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 03-09-11, 08:27 AM   #1
campbell3d
Newbie
Thread Starter
 
Join Date: Mar 2011
Bikes:
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Any experience with Shimano press fit BB?

I bought a used 2010 GT SRS 1 bike frame, and it has a Dura Ace SM-FC7800P BB. I don't have any experience with press fit BBs and wanted to ask a few questions before I bought any tools that I really don't need (yet).

1. I noticed there is no inner shell between the cups? Is this normal?

2. If this is normal, I figured I'd keep them in the frame since it's relatively new. But if I were to remove them, has anyone ever removed them by tapping them out or do I need to buy the shimano bb13 tool to remove?

3. Lastly, if you've had experience, how long do the bearings last and how well do they perform?

Thanks!
campbell3d is offline   Reply With Quote
Old 03-09-11, 09:41 AM   #2
Burton
Certified Bike Brat
 
Burton's Avatar
 
Join Date: Jan 2011
Location: Montreal, Quebec
Bikes:
Posts: 4,251
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by campbell3d View Post
I bought a used 2010 GT SRS 1 bike frame, and it has a Dura Ace SM-FC7800P BB. I don't have any experience with press fit BBs and wanted to ask a few questions before I bought any tools that I really don't need (yet).

1. I noticed there is no inner shell between the cups? Is this normal?

2. If this is normal, I figured I'd keep them in the frame since it's relatively new. But if I were to remove them, has anyone ever removed them by tapping them out or do I need to buy the shimano bb13 tool to remove?

3. Lastly, if you've had experience, how long do the bearings last and how well do they perform?

Thanks!
Most of the questions concerning shells and spacers are well covered in the installation manuals that come with these things. Alternatively they are usually avalable as PDF references on the Shimano website at techdocs.shimano.com. I believe the technical service instruction you`re looking for is SI-0053A-001.

The proper tools for installing and removing any press-fit bearing or headset installation are highly suggested. Knocking out anything using a method that doesn`t keep the assembly straight risks deforming the metal and changing the tolerances. Bearing tolerances on oversized bearings are a problem already - you don`t want to look for trouble.

Haven`t had anything like this out there long enough myself to have any indication of durability. Performance is very subjective - real world performance isn`t noticably different from other top end installations, although thats just my own impression.
Burton is offline   Reply With Quote
Old 03-09-11, 10:01 AM   #3
campbell3d
Newbie
Thread Starter
 
Join Date: Mar 2011
Bikes:
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Thanks Burton. I had looked at the techdoc before and saw that inner cover didn't have to be installed if there where no openings inside the frame.

Something that I wondered is if this affects stability or not, and if anyone had this setup, how has had it worked for them?

Since I'm doing a build with this frame, I didn't want to remove the BB if there was really no need to yet. Visually it looks fine, just not having the inner cover between the two adapters worried me a little.
campbell3d is offline   Reply With Quote
Old 03-09-11, 02:42 PM   #4
operator
cab horn
 
Join Date: Jun 2004
Location: Toronto
Bikes: 1987 Bianchi Campione
Posts: 28,306
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Besides being outdated and incompatible with anything else they work just fine.

Last edited by operator; 03-09-11 at 02:46 PM.
operator is offline   Reply With Quote
Old 03-09-11, 04:43 PM   #5
Burton
Certified Bike Brat
 
Burton's Avatar
 
Join Date: Jan 2011
Location: Montreal, Quebec
Bikes:
Posts: 4,251
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by campbell3d View Post
Thanks Burton. I had looked at the techdoc before and saw that inner cover didn't have to be installed if there where no openings inside the frame.

Something that I wondered is if this affects stability or not, and if anyone had this setup, how has had it worked for them?

Since I'm doing a build with this frame, I didn't want to remove the BB if there was really no need to yet. Visually it looks fine, just not having the inner cover between the two adapters worried me a little.
OK Lets read between the lines a little. If there were MAJOR openings inside the bottom bracket shell (aside from miniscule breather holes) then condensation could easily run down the tubes, collect in the bottom bracket shell and contaminate the bearings. In those cases something to protect the bearings would be a good idea. The cover in my bike is plastic and can`t possibly affect performance, but does a pretty good job of shielding the bearings.

And I agree - you really don`t want to take apart anything thats perfectly functional. If the bearings spin smoothly - just ride it!
Burton 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 08:03 AM.