Press/Push Fit 30 Question

DaveS

Active Member
Location
Suffolk UK
Are they the same thing please? BB 30 is different, 42 shell, but is press/push fit 30 just two names for the same thing?
 
Location
Loch side.
No they are not. There are two types of BB30 BB shells. The one shell is machined to exact tolerances so that the bearing can slip-fit into it. These shells are usually aluminium and machined precisely and thus an expensive part of the frame's manufacturing process.
The other type's shell is machined less accurately and usually you'll find this on carbon fiber shells where machining cannot be done accurately in anyway. In this type the shell's ID is larger than the bearing's OD. A soft-ish plastic cup is first pressed into the shell and the bearing then pressed into the cup itself. The soft cup compensates for machining intolerances.

Press-fit BB30 is thus like newer Hollowtech Shimano press-fit BBs and most BB30 new bikes will come with this style.

In spite of the two different styles of shell, the crank remains compatible with both since it only "sees" the bearing ID and overall shell width, which remains the same in both cases.
 
OP
DaveS

DaveS

Active Member
Location
Suffolk UK
Thanks. Apologies for not making myself clear. I understand the difference between direct bearing mount, BB 30, and cup mount, Press Fit 30, but I see the term Push Fit 30 also being used and wondered if Push Fit/Press Fit were one and the same, 46mm shell with cups. BB 30 is the standard introduced supposedly by Cannondale and uses no cups, but a 42mm shell and circlips.
 
Location
Loch side.
Thanks. Apologies for not making myself clear. I understand the difference between direct bearing mount, BB 30, and cup mount, Press Fit 30, but I see the term Push Fit 30 also being used and wondered if Push Fit/Press Fit were one and the same, 46mm shell with cups. BB 30 is the standard introduced supposedly by Cannondale and uses no cups, but a 42mm shell and circlips.
Yes, press-fit and push-fit are one and the same.
 
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