How? Bottom Bracket - Old bike / New Crank

[8ball]

This has to be the most basic question for 99% of you, but I don't have a clue...

How do I fit a modern crank in a old frame?

The size of the old (70's Schwinn) bike's BB is a large diameter, the BB of the MTB I'm stripping is much smaller. Do I use part of the old bike's hardware with the crank (Shimano) or is there some sort of adapter that I need?

I'm guessing that there is already a topic on this. Hopefully someone can point me there, or help me here.

Thanx, 8ball

 

[deorman]

The entire assembly is different. There are adapter crank or bearing sets to use a 3-piece set-up on the 1-piece bracket.
Check this. http://www.bikeworldusa.com/index.php/cPath/124_70_80

 

[8ball]

There are adapter crank or bearing sets to use a 3-piece set-up on the 1-piece bracket.

Ahhhh haaaa. I appreciate the information. For some reason, was thinking it was some sort of jerry-rig using found parts (like much of my build).

The link provided gave me a good overview... is the vendor in your link your source too?

Thank you deorman

 

[deorman]

I've seen the stuff before, this company was recommended by someone here. I haven't bought from them myself.

 

[aka_locojoe]

bikeworldusa are great people to do business with.

 

[8ball]

I ended up buying the TruVativ brand bottom bracket converter at Harris Cyclery because of their Sheldon Brown "connection", the fact that he recommended it, and since they had the item in stock (many other online places were out-of-stock).

Great help guys, gracias.

 

[chrisharne]

I also used the Truvativ kit, and I can highly recommend it. I did a writeup with pictures on my blog... Dura Ace cranks on a war-time Schwinn New World - here's pics / link:

http://37-590.blogspot.com/2009/05/bott ... piece.html

 

[8ball]

I also used the Truvativ kit, and I can highly recommend it. I did a writeup with pictures on my blog... Dura Ace cranks on a war-time Schwinn New World

YES!!!!

 

[Pinche]

You could always hack apart a frame with that style bottom bracket and weld it into a set of larger one piece crank style bottom bracket cups. It won't come out but then you can use three piece cranks. Otherwise just cough up the twenty bucks and buy the adapter cups.

 

[denman]

Well I bought a Truvative BB conversion kit and if I had not had a lathe at work to skim off about .020 off the cups I could have NEVER pressed the cups into the frame. I will use the Tioga kit from now on.......Ride hard dudes!!!!

 

[Bendix]

Well I bought a Truvative BB conversion kit and if I had not had a lathe at work to skim off about .020 off the cups I could have NEVER pressed the cups into the frame. I will use the Tioga kit from now on.......Ride hard dudes!!!!

i wouldn't give up on that style- i've done many schwinns and never had a real issue. probably just 'luck of the draw' on that particular bb/adapter combo. worth it imho to be able to use a high quality bb and have a choice of many spindle lengths......