RandomTroll

I re-greased the bearings of the hub of the front wheel. 1 side was dry, the other not. I last greased it 1,381 miles ago, 2 months ago.
I keep it inside; I haven't been out in the rain. I cleaned it thoroughly and couldn't see anything wrong. The bearings are loose (no retaining ring): I can't forget the grease on either side. The hubs have seals. They're Shimano STX and at least 15 years old.

HillRider

Any chance you greased one side twice and forgot the other?

RandomTroll

No: the bearings wouldn't have stayed in the race without grease. And it worked well for most of the last 2 months.

FBinNY 

It's the Coriolis effect. Odds are the left bearing went dry first. If you lived in the southern hemisphere the right one would have gone dry first.

There's not much you can do about it, except move to someplace close to the equator.

Slash5

I know when I worked on buses, the curbside brakes always wore out first due to the dirt and crap on the shoulder.

HillRider

Cute analogy but not relevant. If one side of the hub has really lost it's it's grease but was properly lubed at first, this is unprecedented in my experience. The grease had to go somewhere and, if it leaked out, it should have been obvious on the hub's exterior.

Jeff Wills

If both sides were packed full to begin with, think about this: the hub shell is rotating about the axle. The axle has threads. Any grease that comes in contact with the axle will be pumped from one side to the other by the threads.

Doctor Morbius

There's no rational explanation unless the grease on one side was somehow contaminated and broke down. It'll have to remain one of life's mysteries like Easter Island, Stone Henge and people's fascination with the Kardashians.

rmfnla

rmfnla

Except most axles are not threaded all the way, only on the ends...

Jeff Wills

Still... any excess grease would be pumped away from the bearings on one side and into the bearings on the other side.

Andrew R Stewart 

Seems to me that a test of this theory might be to fill the hub shell completely with grease. So if a threading direction did "pump" grease to one side there would be excess grease coming out of one side only (after the initial squeeze out). (There being no empty space for the losing grease side to feed into).

Well, I've done that for many thousands of miles on a number of bikes with campy NR hubs. I've injected grease in all of the three ports at different times so that grease comes out of the other two ports. Many times on many bikes over many years. every few years I take the hub(s) apart to really clean out them and they have always had a lot of grease on both sides. Equally retaining old grease. I never have noticed one side's dust cap bleed out being more then the other side's.

So I think the threading acting as a pump for grease isn't what is happening for the OP. Andy.

Andrew R Stewart 

Further adding to this thread- I do see frequently rear hubs with significantly different grease conditions from side to side. But I attribute this to the bearing design differences. One side is deeper from the outside then the other. or has better sealing. or has greater loading. But as the Op mentioned front hubs... (IIRC) I don't really know what happened if the two sides were REALLY greased the same. Andy.

jyl

Most likely you are turning harder and faster to one side, so the g force (lateral acceleration) is pushing grease to the other side of the hub. Could be due to your daily route, see if it has more hard fast right turns or more hard fast left turns.

You might want to check your tires and chain, they may have uneven wear too.

The solution may be to use higher viscosity grease on one side of the hub.

Andrew R Stewart 

If this were the case we'd see this phenom on track bike hubs all the time. This would be talked about as part of the differing maintenance between road and track rigs. That it isn't ever mentioned or noted having happened suggests this isn't the cause of the OP's problem. Andy.

jyl

With track bikes, the lateral acceleration effect I described is balanced by the threaded axle pumping effect mentioned by Jeff Wills. The axle threads pump the grease to the left (NDS), while the lateral acceleration pushes the grease to the right (DS). This system is most balanced at the equator, as explained by FBinNY, but works adequately at most latitudes.

HillRider

I think (hope?) Jeff and the other offering this and similar "explanations" are doing so in jest.

Andrew R Stewart 

So if I rode around a track in a clockwise direction would both the axle thread direction (and it's pumping force) as well as the lateral forces remove the grease even faster? Again I just don't see this happening. Andy

2manybikes

The grease goes wherever socks go to in the dryer. It must be another dimension. I would not want to live there as greasy socks would be a big mess.

Andrew R Stewart 

Won't be the last time I debate a joke Andy

trailangel

""I re-greased the bearings of the hub of the front wheel. 1 side was dry, the other not. I last greased it 1,381 miles ago, 2 months ago.""

OK, so who re-greases hubs every 2 months?
The answer to this mystery is simple. In your mind you knew you forgot to do one side, so you took it apart to finish the job.

rmfnla

No, I think he's serious.

Perhaps he's thinking of the threads on old Campy BB cups.

Still, pretty high hopes for those little threads on an axle...

jyl

That is why velodromes are not ridden clockwise! When they tried it, grease spewed out of the NDS side of the bottom brackets, onto the track, and carnage ensued. Terrible crashes, and all cycling countries outlawed clockwise racing.

rmfnla

Dogs and cats living together...

Andrew R Stewart 

You know, this explains why when I mounted a tire generator on the wrong side and then test rode it a cone of darkness was sucked into the light and I didn't need to pedal. Andy