refresh my memory on reverse threading

Subscribe
1  2 
Page 1 of 2
Go to
02-17-15 | 04:11 PM
  #1  
... besides fixed bb cups and left crank arm pedal threads.

did campagnolo ever use reverse threading in bb spindles for crank bolts?

i remember reading something ...

anyway, i can't remove a right (ds) crank bolt from a late '70s campy bb spindle, and am hoping i'm not overlooking the obvious. the bolt takes a 6mm allen wrench, which makes even more difficult.

maybe pb blaster?
Reply 0
02-17-15 | 04:16 PM
  #2  
Are you using a fresh allen head socket with a long breaker bar? If not, invest in a set. Allen wrenches provided limited leverage.
Reply 0
02-17-15 | 04:18 PM
  #3  
Crank bolts should always be clockwise to tighten and counter-clockwise to remove. They are all just conventionally threaded bolts, not reversed threaded as the pedaling and crank rotation does not affect their tightness. If it is, I can't imagine why.....
Reply 0
02-17-15 | 05:19 PM
  #4  
^ the left (nds) bolt came out easily. that's why i'm surprised with this ds bolt.

i remember a bf post about something else crank related with reverse threading. just can't remember what it was. maybe i'm making it up.

Quote: Are you using a fresh allen head socket with a long breaker bar? If not, invest in a set. Allen wrenches provided limited leverage.
good idea. i have a very sturdy allen wrench and used an adjustable wrench with it for extra leverage.

the bolt/spindle is soaking in a light oil. maybe that will help.
Reply 0
02-17-15 | 05:24 PM
  #5  
Freeze off is better than PB IMHO
Reply 0
02-17-15 | 05:35 PM
  #6  
On the drive side bolt, try tightening just a touch, then back it off counter clockwise. Sometimes helps to break it free.

Learned that tip here, from someone. And it sure is a good one. Worked for me twice since.
Thank you, who ever you are.
Reply 0
02-17-15 | 05:52 PM
  #7  
I think there were some later Campy cranks that had the self extractors that one side was left hand (or maybe both?). From what I recall, these used 7mm allen keys.

I've never seen '70s/'80s crank bolts (Nuovo/Super Record) that were allen key. Normally these are 15mm hex.
Reply 0
02-17-15 | 07:27 PM
  #8  
Quote: Crank bolts should always be clockwise to tighten and counter-clockwise to remove. They are all just conventionally threaded bolts, not reversed threaded as the pedaling and crank rotation does not affect their tightness. If it is, I can't imagine why.....
Quote: ^ the left (nds) bolt came out easily. that's why i'm surprised with this ds bolt.

i remember a bf post about something else crank related with reverse threading. just can't remember what it was. maybe i'm making it up.
Jobst Brandt had this to say:

Quote:
Loss of crank bolt preload is greater on left than right cranks, because left cranks transmit torque and bending simultaneously while right cranks transmit these forces separately. The left crank transmits driving torque through the spindle to the right crank and chainwheel while the right crank drives the chainwheel directly.
Reply 0
02-17-15 | 07:36 PM
  #9  
Quote: I think there were some later Campy cranks that had the self extractors that one side was left hand (or maybe both?). From what I recall, these used 7mm allen keys.

I've never seen '70s/'80s crank bolts (Nuovo/Super Record) that were allen key. Normally these are 15mm hex.
My guess is that this^ or something like this, is what you're dealing with, might even be a non-Campy self-extractor installed on the Campy crank...so pics would help!
If my guess is correct you would turn the Allen-head bolt CLOCKWISE to effect the self-extraction.
Reply 0
02-17-15 | 07:39 PM
  #10  
Quote: Freeze off is better than PB IMHO
+10!^^
Reply 0
02-17-15 | 07:41 PM
  #11  
Quote: Jobst Brandt had this to say:
I suspect Jobst just "overthunked" things on the crank bolts.......
Reply 0
02-17-15 | 08:15 PM
  #12  
Quote: I suspect Jobst just "overthunked" things on the crank bolts.......
We engineers are prone to that.
Reply 0
02-17-15 | 08:35 PM
  #13  
So THAT'S what's wrong with me?

I knew I should have been an engineer.
Reply 0
02-17-15 | 08:58 PM
  #14  
Quote: I think there were some later Campy cranks that had the self extractors that one side was left hand (or maybe both?). From what I recall, these used 7mm allen keys.
The retaining rings for the Campagnolo Victory and other Campagnolo self-extractors were left hand thread on both sides, but the Allen bolt that actually pushed against the ring to remove the arm are standard thread. Unless the self-extractor was removed from the arm for some reason, there was no need to mess with the left hand thread. Shimano and other self-extractors used standard 22 x 1 thread for their equipment.
Reply 0
02-17-15 | 09:55 PM
  #15  
Quote: The retaining rings for the Campagnolo Victory and other Campagnolo self-extractors were left hand thread on both sides, but the Allen bolt that actually pushed against the ring to remove the arm are standard thread. Unless the self-extractor was removed from the arm for some reason, there was no need to mess with the left hand thread. Shimano and other self-extractors used standard 22 x 1 thread for their equipment.
thanks for that.

