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 08-19-12, 08:43 PM   #1
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Bikes:
Posts: 2,355
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Can I resize a Campy 126mm hub down to 120mm?

I am building up a late 70s Medici (120mm rear spacing) with parts from an early 80s Bianchi (126mm spacing). The hubs are Campy Record. I haven't had much luck so far finding a wheelset with 120mm rear spacing or just a 120mm rear (non-track) hub. I've searched this forum and read everything I thought might be useful (including Sheldon Brown's page on this stuff), but I'm still a bit confused. Can it be as easy as pulling off spacers totaling 5-6mm, redishing the wheel, and replacing the 6-speed freewheel with a 5-speed freewheel? Will the axle and skewer work, or do they need to be replaced with shorter ones?

(Before anyone suggests it, I'd prefer not to cold set the frame, at least not at this point. I would consider that as a last resort though.)

Thx...

Skip
smontanaro is offline   Reply With Quote
Old 08-19-12, 09:05 PM   #2
onespeedbiker
Retro Grouch
 
onespeedbiker's Avatar
 
Join Date: Oct 2007
Location: Santa Cruz
Bikes: Yes
Posts: 2,210
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by smontanaro View Post
I am building up a late 70s Medici (120mm rear spacing) with parts from an early 80s Bianchi (126mm spacing). The hubs are Campy Record. I haven't had much luck so far finding a wheelset with 120mm rear spacing or just a 120mm rear (non-track) hub. I've searched this forum and read everything I thought might be useful (including Sheldon Brown's page on this stuff), but I'm still a bit confused. Can it be as easy as pulling off spacers totaling 5-6mm, redishing the wheel, and replacing the 6-speed freewheel with a 5-speed freewheel? Will the axle and skewer work, or do they need to be replaced with shorter ones?

(Before anyone suggests it, I'd prefer not to cold set the frame, at least not at this point. I would consider that as a last resort though.)

Thx...

Skip
Well you have 3 options. #1 you can pull the stays apart 6mm and just use the 126mm hub, #2 you can use a method called cold setting, which is bending the stays out so you change the Medici dropouts to 126mm, or you can switch out the 126mm QR axle (10x26x134mm) and replace it with a QR axle for a 120mm dropouts (10x26x128mm?).

Last edited by onespeedbiker; 08-19-12 at 09:35 PM.
onespeedbiker is offline   Reply With Quote
Old 08-19-12, 09:13 PM   #3
JohnDThompson 
Old fart
 
JohnDThompson's Avatar
 
Join Date: Nov 2004
Location: Appleton WI
Bikes: Several, mostly not name brands.
Posts: 16,782
Mentioned: 12 Post(s)
Tagged: 0 Thread(s)
Quoted: 220 Post(s)
I have NOS Campy axles 129mm end-to-end for use with 120mm OLD spacing.



PM me to work something out.
JohnDThompson is offline   Reply With Quote
Old 08-19-12, 09:20 PM   #4
mrrabbit 
Senior Member
 
mrrabbit's Avatar
 
Join Date: Dec 2007
Location: San Jose, California
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Posts: 3,193
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
1. Grab yourself an axle for 120mm to 122mm spacing.

2. Arrange cones, spacers and lock nuts accordingly:

Dimension "A" = freewheel stop on hub shell to outside of drive side lock nut.

Set A to 29mm minimum for regular 5 speed spacing.
Set A to 35mm minimum for regular 5 speed AND regular 6 speed spacing.


Dimension "C" = outside of lock nut to outside of lock nut

Use the non-drive side as your "buffer", "fudge" side or "play loose side. Try obtain at least 120mm and as high as 122mm.


Once you have achieved the above, test in the dropouts with a strip of chain set on the lowest cog of the freewheel to verify clearance. Then build wheel if not built already - make sure wheel is properly dished such that the rim falls on center between the lock nuts of the new hub.

=8-)
__________________
4000+ wheels built since 1984...

