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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.

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Old 09-17-05, 09:03 PM   #1
peripatetic
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calling all bb mavens

So, ah, is there a definitive way of "feeling," or testing, or checking whether or not one needs to replace their bb bearings without having to initially disassemble the whole damn thing? I don't have all the drivetrain tools, and I'm hoping I can check while simultaneously picking my nose or perhaps snorting some good shag carpet...
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Old 09-17-05, 09:42 PM   #2
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Place the bike upside down and take the chain off the chainrings. Grab the crank arms left and right and see if there is any side to side play. Spin the crankset and see if you can hear any rough crunching noises from the bearings. Otherwise look at the overall condition of your drivetrain. Are the chainring teeth worn ? Check rear derailleur pulley wheels and chain stretch. Parts wear over time together. If any of these drivetrain parts are worn, then it would be a good idea to disassemble the bb and clean and lube the bearings.
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Old 09-18-05, 12:40 PM   #3
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The previous suggestion is a good one.

If ya gots a crank puller, pull the cranks and spin the bb axle by hand. Any gritty/crunchy or hard to spin feelings are no good. BB axle play is also an obvious sign of a repack/replacement.

Your bb type, either adjustable cup/cone or shimano cartridge type dictates the ease and cost of this overhaul.

As long as there's no play in your bb axle, a overhaul is really not that necessary. If you overhaul your hubs, you'll notice the difference a lot more than if you overhaul your BB.
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Old 09-18-05, 02:57 PM   #4
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Thanks for the info, guys. So I was just concerned because I've recently acquired some old bikes, and though I've overhauled the hubs, I haven't done the bbs. At the same time, from all I've read, it seems like the bb overhaul is not often necessary. But I did recently upgrade the drivetrain on an old Raleigh Gran Prix frame to a fixie--brand new cranks &c. I noticed a heavy grittiness during my pedaling though. This is OT, but is it possible that the pedals need to have their bearings overhauled (it's over 30 yrs old)? Or is it just normal to feel a little grittiness in older bikes in general?
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Old 09-18-05, 03:15 PM   #5
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i think i'd check your chainline and chain tension first, given the recent work done. if either are mildy off, they could cause a similar feeling; if badly off, you could get hurt. if you reused the old chain, that can cause a gritty feeling as well if it's worn out. if they're stock pedals, they probably can't be overhauled and wouldn't be worth it anyhow. just drip some oil into them and call it a day.
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Old 09-18-05, 03:56 PM   #6
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Quote:
Originally Posted by dafydd
i think i'd check your chainline and chain tension first, given the recent work done. if either are mildy off, they could cause a similar feeling; if badly off, you could get hurt. if you reused the old chain, that can cause a gritty feeling as well if it's worn out. if they're stock pedals, they probably can't be overhauled and wouldn't be worth it anyhow. just drip some oil into them and call it a day.

Okay, good advice. I put on a used chain, but freshly cleaned and with little wear to it. I had the drivetrain components installed at a good LBS here in the city, in fact checked them myself and they are fine. They are nice old steel-cage pedals, came with the Gran Prix; they're vintage, and I'd rather overhaul them than spend another $40 on some new ones, though. But first I'll double check everything and add some more oil to the parts in question.

Thanks.
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