Bicycle Mechanics - Grease injectable BB?
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03-08-11, 07:26 PM
The advertising brochure for my 1989 bridgestone Comp MB2 says it has a 'grease injectable bottom bracket'. I bought the bike new and am overhauling it after not riding for a long time. I can assure you there is no grease fitting or other provision for injecting grease into the BB. I have replaced the original 3SB spindle and cups and there was nothing different about them. The crank arm bolts are normal - no secret passages. Even if you could shoot grease in via the seat tube, the BB came with a plastic protector, so it couldn't get to the bearings. I'm completely stumped and can only surmise that perhaps it was a feature on the MB1 that got into the brochure by mistake, but I thought I'd ask if any bike has a 'grease injectable' BB, and how does it work??
03-08-11, 08:13 PM
I was curious about your question, so I did a bit of searching. It appears your Bridgestone came with a Suntour bottom bracket. If you do a search for Suntour Grease Guard, you should get some information.
What I found indicates that the injection port is indeed through the (hollow) crank bolt. The bb spindle is also hollow, allowing the grease to reach the bearings through an exit port inside the bb shell. If your replacement spindle and crank bolts don't have these features, then I imagine you're back to a standard bb with normal maintenance.
Go down to Suntour XC Pro Grease Guard BB
See bottom right of photo for BB info
I'm still running my old Sun Tour GG bottom brackets. You grease it through the spindle bolts, and it pumps grease directly to the ball races through two small holes in the spindle. You need to do each side separately, and excess grease weeps out from under the spindle seals and needs to be wiped off.
The original spindle bolts are hollow and a rubber disc under the dust cap keeps them clean.
With regular care (I do it twice a year on the all weather commuter bike) the BB lasts someplace close to forever, without needing disassembly. To take advantage of this feature you'll need a grease gun with a pointy tip.
03-09-11, 12:40 AM
I have a Grease guard BB , NIB , want it?
03-09-11, 07:09 AM
'Ask and ye shall know' :)
Thanks for the info. I never removed the dustcaps when I had the bike originally, and while it was out of my hands the BB was replaced. When I got it back it had the wrong Shimano cassette in it, throwing off the chainline, but the old spindle was with it along with the bearings and cups. I kept the old spindle until the new one came in for comparison, but I just didn't see any grease outlet holes on it - but then again, I wasn't looking for them, either.
BTW, the original BB was a Sugino. I still think that the bike never had the Grease Guard BB. I put it on lawaway back in '90 and it took me a few months to pay it off. $600 was real money to me then. I wouldn't be surprised if the shop owner changed the BB out before I got it.
Anyway, thanks, all! I'm glad I asked. Always good to learn something.
03-09-11, 01:25 PM
Here you go:
Actually, the zerk is just filling the hole until I can find a proper oil cup. It's just for looks anyway since I'm using a cartridge bottom bracket.
03-09-11, 01:29 PM
I have several Suntour grease guard bb's that I plan to hang on to... their rarity might stem from the fact they were really expensive in their day and probably did not sell well despite their good design.
Also have a matching headset in one of my bikes as it was originally equipped with XC Pro.
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