BMW wheel bearings,

BMW motorcycle wheel bearings, 1956 to late 70s

By Duane Ausherman

Wheel bearing basics

The post war (1955 on) BMW was designed to withstand the forces of a sidecar, the same as a car. To properly support a car or truck wheel, the bearings must withstand great side loads. Unlike a car, a solo motorcycle only needs to support forces through the vertical axis of the motorcycle. A BMW, in solo operation, has at least 1000 times the capability that it needs. The system costs a bit more and requires some special maintenance. The system can easily outlast any other moving part on the motorcycle. BMW has the best wheel bearing system of any motorcycle. See the engineering calculations at the bottom of this page.

The wheel hub has a bearing on each side to hold it up and allow it to rotate. These bearings are tapered and have rollers, not balls. The two tapered bearings are opposed to each. That means the tapered parts are angled or pointed in towards each other. Tapered bearings need some preload, or pressure, to obtain maximum life. Cars have some type of externally adjustable nut to set them correctly.

BMW wheel bearing basics

I can't recall ever seeing a BMW wheel bearing fail from wearing out. The most common failure of the bearings is caused by foreign material contaminating the lubricant. It is usually water and soap from high pressure washers. One can reduce the chance of failures by keeping the spray off of bearings in the wheels, steering and swing arms.

The front and rear wheels are different. The rear wheel has a drive spline and a 18" wide rim. The front has a narrow 19" rim. The bearing systems are the same for the front and rear wheel. The only real difference is that the front axle is smaller in diameter than the rear. A spacer is inserted into the front wheel hub to allow for the smaller axle. The front wheel bearings are treated exactly the same as the rear. These bearings are the same size as the rear swing arm bearings.

The spacing system for the BMW is internal. It is in two parts that are located between the bearings. The first, the inner spacer, is in two parts and holds the cones (inner race with rollers) apart. The second, the outer spacer , is one part and holds the cups (outer race) apart. Changing the length of either will change the spacing or preload. BMW provides for this adjustment of the spacing, or preload, by changing the length of the inner spacer. The smaller of the two, comes in many sizes and it resembles a wedding band. Wedding bands are made in small increments, so it would seem that a box full is needed to adjust the spacing. It's actually not so hopeless. The /2 wedding bands are in increments of .1 mm or .004 of an inch. The /5 are made in .05 mm or .002 of an inch. The two bearings and spacers are called a "stack." It is removed as a unit.

Checking the spacing of the /5 and the /2

The BMW method requires removal of the stack to check or change the spacing. This is not only time consuming, but allows for an inaccurate result, especially with the /5. A common failure of the /5 is the bearings becoming loose in the hub. The wheel is then loose on the axle and allows for funny handling and tracking. It is easy to test for this failure and prevent it.

Warning, use only the very short 22 mm wrench from the tool kit or a torque wrench. Using the short wrench makes it hard to over tighten the nut.

I have a very easy test that you can perform to determine the spacing. I call it the "shake the wheel" test. This takes two persons. Have your helper, on the right side, with the 22 mm wrench at the axle nut. Have the pinch bolt loose. You are on the left side with the wheel in your hands. Top and bottom is the best. Try to feel side play, you should feel nothing with the axle nut tight. Loosen the axle nut a turn and feel the play. As you gently wiggle the wheel, have the helper slowly tighten the nut. You should feel the play decrease and finally go away. Yell stop. Repeat this several times and arrive at a tightness of the nut where the play just goes away. It should be about 25 lbs of torque. Change places and repeat until you both arrive at an agreement of the axle nut tightness to eliminate the play. A torque very slightly tighter than this is preloaded properly and gives the longest bearing life.

Typically, especially on the /5, you will have discovered that the nut ends up with only a few lbs of torque. This means that the bearings are spaced too tightly. If the nut is now tightened up to 25 lbs, the bearings will overheat and may spin in the hub. This may ruin the hub.

If the nut is at about 15-20 lbs when the free play goes away, then you have properly spaced bearings. If they are kept clean and lubricated, they will last almost forever.

If you can still feel play with 25 lbs of torque, they are too loose, or you may have a problem.

The easy fix for the /5

To change the spacing means changing the thickness of the inner spacer, or wedding band. By installing a thicker one, it will space the bearings looser. This will fix the problem. This can be done by one of two methods. I will first describe a method that doesn't even require removal of the wheel from the bike.

