Does it really matter if your bottom bracket doesn't fit?

[Andrew_Culture]

I'm transferring everything onto a new frame and I can't get my BB in any further than you can see below. It's in firmly enough, and it's Dura Ace (much to my surprise!) so I'm quite keen not to have to buy another bottom bracket.

 

[Mr Haematocrit]

Looks like a water trap to me.
I would not think that BB would last long fitted like that. I would also want to know why its no it fitting. This suggest a further issue.

 

[Andrew_Culture]

Looks like a water trap to me.
I would not think that BB would last long fitted like that. I would also want to know why its no it fitting. This suggest a further issue.

It looks like it's too wide for the frame. The frame is a Bianchi Nirone and I've had to buy a few bits (shims and whatnot) to accommodate the diameters of various bits of the frame.

 

[RecordAceFromNew]

it's Dura Ace (much to my surprise!) so I'm quite keen not to have to buy another bottom bracket.

It might have been for 73mm bb shell, unless the frame's thread is crudded up. You can introduce spacers. Some DA bb's like that have very specific (and uncommon) chainset compatibility - do you have a chainset that matches and gives you a suitable chainline?

 

[ufkacbln]

Having the bottom bracket out of alignment can affect shifting and make it difficult to set up

 

[ayceejay]

Its not an Italian/BSA thing is it?
Are you screwing it in in the right direction?
I think you will damage the frame unless it goes all the way in.

 

[Andrew_Culture]

Its not an Italian/BSA thing is it?
Are you screwing it in in the right direction?
I think you will damage the frame unless it goes all the way in.

Yeah, after much screwing it the wrong way I figured it out

 

[dan_bo]

Its not an Italian/BSA thing is it?
Are you screwing it in in the right direction?
I think you will damage the frame unless it goes all the way in.

Italian BBs are bigger (larger diameter) than BSA.

 

[TheDoctor]

Plus one side of Italian BBs is threaded t'other way round.
You can fit one side of a BSA BB into an Italian frame (although it's a bit loose), but the other one won't go however hard you try.
DAMHIKT.

 

[Broadside]

It might have been for 73mm bb shell, unless the frame's thread is crudded up. You can introduce spacers. Some DA bb's like that have very specific (and uncommon) chainset compatibility - do you have a chainset that matches and gives you a suitable chainline?

You've got me thinking that I have refitted the BB on my wife's bike badly now as it looks a lot like the OP photo, might need to go and check the threads for 'crud '...!!

 

[RebornBumbler]

Assuming it's all tight, wouldn't a suitable o-ring keep it adequately clean and dry ?

 

[Andrew_Culture]

You've got me thinking that I have refitted the BB on my wife's bike badly now as it looks a lot like the OP photo, might need to go and check the threads for 'crud '...!!

But does it ride okay?

 

[Broadside]

But does it ride okay?

Yes it rides perfectly. The play with the previous BB has gone and it changes gear nice and crisply so all is good. My wife never noticed that the previous BB was knackered, she thought the parcels in the post were presents I was buying for myself! She just gets on the bike and rides it, maintenance is my department!


I should say that I did have to move the front derailleur to improve gear changing but this was mostly because I had set it too low when originally fitting it a couple of months prior.

The comments above, particularly from mr H are making me wonder if something is wrong so I think I had better strip it down again.

 

[andrew_s]

I'd recommend putting a spacer between the frame and BB flange rather than leaving a gap.
It's relatively normal to make small changes in chainline by fitting a spacer, so they are readily available (eg Hope)