Go Back  Bike Forums > Bike Forums > Bicycle Mechanics
Reload this Page >

How to de-seize this eccentric bb

Notices
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.

How to de-seize this eccentric bb

Old 04-23-23, 04:57 PM
  #1  
Junior Member
Thread Starter
 
juntjoo's Avatar
 
Join Date: Apr 2022
Location: SWFL
Posts: 125

Bikes: Cannondale Bent 2, Fuji Royale, Mongoose Snare

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 103 Post(s)
Liked 8 Times in 6 Posts
How to de-seize this eccentric bb

I've actually done it a couple times already but apparently it wasn't easy hence I'm here again struggling. I've used a torch on it and a mallet directly on the bb and a piece of wood + hammer "eccentric" parts and I'm using a spanner wrench that fits okay so I don't get a GREAT grip on it, I've just used it to rotate it... I don't want to break anything but I don't know what I'm hitting as I don't quite get how it works.

It's got those two bolts one seemingly going through both parts of the eccentric part the wedge and the other side then another little bolt that is up at the edge there for idk. I don't see a way to push the wedge out from the back, the right side. I may have lubed it last time but I don't wanna get all dirty if not necessary. It should have gotten enough from from before plus torching it now. What's the trick with these? Even if I lube it again, which I'm not sure how it will get in there, I still want to know how to apply pressure to it. Suggestions? It's a Cannondale recumbent Bent 2.


​​​​​
​​
juntjoo is offline  
Old 04-23-23, 08:04 PM
  #2  
Senior Member
 
Join Date: Jan 2009
Location: San Diego, CA
Posts: 3,721
Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 859 Post(s)
Liked 1,096 Times in 765 Posts
This may help.
Crankycrank is offline  
Likes For Crankycrank:
Old 04-23-23, 09:22 PM
  #3  
Senior Member
 
soyabean's Avatar
 
Join Date: Feb 2022
Location: GMT-5
Posts: 972
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 568 Post(s)
Liked 424 Times in 280 Posts
This is why I anti-seize almost everything.

"Grease" and "lube" belong on parts that are supposed to move in friction.

Grease is NOT an anti-seize. Try that stunt on automotive and you're in for a surprise on its next servicing.
soyabean is offline  
Old 04-24-23, 12:06 AM
  #4  
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,955

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 141 Post(s)
Tagged: 1 Thread(s)
Quoted: 5910 Post(s)
Liked 2,779 Times in 1,551 Posts
With any kind of luck ammonia might help. Remove the seat post and pour a few oz. down the seat tube to fill the BB shell. Wait 24-48 hours then try your luck.

Otherwise, pressing accross is more likely to work than trying to turn it. The best way would be with a bearing press. Use adaptors to support the frame and to push the eccentric rather than the b spindle.

If you don't have an auto mechanic friend, or other access to a press, you can use a hammer. Be sure to properly support the frame on an anvil of some type so the energy is concentred on the eccentric.
__________________
FB
Chain-L site

An ounce of diagnosis is worth a pound of cure.

Just because I'm tired of arguing, doesn't mean you're right.

“One accurate measurement is worth a thousand expert opinions” - Adm Grace Murray Hopper - USN

WARNING, I'm from New York. Thin skinned people should maintain safe distance.
FBinNY is offline  
Likes For FBinNY:
Old 04-24-23, 01:14 AM
  #5  
Junior Member
Thread Starter
 
juntjoo's Avatar
 
Join Date: Apr 2022
Location: SWFL
Posts: 125

Bikes: Cannondale Bent 2, Fuji Royale, Mongoose Snare

Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 103 Post(s)
Liked 8 Times in 6 Posts
Thanks!

Close, but it was another video underneath this one that that explained how to tap it out. Mine is a lil different where I just needed to thread the bolt into the other side then tap it through. Easy as pie. Didn't even need to take off the crank arms

juntjoo is offline  
Likes For juntjoo:
Old 04-24-23, 03:24 PM
  #6  
Senior Member
 
Join Date: Apr 2005
Location: Northern CA
Posts: 743

Bikes: Cannondale tandems: '92 Road, '97 Mtn. Mongoose 10.9 Ti, Kelly Deluxe, Tommaso Chorus, Cdale MT2000, Schwinn Deluxe Cruiser, Torker Unicycle, among others.

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 279 Post(s)
Liked 207 Times in 129 Posts
Soyabean: anti-seize isn't a great solution for eccentrics because they do indeed need to rotate. Lubrication allows for proper timing chain tightening. Anti-seize is great for car parts that are serviced ONCE and then left until they're worn out and need to be removed with an impact wrench and replaced. Bicycle parts with metal mated surfaces are a different scenario. They need to be serviced at regular intervals and when they're serviced, they're undergoing motion. Threads, for example, require grease to function properly over their lifetimes to prevent rust, galling & stripping. Seat posts also need grease to slide in and out easily. Waterproof grease does a great job displacing water. I find anti-seize to be too thin to address this. However, a mixture of grease and anti-seize can be a great compromise.