Pull the axle. Remove the 5 bolts holding the chrome hub cap onto the wheel. Carefully remove the cap and the seal holder. Be careful, the cone of the outer bearing can fall on the ground, or it may stick to the seal holder. The wedding band may even stick to the bearing too. Remove the wedding band. Try to pull the outer bearing race, or cup, from the hub. If it comes out, then it is already spun in the hub and should have been felt, during the test, as play that didn't go away. The bearing will probably still be ok, but the hub is not. See "fixing or replacing the hub" below.

Replace the wedding band with a thicker one or add a "shim" to the existing one. Shims are available from me and wedding bands are available from your BMW dealer. Which size of wedding band do you need to buy? You probably don't even have a micrometer, much less a metric one. With shims it doesn't matter. More on shims below.

For a quick test, reinstall everything, but the chrome hub cap. Don't forget to put the top hat spacer into the seal holder. Those 5 bolts don't really do anything in this test so just use one to keep the parts from falling on the ground. Reinstall the axle and perform the "shake the wheel" test again. To reinstall the axle, be sure that you know how to do it, or go to http://www.softcom.net/users/w6rec/axlepics.jpg to see the correct and incorrect way. Keep adding spacers or shims until the play just goes away when the nut is about 15-20 lbs of torque. It is better to be too loose than to be too tight. If one wedding band produces a spacing that is 10 lbs and another one produces 25 lbs, go for the 25 lbs. You could lap the wedding ring down a bit and get 15-20 lbs too. Shims make the spacing easy. Install all 5 bolts and go riding.

This "easy fix" only fixes the spacing. This method assumes that both bearings, seals and lubrication are ok. If your bike has junk bearings, no lube or shot seals, then you are wasting time with this type of procedure.

Full service of the /5 bearings

For both the /2 and /5, BMW recommends about the same maintenance schedule for wheel bearings. Here you will learn how to get more reliability and with less service. BMW wants us to remove the "stack" every 8 or 16 k miles and fully lube and check the spacing. This is not needed and on the /5, and it can harm the hub.

The reason for renewing the lube is twofold. One, it assures lubrication. Two, it cleans out dirt. A type of greasing tool can be bought or made that will lube both bearings without removing anything, but the axle. With that tool, one can give it a shot of grease every time a tire is changed. Not a lot of grease, but a pump or two. The first I knew of this tool was when my ace mechanic, Brian Hilton, suggested it. He made one and it worked beyond our expectations. It just slides into the axle hole and has O-rings to seal off the bearings. A hole through the center allows new grease to be pumped into each bearing from one side. The old grease is pushed out the other side. The hub isn't threatened by being heated or the hammering on the bearing stack.

This tool can be purchased from Ed Korn at http://www.cycleworks.net/ very cheaply. The shot is so close that it is distorted a bit. It is exactly 2" long.

To remove the /5 bearing stack

1. Remove the wheel.

2. Remove the 5 bolts, seal holder and hub cap.

3. Insert an axle into the brake drum side. This is backwards, or the "wrong" side.

4. Install the BMW special tool. Get a 3/4" X 4" plumbing nipple from any hardware store. Depending upon the model of BMW you may find that 4" is slightly too long or too short. You can use one of the top hat spacers to make up for a short one.

5. Put the washer and nut on the axle threads. The nut should tighten up on the nipple, which puts pressure on the bearings. This holds the "stack" together.

6. Heat the hub up to about 250 F degrees. Set the wheel on the floor and hold it up between your legs. Hold the axle in one hand and use a plastic hammer to gently tap the stack out of the hub with the other hand. If it doesn't come out easily, then heat it up more. Keep the axle totally straight so that the bearings stay straight. If they get cocked off to one side, they will try to gouge the inside of the hub. Don't try to drive it out cold, you will ruin the hub. If it doesn't come out easily, then heat it more.

7. Disassemble the stack, noting the position of the top hat spacers on each end. The left top hat spacer will have stayed in the seal holder when you removed it. The bearing cone often sticks to the seal holder. These top hat spacers are for one purpose, to transfer pressure from the axle to the bearing stack, through the seal. The top hats ride in the seals so they need to have a smooth surface.

From Left to Right

The top hat thrust spacer, seal holder (this one is from a /6) bearing cone, bearing cup, wedding band spacer, Inner spacer, outer spacer, bearing cup and the bearing cone. No top hat spacer is shown on the right end.

