What's new
Van's Air Force

Don't miss anything! Register now for full access to the definitive RV support community.

Wheel bearing grease

mdoyle

Well Known Member
Patron
I know there is a special aviation wheel bearing grease, do I really need to buy it or will any high quality wheel bearing grease be adequate?
There has been much discussion about the superiority of the Michelin Airstop inner tubes, are they so much better that I need to not use the Van's supplied tubes and purchase the Airstops?
 
mdoyle said:
I know there is a special aviation wheel bearing grease, do I really need to buy it or will any high quality wheel bearing grease be adequate?
There has been much discussion about the superiority of the Michelin Airstop inner tubes, are they so much better that I need to not use the Van's supplied tubes and purchase the Airstops?
Answers -

1. Only if you like spending money unecessarily! I'd recommend something from a major brand supplier with EP additive.

2. Only if you like having to add air every 2-3 weeks. I have the air stops and add once every 3-4 months.
 
Low Pass said:
2. Only if you like having to add air every 2-3 weeks. I have the air stops and add once every 3-4 months.

I have the Vans tubes and tires. 18 months and 245 hours later, I have only added air twice. Once was to increase the air preasure when I went from a nose wheel to a tailwheel plane. I'm not sure why people are having so many problems with the Vans tubes. Possibly the cores are cheap and leaking.
 
Aeroshell #16

mdoyle said:
I know there is a special aviation wheel bearing grease, do I really need to buy it or will any high quality wheel bearing grease be adequate?

My Grumman Maintenance Manual calls for MIL-G-25760 grease for the wheel bearings.... similar Cleveland wheels.

This is easy to get at any aviation supply place as AeroShell #16 grease. I would personally stick with the aviation stuff....

gil in Tucson
 
I use an automotive high temp EP wheel bearing gease that I used in a car years ago. I was too cheap to go buy a new grease. If you need to buy grease, purchase the Mil spec grease that is called out by the manufacturer.

The tubes supplied needed air once a month when inflated to 40. At 30 days, they would have only 20 psi in them.

The 'Air Stop' tires are ran at 30-35 psi and only add air (typically 5 psi addition) about every 3 or 4 months.

I now have over 1,964 hobbs hours after 9 years.

What ever grease you use, stick with it else you need to wash the bearings out with solvent. I only regrease the bearings about every two years or every other tire change.
 
What the manfacturer says....

Well I replied too soon, and didn't follow my own advice and check what the manufacturer actually says.... I'm guessing this is a later product than my 1977 era Grumman Manual... :)

Parker has their Technical Service Manual here...

http://www.parker.com/ag/wbd/cleveland/pdf/Wbtech.PDF

It calls out a later MIL-Spec, equivalent to AeroShell #22.

The Parker web site is here for aerospace products....

http://www.parker.com/ead/cm1.asp?cmid=349

UPDATE

I would disagree with Gary S. on not completely cleaning the old grease out and re-greasing each condition inspection. You need to fully remove the old grease to perform a good inspection....

A good reference on wheel bearings is here, describing the process....

http://www.sisuservices.com/Bearings.htm

It is item e(7) in FAR 43 - Appendix D

(7) Wheels--for cracks, defects, and condition of bearings.

How can you check the bearing condition when it is full of old grease?

gil in Tucson - don't act like Tim Allen.... :)
 
Last edited:
az_gila said:
How can you check the bearing condition when it is full of old grease?

gil in Tucson - don't act like Tim Allen.... :)

If there is something wrong with the bearing, you can see it, and hear it when you put the airplane way.

I have replaced TWO bearings on my airplane. Without cleaning the old grease out, I could see SPOTS on the bearing rollers and races.

I left the airplane in Sacramento and flew home commercial due to weather (RAIN). I got sick and it was too weeks till I went back to get the airplane. At the next condition inspection, I found SPOTS on the bearings. I assume that it was from the rain. They were smooth but I replaced them anyway. Yes I did clean them to examine closer but they did not need cleaned to find the potential defect.

