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#11
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Cup & Cone Bottom Brackets - Any Sources?
On Mar 26, 1:48*pm, Hands Of Stone wrote:
On Mar 25, 6:09*am, landotter wrote: On Mar 25, 6:29*am, Hands Of Stone wrote: I am looking for a source for high-quality conventional cup & cone BBs (JIS square taper). *Ritchey used to still make some but they are no longer shown on his site. *Any ideas? Any particular reason a cartridge BB won't work for you? FWIW--I believe the new version house brand square taper BB at Nashbar is being made by RPM in Taiwan and has an aluminum lock ring. Well made and a steal at $15. No, I have nothing against cartridge. *I just like everything about the old-school BBs (except for the fixed cup): I run'em cageless with a few extra balls, regrease and replace bearings (cheaply) when needed, plus I like being able to adjust the bearings. *Why fix what ain't broke? *Having said that, I may go with your idea as I am always a sucker for a good deal. It's a stupidly nice BB for the money. As much as I like loose ball hubs and headsets, which are easy to maintain--I do love cartridge BBs. I've never managed to wear one out--though the most miles I ever put on one was 30K on a UN73. It's a superior technology, for sure. Careful with the alloy cups, btw--you'll want to use loctite, these guys like to work loose if assembled with grease. |
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#12
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Cup & Cone Bottom Brackets - Any Sources?
landotter wrote:
On Mar 25, 6:29Â*am, Hands Of Stone wrote: I am looking for a source for high-quality conventional cup & cone BBs (JIS square taper). Â*Ritchey used to still make some but they are no longer shown on his site. Â*Any ideas? Any particular reason a cartridge BB won't work for you? FWIW--I believe the new version house brand square taper BB at Nashbar is being made by RPM in Taiwan and has an aluminum lock ring. Well made and a steal at $15. Jobst Brandt |
#13
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Cup & Cone Bottom Brackets - Any Sources?
datakoll writes:
try ... EPDI, ... EPDI ?? The European Post Doctoral Institute ?? - Don Gillies San Diego, CA, USA |
#14
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Cup & Cone Bottom Brackets - Any Sources?
The current design of the BBs one of the last holdovers from ancient
times that is still a perpetual problem. As I mentioned before, if it has a left hand thread, the design is faulty, the thread being a crude patch for the design problem, just as it is for pedal threads that fail in spite of the orientation. Left hand threads are used to cover for a moving interface that tends to unscrews itself in use. As is visible on pedal crank faces, pedals regardless of tightening, move in their contact with the crank and by fretting erode the crank face. This erosion leads to cracks that cause pedal eyes to fracture and throw the rider to the ground if standing at the moment of failure. Like pedals, BB cups also fret in the BB shell but, with the larger thread, were moderately secure with right hand threads if tightened to nearly unmanageable torque. That is why left hand threads are used today to hide that they move. In time, the threads of the right hand cup or BB shell become eroded to oblivion in time depending on which of the two is the harder material. With steel hardened bearing cups, the BB shell loses all its threads while with aluminum cups, the right hand cup loses its threads. Shimano has used a clamping method for left crank attachment to the spindle that would also work for the BB. Meanwhile, cartridge bearings fret on the inside and outside while the retaining cup frets in the BB shell. That is what is wrong with the current design especially with cartridge bearings. In the short term, the current design works if monitored often and maintained, but when the thread is gone, it presents a difficult problem. Jobst Brandt |
#15
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Cup & Cone Bottom Brackets - Any Sources?
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#16
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Cup & Cone Bottom Brackets - Any Sources?