8. Clean the bearings and inside spacers of all grease.

9. Inspect the bearings for pitting and stains from water. Replace as needed.

Time out. You aren't really ready to do the spacing just yet. This part of the procedure is my addition, but it is worth the trouble. I have had lots of experience with the /2 and later the /5. The axle nut tightness thing was found to be a bit spongy on the /5. Not at all solid like the /2. I like to partially fix this. BMW didn't machine the spacers very well. They had two defects.

First, inspect the the outside spacer, larger part of the inside spacer, and the wedding band spacer with a good eye or magnifying glass. The machined ends are poorly cut. They are rough. Cleaned up faces offer more surface mating area. This reduces some of the spongy feeling.

Second, the ends should be parallel with each other and square with respect to the length. About all you can do is to get them parallel.

I lap them to be smooth and as square as I can measure. I use a glass plate as my surface. It is 9" X 15" and useful for fork work too. I use #400 grit black paper for the abrasive surface. Add solvent to the paper to reduce it's tendency to clog up. Rub them in a circular pattern. Change the place you hold it by 30 degrees. This will insure accurate lapping. As they start to clean up, check for parallelness if you can. I have seen them .001" out of parallel.

Spacers on #400 grit water proof paper on a glass plate.

10. With only a drop or two of oil on each bearing, reassemble the stack and the tool on the axle. Put the washer and nut on and only finger tighten it.

11. Put the stack in a vise, vertically, and tighten it on the nut.

12. Use the tommy bar, or a screwdriver, in the axle hole to tighten and loosen the axle. As you slowly tighten the axle, continue to rotate the bearings by hand. The large outside spacer should be easy to move sideways with medium thumb pressure. That's the visible part between the bearings.

13. Expect the spacer to tighten up at a higher torque than you found by the "shake the wheel" test. If the spacer gets tight at a torque lower than 25 lbs. the spacing is too tight. If the spacer is still loose at 25 lbs. the spacing is too loose. BMW wants you to change the wedding band spacer until you reach the correct spacing. With shims, you can just add them until the correct spacing is reached.

14. When the outside spacer moves, with medium thumb pressure, at 25 lbs of torque, BMW is happy. Don't you be, because this is wrong. What BMW didn't know is that when the heated hub cools, it contracts and shrinks down on the stack and tightens it up considerably. I go for the stack to be slightly loose at 25 lbs. We will shim it to perfection later. It's time to reassemble.

15. Lube both bearings and assemble everything on the axle. You can't over lube it. Tighten it up to about 10-15 lbs. Set aside.

16. Heat the hub as before and slide the stack in quickly. It will go easily as the hub is expanded and the cool steel stack is contracted. If you have any doubts, freeze the stack first. BMW did it by freezing the stack in dry ice for an hour and putting the stack into a room temperature hub.

17. Perform the "shake the wheel" test again. If it tightens up at a lower torque than 15-20lbs, add one shim at a time until it passes the test. The shim goes under the "wedding ring" spacer. Now it is "captured" in place.

18. Install the hub cap and 5 bolts. Tighten them only when an axle is installed. This causes the seal to "center" itself. If the seal holder is tightened up "off center," the seal will rub on one side and fail quickly. This "worn space" may allow contaminates into the system.

From now on, you only need to give the bearings a shot of grease at each tire change and perform the "shake the wheel" test. You won't need to do a full service for a long time. I would want to look at it again in 50,000 miles. By not removing the bearings every 8-16 k, the hub is less stressed. Find the greasing tool and use it.

The ultimate test is to ride 100 miles on a day of 100 degrees and then perform the "shake the wheel" test. It should still tighten up at less than 25 lbs.

Balance the wheel at every tire change. Static balance is good enough up to any speed that a stock /5 will reach.

Fixing or replacing the hub

A hub with a spun bearing is evidenced by you being able to lift the outer race out of the hub, without the use of heat. The usual bearing to spin out is the one on the left side, but the inside one can spin out too. If the race just barely slides out then maybe one can get away with Locktite to hold it. If the race is loose and wobbly then replace the hub. A really excellent machinist can bore it out and press in a sleeve. It is very hard to maintain "centers" with the brake drum. You may trade one problem for another one. Finding a good used hub is very difficult. Most of them have already been bought up fixing this common problem. A seller may not be able to determine if the hub has been spun out.

