Cycling and bicycle discussion forums. 
   Click here to join our community Log in to access your Control Panel  


Go Back   > >

Bicycle Mechanics Broken bottom bracket? Tacoed wheel? If you're having problems with your bicycle, or just need help fixing a flat, drop in here for the latest on bicycle mechanics & bicycle maintenance.

User Tag List

Reply
 
Thread Tools Search this Thread
Old 02-21-05, 11:08 AM   #1
Portis
Banned.
Thread Starter
 
Join Date: Sep 2003
Location: Home alone
Bikes: Trek 4300 X 2. Trek 1000, Trek 6000
Posts: 6,019
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
This is probably a dumb question, but i thought i read somewhere that you can use a 68 mm bb in a 73 mm shell? Yes/No? Or was it the other way around?
Portis is offline   Reply With Quote
Old 02-21-05, 11:29 AM   #2
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
The threading for ISO 68/73 mm bottom brackets is the SAME (as far as I understand), it's just a question of how far the cups stick out from the. Sheldon Brown sez: http://sheldonbrown.com/gloss_bo-z.html#bottom
moxfyre is offline   Reply With Quote
Old 02-21-05, 12:54 PM   #3
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Posts: 26,492
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Quote:
Originally Posted by Ranger
This is probably a dumb question, but i thought i read somewhere that you can use a 68 mm bb in a 73 mm shell? Yes/No? Or was it the other way around?
Not one that I've ever tried. The test would be if the left crankarm hits the chainstay. Depending on the crank it might work well enough to be rideable, but I think that it's kind'a nice to have the crank centered on the frame.
Retro Grouch is offline   Reply With Quote
Old 02-21-05, 01:02 PM   #4
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Retro Grouch
Not one that I've ever tried. The test would be if the left crankarm hits the chainstay. Depending on the crank it might work well enough to be rideable, but I think that it's kind'a nice to have the crank centered on the frame.
It would depend on the length of the spindle I suppose... and the amount of adjustability available in the cups.
Ranger, if this is an old adjustable bottom bracket, the cups are certainly interchangeable between 68 mm and 78 mm shells--provided that the threads match.
moxfyre is offline   Reply With Quote
Old 02-21-05, 01:18 PM   #5
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Posts: 26,492
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Quote:
Originally Posted by moxfyre
It would depend on the length of the spindle I suppose... and the amount of adjustability available in the cups.
Ranger, if this is an old adjustable bottom bracket, the cups are certainly interchangeable between 68 mm and 78 mm shells--provided that the threads match.
You're right. Goes to show how long it's been since I did anything with a bottom bracket that had separate cups.
Retro Grouch is offline   Reply With Quote
Old 02-21-05, 01:21 PM   #6
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Retro Grouch
You're right. Goes to show how long it's been since I did anything with a bottom bracket that had separate cups.
Am I really out-retro-grouching you? 2 out of my 3 bikes have adjustable BBs, mostly cause I'm cheap and they worked fine when I got them.
moxfyre is offline   Reply With Quote
Old 02-21-05, 01:34 PM   #7
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Posts: 26,492
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Quote:
Originally Posted by moxfyre
Am I really out-retro-grouching you? 2 out of my 3 bikes have adjustable BBs, mostly cause I'm cheap and they worked fine when I got them.
I'm a retro grouch, but not a reactionary grouch. I'd hold onto an adjustable BB until the spindle bearing races pitted or something like that, then I'd swap it for a cartridge in a heartbeat.
Retro Grouch is offline   Reply With Quote
Old 02-21-05, 01:38 PM   #8
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Retro Grouch
I'm a retro grouch, but not a reactionary grouch. I'd hold onto an adjustable BB until the spindle bearing races pitted or something like that, then I'd swap it for a cartridge in a heartbeat.
Agreed. Just hasn't happened yet for me.
moxfyre is offline   Reply With Quote
Old 02-21-05, 01:42 PM   #9
Berodesign
Senior Member
 
Join Date: Sep 2004
Bikes:
Posts: 517
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by moxfyre
Agreed. Just hasn't happened yet for me.

HEATHENS!!!

HERETICS!!!

SARACENS!!!
Berodesign is offline   Reply With Quote
Old 02-21-05, 01:51 PM   #10
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Berodesign
HEATHENS!!!

HERETICS!!!

SARACENS!!!
Cheapskate right here. I also enjoy playing with loose ball bearings and the ability to flip a spindle around.
moxfyre is offline   Reply With Quote
Old 02-21-05, 01:56 PM   #11
squeegy200
Senior Member
 
squeegy200's Avatar
 
Join Date: Oct 2004
Location: Southern California
Bikes: Colnago Altain, Klein Pulse II, Stumpjumper FSR, GT Zaskar LE, Pedalforce RS2
Posts: 1,377
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by moxfyre
Cheapskate right here. I also enjoy playing with loose ball bearings and the ability to flip a spindle around.
I loved my old Campy bottom bracket. It was lightweight and beautiful. But I rode on it for over two years and when I pulled it out, it was rusted and pitted.

