Can I switch the BB between frames?

mattolsen said:

[font=Arial]I've got an old 1980s Peugot steel frame bike in good shape. Everything works nicely, and the components are fine. Definitely not like top-of-the line stuff that's out today, but it's good enough for me. But it's a heavy steel frame. I recently acquired a lightweight Trek 2100 carbon and aluminum frame circa 1996 on eBay. What I want to do is strip everyything off the Peugot and put it on the Trek frame. I've had no prob with the rims, handlebars, brakes, derailleurs, etc. But I don't know what the heck I'm doing with the BB and crank. I'll probably just bring it to a LBS and let them handle it. My question is will this even work? Can you take the BB and crank from an 80s Peugot and put it on a 1996 Trek frame?[/font]

yeah, if the Pug has english threading,which I found on mid 80s pugs. But I wouldn't bother.

boudreaux said:

yeah, if the Pug has english threading,which I found on mid 80s pugs. But I wouldn't bother.

Why wouldn't you bother?

mattolsen said:

Why wouldn't you bother?

Just can't get my head around cup and ball BB since I've had the luxury of dealing with cartridge types for so many years.

mattolsen said:

Why wouldn't you bother?

From the description you gave in your first post, it sounds like the Trek 2100 is a better bike all the way around. Why would you want to take older less advanced components off of the circa 1980 bike and put it onto a 1996 frame that should already have superior components on it? The technology on these bikes changes pretty drastically in a decade so there wouldn't be any advantage to it.

Doctor Morbius said:

From the description you gave in your first post, it sounds like the Trek 2100 is a better bike all the way around. Why would you want to take older less advanced components off of the circa 1980 bike and put it onto a 1996 frame that should already have superior components on it? The technology on these bikes changes pretty drastically in a decade so there wouldn't be any advantage to it.

The Trek is just a FRAME (and fork), not a complete bike. I realize the components on the PUG arne't up to today's standards, but they're already bought and paid for! :-) I got a really good deal on the frame. So this is a cheap upgrade for me. I know you could really do it up right and put brand new shimano everything on this Trek frame, but right now my finances don't allow that. I'm just trying to see if it's possible to yank off all the Pug stuff and put it on the newer way better frame. So far I've been able to do everything except the crank and BB..... well I haven't run any cables yet, but I think that will go smoothly.

mattolsen said:

The Trek is just a FRAME (and fork), not a complete bike. I realize the components on the PUG arne't up to today's standards, but they're already bought and paid for! :-) I got a really good deal on the frame. So this is a cheap upgrade for me. I know you could really do it up right and put brand new shimano everything on this Trek frame, but right now my finances don't allow that. I'm just trying to see if it's possible to yank off all the Pug stuff and put it on the newer way better frame. So far I've been able to do everything except the crank and BB..... well I haven't run any cables yet, but I think that will go smoothly.

How'd you get the FD on that trek seattube that's 13/8" diameter and the pug is what, 11/8"?

boudreaux said:

Just can't get my head around cup and ball BB since I've had the luxury of dealing with cartridge types for so many years.

One more question. I see what you're saying. So if I dropped a cartridge in there, can I still use the cranks off the Pug? Sorry for my ignorance here.

boudreaux said:

How'd you get the FD on that trek seattube that's 13/8" diameter and the pug is what, 11/8"?

Forgot to include this - I'm not using the FD. It's going to be a 6 speed with just the rear. (not many hills where I bike) But yeah, there's no way it would have fit.

mattolsen said:

One more question. I see what you're saying. So if I dropped a cartridge in there, can I still use the cranks off the Pug? Sorry for my ignorance here.

Not unless the cartridge has the same spidle length. If it doesn't the chainline can be way off or the crank arms or chainrings could hit the stays....Also another issue with BB spindles, is the taper,JIS or ISO. They aren't 100% compatible and the new spindle taper would have to match the crank.

mattolsen said:

One more question. I see what you're saying. So if I dropped a cartridge in there, can I still use the cranks off the Pug? Sorry for my ignorance here.

there are definitely square taper cartridge BB's out there. some possible sources:
- your LBS might be able to hook you up, or
- eBay/Craig's List/other online stores or
- a VeloSwap type thing.

i have one lying around, but the spindle length is for a triple.

