Bottom bracket identification help

Lucky Luke

The BB on the wife's winter bike needs replacing . Have just taken it out to discover iits not a Shimano as I first thought (as I needed a Shimano BB remover to take it out ) but it's a Power Pro components BB 7420 . Is this a Shimano copy ? If so what's the Shimano equivalent ? Originally it was on a Specialized Dolce with a Specialized chainset if that's any help .

leonlikestrees

Is it a square taper BB? If so, you just need to get a replacement with the same length axle. You can measure it nicely with a vernier, or clumsily with a ruler.

If it's splined, then it'll be ISIS, as as far as I am aware Shimano only ever licensed the octalink splines to crank manufacturers,so you have to buy a shiman oBB. Again, measure the length of axle and that should be enough.

The BB shell width will almost certainly be 68mm, but you could measure that too just to check, and thread will be English thread (pretty much the standard)

Lucky Luke

Yes it's a square taper (well like the Campag ones on our other bikes) .

As you suggested have (clumsily with a ruler) measured the axle length seems to be 111mm which I seem to remember is the length of the lower spec Campag BBs for a double chainset . Am thinking I could just buy a Campag 111mm BB then ? The Specialized chainset is a triple though but I suppose if the axle length is the same it shouldn't matter ?

Thanks

Lucky Luke

It is indeed English thread ( have just taken it out of a Ribble winter frame)

The Mechanic

Powerpro BBs are made by FSA. You can still get them. However, any shimano sqare taper or the correct length will do. You can also use Stronglight as well.

Lucky Luke

So the size of the squares is universal then ?

The Mechanic

Not quite. Shimano, sometimes called JIS is different from Campag, sometimes called ISO. You can mix them but it is not advisable as the cranks go too far/not far enough on the taper.

Lucky Luke

Right , cheers . Have just been down to Ribble with said BB . They confirm what you say and I have now bought a Shimano UN54 to replace . Thanks again .