hamster

Mine don't spin smoothly. I took one apart, cleaned out the grime, and now I'm wondering what to use to lube the inside before resealing.

* WD40?
* Spray silicone?
* Red Devil grease?
* Dip it into molten paraffin wax?
* Toss it and buy a new one?

hamster

Generously sprayed it with silicone lube, let it dry, reassembled. Seems to spin OK. Most of the remaining friction is between the rubber seals and the cylinders. Will give it a try tomorrow.

Airburst

Whenever I repack cartridge bearings, I just inject the same grease I use on most bearings into them with a grease gun that has a fairly narrow tip. I can't vouch for silicone-based lubricant, at least not for use on bikes...

Kimmo

Wow, someone who bothers to pull cartridge bearings apart.

I'd love to see loose-ball versions of modern BBs... wonder if the various preload systems that are part of the cranks these days would be adequate.

Looigi

Many cartridge bearings can be disassembled. Remove the seal, press out the ball spacer, move all the balls one side, then lift out the inner race. Reassemlbe in the reverse order. That's usually not necessary. Just remove the seals, flush out the bearing with solvent, then reapply grease.

In removing press fit BB bearings, you often need to press them out by applying force to the inner race. This can damage (dent) the balls and races if the required force is high enough or is unevenly applied. If I need to press out bearings, I always replace with new. Of course, when installing, you want to push on the race with the press fit and not on the other race.

I found it useful to periodically add grease to my BB30 bearing every 1-2k miles or so. Remove the crank, remove the outer seal of the bearing, push in some compatible grease, reassemble. These bearings often have loose seals and little grease to make the spin more freely. This allows water in and grease out greatly shortening their life.

Kimmo

Most, AFAIK. It'd take a riveted bearing carrier to stop me, if I could be bothered.

I was more thinking of this; often pretty hard to remove them non-destructively, and disassembling in situ = PITA, if possible.

They're a PITA to disassemble in the best of circumstances. I like the almost-cartridge style you come across occasionally, like the BBs inside 6500 STIs. No integral seals, just an easily-removable plastic bearing carrier that easily pops out.

HillRider

None of the above. Use any decent automotive bearing grease or specific bike grease (Phil's, Finish Line, etc.) WD-40 and silicone spray are way to thin to last long.

squirtdad

OT but WD40 is not a lubricant.

MileHighMark

Chances are you're going to kill those bearings in short order. In addition to not offering sufficient lubrication under load, the silicone lube won't act as a barrier to dirt/water.

cxwrench

To back everyone else up, silicone spray IS NOT FOR BEARINGS. Grease if for bearings. You should take it back apart again and get some grease in those bearings ASAP, or your bb will be ruined in short order.

chriskmurray

Red Devil grease is a bicycle bearing grease which in those options is what I would use, the rest are very poor lubricants for bearings seeing heavy loads like BB's.

cny-bikeman

There are numerous greases that are more than sufficient for the relatively light loads that are present on all bicycle bearings, including the bottom bracket. A "waterproof" or marine grade grease is best.

Kimmo

Yep, the stuff they use for boat trailer wheel bearings is pretty well-formulated for our needs.

hamster

25 miles, so far no outward signs that silicone isn't working. I'll do one more ride and then take it off again and inspect.

Red Devil is very thick, the consistency of a jelly or toothpaste, and I don't see why it would be a good idea. I think it would just jam the bearings. I had another sacrificial bearing that came with a SRAM X9 crank, took it apart, it was packed with something like Red Devil inside. It was barely spinning. Started spinning after generously washed it with WD-40 and got most of the grease out.

Airburst

The drag from even the heaviest grease won't be noticeable when the bearing's actually installed, you've got a lot of leverage to turn it, after all, and it doesn't increase with the load on the bearing.

HillRider

25 miles is nothing and you are indeed doing bearing damage. Properly lubed bottom bracket bearings should last 10's of thousands of miles. Yours certainly won't if you continue to use that silicone spray.

I didn't recognize the "Red Devil" brand name but a moderately heavy body grease (jelly or toothpaste consistency is fine) is the proper type and, no, it won't "jam' the bearings, it will protect them. Use it.

cxwrench

You're getting some really solid advice here and it sounds like you don't want to believe it. Trust us, you need to grease those bearings. It's pretty obvious that this is your first time doing something like this. My first time was 40 years ago. You posted on the forum asking what to do. People w/ decades of experience are telling you what to do. Take the advice and you're good. Ignore it and you'll be buying new bb bearings in a month.

hamster

Put another 25 miles on the bike, took off the crankset, took out the bearing. It looked normal with no evidence of damage. Just in case, packed the bearing with red devil grease and reassembled. It spins with more resistance than before, especially when the crank bolt is tightened to spec. By my back of the envelope estimate, we're talking about power losses of ~2 watt at 90 rpm, so, not a big deal.

Gravity Aided

Marine bearing grease works great for me, and I still winter cycle a decent amount. I wouldn't think of not using marine bearing grease or white lithium grease at least on a bottom bracket.