize that your front chainline is likely less than 51.5mm, but you'd have to provide that info.
Last edited by Unca_Sam; 08-22-19 at 10:02 AM.
08-22-19, 10:20 AM
#6
Senior Member
My first thought was "How do you shim a square taper BB?" Then, "Can you shim a square taper BB??"
You mean, shim out the cogs in the back though, don't you. Here's why:
With the current setup, simple math says that a 42 mm chainline is only 8 mm wider than your BB shell, and the small spindle (Dura-Ace?) you're using is overshooting the chainline by 9mm. You can't change the crankset or chainrings, they have to sit against the taper firmly. Therefore, move your cassette or freewheel or single cog right 9 mm, since you have 18mm there.
You mean, shim out the cogs in the back though, don't you. Here's why:
With the current setup, simple math says that a 42 mm chainline is only 8 mm wider than your BB shell, and the small spindle (Dura-Ace?) you're using is overshooting the chainline by 9mm. You can't change the crankset or chainrings, they have to sit against the taper firmly. Therefore, move your cassette or freewheel or single cog right 9 mm, since you have 18mm there.
