One-Piece Crank Conversion

Andrew Westberg said:

I'm attempting to convert a cheap U.S. mountain bike's bottom bracket
to an I.S.O. cartridge style bracket. I'm thinking about using the
TruVativ adaptor for the conversion. The problem I'm having is that
I don't know how to remove the two cups left over from the one-piece
crank style open bearing holders. They seem to be wedged pretty
tightly in the bottom bracket. Any ideas on how to get these out?

If the bottom bracket is the American style, and not the Euro style, the
cups are pressed in and need to be hammered/extracted out. They can't be
unscrewed.

Profile makes adaptors to use Euro bottom brackets in American shells,
mainly for BMX bikes. They're not cheap.

--
Phil, Squid-in-Training

"Phil, Squid-in-Training" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

Andrew Westberg said:

I'm attempting to convert a cheap U.S. mountain bike's bottom bracket
to an I.S.O. cartridge style bracket. I'm thinking about using the
TruVativ adaptor for the conversion. The problem I'm having is that
I don't know how to remove the two cups left over from the one-piece
crank style open bearing holders. They seem to be wedged pretty
tightly in the bottom bracket. Any ideas on how to get these out?

If the bottom bracket is the American style, and not the Euro style, the
cups are pressed in and need to be hammered/extracted out. They can't be
unscrewed.

Profile makes adaptors to use Euro bottom brackets in American shells,
mainly for BMX bikes. They're not cheap.

Agreed. The cups for the one-piece crank are pressed in- back in the
day, we'd pop them out with a big punch and a stout hammer.

This item:
http://www.jensonusa.com/store/product.aspx?i=BB610Z00
will allow you to install a three-piece crank in an American BB shell.
However, I'd only consider it on a nice, old bike such as a '70's
Schwinn Super Sport or a vintage (!) BMX bike. A Murray or Huffy isn't
worth the $18 for the adapter, much less a crankset.

Jeff

Jeff Wills said:

"Phil, Squid-in-Training" <[email hidden]>
wrote in message
news:<[email hidden]>...

Quoted message said:

Andrew Westberg said:

I'm attempting to convert a cheap U.S. mountain bike's bottom
bracket to an I.S.O. cartridge style bracket. I'm thinking about
using the TruVativ adaptor for the conversion. The problem I'm
having is that I don't know how to remove the two cups left over
from the one-piece crank style open bearing holders. They seem to
be wedged pretty tightly in the bottom bracket. Any ideas on how
to get these out?

If the bottom bracket is the American style, and not the Euro style,
the cups are pressed in and need to be hammered/extracted out. They
can't be unscrewed.

Profile makes adaptors to use Euro bottom brackets in American
shells, mainly for BMX bikes. They're not cheap.

Agreed. The cups for the one-piece crank are pressed in- back in the
day, we'd pop them out with a big punch and a stout hammer.

This item:
http://www.jensonusa.com/store/product.aspx?i=BB610Z00
will allow you to install a three-piece crank in an American BB shell.
However, I'd only consider it on a nice, old bike such as a '70's
Schwinn Super Sport or a vintage (!) BMX bike. A Murray or Huffy isn't
worth the $18 for the adapter, much less a crankset.

Jeff

Nice, that's relatively cheap. I thought they were more expensive.

The big problem would be if the two sides weren't perfectly square with each
other. The fact that they use three fixing points kinda sucks because,
unless the faces of the BB shell were perfectly aligned with each other,
it'd be very easy to get the adapter crooked in the BB.
--
Phil, Squid-in-Training

Thanks all, I was able to punch them out. I just had to work my way around
it from the opposite side.

-Andrew

"Jeff Wills" <[email hidden]> wrote in message
news:[email hidden]...

Quoted message said:

"Phil, Squid-in-Training" <[email hidden]> wrote in

message news:<[email hidden]>...

Quoted message said:

Quoted message said:

Andrew Westberg said:

I'm attempting to convert a cheap U.S. mountain bike's bottom bracket
to an I.S.O. cartridge style bracket. I'm thinking about using the
TruVativ adaptor for the conversion. The problem I'm having is that
I don't know how to remove the two cups left over from the one-piece
crank style open bearing holders. They seem to be wedged pretty
tightly in the bottom bracket. Any ideas on how to get these out?

If the bottom bracket is the American style, and not the Euro style, the
cups are pressed in and need to be hammered/extracted out. They can't

be

Quoted message said:

Quoted message said:

unscrewed.

Profile makes adaptors to use Euro bottom brackets in American shells,
mainly for BMX bikes. They're not cheap.

Agreed. The cups for the one-piece crank are pressed in- back in the
day, we'd pop them out with a big punch and a stout hammer.

This item:
http://www.jensonusa.com/store/product.aspx?i=BB610Z00
will allow you to install a three-piece crank in an American BB shell.
However, I'd only consider it on a nice, old bike such as a '70's
Schwinn Super Sport or a vintage (!) BMX bike. A Murray or Huffy isn't
worth the $18 for the adapter, much less a crankset.

Jeff