Tom Sherman wrote:
The current design of the BBs one of the last holdovers from ancient times that is still a perpetual problem. As I mentioned before, if it has a left hand thread, the design is faulty, the thread being a crude patch for the design problem, just as it is for pedal threads that fail in spite of the orientation. Left hand threads are used to cover for a moving interface that tends to unscrews itself in use. As is visible on pedal crank faces, pedals regardless of tightening, move in their contact with the crank and by fretting erode the crank face. This erosion leads to cracks that cause pedal eyes to fracture and throw the rider to the ground if standing at the moment of failure. Like pedals, BB cups also fret in the BB shell but, with the larger thread, were moderately secure with right hand threads if tightened to nearly unmanageable torque. That is why left hand threads are used today to hide that they move. In time, the threads of the right hand cup or BB shell become eroded to oblivion in time depending on which of the two is the harder material. With steel hardened bearing cups, the BB shell loses all its threads while with aluminum cups, the right hand cup loses its threads. Shimano has used a clamping method for left crank attachment to the spindle that would also work for the BB. Meanwhile, cartridge bearings fret on the inside and outside while the retaining cup frets in the BB shell. That is what is wrong with the current design especially with cartridge bearings. In the short term, the current design works if monitored often and maintained, but when the thread is gone, it presents a difficult problem. I just throw out the bicycle if I have problems with the bottom bracket. In contrast, I had my involuntarily threadless BB bored out and a hardened threaded steel sleeve silver soldered to keep my custom frame of many years in service. I have a great frame builder and bikie friend who has great metal working skills who also made the pedal crank modification which solved the pedal to crank problem. Jobst Brandt |
#17
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Cup & Cone Bottom Brackets - Any Sources?
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#18
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Cup & Cone Bottom Brackets - Any Sources?
"jim beam" wrote:
[...] otoh, by not simply replacing a worn out frame, you're deliberately avoiding bothering to research improvements in frame design such as over-size tube which help mitigate shimmy. or aluminum. Aluminium makes for a very poor frame. Aluminium alloy with proper heat treatment can make a perfectly fine frame however. or carbon. Just carbon? Is this a diamond frame (pun intended)? as someone that like to express opinion on these materials, the least you should do is bother to actually use them. One would think a former materials scientist would be more precise in terminology. Even a "lightweight" knows better. -- Tom Sherman - Holstein-Friesland Bovinia The weather is here, wish you were beautiful |
#19
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Cup & Cone Bottom Brackets - Any Sources?
On Mar 26, 7:46*pm, (Donald Gillies) wrote:
datakoll writes: try ... *EPDI, ... EPDI ?? *The European Post Doctoral Institute ?? - Don Gillies San Diego, CA, USA EPDI stocks EOM Shimano back to year one. They're in Bakersfield |
#20
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Cup & Cone Bottom Brackets - Any Sources?
On Mar 28, 10:28 pm, jim beam wrote:
wrote: Tom Sherman wrote: The current design of the BBs one of the last holdovers from ancient times that is still a perpetual problem. As I mentioned before, if it has a left hand thread, the design is faulty, the thread being a crude patch for the design problem, just as it is for pedal threads that fail in spite of the orientation. Left hand threads are used to cover for a moving interface that tends to unscrews itself in use. As is visible on pedal crank faces, pedals regardless of tightening, move in their contact with the crank and by fretting erode the crank face. This erosion leads to cracks that cause pedal eyes to fracture and throw the rider to the ground if standing at the moment of failure. Like pedals, BB cups also fret in the BB shell but, with the larger thread, were moderately secure with right hand threads if tightened to nearly unmanageable torque. That is why left hand threads are used today to hide that they move. In time, the threads of the right hand cup or BB shell become eroded to oblivion in time depending on which of the two is the harder material. With steel hardened bearing cups, the BB shell loses all its threads while with aluminum cups, the right hand cup loses its threads. Shimano has used a clamping method for left crank attachment to the spindle that would also work for the BB. Meanwhile, cartridge bearings fret on the inside and outside while the retaining cup frets in the BB shell. That is what is wrong with the current design especially with cartridge bearings. In the short term, the current design works if monitored often and maintained, but when the thread is gone, it presents a difficult problem. I just throw out the bicycle if I have problems with the bottom bracket. In contrast, I had my involuntarily threadless BB bored out and a hardened threaded steel sleeve silver soldered to keep my custom frame of many years in service. otoh, by not simply replacing a worn out frame, you're deliberately avoiding bothering to research improvements in frame design such as over-size tube which help mitigate shimmy. or aluminum. or carbon. as someone that like to express opinion on these materials, the least you should do is bother to actually use them. I have a great frame builder and bikie friend who has great metal working skills who also made the pedal crank modification which solved the pedal to crank problem. what "crank problem" is that? when is the last time you saw pedal eye breakage on an "unmodified" crank? For me, it was about a year ago - at least, a significant crack that I caught (by sound, which is saying something, because I'm hard of hearing) before it broke, on a 9-speed Veloce LH arm. |
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