/2 wheels

The front and rear wheels are exactly the same on the Earles fork twins and on the singles. The twins have 40 spokes and the singles have 36. The wheels are interchangeable between front and rear. In 68 and 69, BMW produced a model we usually call the US model. It has telescopic forks and has different front and rear wheels. The wheel bearing system is exactly the same as the others. This article calls the entire production of all models, twins and singles, from 1956 through 1969, the /2.

The bearings are the same for the front and rear wheel of any one model. The twin uses the 30204 and the single, a smaller bearing, the 30203. The only real difference is that the front axle is smaller in diameter than the rear. A spacer is inserted into the front wheel hub to allow for the smaller axle.

The wedding bands are in increments of .1 mm, or .004." My shims are in increments of .002" or 2 times more accurate. In spacing one stack, it isn't a big deal to lap the spacers to get it perfect. If you will be doing this on several wheels, consider the time savings and accuracy of using the shims.

The hubs are steel so the expansion, from heat, of the bearings and hub is identical. The amount of interference fit can be much less. This virtually eliminates the chance of spinning the bearings in the hub. I have only seen one /2 hub fail from spinning bearings. Before 1965 the seals were made of felt and not very effective. In 65, BMW changed to a modern knife edge seal and they worked much better.

The "shake the wheel" test works well on the /2. It will fail much less than the /5. The change in spacing from the "axle in the vise" to the fully assembled wheel is much less and almost insignificant. Because of this, we assumed that it would work the same way in the /5. It didn't. In my opinion, BMW was also lulled into this fallacy.

/2 bearing removal and spacing

The /2 has a seal holder, with 4 holes, that requires a special tool to remove it. Buy or make one. Never use a hammer and punch to remove the seal holder. It is very important to mention that this seal holder does not need to be tight. Tightness only makes trouble. I only put it on about hand tight. That means hand tight using the tool below, but not with a breaker bar in it, just by hand. This dust cover has nothing to do with the pre-load on the bearings in any way. In the center of the dust cover is a tension bushing. If you removed that bushing and installed it on the axle, you could leave the dust cover off entirely. The bearings would get dirty, but the bearings system would be fine. Tightening the dust cover only makes trouble.

Directly under the hub cap is a wavy washer that keeps tension on the hub cap. The seal holder and seal are only needed to keep foreign material out. The bearings don't need them or the wavy washer and hub cap for spacing purposes.

The left one is my homemade tool. It is make from an old seal holder. Pins were pressed into the four holes. A half inch drive socket was welded on the back side.

The right one is a seal holder in poor condition and chrome plated. Stock is cadmium plated. See the two holes hogged out by using a punch? It is perfect for making another seal tool.

1. Remove the wheel.

2. Remove the seal holder and hub cap. This can be a problem. I will go into some detail about removing the seal holder and felt seals. My examples are of the older type seal holder used up to 1965. 1965 and later have a far better seal system.

A typical seal holder that was mangled by a PO. The tool won't work as it won't seat into the 4 holes.

Drill out the holes with a numbered bit #15 which is .178". Only go to the bottom of the old hole.

Gently tap the tool into the seal holder to bottom it out. Otherwise it will try to climb out.

The shows a breaker bar in the tool, my foot holding the tool in and getting ready to jar it loose with a hammer hit or two. If it doesn't come out easily then use your 1/2" air impact wrench on it. If you don't have one, go to your local tire shop. They have one hooked up to air all of the time. I have never been charged as it only takes a few seconds to get it off. If you don't have this option there is one more "shade tree" way that usually works.

Use a butane torch to heat the seal holder up. Since they are both of the same steel there is no thermal expansion difference to exploit. What happens, I believe, is that the parts are forced by heat to so some moving and the old dry grease is possibly able to lubricate the threads. When I do this I allow it to cool completely again and then try the hammer again.

This is what you will see as the dust cover is removed.

This shows the axle installed in the seal holder exactly the way it would be on the bike. Use your other hand to tap the bushing and seals out of the dust cover. Do this with the axle only a couple of inches above a soft surface. It comes out easily and the axle is going to fall all of the way through the dust cover. You don't want it hitting the concrete from 3 feet and bunging up the threads.

After it falls out and you take it apart, the pieces look like this. From l. to r. dust cover, smaller felt seal, thrust bushing, flat washer, larger felt seal and it's holder.

Here is another view of the small parts and in the same order as above.

