anyway to seal up bottom bracket bearings ?
 

Ok I have a cheapo play bike...Mongoose Dolomite,,,the BB bearings are NOT sealed,,,I have greased them but is there a way to seal where the crank goes thru to stop water/dirt intrusion ?

When you grease them , you can grease the BB axle where the bearings ride and as the axle spin it will do it own seal around the opening of the cups.

Foam cut to fit or O rings between crank and BB face. First step though is to overhaul it and reassemble with a marine/waterproof grease, and enough of it to provide a continuous seal.

For not a lot of money you can put a lower end Shimano or other sealed BB and be done with your problems. One time expense and no greasing required. Roger

You sure it's not sealed?

I googled "Mongoose Dolomite" and the pictures showed a Shimano crank. That leads me to think it would have a low end cartridge bottom bracket. BB spindle length for that bike might be wider than is commonly available due to those fat tires.

uh,,,yea,,,im sure :) I took it apart yesterday...there is the crank spindle and two cage bearings,,,dry,,,no grease,,,t has the adjusting nut on one side and fixed on the other,,,a name that looks like china on the spindle...Jen Wang or something

you can't use the typical "accordion" that takes up the empty space in the bb and seals against water getting in the hole in the bottom of the BB shell?

Don't mistake a sealed bearing with one that won't get contaminated with rain and grit over time. I've had many dozens of customers come to understand that water gets past any efforts of humans to keep it out. Andy.

The best way to seal that gap between the spindle and cups (without replacing the whole bottom bracket with a cartridge-type) is to replace the cups with some that have rubber seals built-in, like these: YST CORPORATION KING RITZ ENTERPRISE CO., LTD. - bicycle parts, threaded head set, ahead-cap, sensor, differential gear device, bicycle accessories range
http://bikeforums.net/attachment.php...hmentid=409440
We used to sell them for less than $10 at my old shop.

That may be the least expensive manufactured solution, but the DIY ones I mentioned are inexpensive and do not require BB disassembly. I found some similar with a search but they're over $40 on ebay. Also, some of those cups were thick enough that one had to use a different spindle to get the proper chainline.

Here is what I have...now is there a better way or bearing ? have tons of o rings ...would I just slide it over the crank spindle up tight against the adjustment nut ? Not sure it will stay there....super glue ?

And thats just how it came out...no grease...pretty dry...I still dont know why I dont plug the holes in the frame on the inside of the BB and drill a hole and put in a grease fitting...then pump full of grease ??? Or is this overkill....

I am a noob so don't mind me but I do believe I read that Forrester recommended something like that in his book "Effective Cycling"...

You would have to fully seal the space between the bearing cups with a rigid tube.. Used to be a Zirk Kit ,the sleeve between the cups
rigid plastic, then you drilled thru shell Zirk is a common grease fitting.

O rings slip snug on the spindle stay there because the crank arms are put on , next .. so use just the right number of Rings.


Not unusual to go really sparing on grease when making a run of several thousand things to cut grease expenditure overall .

A really cheap selling bike the motivation to use none is strong..

A drain hole at the bottom of the BB would be a good idea since moisture will almost always find a way in and needs a way to escape and seeing how you have holes for the other connecting tubes to the BB they may be open from the top as well and will just pool moisture if the BB holes are plugged. I really don't understand why mfrs. don't put drain holes in all frames, seems like a no brainer.

WHY would I have to seal off the space ?? Why not just pump the space full of grease ?

My crank arms are far away from the bb so I would need a bunch of orings on either side

BB shells are Predominantly open inside, to the tubes attached to it.
You would be be filling up the seat tube, chainstays,& ,down tube ends with the grease otherwise ..


if you say so .. O ring + some rubber hose on each end , instead..

The act of putting the crank arm on is the force keeping the O ring against the Face of the cup

it wont tend to stay close enough on its own ...

Ive greased an wrapped pipe-cleaners around the spindle
before to try to get the BB grease to stay uncontaminated longer..



You could go out and look for another BB.. there were some made in past years
with a channel for the O ring in the cup's. edges.




the engineers want to move the Bearings further apart these days .

lighter stiffer faster ..

The O-ring suggestion was for a smalll gap, foam for larger. Get a single piece of foam pipe insulation at a hardware store and cut the length you need for each side. put a thin layer of grease on the axle (not on the flats), the face of the BB and the crank arm. Or you can put grease on the BB and crank arm and just run a bead of silicone seal in the gap - easily removable. I agree that a drain hole in the bottom may be a good idea, especially if you ever leave your seat post off in the rain.

Also don't neglect the headset if you don't have fenders. First overhaul the headset. Before you reassemble find a discarded inner tube (bike shop will have) large enough to easily stretch over your head tube. Cut about a 2" section, grease the inside and fit it over the head tube. Reassemble the headset/fork and pull the inner tube down over the lowest part of the headset that is on the fork.

yea the holes from the tubes are real small...blow up my pic and you can see them...I would plug them BEFORE filling the bb thru a grease fitting....

I just pulled the headset,,,same thing ...dry....no surprise....I already drilled the hole,,,but im thinking of the grease fitting...but im not sure IF ill keep this bike or sell it and buy a decent one...I want to try it in the snow first...its heavy, almost 50 pounds and it gives a workout but I like that....ive ridden it only about 200 miles and its fun for a cheapo bike,,,I have a Giant hybrid and a Giant carbon road bike...I basically bought this for a crap weather winter bike...or to ride when trail riding with my wife on her hybrid as my speed would be slower and we could ride more together...

a rolled up piece of alumimum drinks can with the wrap over glued together , may Do, fine.

A liberal application of waterproof grease will do the same as all the tricks people have posted, with a LOT less work. I have used this style of grease on open bearings for years and have yet to replace one I greased. I also open up the seals on sealed bearings and fill them with this grease too.

-SP

Yes, Stein made a Zerk fed BB sealing kit. As FB describes, a plastic sleeve (with a rubber center ring to allow some compression), a Zerk fitting with a long threaded section and a bunch of compression seals and "O" rings sized to fit over the axle but inside the crank arm. I installed many BITD. I still have one or two NIB on my shelves. But I'll never sell them. Instead I'm waiting for the bike mechanic's museum to open and I'll donate one. Andy.

BITD one of my mechanics installed the just mentioned Stein sealing system in his bike. He grabbed the grease *** and pumped away. But soon the *** ran out of grease so he refilled it and continued. After some time he asked me to take a look. We confirmed that the grease was leaving the ***. I told him the only thing he could do was to take it all apart (which is a pain given the Zerk's access hole's lining up with the internal sealing sleeve) and he'd probably find his frame full of Phil. He did and he did. Seems that he didn't remove the OE seals from the BB cups, they were tight enough so that the next point of escape was found by the pressured grease. We estimated that the DT was about half full. Andy.

is there such a thing as non waterproof grease ??? I really dont think so