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#1
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Cotterpin bb conversion
I'm working on getting a 1960s Torpado up and running and have removed the
cranks and bottom brack spindle but can't get the fixed cup off (it's got three notches, not opposing flat faces, and I don't have the proper diameter lockring and hammering with a screwdriver is just damaging my screwdriver). I'm thinking that I could just leave the fixed cup on an get a new bottom bracket for the other side and put on newer square-taper cranks. So I've got few questions: 1. If I dremel or otherwise get a good hold on the cup to put the frame in the bench vice, which way is the fixed cup threaded? 2. If I go for a new square-taper spindle, is there a formula for determining a proper spindle length? Current spindle is 134mm end-to-end, 42mm edge-of-cone-to-end driveside, 32mm non-driveside. The bearings look to be the same size (1/4"?) as other bottom brackets so I'm assuming I can use the fixed cup that's well fixed in there. Thanks in advance, Seng |
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#2
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Cotterpin bb conversion
Keeper of the Mighty Macaulay wrote:
I'm working on getting a 1960s Torpado up and running and have removed the cranks and bottom brack spindle but can't get the fixed cup off (it's got three notches, not opposing flat faces, and I don't have the proper diameter lockring and hammering with a screwdriver is just damaging my screwdriver). There's a trick to doing these with a big bolt. See: http://www.sheldonbrown.com/tooltips/bbcups.html I'm thinking that I could just leave the fixed cup on an get a new bottom bracket for the other side and put on newer square-taper cranks. That's perfectly reasonable if the cups are in decent shape. 1. If I dremel or otherwise get a good hold on the cup to put the frame in the bench vice, which way is the fixed cup threaded? Italian thread is right-hand on both sides, lefty loosey. 2. If I go for a new square-taper spindle, is there a formula for determining a proper spindle length? Current spindle is 134mm end-to-end, 42mm edge-of-cone-to-end driveside, 32mm non-driveside. The bearings look to be the same size (1/4"?) as other bottom brackets so I'm assuming I can use the fixed cup that's well fixed in there. That's true. You'll also want to match the distance betwixt the cone ridges on the spindle. Italian bikes generally have 70 mm shells and call for a 5** series spindle. How long it needs to be is not a matter of formulae, but has to do with the crankset you choose and the desired chainline. See: http://sheldonbrown.com/bbsize for detailed info on that. Sheldon "I'd Use A Shimano Cartridge Unit..." Brown +-------------------------------------+ | Only those who attempt the absurd | | will achieve the impossible. | | --Albert Einstein | +-------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide http://captainbike.com http://sheldonbrown.com |
#3
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Cotterpin bb conversion
Keeper of the Mighty Macaulay wrote:
I'm working on getting a 1960s Torpado up and running and have removed the cranks and bottom brack spindle but can't get the fixed cup off (it's got three notches, not opposing flat faces, and I don't have the proper diameter lockring and hammering with a screwdriver is just damaging my screwdriver). There's a trick to doing these with a big bolt. See: http://www.sheldonbrown.com/tooltips/bbcups.html I'm thinking that I could just leave the fixed cup on an get a new bottom bracket for the other side and put on newer square-taper cranks. That's perfectly reasonable if the cups are in decent shape. 1. If I dremel or otherwise get a good hold on the cup to put the frame in the bench vice, which way is the fixed cup threaded? Italian thread is right-hand on both sides, lefty loosey. 2. If I go for a new square-taper spindle, is there a formula for determining a proper spindle length? Current spindle is 134mm end-to-end, 42mm edge-of-cone-to-end driveside, 32mm non-driveside. The bearings look to be the same size (1/4"?) as other bottom brackets so I'm assuming I can use the fixed cup that's well fixed in there. That's true. You'll also want to match the distance betwixt the cone ridges on the spindle. Italian bikes generally have 70 mm shells and call for a 5** series spindle. How long it needs to be is not a matter of formulae, but has to do with the crankset you choose and the desired chainline. See: http://sheldonbrown.com/bbsize for detailed info on that. Sheldon "I'd Use A Shimano Cartridge Unit..." Brown +-------------------------------------+ | Only those who attempt the absurd | | will achieve the impossible. | | --Albert Einstein | +-------------------------------------+ Harris Cyclery, West Newton, Massachusetts Phone 617-244-9772 FAX 617-244-1041 http://harriscyclery.com Hard-to-find parts shipped Worldwide http://captainbike.com http://sheldonbrown.com |
#4
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Cotterpin bb conversion
On Mon, 24 May 2004 16:12:58 -0700, Keeper of the Mighty Macaulay wrote:
I'm working on getting a 1960s Torpado up and running and have removed the cranks and bottom brack spindle but can't get the fixed cup off (it's got three notches, not opposing flat faces, and I don't have the proper diameter lockring and hammering with a screwdriver is just damaging my screwdriver). Which way are you trying to turn it? I'm thinking that I could just leave the fixed cup on an get a new bottom bracket for the other side and put on newer square-taper cranks. So I've got few questions: Don't do that. Those old bottom-brackets are a RPITA. Get a sealed one. Much better. 1. If I dremel or otherwise get a good hold on the cup to put the frame in the bench vice, which way is the fixed cup threaded? Depends on the type of frame. Check Sheldon Brown's website for details. One thing to check is the width of the bottom bracket shell. If it is 68mm, it is likely British, and so the right cup will be left-hand thread. If it is 70mm, it is likely Italian, so right-hand thread. I donno what a Torpado is, though, so .... hope it ain't French. -- David L. Johnson __o | There is always an easy solution to every human problem - neat, _`\(,_ | plausible, and wrong. --H.L. Mencken (_)/ (_) | |
#5
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Cotterpin bb conversion
On Mon, 24 May 2004 16:12:58 -0700, Keeper of the Mighty Macaulay wrote:
I'm working on getting a 1960s Torpado up and running and have removed the cranks and bottom brack spindle but can't get the fixed cup off (it's got three notches, not opposing flat faces, and I don't have the proper diameter lockring and hammering with a screwdriver is just damaging my screwdriver). Which way are you trying to turn it? I'm thinking that I could just leave the fixed cup on an get a new bottom bracket for the other side and put on newer square-taper cranks. So I've got few questions: Don't do that. Those old bottom-brackets are a RPITA. Get a sealed one. Much better. 1. If I dremel or otherwise get a good hold on the cup to put the frame in the bench vice, which way is the fixed cup threaded? Depends on the type of frame. Check Sheldon Brown's website for details. One thing to check is the width of the bottom bracket shell. If it is 68mm, it is likely British, and so the right cup will be left-hand thread. If it is 70mm, it is likely Italian, so right-hand thread. I donno what a Torpado is, though, so .... hope it ain't French. -- David L. Johnson __o | There is always an easy solution to every human problem - neat, _`\(,_ | plausible, and wrong. --H.L. Mencken (_)/ (_) | |
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