How frequent do Shimano bb's go bad
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How frequent do Shimano bb's go bad
Last fall I suspected something might be wrong but the LBS owner said "those bottom brackets" rarely go bad. Yeah, should have listened to my intuition. Today I was on a 100 mile ride and had to cut it short because of what felt like the bb going bad. A fair amount of "clunking" or grinding feeling coming through the crank arms and pedals. Got it home, cleaned off the bike and slowly turned the cranks on the workstand and something definitely feels right. The bike is a 97 Bianchi Trofeo and 6-7 years ago the bike shop replaced the original Miche bottom bracket with a sealed Shimano unit.
So, how often do they need to be replaced?
So, how often do they need to be replaced?
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1984 Gitane Tour de France; 1968 Peugeot PL8; 1982 Nishiki Marina 12; 1984 Peugeot PSV; 1993 Trek 950 mtb; 1983 Vitus 979; Colnago Super, mid-80's Bianchi Veloce, 1984 or 85 Vitus 979
1984 Gitane Tour de France; 1968 Peugeot PL8; 1982 Nishiki Marina 12; 1984 Peugeot PSV; 1993 Trek 950 mtb; 1983 Vitus 979; Colnago Super, mid-80's Bianchi Veloce, 1984 or 85 Vitus 979
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As with all mechanical things, it depends. It depends on what kind of riding you do, like whether you ride in the rain or not, or whether you have the correct bike washing technique. Nevertheless, Shimano sealed cartridge-type bottom brackets (I'm assuming this is a square taper) are pretty hard to kill, especially the good ones that are Ultegra/XT level or above. Your LBS owner was right in that generally speaking, those Shimano sealed cartridge BBs rarely go bad as I have a Dura Ace unit that's seen better than 10k and still spins smoothly.
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Today was the first ride I've done in rain. Usually only on dry pavement because I know if it rains here it'll be sunny again in a day or two.
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1984 Gitane Tour de France; 1968 Peugeot PL8; 1982 Nishiki Marina 12; 1984 Peugeot PSV; 1993 Trek 950 mtb; 1983 Vitus 979; Colnago Super, mid-80's Bianchi Veloce, 1984 or 85 Vitus 979
1984 Gitane Tour de France; 1968 Peugeot PL8; 1982 Nishiki Marina 12; 1984 Peugeot PSV; 1993 Trek 950 mtb; 1983 Vitus 979; Colnago Super, mid-80's Bianchi Veloce, 1984 or 85 Vitus 979
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Nothing lasts forever but Shimano square taper and even Octalink bottom brackets are very durable. I've gotten well over 25,000 miles on both types with no problems. That said, nothing last forever and it might indeed be the bb bearings are failing. BTW, did you remove the chain from the chainrings while you were testing the crank? You have to be sure you are checking only the bb bearings, not them plus the chain plus the rear wheel, etc.
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That said, nothing last forever and it might indeed be the bb bearings are failing. BTW, did you remove the chain from the chainrings while you were testing the crank? You have to be sure you are checking only the bb bearings, not them plus the chain plus the rear wheel, etc.
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1984 Gitane Tour de France; 1968 Peugeot PL8; 1982 Nishiki Marina 12; 1984 Peugeot PSV; 1993 Trek 950 mtb; 1983 Vitus 979; Colnago Super, mid-80's Bianchi Veloce, 1984 or 85 Vitus 979
1984 Gitane Tour de France; 1968 Peugeot PL8; 1982 Nishiki Marina 12; 1984 Peugeot PSV; 1993 Trek 950 mtb; 1983 Vitus 979; Colnago Super, mid-80's Bianchi Veloce, 1984 or 85 Vitus 979