Bottom Bracket - Cup & Cone to Sealed

[HovR]

So I'm upgrading a knackered cup & cone BB to a sealed square taper unit. The spindle length of the old unit is 118mm, and the shell width is 68mm.

Am I right in thinking it will just be a straight swap for a sealed unit with the same measurements, like this one?

Thanks in advance.

 

[PpPete]

Just check that the old spindle is symetrical. Sometimes one side is longer outside the "cone" than the other.
I think Sheldon has the conversion if that is the case.

 

[fossyant]

Straight swap with same measurements. You will be glad to get rid of cup and cone

 

[HovR]

Just check that the old spindle is symetrical. Sometimes one side is longer outside the "cone" than the other.
I think Sheldon has the conversion if that is the case.

Thanks, I thought there might be something like this but wasn't quite sure!

Just remeasured my spindle, one side is 32mm, whilst the other side is 35mm, and the overall length is 119mm (was slightly off on the initial measurement).

I Googled for the sheldon conversion which suggests I should be using a 122mm spindle length for a modern symetrical BB (does this sound right?) in which case I'll be ordering this BB.

The chainset is J.I.S standard, which I assume the BB will be with it being Shimano. Is that correct?

Thanks again!

 

[andrew_s]

Yes, Shimano BBs are all JIS.
BB length isn't all that critical, so long as the inner ring doesn't hit the chainstay and the front mech can still reach far enough to shift onto the big ring. Have a look where your existing BB puts the chainrings so you've an idea of the margin of error. I often run a slightly short BB because I do most of my riding on the large chainring.