I had several OLD TIMERS look at the bearing and tell me that I am wasting my money by replacing them.
 
bearings

bearing can fail several differewnt ways, inner races (need to be clean to inspect), outters no cleaning neccesarry and rollers..wellll careful as abrasive step wear on the end of the roller is some times difficult to detect. if youve got them apart for repack and they are at the threshold of failing. you wont see that on greasy bearings. whats another few minute to do the job right.those water marks mentioned earlier are problay harmless. people get away with less than standard bearing service because so few miles are accumulated on these bearings. use any good high temp extreme pressure (EP) lubricant and you'll be ok. jmho
 
Vans suggests Aeroshell #5. Is there really any reason not to use a high quality semi-synthetic automotive wheel bearing grease? Its a long drive to the airport and a short trip to the AutoZone!
 
ctbecker said:
Vans suggests Aeroshell #5. Is there really any reason not to use a high quality semi-synthetic automotive wheel bearing grease? Its a long drive to the airport and a short trip to the AutoZone!
The party line used to be...those automotive greases aren't intended for flight level temperatures. Coldest I've ever seen at normally aspirated altitudes was like 9F, though. Not like we're flying up to FL400. Even so I still use A/S #5 on my wheel bearings & tailwheel fork & what not.
 
ctbecker said:
Vans suggests Aeroshell #5. Is there really any reason not to use a high quality semi-synthetic automotive wheel bearing grease? Its a long drive to the airport and a short trip to the AutoZone!
No reason. Works for me.
 
Aeroshell 22

Is better for wheel bearings. A "high performance" grease if you will compared to #5
 
Another consideration

Light airplane wheels are quite small in diameter. That means they spin very fast at 75 mph. Wheel bearing grease of high viscosity (car grease) could contribute to bearing skidding, and therefore premature wear. If you are thinking about saving a few sheckels on grease, maybe look at boat trailer grease. Less viscosity, made for small-diameter, high speed tires.
 
You made me wonder how fast....

Yukon said:
Light airplane wheels are quite small in diameter. That means they spin very fast at 75 mph. Wheel bearing grease of high viscosity (car grease) could contribute to bearing skidding, and therefore premature wear. If you are thinking about saving a few sheckels on grease, maybe look at boat trailer grease. Less viscosity, made for small-diameter, high speed tires.

John,
My calculations for a 13" (O.D.) main tire @ 75mph comes out to be about 1950 rpm.
I'm not a bearing expert, but from my "industrial" experience I don't think this is terribly fast for a tapered roller bearing using grease as a lubricant.
On the other hand, I think all the points you made are very relavant. And the fact that you mentioned "bearing skidding" tells me that you know quite a bit about bearings :)

Mark
 
USED IT FOR 24 Years..

Yukon said:
Light airplane wheels are quite small in diameter. That means they spin very fast at 75 mph. Maybe look at boat trailer grease. Less viscosity, made for small-diameter, high speed tires.
STA-LUBE makes a blue grease (really stickey) for boat traliers. This grease has served me well and you can get it at NAPA autoparts.
 
ctbecker said:
Vans suggests Aeroshell #5. Is there really any reason not to use a high quality semi-synthetic automotive wheel bearing grease? Its a long drive to the airport and a short trip to the AutoZone!

One can get a lot of varying advice from builders' forums. Some of it reflects real knowledge, some of it reflects sheer ignorance, and some of it reflects a desire to penny-pinch and cut corners.

The difficulty is in determining which is which.

In this particular case if you are in any doubt you can play it safe and go with Van's recommendation. Then, at least, you cannot go wrong.

Personally, I used Aeroshell #5.
 
Wheel bearing grease again

The thread about wheel bearing grease got me to thinking. I know that it can be dangerous to think too much.

