Servicing BMW Airhead motorcycle wheel bearings

5 Апр 2015 | Author: | Комментарии к записи Servicing BMW Airhead motorcycle wheel bearings отключены

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BMW Airhead Motorcycles:

Section 4: Bearings; preload servicing.

wheel information.

© Copyright, R. Fleischer

section 54, subsection 4

Recommended preliminary study:

It a critique of the BMWMOA-ON magazine of 2004.

Please do not be concerned if you do not at first, everything in the above or below article, Duane’s, as will be fully offered in my article you are reading.

(2) Duane article on Wheel bearings:

You MAY have to hunt for it, he sometimes addresses in his website.

DO. read those above two wheel articles, BEFORE you read the of my article, below. Duane’s also covers the /2 bikes. His article on the wheel bearing was expanded by him, is now much extensive, and his SHAKE method is one I used for many decades and DO use myself now and then, YOU should what it is, and how to use it.

Duane I do not agree of the time; but we do NOT have serious with his article.

It is my belief the information I present so verbosely is much more accurate, and better for a long bearing HOWEVER, Duane’s method work, if you do it just as he says. but you have some experience.

W hat below, is a long article. the time to read it slowly. You probably want to re-read and my following article more once.

As you start work on own wheel(s), re-read as you go. Every I can think of is incorporated into my below, so it does appears at first. You will find it simple. after you have done just one wheel, in with my procedure and information.

Be you have a lot of reading and understanding to go


Some literature is confusing, or JUST PLAIN on some details of servicing BMW wheel bearings. FOR JUST ONE EXAMPLE, some Clymer’s will FAIL to tell you to THE HUB on early model Airheads in to remove a bearing, or even removing the entire ‘bearing as an assembly. Removing the bearings the ALUMINUM HUB wheels (early NO cast-in-place steel sleeve) heating WILL RUIN THE or; injure it badly.

Part 1: discussion

BMW airhead motorcycles are tolerant to abuse and poor Our human bodies are NOT tolerant to dumped on the road (especially at from a motorcycle. Of all the items are safety related, the most in my mind at least, is YOUR and mental condition, and somewhere in position is the condition of wheels, and brakes.

Please read article, and THEN decide if you are to do this work. NOTE working on wheel bearings and is serious business. HOWEVER, IT IS NOT COMPLICATED, AND SOMEONE OUT OF THE BEGINNER AND INTO LOWER MIDDLE OF CAN CERTAINLY SERVICE WHEEL


Failure to properly maintain bearings (and their up through 1984 models; BMW to ball bearings in 1985) can be to your health. A seized up at speed is serious.

In MY opinion, the for preload that BMW specifies has a too high a top limit. It is my belief setting preload that will squeeze out lubricant, and the bearing to overheat.

BMW used (up to the to sealed ball-bearing assemblies in and the R65LS ball bearings a bearing that consists of ground and hardened rollers set in a That caged roller is set on an angle to exactly match its a hardened and precision ground race, thus the name roller bearing’. This was used for the wheel bearings and arm bearings and steering head in the /5 and later.

This bearing is often a Timken bearing, although is a trade company name. The name is Tapered Roller These same type of but larger of course, were in almost all old automobiles and trucks.

type of bearing is very long lasting if serviced and 250K miles of use is NOT unheard of.

proper and regular servicing, will not fail without you a developing problem during an and servicing. The tapered roller in the applicable Airhead’s wheels and arms is a common type A. which is 17 mm x 40 mm x 12 mm, available at any bearing Bearings and their associated race come as a matched set and NOT be mixed up. #30203, not- A. can be

I prefer the NON-sealed bearings at places. THE SECRET to long life is to clean and re-grease regularly and to have GOOD bearing SEALS and clean in those seals. Every the bearings are cleaned and re-greased extends their life.

New help ensure this, so do NOT to replace the seals.

