For my job I get the opportunity to visit many different types of manufacturing facilities. Last week I was in a major bearing manufacturer’s plant where they make and assemble wheel bearing hubs, water pumps and other automotive parts. I saw how they made and assembled a wheel hub for some type of vehicle (don’t know which one) from start to finish. Very impressive – from the inspection of the material used, to the machining of the parts, to the measurement of EACH part to be matched with other measured parts, to the assembly, to the testing of EACH for run out, to the noise testing of EACH hub run up to 1600RPM…

It was amazing to me how many checks and tests and measurements were involved (all automated of course) in the mass production of a fairly simple wheel hub - not like the one on my Ram.

What I couldn’t believe was the amount of grease that was put into the “sealed” hub bearings before the final assembly. I asked my guide about the incredibly small amount of grease and he said that the grease was put in by weight and that too much was bad for the bearing. The amount put in was barely enough to cover about three of the 16 rollers in this hub – less than the amount of toothpaste I put on my toothbrush. It seems amazing that after all of the processes they go through to make and check the hub that they do not put in more grease.

I can’t understand how less grease could be better.

Anyone here a bearing expert that can explain this to me, or are they just making sure you have to buy a replacement part sooner.

 

Finally a topic I can speak to. I work in the bearing business. The best thing for the bearing business is too much grease. It is far and away the number one reason for bearing failure!

Grease serves two main purposes. One: To lubricate Two: To carry away heat generated by the compresion of the rolling element (Ball, needle, spherical roller, cylindrical roller).

The only place grease performes it's number one function is in between the rolling element in it's load zone and the outer raceway(Race).

In a ball bearing, such as the ones you saw manufactured; we see "point contact" the ball only truely makes contact at one point, for some, like the ones you viewed that contact is less than the that of this next character .

Any more lubrication than that is not just waisted but actually begins to generate heat. Think of running in a pool of water up to your ankles. Now, think of running in a pool of water up to you hips. You still end up with just as much water under your feet but it is much harder to move forward.

I am glad to pass this information along, I have been in the bearing business now for about 15 years and would be glad to give you anymore information you would like.

 

My front bearings have 302,600 miles on them and are still quiet and smooth. I know the day is coming, but with the heavy use I have I am impressed. Same for the U joints and center bearing. Front end has never been aligned.

 

That's pretty cool Tfeore!

How much do the rollers flex on, say, something the size of our wheel bearings? That is pretty cool that they only make contact the size of a . ! So are they made out of a "springy" steel or are they hardened (if they are that would mean any flex is a bad thing, right?)

Who says you can't learn anything on a Sunday?

 

Different manufacture, different philosophy. The rolling element actually does compress through the load zone, there is a fine balance when it comes to heat treating. Too hard, brittle product, too soft, rollers wear quickly. Bearings are really quite amazing. It always frustrates me when a guy comes to the counter and complains about a 25mm bearing assembly costing 15 bucks. People have no idea what goes into one. Oh well, I like the mystery of it all!

 

Would the same small amount of grease apply to non-sealed bearings? Are there applications/types of bearings that this does not apply to?

Gives a whole new meaning to "packing" a bearing, huh?

 

That's exactly what I thought, Andy! My buddy was talking the other day about how he packed so much grease into his wheel bearings on his 78 2WD, maybe it wasn't such a good thing...

 

If it's an open bearing it will throw out what's not needed. Grease will circulate in and out of the bearing. It's very important to use the correct lube for the bearing.

AlpineRAM

 

When you refere to "Packing" your wheel bearings you are setting yourself up for the next several thousand miles and lots of space for extra grease. Technically the bearings sidewinder talks about are know as "lubed for life"

You pack as much grease as you can in between the tapered rollers and what you don't need gets pushed away and into a cavity.

The sealed ball bearings originaly discussed only have a small "cavity" to escape to. Your front wheel bearings have ~20X as much space so 20X as much grease ends up being ok...sorta...

 

The old man has to add what we "used to do" Before wet wheel bearings that big trucks now use, the bearings had to be packed regularly. One option that I always did was to put a grease fitting in the grease cap. At each truck lube, fire about three shots into each wheel. What it did not want would push out the felt seal at the back of the wheel. Of course this was with wheel bearing rated grease. Never lost a bearing. Rarely had wear enough to rate changing the bearing at brake replacement time.

 

I would say with that kind of maintenance you wouldn't be looking to lose a bearing. Your shots of grease helped expel the contaminates as well as refresh the lubricating properties of the grease.

Bearings are an amazing product that we all pay little attention to. When they do their job nobody knows they exist, when they fail we all pay the price(Lost production = higher sales prices). Bearings are an intergal part of our every day lives. We need them like we need the railroad, the truckers, lineshoremen.

OK, I'm off my soapbox!!!! Which coincidently could not have been made without bearings....

 

Ok ... here is a question for you.
When I am using the shop's wheel bearing grease packer, should I be wiping off the excess grease on the outside and just rely on the stuff between the bearings to do the job ?? I always thought more was better but then again, I didn't think about the heat issue.

PISTOL

 

OK, I'm off my soapbox!!!! Which coincidently could not have been made without bearings....

CAREFUL, wouldnt want it to roll and you fall off.

good info, maybe i may want to re-think my servicing of my snowmobile, every year i take the seals out of the "sealed" roller bearings, clean them and pack grease in them, some seeps out, but since doing this (the past eight years) i have not lost a bearing. guess i have been lucky, i was losing one, (and the idler) every ride. now this is the ritual my riding group goes thru every fall.

 

P.W. the extra grease will make no difference. The grease will spin away with centrifigal force. You don't really have to worry about it for tapered roller bearings. As far as upersleder's bearings, if you are going through that much hassle to protect a 15$ bearing you should be buying new ones!!!! Look at the inner race, get the part number and I'll get you some new ones....Don't waste your time. But if it's a ritual and you guys have fun doing it then by all means go for it!!!!

 

i do get new ones every few years, but when you have eleven on the sled it can get kind of expensive, so the few hours and a little synthetic amsoil grease lets me go on a couple more rides for the season.
which brings me to one of my favorite sayings.....NOTHIN MONEY CANT FIX!!!