When I was younger and did all my own car maintenance I used to repack my wheel bearings every XX,000 number of miles (I can't remember the number). Now on an RV that is flown say 100 hours per year and makes one take off and one landing each hour, that's 200 per year. Let's assume that you have a mile taxi to take off and the wind changes and you have a mile to taxi again when you land. That's two miles per hour flown or 200 miles per year. It seems that repacking the wheel bearings every year or 100 hours isn't necessary. I certainly didn't do my cars bearings every 200 miles. I know that landing is harder because of the almost instant spin-up of the wheel, but this still seems overkill on the repacking thing. I'm also assuming that the bearings are not getting wet.

I still have the can of wheel bearing grease that I bought in 1962.

Bruce Reynolds
RV-6A 470 hours on grass
 
Gary Bricker

One of the main reasons to repack is to clean. The seals we use on aircraft are trash so they get lots of dirt in them.
 
Wheel bearing grease.

The folks at my FBO have suggested two choices for greasing my wheel bearings.

Blue High Temperature Grease. Li Comp NLGI No2. This one states "For Wheel Bearings" on the label.

or-

SILOO All Purpose white lithium grease. Label recommends for Automotive/Industrial and General Purpose use.

Bearings for the main gear are packed with a red grease and I would not normally be inclined to mix lubricants of different specifications so I intend to leave these alone. The Nose Wheel bearing is dry.

What are the recommendations of this community?
 
Cleveland Wheels & Brakes Tech Service Guide

The Cleveland Wheels & Brakes Tech Service Guides lists:
Wheel Bearings - Grease per MI L-G-81322
Aeroshell 22
Mobil 28

Now that is what we are suppose to use. For the past 12-years, I have used what ever I had on the shelf that I also use on my car and truck.

If you do not know if your new lubricant is compatible with the old, clean the old out with SOLVENT and repack with the new lubricant.
 
is aeroshell 22 red?

I sure would love to get some of the actual red grease that Cleveland uses, so that I would not need to clean out my brand new bearings. Is it a fair assumption that if it complies with the same mil-spec, it is compatible?
 
Check their instructions....

I think I rememeber my Groves came with a packing only grease and the warning that it was not for installation. A bearing packer tool is very inexpensive and handy to completely flush and refill bearings in a jiffy. The Aeroshell 22 in mine is tan colored.
 
I've been happy with Aeroshell 33

I don't use the more common, low numbered Aeroshell greases, but I've been getting good service from the synthetic Aeroshell 33. It is more expensive, but I believe it is worth it. It is dark green.

I use it on everything on the Skipper (wheel bearings, gear bushings, steering linkages, rudder pedals, etc.) It's not rated for high pressure wheel bearings (like big jets) but works fine on our light aircraft.

Here is some good info from the Beech Aero Club that might be helpful... I have direct experience chipping out the old clay base of dried up grease :eek: Never again!

But when the most common Aeroshell products hit the scene, they were (and are) based on what Shell Oil calls ?Microgel?. Microgel is Bentonite, AKA ?fine clay?. I used to use it to make drilling mud, for drilling water wells. In my experience, the clay does a poor job of holding the lube oil in suspension. Over time, it dries out as the oil drains from it; just like a lump of wet clay will dry out on your back porch. Unlike other grease carriers, when it dries out, it hardens up.

The prevention is to use a Lithium-based grease. If you must stick with an Aeroshell grease, the only one I?m aware of is their newer Aeroshell 33. It can?t be a coincidence that Boeing drove a new spec that led to the AS33 development. One of the published reasons, as casually mentioned on the Aeroshell website, was to move away from the clay-based grease. I?d bet my bottom dollar that they encountered lubrication and servicing failures related to bleed-out, and the associated dry joints, with the clay-based greases. One advantage is that the AS33 is touted as an all-purpose aviation grease; airframe, wheel bearings, etc.

- The conventional (cheaper) AS greases aren?t a problem where there are large clearances or sliding surfaces. Frequent lubrication with fresh grease also minimizes the exposure. Most shops will have fresh grease due to turnover. Most owners have aged grease in their guns, when they only use them once per year.