Tapered bearings need to be properly The term preload simply the amount of pressure the inner part of the bearing has into the of the outer portion of the bearing. Too and the free-play is hard on the bearing and its life and the bike will instabilities; too much and the bearing hot, melts/squeezes out the lubricant, and has a life.

I will expand on later.

What can kill is not just a lack of lubricant or from excessively high Using a strong spray a water hose directly at the can force water into the a NO NO!

The R65LS model was made January 1981 to about of 1985, front wheels a BALL bearing, 17 x 40 x 12, type part 36-31-1-242-854. Those are not in this articles sections on adjustment.

Since all the airheads previously use 17 x 40 bearings, guess the dust/dirt/water SEALS size is. 17 x 40 mm.

From 1985 the Airheads a #6005 bearing, which is 25 x 47 x 12 mm. is a crossover on the R65LS at 1985-86, but apparent when you see the wheel.

A bit basic information:

Being on an and with a set of these bearings on the left and right side of the some means must be to adjust for some known or loading, preload if you will, for to operate against their race (the ring). In our BMW the inner part of these are set into the wheels with the end pointed inwards. [In case you are yes, there ARE tapered bearings that are assembled the small end pointed OUTwards.

The ones like this on that I know of, are the Ural’s. I ran into this on the Ural The are adjusted very differently; and are NOT as precise for preload, as the BMW type]

If the is too high, the lubricant will be out as the bearings rotate, metal to contact will then the bearings will get very and just might weld to other at a most inappropriate You may or may not get any advance notice from etc. If the preload is way too loose, the can move sideways, and angularly, and you have poor handling, can also lead to high wobbles.

Bearing manufacturer’s specify loading (preload) and if a bearing’s is within the manufacturer’s range of values, the bearing has EXTREMELY life. If the lubricant or preload is either too tight or too loose, the life is shortened. It is important the lubricant not get contaminated.

Water and are BAAAAAD!

I HAVE SEEN preload and lack of lubricant wheels to seize on the axles. has happened in every instance I have seen, on the REAR It HAS happened to front axles.

is very dangerous, and if you do not have an at least your wallet get thinner, when you find out it costs to do the repair. Problems EVER occur if you clean and and check preload at every or other tire change. do not force water through the when washing the bike.

The design of roller bearings to PARTIALLY trap lubricant the surfaces. On most of the old cars and which have separate and inner bearings at the wheels, at the outer bearing is usually the Timken type, the inner be the same (or another type of perhaps a ball type).

In any the adjustment on the old autos and trucks is always by an adjustable nut on the end of the axle, a safety lock nut or more a cotter key, pushed a 90° hole near the end of the axle. type of adjustment and locking is not with most telescopic systems, nor the swing arms, it IS possible to design them to be in some similar fashion.

preload is NECESSARY. It is best unless you have a fair of experience, with NO seals in and the bearings cleaned and OILED, NOT If you are using a modern non-melting grease, and NO seals, you can, experience. do preload by FEEL, as you tighten the axle nut.

you can add the seals. Some of us old-timers lots of experience can even do it enough WITH the seals in Although it is ‘maybe-acceptable’ to do it this it is NOT very accurate, and bearing COULD suffer.

I HIGHLY you do it ‘my way’, which is outlined in this article. if you do the preload check in the also ‘feel’ manner, as here and in website, DO get advice if you are not experienced, and DO NOT do it if the hub are really quite cold.

that this article spacers that press against the inner race of the and a string and string scale is and, again, this MY METHOD, is VASTLY more than the ‘feel method’. it is very repeatable in accuracy. explain more as you read the of this article. NOTE, that the string and string method is somewhat harder to do the early wheels (that to be heated to remove the entire pack as an assembly).

Thus, the test, done with the pack OUT OF THE HUB, works That is NOT the shake test, is done with the wheel in the hub assembled, axle tightened.

BMW has a number of internal designs for the On all the pre-1985 wheels (except with ball bearings), the is usually set by the thickness of one spacer the wheel hub. However, /5 and /6 wheels also have a diameter internal sleeve, sets the distance between the races when the outer are being installed; I’ll that in more depth as this large sleeve also can be used to set preload.

