Bottom bracket assembly
01-24-08, 07:24 PM
#1
Newbie
Thread Starter
Join Date: Jan 2008
Posts: 1
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Likes: 0
Liked 0 Times
in
0 Posts
Bottom bracket assembly
Greetings- I'm trying to help my son put his Fit back together. He's got a Profile (?) 3-piece bracket assembly, and we're having difficulty figuring out how the pieces go together. The spacer provided seems too wide, as the bearings won't both thread quite all the way in. There are several other spacers included, and I'm unsure which are needed, and how they should be arranged. Does anyone have any exploded-view pics of how a typical assembly like this is set up? I worked on bikes when I was a kid- this thing is a lot different than mine ever were. I'm used to working on cars and ATVs and the like- I can't believe a bicycle is giving me a run for my money!
Any help would be appreciated...
Thanks!
Rybob's dad
Any help would be appreciated...
Thanks!
Rybob's dad
01-24-08, 07:39 PM
#2
Cat 6
Join Date: Dec 2007
Location: Mountain Brook, AL
Posts: 7,482
Mentioned: 27 Post(s)
Tagged: 0 Thread(s)
Quoted: 500 Post(s)
Liked 183 Times
in
118 Posts
Not sure if will help you with the specifics on your crankset, but the Park Tool site may be a good place to start
__________________
72 Frejus (for sale), Holdsworth Record (for sale), special CNC & Gitane Interclub / 74 Italvega NR (for sale) / c80 French / 82 Raleigh Intl MkII f&f (for sale)/ 83 Trek 620 (for sale)/ 84 Bruce Gordon Chinook (for sale)/ 85 Ron Cooper / 87 Centurion IM MV (for sale) / 03 Casati Dardo / 08 BF IRO / 09 Dogma FPX / 09 Giant TCX0 / 10 Vassago Fisticuff
72 Frejus (for sale), Holdsworth Record (for sale), special CNC & Gitane Interclub / 74 Italvega NR (for sale) / c80 French / 82 Raleigh Intl MkII f&f (for sale)/ 83 Trek 620 (for sale)/ 84 Bruce Gordon Chinook (for sale)/ 85 Ron Cooper / 87 Centurion IM MV (for sale) / 03 Casati Dardo / 08 BF IRO / 09 Dogma FPX / 09 Giant TCX0 / 10 Vassago Fisticuff
01-24-08, 07:56 PM
#3
Senior Member
Join Date: Feb 2004
Location: St Peters, Missouri
Posts: 30,225
Bikes: Catrike 559 I own some others but they don't get ridden very much.
Mentioned: 16 Post(s)
Tagged: 0 Thread(s)
Quoted: 1572 Post(s)
Liked 643 Times
in
364 Posts
One of the problems of searching bicycle advice sites is that BMX can be quite different from other kinds of bikes. Consequently, you can get a lot of advice, even from good sources, that isn't applicable.
It's been several years since I've installed a BMX 3-piece crank so some of my memories might not be spot-on. Is this a new installation or has that crank been in that particular bike before?
As I remember, there is a tubular spacer that surrounds the spindle and fits between the two bearings. That may have to be cut to fit your particular bike. I used to hold the bearings up against the bottom bracket shell and measure the distance between them.
The bearings and spindle are press fitted parts. I used to put them in the freezer to make it easier to push all of the parts together. Sometimes I used a big bench vise to press the bearings into the bottom bracket shell. Press the bearing cups and spacer into the frame and press the spindle through the bearings. Then take the handleful of spacers that you have left and trial fit them on each side of the spindle to space the crank arms equi-distance from the frame. Tighten the bolts that hold the crank arms onto the spindle and you should be good-to-go.
It's been several years since I've installed a BMX 3-piece crank so some of my memories might not be spot-on. Is this a new installation or has that crank been in that particular bike before?
As I remember, there is a tubular spacer that surrounds the spindle and fits between the two bearings. That may have to be cut to fit your particular bike. I used to hold the bearings up against the bottom bracket shell and measure the distance between them.
The bearings and spindle are press fitted parts. I used to put them in the freezer to make it easier to push all of the parts together. Sometimes I used a big bench vise to press the bearings into the bottom bracket shell. Press the bearing cups and spacer into the frame and press the spindle through the bearings. Then take the handleful of spacers that you have left and trial fit them on each side of the spindle to space the crank arms equi-distance from the frame. Tighten the bolts that hold the crank arms onto the spindle and you should be good-to-go.
