Help! Bottom Bracket Question.
 

I just inherited a Gary Fisher Paragon Steel Frame Mountain bike. It has nice components but the only problem is the bottom bracket is toast. It has the press in style bearings/bracket. The bracket/bearing has backed itself out about a 1/4 inch. I think the bottom bracket housing has become slightly enlarged due to bottom bracket changes over the years. Does anyone have any suggestions on a fix. (i.e. oversize bearings, threading the bracket to accept a more common type bracket etc. I hope someone has run into this before and solved the issue.)Thanks

Pics?

I have no idea what sort of BB you mean (surely not ashtabula), but then I'm not down with MTBs...

Take it to a Garry Fisher / Trek dealer, they will have specific knowlage for this product if it's a press fit BB.

Don't think you have a press fit BB, these are normally seen in Alu and CF frames, and yours is steel. You probably have an exteral bearing BB, even if this had become loose, the shells are made from aluminium, and so should not have demamged the steel frame, at worse, you may need to get the BB faced & tapped.

Would also be worth checking exactly what your bike is (re-decaled?), as accorcing to bikepedia, the Paragon was only avaliable with a steel frame back in 1993, if this is the case, if orginal, the BB will be a normal square taper cartridge, comments for the external BB also apply

There are press-fit BB shells for steel frames in sizes other than Ashtabula, but they're mostly confined to BMX. The two I've seen are Mid and Spanish, and they both have a smaller diameter shell than Ashtabula. I think there are a few MTB frames that have them, but they tend to be dirt-jumpers and things like that, and I don't think Gary Fisher make any jump bikes. Both sizes have only been around a few years though, as far as I know. How old is the bike?

Pics would also help

I am not sure of the year. Here are some pictures I hope they help. I know the paint is in pretty bad shape on the bike but with a little clean up and paint I think it will look pretty good. http://bikeforums.net/attachment.php...hmentid=201045http://bikeforums.net/attachment.php...hmentid=201046http://bikeforums.net/attachment.php...hmentid=201047http://bikeforums.net/attachment.php...hmentid=201048http://bikeforums.net/attachment.php...hmentid=201049

That's the old-school Fisher setup. It's proprietary. I'd suggest using Loctite 680 to retain the new bearings.

Can't tell from the pictures, but I want to assume that the BB is a standard screw in type. If so, just unscrew it however possible.

from the last picture, it looks like a common (probably english threaded) bottom bracket. it may have been installed wrong or is the wrong bb, because the drive side looks like it is missing the lockring, but the driveside is not subbposed to have a lockring. or, more likely, you are correct, and the driveside cup just backed out about an quarter of an inch. if it was mine i would tear it apart and see what's up, but it may be prudent to send it to the LBS and let THEM tell you what's up.

huey...

BTW, it may be that somebody put in an 72mm axle in a bb made for a 68? (is this even possible) and had to leave the driveside cup out a few millimeters to compensate.

Actually, you're seeing a proprietary Gary Fisher bottom bracket there. The bottom-bracket shell is an unthreaded tube. At one point Klein also had something similar to this.

mechbgon,

i have no doubt that you know more about it than me.

it's not the first time i've been wrong!, nor the last i suppose...

huey

Mechbgon- Your right, I found a site online illustrating a parts breakdown for an old style Gary Fisher BB. It is pushed in and I got it out, my concern is on the drive side the bearing does not press in as tight as the other side. It does not take a lot of pressure. Is there any "fix" for this? Will loctite be strong enough even if the bb casing is slightly worn? Any suggestions gladly welcomed.

Like I said, I'd use Loctite 680, which is a retaining compound that's formulated to fill gaps like that. If it doesn't get the job done, you can move on to more drastic measures like JB Weld.

I think there's a loctite compound specially designed for situations like this, I just can't remember what it's called.

Edit

mechBgon beat me to this post, and managed to remember the name too.

I'll give it a try. Thanks

I would be hesitant to use JB weld, unless you didn't intend to ever remove it. It may be more prudent to find a replacement BB IMHO. ;)

If this works it may be a better idea. http://www.biketoolsetc.com/index.cg...r-Spindle&q=&s=
The bottom of the page for the ones that are not threaded.

The BB shell on these proprietary Gary Fishers is so small that you wouldn't be able to get that cartridge BB into the shell. It is what it is.

Or a nice normal frame that doesn't use an orphaned, dead-end un-standard BB shell. It's not like they're hard to come by, a nice steel Stumpjumper perhaps?