this is a campy bb from the late '70s that has its drive-side crank bolt stuck.

so i'm really talking about the thread direction of the spindle that receives the bolt that pulls and holds the arm secure.

was there ever a spindle reverse threaded?

i think this previous owner, for whatever reason, liked these 6mm allen key bolts instead of the normal 14mm or 15mm ones, 'cause another of the bikes i got from him had these same bolts in a sugino mighty crank.
Reply 0
02-17-15 | 09:59 PM
  #16  
Quote: Freeze off is better than PB IMHO
noted!

Quote: On the drive side bolt, try tightening just a touch, then back it off counter clockwise. Sometimes helps to break it free. Learned that tip here, from someone. And it sure is a good one. Worked for me twice since.
Thank you, who ever you are.
ok, i'll try. thank that someone for me too.
Reply 0
02-18-15 | 07:14 AM
  #17  
Quote: this is a campy bb from the late '70s that has its drive-side crank bolt stuck.

so i'm really talking about the thread direction of the spindle that receives the bolt that pulls and holds the arm secure.

was there ever a spindle reverse threaded?
No.

Quote:
i think this previous owner, for whatever reason, liked these 6mm allen key bolts instead of the normal 14mm or 15mm ones, 'cause another of the bikes i got from him had these same bolts in a sugino mighty crank.
Can you post a picture of what you have so we know what we're all talking about?
Reply 0
02-18-15 | 10:23 AM
  #18  
Quote: On the drive side bolt, try tightening just a touch, then back it off counter clockwise. Sometimes helps to break it free.

Learned that tip here, from someone. And it sure is a good one. Worked for me twice since.
Thank you, who ever you are.
I have used this trick several times with freewheels and fixed BB cups. I also find that an abrupt jerk often works better than steady torque, so I often do the double jerk maneuver -- quick tightening motion followed by a stronger loosening motion. Sometimes the ol' rubber mallet on the end of the wrench works, as well.
Reply 0
02-18-15 | 10:36 AM
  #19  
Quote: We engineers are prone to that.
I resemble that remark. (4th generation engineer who has raised a 5th generation engineer.)
Reply 0
02-18-15 | 01:24 PM
  #20  
Sounds like this is a standard "Shimano style" fixing bolt, typical of what would come on a Shimano sealed BB unit, and so it's a standard RH thread and only difference is the tool you use to unscrew it (in a conventional CCW manner): an Allen key instead of a 15 or 14mm wrench.
I was mistaken to think it could have been a self-extracting bolt set-up, and certainly would not be an after-market brand on a Campy crank as that is not possible.
If it was in my shop, I'd use the Monster Truck Tool: an electric impact wrench with an Allen key socket...brace the frame for explosive torque and wear eye protection!
No bolt has ever won in contest against this tool, but sometimes the results are NOT pretty (as in total destruction)!
Still, it's very satisfying when the smoke clears and you're left holding the little b*stard bolt or nut that was making life difficult.
Well worth the $80 or so that Harbor Freight got off me for this thing, and has busted out some really tough BB fixed cups, too!
Reply 0
02-18-15 | 04:06 PM
  #21  
Quote: post a picture of what you have...


like i said, the nds bolt came out fine. this ds bolt won't budge.

since the campy bb is hollow, i flipped the bike laying on its ds side and sprayed a light oil in the spindle, nds side, and left it for hours. didn't help. i'm thinking it's the bolt washer that's seized to the arm.

thanks for all the help, youse guys.



Reply 0
02-18-15 | 04:08 PM
  #22  
Quote: I resemble that remark. (4th generation engineer who has raised a 5th generation engineer.)
I'm curious to know what kinds!
Reply 0
02-18-15 | 04:20 PM
  #23  
Quote: I'm curious to know what kinds!
Maternal grandfather's father: mine safety engineer, combination of structural, ventilation, chemical, and first aid
Maternal grandfather: engineer corps in WWI -- trenches and bridges in France
Paternal grandfather: merchant ship engines; chief engineer, McBride sugar plantation, Kauai, HI
Uncle: electrical (Hewlett-Packard lifer, IEEE President in 1985)
Father: aerospace (McDonnell-Douglas lifer, Manned Orbiting Laboratory)
(Wife's father: aerospace -- designed pressure regulator on Atlas missile)
Self: electrical; also environmental (air and energy)
Son: hydrogen fusion (plasma physics)
Reply 0
02-18-15 | 04:22 PM
  #24  
here's the nds bolt and ... um ... tool.



freeze off? pb blaster? naval jelly? what's the rx?


Reply 0
02-18-15 | 04:26 PM
  #25  
[MENTION=531]John E[/MENTION]:
Reply 0
1  2 
Page 1 of 2
Go to