Replacing Bottom Brackets?
 

Hey all, I own a mid 70s Takara (I posted it in the Japanese bikes thread here I believe). Anyways, I think the bottom bracket is pretty much done for on it. When turning the cranks under pressure there are two distinct spots on every rotation that "clunk" (can't think of any better description besides that, sorry). I do have a new bike, a Giant Defy 2, which I love dearly. But I still do love the silky ride of my old steelie and don't want to let her go because I need a "commuter" bike as well. I wont be taking my new bike around campus to get to class/to go to the store/for leisurely rides mainly because I would hate for it to get stolen. Any advice/help would be great, like... can it be repaired? if so, how much do you think it would cost for a local shop to do so? or can I do it myself? Sorry for the long-winded post.

Happy riding!
Charlie

Other than needing a few specialized tools, it is an easy fix. If you decide to open it up, replace the bearings (do not reuse them, they are cheap) and the grease as well. If you see significant wear on the spindle or the cups, time to look at a cartridge replacement. BB choices depend on the crank. And if you have an old cottered crank, this would be a good time to upgrade.

Find a shop you trust, or a good co op. Seems like Minneapolis has some good co-ops, so that is where I would start.

Thanks for the response, yeah there are a few decent shops around town so ill check them out, might be a good time to simplify/upgrade the drivetrain.

BB's on older bikes are a service item that is often neglected. Anytime you pick up a older bike i would be well advised to service the BB and wheel bearings. The grease will dry up with age and you will destroy the bearing cups and cones if that happens.

80's bike it probably has a square taper shaft. A Shimano UN54 sealed unit will probably plug and play. Need to measure the width of the old spindle. Looking about $30 for the part and what ever labor the shop gets you for. Its a 20 minute job as long as nothing is stuck.

I usually go sealed if I can afford it at that moment. So much smoother and trouble free IMHO. You think it's silky now, imagine it with a sealed cartridge BB:D.,,,BD

Lets hope the prices aren't too bad then, because I really do like the bike. My new Defy is light and fast and everything, but there's still something to be said about the smooth ride of steel. I also like the look of steel bikes more than most aluminum/carbon/Ti bikes.

EDIT: just checking in with one of the more popular bike shops around campus (funny story, Erik's bike shop moved in RIGHT next door to them, so I like to give them business when I can) and I might convert it to a single speed, because a BB overhaul with a single speed conversion would only run like $30-$50 YAY.

What am I missing? A BB overhaul should be the same price regardless of whether it's geared or SS, no?

$30 to $50 sounds about like the average cost regardless. You might be getting a slightly shorter spindle to get a better chain line, but otherwise the same price.,,,,BD

I've not yet found a reason to replace the BB in any of the bikes I've done yet, and they've all been cup and cone. Every one has had nice smooth bearing surfaces, spindles have been in good shape, etc. I did by the Hozan lockring tool and my BB service became a joy. I remove everything but the fixed cup, remove all traces of old grease, grease 'em back up and install. I've yet to have one not be smooth as buttah. BB service is all about the tools to do it right and to set the compression on the cups properly. If I ever wear one of my own out I'd probably replace it with a Shimano sealed BB.

I have to imagine that cup and cone BBs will last a DANGED long time properly and regularly serviced. Now that I have this ultrasonic cleaner my bikes will all get torn down every winter (I can only have a maximum of 5 so we're not talking a huge stable)...including the BBs.

+1 Out of the last 100 bikes or so, less than five needed new bottom brackets. The old cup and cone bb are very durable. (I have had a handful of cartridge bb that were shot.) Clean them up, install 22 new ball bearings at 2 cents each, plus a dob of grease and they are good to go. so 50 cents versus $50...

Yes, but that means periodic maintenance, which most people fail to do. Cartridge BB? None, forget it and ride. I have found 15 year old bikes with the original in good shape. Not trying to sound like a jerk, but if you ride often the conversion is worth it.,,,,BD

+1 The advantage to a cartridge bb is you basically set it and forget it (until it wears out). They do not last as long, but they do not require any maintenance either.

Maintenance? I find that my winter bike needs a complete overhaul every spring, but the fair weather bikes? Eh, I'll lube the chain if I feel like it...if it's got a cottered bb, I'll drip some Rotella down the seat tube...

Never had a problem, all very smooth, and really, no maintenance. Now, if it's a bike I put 100+ miles on per week, of course I'll tear it down yearly, but for the occasional riders? Meh.

I went from an old cup and cone BB to a cartridge style, but had the store put it in because I didn't have any of the tools for removal or installation. $20 for the BB, $9 for labor... I never realized how much drag that old dried up and pitted BB caused until the new BB was installed, smooth as silk! :)