Can I replace an ISO square tapered spindle with JIS?

[its_all_calypso]

Hi all,

I have what I'm fairly certain is an ISO spindle in a French BB, I'm just wondering if it's possible to swap to a shorter JIS spindle? The bb didn't come with cranks and most that I am looking at require a JIS spindle.

Thanks in advance!

 

[Chris S]

Yes, see Sheldon Brown.

 

[andrew_s]

Should you try putting JIS cranks on your existing (probably) ISO spindle, what you have to watch out for is the crank bolt bottoming out on the end of the spindle before the taper is properly tight. Put it on tight, then remove the crank bolt and check there's still a gap between the spindle end and the washer flats in the crank.

Freshtripe will sell you a modern Velo Orange French threaded cartridge BB with a JIS taper for around £40
https://freshtripe.co.uk/velo-orange-grand-cru-french-threaded-bottom-bracket/

 

[FrankCrank]

Another possibility is to use a threadless BB. Kill two birds with one stone

 

[its_all_calypso]

Another possibility is to use a threadless BB. Kill two birds with one stone

I had considered it but I'm trying to spend as little as possible since the bike will be a beater, I have a bb already and it threads on fine, was just looking to get a shorter axle for a single speed/track crank (it's a track frame). If I end up enjoying the bike then I'll definitely look into this in the future though!

 

[its_all_calypso]

Should you try putting JIS cranks on your existing (probably) ISO spindle, what you have to watch out for is the crank bolt bottoming out on the end of the spindle before the taper is properly tight. Put it on tight, then remove the crank bolt and check there's still a gap between the spindle end and the washer flats in the crank.

Freshtripe will sell you a modern Velo Orange French threaded cartridge BB with a JIS taper for around £40
https://freshtripe.co.uk/velo-orange-grand-cru-french-threaded-bottom-bracket/

Yeah I was worried about this, hence the reason I'm looking for a JIS spindle. Thanks for the heads up!

 

[rogerzilla]

9mm shorter for JIS, assuming a symmetrical BB. The JIS taper is basically an ISO taper with some of the end cut off.