Disclaimer:

1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:

Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
mrrabbit is offline   Reply With Quote
Old 08-20-12, 09:50 AM   #5
Kimmo
bike whisperer
 
Kimmo's Avatar
 
Join Date: Dec 2009
Location: Melbourne, Oz
Bikes: velospace.org/viewcluster?c=873
Posts: 7,115
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 4 Post(s)
Buy a shorter axle? If you like... or just put in a vise with some ally plate, and pick up a hacksaw and a file...
Kimmo is offline   Reply With Quote
Old 08-20-12, 10:06 AM   #6
mrrabbit 
Senior Member
 
mrrabbit's Avatar
 
Join Date: Dec 2007
Location: San Jose, California
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Posts: 3,193
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
Quote:
Originally Posted by Kimmo View Post
Buy a shorter axle? If you like... or just put in a vise with some ally plate, and pick up a hacksaw and a file...
And destroy a perfectly good vintage 126mm axle that would otherwise be available for later, when someone else has offered a 120mm?

=8-)
__________________
4000+ wheels built since 1984...

Disclaimer:

1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:

Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
mrrabbit is offline   Reply With Quote
Old 08-20-12, 03:38 PM   #7
eddy m
Senior Member
 
Join Date: Jun 2003
Bikes:
Posts: 618
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 0 Post(s)
Quote:
Originally Posted by mrrabbit View Post
And destroy a perfectly good vintage 126mm axle that would otherwise be available for later, when someone else has offered a 120mm?

=8-)
I would saw that thing in a New York minute.

em
eddy m is offline   Reply With Quote
Old 08-20-12, 06:50 PM   #8
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Bikes:
Posts: 2,355
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
> PM me to work something out.

Thanks. PM sent.

S

smontanaro is offline   Reply With Quote
Old 08-20-12, 06:51 PM   #9
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Bikes:
Posts: 2,355
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
I prefer to not saw a perfectly good axle (which I might need at a future date). What is "ally plate"?
smontanaro is offline   Reply With Quote
Old 08-21-12, 12:49 AM   #10
fietsbob 
coprolite
 
fietsbob's Avatar
 
Join Date: Jun 2010
Location: NW,Oregon Coast
Bikes: 7
Posts: 22,182
Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1134 Post(s)
Might get it to work uncut to remove the QR springs.
that frees up some space in the QR ends
to let the axle come a hare past the outer face of the dropout..

but still clamp down the QR.
fietsbob is offline   Reply With Quote
Old 08-21-12, 07:49 AM   #11
smontanaro 
Senior Member
Thread Starter
 
Join Date: Aug 2007
Location: Evanston, IL
Bikes:
Posts: 2,355
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 86 Post(s)
Quote:
Originally Posted by mrrabbit View Post
1. Grab yourself an axle for 120mm to 122mm spacing.

2. Arrange cones, spacers and lock nuts accordingly:
...
Thanks for the instructions. I always wanted to build a wheel. This will be my next step in that direction. One question, though. You mentioned two values for dimension A:

Quote:
Set A to 29mm minimum for regular 5 speed spacing.
Set A to 35mm minimum for regular 5 speed AND regular 6 speed spacing.
Does the 29mm value hold for Suntour Ultra 6-speed (narrow) freewheels as well? I'm scouting around for possibilities. One is to just try and use the existing 6-speed Suntour freewheel which is on the hub now. I still have to figure out exactly what it is. It's probably a regular spaced freewheel, but maybe it's an Ultra-6.
smontanaro is offline   Reply With Quote
Old 08-21-12, 07:57 AM   #12
mrrabbit 
Senior Member
 
mrrabbit's Avatar
 
Join Date: Dec 2007
Location: San Jose, California
Bikes: 2001 Tommasini Sintesi w/ Campagnolo Daytona 10 Speed
Posts: 3,193
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 1 Post(s)
If you want to go with a "Narrow 6" which is supposedly what the Suntour Ultra-6 is, then Dimension A needs to be a minimum of 31mm.

(Hopefully it's not a regular 6...which are pretty rare nowadays...)

Whether you can finish the non-drive side or not for the OLD - only testing will tell...

=8-)
__________________
4000+ wheels built since 1984...

Disclaimer:

1. I do not claim to be an expert in bicycle mechanics despite my experience.
2. I like anyone will comment in other areas.
3. I do not own the preexisting concepts of DISH and ERD.
4. I will provide information as I always have to others that I believe will help them protect themselves from unscrupulous mechanics.
5. My all time favorite book is:

Kahane, Howard. Logic and Contemporary Rhetoric: The Use of Reason in Everyday Life
mrrabbit 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 08:18 PM.