68x127 bottom bracket & crank question

(Kelling) said:

Do I get a shorter bottom bracket to use with this crank? What length would I get? How does one
determine/measure/specify/pair this up with a crank?

I asked similar questions when I upgraded to a triple crank on my 1980 road bike. It had an old cup
'n' cone bottom bracket and I had no idea how to sort out what BB cartridge to use with my cranks. I
asked here on rec.bicycles.tech and got the answer, "Use the size that's specified by the
manufacturer".

I went to the Shimano site and downloaded a spec sheet for my cranks.

bike.shimano.comtech info a.aspOpen ↗

Sure enough, there was a BB specification right in the document. I'd never replaced cranks before,
but it went together easily. After a few adjustments on the new derailers, everything worked great.

My 2¢

Bill Kingson Caribou, Maine

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

Quoted message said:

Hi!

Please help a learning-at-home, do it yourself bike mechanic:

I recently replaced the 68x127 bottom bracket on my Trek 930 mountain bike, successfully. Then I
thought I'd replace a couple chain rings on the crank, but got a good deal on a crank set. Oops,
didn't know what I got wouldn't work, I obviously assumed a bit too much universality... when I
mount the new crank on the bottom bracket, the chainrings are way too far away from the frame, the
front deraileur doesn't go out that far.

Comparing the old crank to the new, the old crank's mounting hole doesn't 'reach' as far
inside of the chainrings as the new one does, therefore the new one sets the rings out too
far. (Make sense?)

Do I get a shorter bottom bracket to use with this crank? What length would I get? How does one
determine/measure/specify/pair this up with a crank?

What do I look for when purchasing a new crank? How does one determine/measure/specify how far the
mounting hold 'reaches' in? I'm wondering if I'll be able to find an inexpensive replacement for
the Exage 500LX crank I have now.

Thanks in advance for your tips and knowledge,

David

Ask the person who sold you the crank what model it is and then get the correct spindle for that
crank. What don't you like about your Exage LX crank? It is 110/74, making it much more useful than
anything Shimano mankes today. Virtually every ring size from 24 to 58 teeth is readily available
everywhere on earth!

--
Andrew Muzi yellowjersey.orgyellowjersey.orgOpen ↗ Open every day since 1 April 1971

"A Muzi" <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

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

Quoted message said:

Hi!

Please help a learning-at-home, do it yourself bike mechanic:

I recently replaced the 68x127 bottom bracket on my Trek 930 mountain bike, successfully. Then I
thought I'd replace a couple chain rings on the crank, but got a good deal on a crank set. Oops,
didn't know what I got wouldn't work, I obviously assumed a bit too much universality... when I
mount the new crank on the bottom bracket, the chainrings are way too far away from the frame,
the front deraileur doesn't go out that far.

Comparing the old crank to the new, the old crank's mounting hole doesn't 'reach' as far inside
of the chainrings as the new one does, therefore the new one sets the rings out too far. (Make
sense?)

Do I get a shorter bottom bracket to use with this crank? What length would I get? How does one
determine/measure/specify/pair this up with a crank?

What do I look for when purchasing a new crank? How does one determine/measure/specify how far
the mounting hold 'reaches' in? I'm wondering if I'll be able to find an inexpensive replacement
for the Exage 500LX crank I have now.

Thanks in advance for your tips and knowledge,

David

Ask the person who sold you the crank what model it is and then get the correct spindle for that
crank. What don't you like about your Exage LX crank? It is 110/74, making it much more useful
than anything Shimano mankes today. Virtually every ring size from 24 to 58 teeth is readily
available everywhere on earth!

David says: The old one is quite worn, it has some "short teeth" on it and is starting to skip when
I push hard. Thanks for the suggestions!