Bottom bracket question
01-15-16 | 09:18 AM
#1
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From: Elwood Indiana
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Bottom bracket question
I have an Italian frame coming with an Ofmega square taper bottom bracket. Will this work with my Campy Victory cranks?
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01-15-16 | 09:37 AM
#2
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Maybe, but you need to know the spindle length and taper. At a minimum we would need to know the model of the ofmega bb.
Compare: VeloBase.com - Component: Campagnolo 403/100, Victory
VeloBase.com - Component: Ofmega Gran Premio
The difference between those two is 9mm, so no, it wouldn't work. The chainline would be wrong.
Compare: VeloBase.com - Component: Campagnolo 403/100, Victory
VeloBase.com - Component: Ofmega Gran Premio
The difference between those two is 9mm, so no, it wouldn't work. The chainline would be wrong.
01-15-16 | 09:50 AM
#3
Aspiring curmudgeon
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From: Saint Louis
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Some Ofmega cranks used a proprietary spindle taper that was different than JIS and ISO. Be careful.
Square Taper Bottom Bracket Interchangeability
Square Taper Bottom Bracket Interchangeability
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01-15-16 | 09:55 AM
#4
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From: Elwood Indiana
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I won't know until the frame arrives. The bottom bracket I have now for the Victory cranks are english thread. I may just put them on the trade thread and get the right one. Thanks.
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01-15-16 | 09:58 AM
#5
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Some Ofmega cranks used a proprietary spindle taper that was different than JIS and ISO. Be careful.
Square Taper Bottom Bracket Interchangeability
Square Taper Bottom Bracket Interchangeability
Obviously the danger is that the campy crank will go down a bit too far on the spindle, affecting your chain line and chainstay clearance. Worse case is that it will bottom out on the spindle before the crank bolt is tight. Easy enough to try.
01-16-16 | 04:24 AM
#7
verktyg
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Bikes: Current favorites: 1988 Peugeot Birraritz, 1984 Gitane Super Corsa, 1980s DeRosa, 1981 Bianchi Campione Del Mondo, 1992 Paramount OS, 1988 Colnago Technos, 1985 RalieghUSA SBDU Team Pro
Chainline, chainline, chainline.... 
Chainline obsession was a peculiar affectation in Britain when they used stiff 1/8" wide chains with 3 speed hubs.
With modern, narrow, flexible chains a 1/4" difference in the position of the chainrings isn't as big of an issue as it once was. Consider modern 10 and 11 speed bikes with short rear triangles...
verktyg
Chas.
Chainline obsession was a peculiar affectation in Britain when they used stiff 1/8" wide chains with 3 speed hubs.
With modern, narrow, flexible chains a 1/4" difference in the position of the chainrings isn't as big of an issue as it once was. Consider modern 10 and 11 speed bikes with short rear triangles...
verktyg
Chas.
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Last edited by verktyg; 01-16-16 at 07:05 AM.
01-16-16 | 06:19 AM
#8
What??? Only 2 wheels?
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While that may be true, back in the day people used to use Ofmega/avocet and campy cranks and bottom brackets together all the time. It may work. Try it.
Obviously the danger is that the campy crank will go down a bit too far on the spindle, affecting your chain line and chainstay clearance. Worse case is that it will bottom out on the spindle before the crank bolt is tight. Easy enough to try.
Obviously the danger is that the campy crank will go down a bit too far on the spindle, affecting your chain line and chainstay clearance. Worse case is that it will bottom out on the spindle before the crank bolt is tight. Easy enough to try.
One minor correction though. The crank bolts will always tighten up against something so the fact that they tighten is not an indicator of success. If the spindle sticks out too far through the square hole, not likely, the bolt will tighten against the spindle end but the crank arm will be loose. If the square hole bottoms out against the shoulders of the taper the bolt will get tight but the crank arm will not be seated properly against the taper, and you probably won't be able to tell just wiggling it by hand since the bolt will stabilize the arm. If the hole is smaller than the taper (assuming the angle is the same 4deg for both) then the arm won't go onto the spindle as far as you like, moving the chainline further out and potentially deforming the hole. You can see that problem without having to tighten the bolt fully. If the taper angles aren't the same (check Sutherlands) then it may seem to have tightened but is a bad fit.
And you probably knew all this already.
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01-16-16 | 06:44 AM
#9
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I'd wait, get it, and see.
I had two Italian frames tham came with Ofmega BB's and Ofmega Mistral cranksets. I honestly can't remember if I ever swapped a Campy crankset onto them, but I think I did put a Chorus crankset on one of them.
I had two Italian frames tham came with Ofmega BB's and Ofmega Mistral cranksets. I honestly can't remember if I ever swapped a Campy crankset onto them, but I think I did put a Chorus crankset on one of them.
01-16-16 | 07:09 AM
#10
verktyg
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Agreed - try it.
One minor correction though. The crank bolts will always tighten up against something so the fact that they tighten is not an indicator of success. If the spindle sticks out too far through the square hole, not likely, the bolt will tighten against the spindle end but the crank arm will be loose. If the square hole bottoms out against the shoulders of the taper the bolt will get tight but the crank arm will not be seated properly against the taper, and you probably won't be able to tell just wiggling it by hand since the bolt will stabilize the arm. If the hole is smaller than the taper (assuming the angle is the same 4deg for both) then the arm won't go onto the spindle as far as you like, moving the chainline further out and potentially deforming the hole. You can see that problem without having to tighten the bolt fully. If the taper angles aren't the same (check Sutherlands) then it may seem to have tightened but is a bad fit.
And you probably knew all this already.
One minor correction though. The crank bolts will always tighten up against something so the fact that they tighten is not an indicator of success. If the spindle sticks out too far through the square hole, not likely, the bolt will tighten against the spindle end but the crank arm will be loose. If the square hole bottoms out against the shoulders of the taper the bolt will get tight but the crank arm will not be seated properly against the taper, and you probably won't be able to tell just wiggling it by hand since the bolt will stabilize the arm. If the hole is smaller than the taper (assuming the angle is the same 4deg for both) then the arm won't go onto the spindle as far as you like, moving the chainline further out and potentially deforming the hole. You can see that problem without having to tighten the bolt fully. If the taper angles aren't the same (check Sutherlands) then it may seem to have tightened but is a bad fit.
And you probably knew all this already.
https://www.flickr.com/photos/282672...57627678462359
verktyg
Chas.
__________________
Don't believe everything you think! History is written by those who weren't there....
Chas. ;-)
Don't believe everything you think! History is written by those who weren't there....
Chas. ;-)
01-16-16 | 07:20 AM
#11
What??? Only 2 wheels?
Joined: Apr 2010
Posts: 13,496
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From: Boston-ish, MA
Bikes: 72 Peugeot UO-8, 82 Peugeot TH8, 87 Bianchi Brava, 76? Masi Grand Criterium, 74 Motobecane Champion Team, 86 & 77 Gazelle champion mondial, 81? Grandis, 82? Tommasini, 83 Peugeot PF10
__________________
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
Real cyclists use toe clips.
With great bikes comes great responsibility.
jimmuller
01-16-16 | 07:57 AM
#12
Old fart
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From: Appleton WI
Bikes: Several, mostly not name brands.
Some early production Avocet cranks used the old Ofmega-taper spindles, but most used Campagnolo-compatible spindles.
01-16-16 | 07:59 AM
#13
Old fart
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From: Appleton WI
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