Since then I've pulled the BB out every 500 miles and cleaned and regreased. I was especially diligent during the rainy season. That practice became tiresome quickly and now I use the heavier cartidge bottom brackets and don't worry about it anymore.
squeegy200 is offline   Reply With Quote
Old 02-21-05, 03:50 PM   #12
Retro Grouch 
Senior Member
 
Retro Grouch's Avatar
 
Join Date: Feb 2004
Location: St Peters, Missouri
Bikes: Rans Rockst (Retro rocket) Rans Enduro Sport (Retro racket) Catrike 559, Merin Bear Valley (beater bike).
Posts: 26,492
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 37 Post(s)
Quote:
Originally Posted by Berodesign
HEATHENS!!!

HERETICS!!!

SARACENS!!!
Yup. I like cassette freehubs much better than spin-on freewheels too. Oh, and I think that down tube shifters are like having the gear shift located on the running board of your car.
Retro Grouch is offline   Reply With Quote
Old 02-21-05, 03:51 PM   #13
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Retro Grouch
Yup. I like cassette freehubs much better than spin-on freewheels too. Oh, and I think that down tube shifters are like having the gear shift located on the running board of your car.
I'll agree that cassettes are just plain better. My road bike has downtube shifters and I've never used brifters... but I like downtube shifters just fine except when going slowly and it's hard to balance.
moxfyre is offline   Reply With Quote
Old 02-21-05, 04:54 PM   #14
Bike_13
lover ....
 
Join Date: May 2004
Bikes:
Posts: 243
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by squeegy200
Since then I've pulled the BB out every 500 miles and cleaned and regreased. I was especially diligent during the rainy season. That practice became tiresome quickly and now I use the heavier cartidge bottom brackets and don't worry about it anymore.
I find it very relaxing actually, and extremely satisfying when you get a nice old Nouvo Record BB to spin smooth as butter. Modern cartridge BBs never do that.

But they are a lot easier. I have them on all my MTBs.
Bike_13 is offline   Reply With Quote
Old 02-21-05, 06:09 PM   #15
Rowan
Has opinion, will express
 
Join Date: Jun 2003
Bikes:
Posts: 14,651
Mentioned: 4 Post(s)
Tagged: 0 Thread(s)
Quoted: 50 Post(s)
Quote:
Originally Posted by Bike_13
Modern cartridge BBs never do that.
Because of the seals?
Rowan is offline   Reply With Quote
Old 02-21-05, 06:59 PM   #16
moxfyre
cyclist/gearhead/cycli...
 
moxfyre's Avatar
 
Join Date: Oct 2004
Location: DC / Maryland suburbs
Bikes: Homebuilt tourer/commuter, modified-beyond-recognition 1990 Trek 1100, reasonably stock 2002-ish Gary Fisher Hoo Koo E Koo
Posts: 4,166
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by Bike_13
I find it very relaxing actually, and extremely satisfying when you get a nice old Nouvo Record BB to spin smooth as butter.
Agreed, it's a fun challenge.

Quote:
Modern cartridge BBs never do that. But they are a lot easier. I have them on all my MTBs.
They are equal or better in basically all respects I'd say. But when they break, they're broken. And I find that extremely frustrating. I like to be able to fix everything, even if it's not really worth the time and effort.

I heard that Phil Wood makes fancy cartridge BBs with replaceable bearings that press onto the spindles. In my opinion that is the way they should all be, basically a cup and cone but with sealed bearing cartridges. I'd buy one but they are soooo expensive.
moxfyre is offline   Reply With Quote
Old 02-21-05, 07:06 PM   #17
mtbikerinpa
Senior Member
 
mtbikerinpa's Avatar
 
Join Date: Dec 2004
Location: PA
Bikes: 92 Giant Sedona ATX Custom
Posts: 1,713
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
On my older Giant I have a 73 mm shell and have been running 68 mm BBs for years. It works better IMHO since it runs the bearing in deeper in the frame. Thus it keeps a good bit of crud out(which we have enough of in east coast racing). Ideally the bearing would be placed like the external cup BB(X-type, Hollowtech II) to keep the load spread wider, hence more rigid, but the difference is minimal. If you run a 68 the only concern is your spindle length and if the left(non drive) cup has a shoulder. If it does have a shoulder than it can't take up the slack propperly, in which case its no good. A lot of models are non-shouldered. Adjustible is the way to go.

Last edited by mtbikerinpa; 02-21-05 at 07:11 PM.
mtbikerinpa is offline   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off



All times are GMT -6. The time now is 12:34 PM.