Here they are all scrunched together again and ready to press or tap back into the dust cover.

You may want to remove the seal from the dust cover.

3. Insert an axle into the brake drum side. This is backwards, or the "wrong" side.

4. Install the "BMW special tool." Use a 3/4" X 4" plumbing nipple from any hardware store. Depending upon the model of BMW you may find that 4" is slightly too long or too short. You can use one of the top hat spacers to make up for a short one.

5. Put the washer and nut on the axle threads. The nut should tighten up on the nipple, which puts pressure on the bearings. This holds the "stack" together.

6. Use a hammer to tap the stack out of the hub. Keep the axle totally straight so that the bearings stay straight. If they get cocked off to one side, they will jam against the inside of the hub. The axle will move only about 1/8" with each hit.

7. Disassemble the stack, noting the position of the top hat spacer. The top hat spacer will have stayed in the seal holder when you removed it. This top hat spacer is for one purpose, to transfer pressure from the axle to the bearing stack, through the seal. The top hat rides in the seal, felt or neoprene, so it needs to have a smooth surface.

8. Clean the bearings and inside spacers of all grease.

9. Inspect the bearings for pitting and stains from water. Replace as needed.

Time out. You aren't really ready to do the spacing just yet. This part of the procedure is my addition, but it is worth the trouble.

First, inspect the wedding band spacer, the large outside spacer and the larger part of the inside spacer with a good eye or magnifying glass. The machined off ends are poorly cut. They are rough. Cleaned up faces offer more surface mating area.

Second, the ends should be parallel with each other and square with respect to the length. About all you can do is to get them parallel.

I lap them to be smooth and as square as I can measure. I use a glass plate as my surface and #400 grit black paper for the abrasive surface. Add solvent to the paper to reduce it's tendency to clog up. As they start to clean up, check for parallelness if you can. The /2 stack tightens up really well and feels solid, compared to the /5.

10. With only a drop or two of oil on each bearing, reassemble the stack on the axle. Put the washer and nut on and finger tighten it.

11. Put the axle, with the stack, in a vise, vertically, and tighten it on the nut.

13. BMW wants you to change the wedding band spacer until you reach the correct spacing. With shims, you can just add them until the correct spacing is reached. When the outside spacer moves with medium thumb pressure, at 25 lbs of torque, you are finished.

14. Lube both bearings and assemble everything on the axle. You can't over lube it. Tighten it up to about 10-15 lbs.

15. Drive the correctly spaced and lubed stack back into the hub. It will go in with about the same hit as removing them.

16. Install the seal holder, but don't tighten it very much.

17. Install the wheel and axle. To reinstall the axle, be sure that you know how to do it or go to http://www.softcom.net/users/w6rec/axlepics.jpg to see the correct and incorrect way. The picture is of a /5 axle, but it is the same procedure.

18. Perform the "shake the wheel" test to check your work. It may tighten up at a slightly less axle nut torque than when originally spacing it. If it is way off, a shim can be added to loosen it.

The disc brake wheels

My wheel bearing info is for the rear wheel on the /7. The front is actually the same thing, but with
slightly different parts. I had no experience with them because I sold my shop about the time that they came out. Our only experience with the "new" front wheel was that the brakes didn't work. From the /5, and later, we really had little trouble with the front wheel bearings. Of course we had the normal failures from owners high pressure spray washing the grease out of the bearings.

I took a few minutes out to check a wheel for your info. The spacing can be tested in the very same way as the rear with the "shake the wheel" test. The results can be divided into three possibilities; too tight, perfect or too loose. We won't worry about "perfect." If it is too tight then the stack needs a longer center spacer. I tried one of the shims that I sell. It goes in exactly the same way as before, except that there is no convenient cavity for it to nest into. I used a dab of grease to hold it and screwed the cap on. Just as the bearing began to touch the shim, it wanted to move sideways. I just inserted the axle to kept it in alignment and hand tightened the cap. Then I again used my homemade cap tool and tightened it up the last few degrees. It stayed in place. If it is too tight then one needs to shorten the center spacer. It can be lapped as before. I would be very concerned with keeping it square. I would find a "holder" to keep it square. One possibility is an old bearing. The best way is to turn it down in a lathe, but few owners have one. If it gets turned too far, just add back with a shim.