Aeroshell website text follows:

"For many years aircraft operators have been seeking to rationalize the greases used on aircraft and to reduce the number of different greases in their inventories. Recently Boeing began research on a new, general purpose, corrosion-inhibiting grease. The aim was for a non-clay based grease that would provide longer life for components and mechanisms and possess improved wear and corrosion resistance. This led to the introduction of the new Boeing Specification BMS 3-33.

"Owing to the wide range of operating temperatures, loads and other environmental conditions required for various aircraft components, several different types of grease with different desirable properties are used during routine lubrication of aircraft components. Boeing, in developing their BMS 3-33 specification, took account of the properties of the different grease types used on aircraft and wrote a specification for a grease which would provide improved performance and which could be used in the widest possible range of grease applications.

"Shell worked closely with Boeing during the development of BMS 3-33 and formulated AeroShell Grease 33 to meet the improved performance properties required by this specification. It was the first, and for several years the only, grease approved to BMS 3-33. AeroShell Grease 33 is also approved to the MIL-PRF-23827C specification."
 
Take your pick Red or Tan

Mobil 28 is Red
Aeroshell 22 is tan and thicker than Mobil 28

I am using Aeroshell because that is what was in mine when I got them.

I work on Blackhawk helicopters at work and they use Mobil 28.
 
Mobil 28 is awesome. Aeroshell 22 is an OK substitute. I always solvent the old out and press the new in.
 
If the bearings are new, they come with a shipping grease. That needs to be cleaned out and the bearing re-packed. I have used, for 29 years on my Warrior and now on my 6A a product called STA-LUBE purchased from NAPA AUTO PARTS It is wheel bearing grease for BOAT TRAILERS. It is stickey stuff, and you will like what you see when you go to service them the next time.............
 
If the bearings are new, they come with a shipping grease. That needs to be cleaned out and the bearing re-packed. I have used, for 29 years on my Warrior and now on my 6A a product called STA-LUBE purchased from NAPA AUTO PARTS It is wheel bearing grease for BOAT TRAILERS. It is stickey stuff, and you will like what you see when you go to service them the next time.............

I guess anything that keeps water out will work, but that bearing has a lot more speed on it than a boat trailer tire OR most car tires.
 
Not true any more....

If the bearings are new, they come with a shipping grease. That needs to be cleaned out and the bearing re-packed. I have used, for 29 years on my Warrior and now on my 6A a product called STA-LUBE purchased from NAPA AUTO PARTS It is wheel bearing grease for BOAT TRAILERS. It is stickey stuff, and you will like what you see when you go to service them the next time.............

They apparently ship them with the newly recommended grease in them now -

Beginning March, 2007 all active wheel assemblies listed in Table A4, except those noted for amphibious application, will be shipped from the Cleveland Wheels & Brakes facility with the bearings packed with Mobil Aviation Grease SHC 100, the approved preferred grease for all Parker Hannifin wheel assemblies.

So Mobil SHC 100 is now the good grease Parker recommends.

Straight from the Parker, hard to navigate, web site with an ugly url...

Gary S. - this is from the latest version of the Aircraft Wheel & Brake Manintenance Manual (their spelling, not mine...:)....)

http://www.parker.com/portal/site/P...lt&languages=EN&parentCh=FindCatlogId#results

Apparently it's a red grease with lithium in it....

http://www.exxonmobil.com/USA-English/Aviation/PDS/GLXXENAVIEMMobil_Aviation_Grease_SHC_100.asp
 
Last edited:
Aeroshell 33

I've been happy with Aeroshell 33 ...I use it on everything on the Skipper (wheel bearings,... -Dave Gribble

I am looking to pack my wheel bearings and I could use some insight. I read that AeroShell 33 is a substitute for Aeroshell 17 which is an airframe grease. The spec on Aeroshell 33 is -100F to +250F; whereas the recommended wheel grease is Aeroshell 22 at -85F to +400F. Help me out here, isn't the Aeroshell 33 a little low for disc brake temperatures?
 
