Bicycle Mechanics - BB replacement trouble

Hello all, I'm taking my 10 year old Nishiki and upgrading some parts to bring it up to date and extend it's life (I'm also cheap). I'm starting with the bottom bracket and crankset, but I've already run into a problem. I want to replace the existing open cups/bearings unit with a sealed one, but when I opened the shell I found this screw sticking out, which holds the plastic cable guide in place. Is a sealed BB going to fit with that screw there? The plastic tab looks to be about 1/4 inch, I was thinking of putting in a shorter screw and hope the new BB has 1/4" clearance. Has anybody done this?

Also, I understand the fixed cup is a pain to get off because it's really tight. Does the fixed side unscrew by turning left to right (clockwise)?. Thank you.


http://www.jmuskie.com/bbracket01.jpg

You don't even really need the screw, the plastic tabs and the pressure from the cable should keep it in place.

You don't even really need the screw, the plastic tabs and the pressure from the cable should keep it in place.

Ditto- but it is kind of nice to have it stay in place. If it's really freaking you out, back the screw out until it's flush with the inside of the BB. It won't move since the cables hold it in place and the screw locates the guide.

The fixed (right) cup on an English BB is left-hand threaded. Loose-ball BB cups are on pretty tight- I usually end up whacking the spanner with a rubber mallet to get it to loosen. Be careful and watch your fingers!

You can remove the screw and use double sided adhesive tape under the cable guide. A smaller screw also works. I have done both successfully. -FTU

I have a similar screw on my bike, but it's a threaded machine screw and it only protrudes a few millimeters inside the BB shell. You might just cut/grind off your screw so it's shorter. There's actually quite a bit of space between the shell and a sealed BB (perhaps 3/8").

Regarding the fixed cup - I had a heck of time getting mine off (spanner kept slipping), so I used the method described in Sheldon's website - clamp the fixed cup in a bench vice and rotate the frame. The hardest part of that is keeping the frame level - works better with two people. Make absolutely sure you're turning it the right way - with a flashlight, look inside the BB and you should be able to see the threads so you'll know for sure. Failing that, your LBS has some special equipment that will get it off.

I have a similar screw on my bike, but it's a threaded machine screw and it only protrudes a few millimeters inside the BB shell. You might just cut/grind off your screw so it's shorter. There's actually quite a bit of space between the shell and a sealed BB (perhaps 3/8").


yeah that thing looks like a wood screw, OP, probably not original anyway. either cut it down, remove it, or go to the hardware store and find a short little machine screw with matching threading and replace it. its your bike, its your call. we wont tell :)

Shorter screw or try this. Remove the screw during the BB install process, then put it back afterwards. Most sealed unit BBs are fatter towards the ends and might not clear the screw, but towards the center offer more clearance.