Once it is all in place there should be no problem. I would be concerned that a less knowledgeable mechanic might open it up and not see it or know what it's purpose is. That could happen with the rear wheel too, but is less likely due to the cavity.

We have used these paper thin shims since the middle 60s and they work very well. We have used them hundreds of times with no problems. Any wheel can be spaced without them, but it takes much longer, i.e. more of the customers money. These shims can be used to space a bearing stack without removing them from the wheel, always a good thing.

Other wheel maintenance

When you change a tire, always balance the wheel. An unbalanced wheel can cause a wobble. See my page "How to balance a BMW wheel."

Check for spoke tension. This is done by plinking the spokes with a metallic tool. They should all sound about the same with a rather musical note. They will rarely be loose, but check them. Spokes on the 70-71 models are a special case and can be seen on one of my pages.

Clean and lube the splines on the rear wheel. Check that the 2 final drive (/5 & /6) drain holes are clear by using compressed air. A wire won't work well.

One is located below the axle. It goes up into the spline area.

The other hole is next to the drain plug hole.

How to obtain shims

I can provide shims for either the /2 or /5. The /5 shims fit the /6 rear and the older R26 and R27 too. Included is a set of 6 and that is enough to do one wheel, in the worst case, and usually two wheels. Print these pages for your instructions. Six shims of various sizes will allow you to shim spacers to within .001," which is more accurate than either the /2 or /5 wedding ring system. The shims are worth about 5 cents each, but the die costs about $900, for each of the two types. A set of six, two of three sizes, of these shims cost $10, postage included. I have changed the way I do it. I want to try the honor system. Email me with your address to w6rec@softcom.net and I will mail them out to you with a SASE. It is up to you to insert payment and return. If you don't know how to use them, or don't like them, just return them in the SASE.

The smaller shim on the left is for the /5/6 and the R26/27 models. The larger one on the right is for the /2 twins. The kit has six shims, two shims of three sizes from .002" to .005". This allows adding length to the inside spacer from .002" up to .020", in increments of .001". This is double the accuracy of changing the /5 wedding bands and four times for the /2.

/5 wheel bearing design specs.

By Brian Mehosky, Timken employee

How long will a /5 BMW wheel bearing last?

Well, the question was asked, so I went to ask the pros at Timken, where I work.

The specific question was:

"If the tapered roller bearings in our scooters were properly maintained, properly preloaded, properly lubed, and never washed out with a pressure washer, or let sand/dirt/debris get into them, how long *would* they last?"

The quick and dirty life calculation is:

L10 (revolutions) = (9.0 * 10E7) * (C90/P)^(10/3)

Where L10 is the 10 percent failure rate (i.e., 90 percent reliability point) (in
revolutions);

C90 is the basic dynamic radial load for an L10 life of 90 million
revolutions (in pounds); and

P is the dynamic radial load (in pounds).

*I* assumed that the total dynamic load on the axles was 600 pounds for the machine, plus 400 pounds for rider(s) and luggage, or 1000 pounds (that may be wrong, since it really is a static load, but you will see that it *just doesn't matter*). Since there are four (4) 30203 single row bearings on both axles, I *also* assumed that the load was shared equally, at 250 lb per bearings (again - *it just doesn't matter*). So P = 250 pounds (force)

The C90 load for a 30203 Timken bearing (I'm *certain* that it is significantly lower for other manufacturers, but we should always use the best in our machines [grin]) is 5190 lb(force).

When *I* punched in the numbers, I got an L10 life expectancy of 2.2 **TRILLION** revolutions. If you assume a tire OD of 2 feet, you need 840 revolutions per mile, so the bearings are only good for 2.6 **BILLION** miles.

Although the dynamic load *may* be greater (probably *is*), it should also be pointed out that a "failure" here in bearing-land is that one or more component of the bearing shows some kind of "damage", like a scuff or mark or pit. The bearing will probably continue to function for a long time in that condition, it's just not recommended. And the *other* 90 percent will last even longer.

As Duane has pointed out, this system is *massively* over-designed. I never realized just *how* massively over designed the bearings are.

Brian

PS - the number also correlates well (within 10 percent) with a similar
calculation based upon ISO method ISO 281 (for our Continental friends) B

Feedback wanted

Please send me comments on this article. If it is confusing, ask your question. I wish to share my experience, not to confuse. If it is useful, let me know. If you see typos, misspellings or errors in grammar let me know. If you wish to read other articles that I have or might write, let me know.

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