FBinNY: All eccentric shells are fully solid - there are no breather holes, so ammonia down the seat tube (or any frame tube) won't reach the eccentric at all. So this won't help the OP.

Juntjoo: I REALLY hate seeing hammers being used on C-Dale eccentrics in your first pic! I've posted my alternative fix method (below) many times on this and other forums. You don't have to hammer it! People, DO NOT HAMMER YOUR ECCENTRICS!!!!

I watched the video and was disappointed to see that Cannondale either spec'd a different eccentric or re-designed their old one.

The old eccentrics were easily un-stuck by running a bottle cage bolt through the other side of the eccentric, through a backing plate (cone wrench) to hold it against the BB shell and into the wedge barrel nut on the inside. (But you can't let the barrel nut move, so thread in your bottle bolt as you unthread the eccentric bolt.) Tightening this easily pulls the wedge in the opposite direction and removes it, or loosens the eccentric for adjustment. No hammers needed. Please, let's work on our bikes like civilized people, ok?

However, the new eccentric doesn't allow this. Too bad because it's an elegant solution that doesn't require hammers or brute force. That said, this same procedure can be used to un-stick one side at least - the threaded-side of the wedge. The bolt-head side is a different story... but can also be pulled out with the use of a bolt and threads. (After circlip and bolt removal.) Once the threaded-side wedge is removed, you could then insert your bottle bolt from the inside of the eccentric shell and remove it similarly on the other side with a nut on the bottle cage bolt against a backing plate (cone wrench). But it sure wouldn't be as straightforward as dislodging the old Cannondale eccentrics. But the lesson is that you still shouldn't ever have to "go at" a tandem eccentric with a hammer or blowtorch!!!! (Especially if you've used ample waterproof grease at installation.)

If an eccentric user wants ease of timing chain adjustment in the field, I recommend upgrading to a Bushnell. Not cheap, but the design totally solves the stuck wedge issue. And I'm happy to say adjusting my Bushnell on a France trip last May was a breeze.

Last edited by LV2TNDM; 04-24-23 at 03:28 PM.
LV2TNDM is offline  
Old 04-24-23, 03:55 PM
  #7  
Senior Member
 
Join Date: Apr 2009
Location: New Rochelle, NY
Posts: 38,955

Bikes: too many bikes from 1967 10s (5x2)Frejus to a Sumitomo Ti/Chorus aluminum 10s (10x2), plus one non-susp mtn bike I use as my commuter

Mentioned: 141 Post(s)
Tagged: 1 Thread(s)
Quoted: 5910 Post(s)
Liked 2,779 Times in 1,551 Posts
2 corrections to above post.

1 most commercial anti-seize compounds are basically grease with added metal particles to prohibit galvanic corrosion. So using one as a preventative for this issue has no drawbacks, except for potentially demanding more clamping force to keep eccentric from slipping.

As for my suggestion re: ammonia. One of us is misreading the OP's problem. I took it to be moving the eccentric within the frame. If so, there's no need for the ammonia to enter the eccentric. It only needs to surround and wick between the eccentric and BB shell. Of course, this won't work if this particular frame's BB shell is not vented to the seat tube.

Last edited by FBinNY; 04-24-23 at 04:00 PM.
FBinNY is offline  
Old 04-24-23, 05:21 PM
  #8  
Senior Member
 
Join Date: Apr 2005
Location: Northern CA
Posts: 743

Bikes: Cannondale tandems: '92 Road, '97 Mtn. Mongoose 10.9 Ti, Kelly Deluxe, Tommaso Chorus, Cdale MT2000, Schwinn Deluxe Cruiser, Torker Unicycle, among others.

Mentioned: 5 Post(s)
Tagged: 0 Thread(s)
Quoted: 279 Post(s)
Liked 207 Times in 129 Posts
Originally Posted by FBinNY
2 corrections to above post.

1 most commercial anti-seize compounds are basically grease with added metal particles to prohibit galvanic corrosion. So using one as a preventative for this issue has no drawbacks, except for potentially demanding more clamping force to keep eccentric from slipping.

As for my suggestion re: ammonia. One of us is misreading the OP's problem. I took it to be moving the eccentric within the frame. If so, there's no need for the ammonia to enter the eccentric. It only needs to surround and wick between the eccentric and BB shell. Of course, this won't work if this particular frame's BB shell is not vented to the seat tube.
All of the anti-seize I've encountered is thin and "dry," as in there's ample creaking and friction whenever the two metals want to slide past each other. But if this is the exception, and it is mixed with water-proof grease, then anti-seize may be adequate. I've found that in 40 years of wrenching that quality grease performs so well with corrosion resistance and preservation of metal parts, I've never seen the need for anti-seize.

And yes, the OP needs the eccentric to break free. But since all eccentrics I've seen have no holes in the wall sections (they need to be smooth, concentric circles for the eccentrics to wedge inside of), no acids, lubes, or other treatments will be of any use when trying to introduce them from any of the adjoining frame tubes.
LV2TNDM is offline  

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
Trackbacks are Off
Pingbacks are Off
Refbacks are Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service -

Copyright © 2024 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.