I guess anything that keeps water out will work, but that bearing has a lot more speed on it than a boat trailer tire OR most car tires.

Touch the grease, then you will understand. The RV tire does go faster than the trailer tire .....................

But for a much shorter period of time.......:rolleyes:
 
Wheel Bearing Grease

I am assembling the Grove main wheels and the instructions say to use AeroShell #22 or similar grease to repack the bearings. Van's instructions say to use Aeroshell #5. The conflict doesn't surprise me - I'm just wondering what most people are using? My advisor recommended using a synthetic grease they use on the airliners.
 
Neither. The red EP synthetic grease you can buy at Autozone is far better than any of the aviation mineral-oil greases.
 
I use a good quality synthetic boat trailer wheel bearing grease. I look for a wide temperature range, the widest in the store that day, and good water resistance.

Dave
 
wheel bearing grease

The best I have found is Mobil 1 wheel brg grease in the tub. The red stuff. Far better than Aeroshell 5 or 22 in my opinion.
Jim
RV-6 N189EM
 
Anybody have working evidence that the red grease performs "better" than the AS22?

I've seen enough dried-up Aeroshell grease on various aircraft parts to make me not want to use it. Also if you take the cap off a tube and leave it standing on a rag, in a month or so the rag will get oily.

Locally sourced grease at 1/5th the cost that is synthetic are some other reasons.
 
Guess I'll buy that Bob. From a lube perspective we could probably get by on Crisco, but the drying and separating are pretty good points.
P.S. Ever see the grease spec'd for C441 trim tab actuators? Its like $130 for a 4 ounce tube.
 
I used Varsol to clean out the factory grease, then went back with Aeroshell #5 for the wheel bearings.

AeroShell Grease 5
Mineral Grease for Aircraft
Wheel bearing and engine accessory grease
Microgel thickened, mineral oil base
Meets MIL-G-3545C
P/N 08-05455
Combines high load-carrying ability with excellent resistance to water and high temperatures. It inhibited against corrosion and oxidation, and has a useful temperature range of -23°C to + 177°C. Used primarily in aircraft wheel bearings and engine accessories operating at high speeds and relatively high temperatures.
I used Aeroshell #6 for the general airframe uses such as greasing the landing gear mounts and the pivot points on the nose gear.

AeroShell Grease 6
General Purpose Airframe Grease
Microgel thickened, mineral oil base
Approved MIL-PRF-24139A
P/N 08-05460
Inhibited against corrosion and oxidation, it features outstanding low temperature torque properties and resistance to water. Useful temperature range of -40°C to +121°C. Used primarily in plain and anti-friction bearings on general aviation aircraft.
 
Aeroshell #5

Because that is what I had in the grease gun and what is generally recommended.
It is also recommended for your Hartzell prop so you only need one kind of grease for wheel bearings and prop.
I know, Aershell #6 for the prop if you think you are going to operate in sub zero temperatures.
 
VANS recommends Aeroshell #5. It's produced to the appropriate aviation spec. I don't see why anyone would want to use anything else......
 
Bearing grease?

Had my first flat and am trying to repack the bearings. I read all the bearing grease threads and bought all the recommended greases, including the Mobil SHC100 aviation grease for my Cleveland wheels. Some of the others I bought are a marine bearing grease, and a Mobil synthetic (non-aviation) grease from an auto parts store. I kept buying new greases to try because all of them are more like a tacky paste wax consistency than what I would think a grease should be like. I am afraid to use any of them because they just don't seem like they would be good lubricants, all too thick and tacky. Originally, I looked at some of them in my freezing cold NJ hangar but the new SHC100 is in my heated apartment and it still has the same consistency.

Can anyone offer some advice??

Thanks! Andy
 
IMO, you can use any good auto wheel bearing grease. If you want, Aeroshell 5 works well also.

Wheel bearing grease is thick, particularly when cold.
 
Back
Top