[font=Arial]Gotcha. I'm pretty mechanically inclinded, but completely inexperienced in regards to the BB/cranks. I've never opened one up; never needed too. I don't have a crank-puller. Do I stand any chance of getting the cranks off the spindle without one? Again, I'm just asking out of sheer ignorance. I've never attempted to do anything do the cranks or bb at all, so I just don't know. Do you need a crank-puller, or can you just knock them off with a blunt object. I took the dustcaps and bolts off last night, and those cranks don't want to come off. Is this something I shoul just let my LBS handle. I like to do as much work as I can by myself. But not if I'm going to break something.[/font]

mattolsen said:

[font=Arial]Gotcha. I'm pretty mechanically inclinded, but completely inexperienced in regards to the BB/cranks. I've never opened one up; never needed too. I don't have a crank-puller. Do I stand any chance of getting the cranks off the spindle without one? Again, I'm just asking out of sheer ignorance. I've never attempted to do anything do the cranks or bb at all, so I just don't know. Do you need a crank-puller, or can you just knock them off with a blunt object. I took the dustcaps and bolts off last night, and those cranks don't want to come off. Is this something I shoul just let my LBS handle. I like to do as much work as I can by myself. But not if I'm going to break something.[/font]

Do it right.Get a crank puller.Bubbas beat em off with a 5 pound hammer.

mattolsen said:

[font=Arial]Gotcha. I'm pretty mechanically inclinded, but completely inexperienced in regards to the BB/cranks. I've never opened one up; never needed too. I don't have a crank-puller. Do I stand any chance of getting the cranks off the spindle without one? Again, I'm just asking out of sheer ignorance. I've never attempted to do anything do the cranks or bb at all, so I just don't know. Do you need a crank-puller, or can you just knock them off with a blunt object. I took the dustcaps and bolts off last night, and those cranks don't want to come off. Is this something I shoul just let my LBS handle. I like to do as much work as I can by myself. But not if I'm going to break something.[/font]

Yes, you could pound it off with a rubber mallet and a lot of patience. Soak the crank/spindle interface with WD-40 or any anti-sieze prior to removal. Removing the BB though would be a lot harder without the proper BB tools. I suggest you let your LBS do it - much less trouble to worry about.

mattolsen said:

[font=Arial]Gotcha. I'm pretty mechanically inclinded, but completely inexperienced in regards to the BB/cranks. I've never opened one up; never needed too. I don't have a crank-puller. Do I stand any chance of getting the cranks off the spindle without one? Again, I'm just asking out of sheer ignorance. I've never attempted to do anything do the cranks or bb at all, so I just don't know. Do you need a crank-puller, or can you just knock them off with a blunt object. I took the dustcaps and bolts off last night, and those cranks don't want to come off. Is this something I shoul just let my LBS handle. I like to do as much work as I can by myself. But not if I'm going to break something.[/font]

don't pound with a blunt object. you'll probably end up enlarging the interface between the crank and BB and set yourself up for a world of hurt.

you can get the tools for not too much (crank puller + BB tools = ? $20 ?) and then you'll be prepared for the future as well. if you're gonna be discarding the old style BB, you may get the LBS to do that (probably need diff tools for 1-time use = not worth it), but maybe do the install of new BB yourself?

All right, well what tools would I need to install a cartridge style bb in the new frame? I could care less about removing the bb from the old frame. That was purely for the sake of putting it in the new frame.

mattolsen said:

All right, well what tools would I need to install a cartridge style bb in the new frame? I could care less about removing the bb from the old frame. That was purely for the sake of putting it in the new frame.

this is what i use. available mailorder all over, and i'm sure from your LBS too.
http://www.parktool.com/tools/BBT_2.shtml