Iso / jis
01-16-22, 04:59 PM
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Iso / jis
Hi , I searched Shel's site and didn't find the answer . I would like to use JIS BB cups with a ISO spindle , is this possible , are the bearing the same ? What size are the bearings ? . I'm not going to use JIS cranks .
Thanks , Mark .
Thanks , Mark .
01-16-22, 05:03 PM
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Most tapered square BB (of any taper spec) use 11, loose, 1/4" balls per cup. There are a VERY few BBs that have used other ball sized but most who have them already know about this. Most wrenches consider the axles interchangeable WRT the cups and how the axle and balls run in them. Andy
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01-16-22, 06:41 PM
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In the context of bottom brackets, the ISO/JIS distinction applies only to the spindles, not the cups. As long as the cups' thread matches that of the bottom bracket, and the thickness of the cup allows for an appropriate chainline and sufficient thread engagement for the lockring, you should be able to make it work.
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01-17-22, 10:32 AM
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If you are replacing the BB and possibly the crank too, then why not go to a more modern BB where the issues of spindle length, offsets and differing versions of square taper won't bother you any more.
If this is a true to period restoration, I can see wanting to stay with the period correct stuff.
If this is a true to period restoration, I can see wanting to stay with the period correct stuff.
01-17-22, 11:01 AM
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here is the link to sheldon on the subject https://www.sheldonbrown.com/bbtaper.html
selected quotes from the link
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.
Conversely, if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.Theoretically, ISO cranks should only be used on ISO spindles, and J.I.S. cranks only on J.I.S. spindles.
In practice, you can very often get away with mixing these sizes, as long as you select a spindle length that gives the desired chainline.
These days, however, most folks are using sealed cartridge bearing bottom brackets. With these, there is no routine maintenance required, so typically the crank will be installed once, and will stay in place unless/until the bottom bracket needs to be replaced. This greatly reduces problems of wear to the interface.
I generally avoid mixing sizes on customers' bikes, but I have a lot of experience mixing ISO/J.I.S. in both directions on my own personal bikes, and it has never given me a lick of trouble.
Taper matching was fairly important back in the day of loose-ball cup-and-cone bottom brackets, because these required regular maintenance/overhauls, and this required removal of the cranks. Every time you remove and re-install a square-taper crank, the hole in the crank is liable to get very slightly larger.
This was particularly an issue when using J.I.S. cranks on ISO spindles, because over time, as the crank went on farther and farther, you could run out of taper, and the square end of the spindle would become flush with the surface the crank fixing bolt/washer pushed against. At that point, further tightening of the bolt won't make the crank any tighter, since the bolt is bumping onto the end of the spindle.
selected quotes from the link
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.
Conversely, if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.Theoretically, ISO cranks should only be used on ISO spindles, and J.I.S. cranks only on J.I.S. spindles.
In practice, you can very often get away with mixing these sizes, as long as you select a spindle length that gives the desired chainline.
These days, however, most folks are using sealed cartridge bearing bottom brackets. With these, there is no routine maintenance required, so typically the crank will be installed once, and will stay in place unless/until the bottom bracket needs to be replaced. This greatly reduces problems of wear to the interface.
I generally avoid mixing sizes on customers' bikes, but I have a lot of experience mixing ISO/J.I.S. in both directions on my own personal bikes, and it has never given me a lick of trouble.
Taper matching was fairly important back in the day of loose-ball cup-and-cone bottom brackets, because these required regular maintenance/overhauls, and this required removal of the cranks. Every time you remove and re-install a square-taper crank, the hole in the crank is liable to get very slightly larger.
This was particularly an issue when using J.I.S. cranks on ISO spindles, because over time, as the crank went on farther and farther, you could run out of taper, and the square end of the spindle would become flush with the surface the crank fixing bolt/washer pushed against. At that point, further tightening of the bolt won't make the crank any tighter, since the bolt is bumping onto the end of the spindle.
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(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
01-17-22, 04:19 PM
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If you are replacing the BB and possibly the crank too, then why not go to a more modern BB where the issues of spindle length, offsets and differing versions of square taper won't bother you any more.
If this is a true to period restoration, I can see wanting to stay with the period correct stuff.
If this is a true to period restoration, I can see wanting to stay with the period correct stuff.
Last edited by markwesti; 01-17-22 at 04:28 PM.
01-17-22, 04:23 PM
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here is the link to sheldon on the subject https://www.sheldonbrown.com/bbtaper.html
selected quotes from the link
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.
Conversely, if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.Theoretically, ISO cranks should only be used on ISO spindles, and J.I.S. cranks only on J.I.S. spindles.
In practice, you can very often get away with mixing these sizes, as long as you select a spindle length that gives the desired chainline.
These days, however, most folks are using sealed cartridge bearing bottom brackets. With these, there is no routine maintenance required, so typically the crank will be installed once, and will stay in place unless/until the bottom bracket needs to be replaced. This greatly reduces problems of wear to the interface.
I generally avoid mixing sizes on customers' bikes, but I have a lot of experience mixing ISO/J.I.S. in both directions on my own personal bikes, and it has never given me a lick of trouble.
Taper matching was fairly important back in the day of loose-ball cup-and-cone bottom brackets, because these required regular maintenance/overhauls, and this required removal of the cranks. Every time you remove and re-install a square-taper crank, the hole in the crank is liable to get very slightly larger.
This was particularly an issue when using J.I.S. cranks on ISO spindles, because over time, as the crank went on farther and farther, you could run out of taper, and the square end of the spindle would become flush with the surface the crank fixing bolt/washer pushed against. At that point, further tightening of the bolt won't make the crank any tighter, since the bolt is bumping onto the end of the spindle.
selected quotes from the link
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.
Conversely, if you install a J.I.S. crank on an ISO spindle, it will wind up about 4.5 mm farther in than it would on a J.I.S spindle of the same length.Theoretically, ISO cranks should only be used on ISO spindles, and J.I.S. cranks only on J.I.S. spindles.
In practice, you can very often get away with mixing these sizes, as long as you select a spindle length that gives the desired chainline.
These days, however, most folks are using sealed cartridge bearing bottom brackets. With these, there is no routine maintenance required, so typically the crank will be installed once, and will stay in place unless/until the bottom bracket needs to be replaced. This greatly reduces problems of wear to the interface.
I generally avoid mixing sizes on customers' bikes, but I have a lot of experience mixing ISO/J.I.S. in both directions on my own personal bikes, and it has never given me a lick of trouble.
Taper matching was fairly important back in the day of loose-ball cup-and-cone bottom brackets, because these required regular maintenance/overhauls, and this required removal of the cranks. Every time you remove and re-install a square-taper crank, the hole in the crank is liable to get very slightly larger.
This was particularly an issue when using J.I.S. cranks on ISO spindles, because over time, as the crank went on farther and farther, you could run out of taper, and the square end of the spindle would become flush with the surface the crank fixing bolt/washer pushed against. At that point, further tightening of the bolt won't make the crank any tighter, since the bolt is bumping onto the end of the spindle.
Last edited by markwesti; 01-17-22 at 04:29 PM.
01-17-22, 09:49 PM
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Got it....and I think it has been well answered....spindle taper and ball bearing size have no direct relationship, unless have a really unusual cone and cup BB
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(looking for Torpado Super light frame/fork or for Raleigh International frame fork 58cm)
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