Once set, preload not change for huge mileages, there is a problem with an race, or someone very over-tightens the axle nut; or to clean and lubricate the bearings.

are one or two other spacers inside the perhaps totally captive the outer races in place, but the one relatively narrow one is available in a of widths. That narrow one is commonly called a Wedding a slang name.

NOTE a change of a single thousandth of an will have a considerable on the preload.

Two hole sizes used on these various Up to 1975 the axle is 14 mm, and from the axle is 17 mm. On the early 14 mm assemblies, one can the bushings and go to 17 mm. but this article is not such things, and it is more than just that the 1974 only being an that requires some machining).

The 14 mm axle was changed to 17 mm as bending of the 14 mm axle was noticed severe usage. BMW had a kit for converting the 14 mm setup to the internal 17 mm. Again, is not part of this article.

discusses this too. and has a photo of the 1974 wheel

INTRODUCTION (yes, these WILL be explained):

1. Servicing the bearings on airheads built roughly the end of 1984 (ie, the models) varies somewhat, and is in this article at the END, in article’s Part 4. The 1985 and models use non-serviceable, replace sealed assembly ball These sealed bearings a fairly long time, and do not regular servicing. Regular IS recommended on the earlier tapered bearings at tire changes. or at every other tire

Duane’s article, and my article, are for the wheel bearings that on Airheads BEFORE 1985.

that the R65LS which was well before that date, have ball for the wheels.

See item #8 below for a bit on the R65LS, ETC.

The tapered bearings are exceedingly sturdy and IF cleaned and lubricated and the preload is

2. On the Paralever and Monolever single REAR suspensions, the REAR bearing is an internal part of the drive, running in an oil bath, and NOT get serviced at regular intervals, and is not of this article. Note, that the Shake method may identify a Monolever or Paralever drive whose large is beginning or has failed. Best to it NOW and fix it, before very expensive damage occurs.

3. The /5 and later to the late seventies have innards that are only by heating the hub and withdrawing everything as an for the REAR; but the front DISC wheels are simply heated and a mandrel, if needed, used to knock out the outer races. The REAR DRUM brake must be heated for removal of S ometime during 1978 the snowflake cast wheels changed internally.

The FRONT now had pressed-in outer races, the DISC brake model did. But the rear drum still had to be heated. This was somewhat in AIRMAIL of 8/1978 and and again in June 2004.

The 1978 (ONLY 1978) DRUM SNOWFLAKE wheel has bolts holding the seal later wheels do NOT have five bolts.

If your REAR wheel has 5 on the left side holding the cap in place, you probably have the needing special attention. The REAR is a special case as above. spoked wheels the 5 bolts need heating to the right bearing. There is to this, so you may want to refer to the 2013 AIRMAIL issue. as you may not to remove the bearing at all!

Do not tighten the 5 bolts until the is in-place with the axle fully. This keeps the new centered.


A simple modification a grinding wheel of some spacer part(s) will the heating process un necessary in instances on the very early which saves some on the wheel bore, as well as servicing vastly easier. see later in this article Duane now covers this in his Frankly, after the modification, the thing to do is to get or make a tool Ed Korn’s special greasing or a long medium needle tip for grease gun, enabling of the inner captive bearing going to heating and removal

For the later wheels where is had withOUT heating, BMW nicely the design, and access to the wheel is generally just a simple of prying out (don’t injure the doing so) the grease seal and its metal spacer, which is just called a Top Hat Spacer. The or hat if you will, on that spacer is the seal if assembled correctly.

Any in this article to lipped means the slangly-called top hat spacer, the hat be also called a brim or spacer by some. Some of the spacers will still be inside the wheel hub on these models, but there is almost a reason to remove them, because hubs that cast-in steel inserts can the races pulled (Kukko puller) or pressed out. heating.

All the early aluminum (no cast-in steel inserts) are heated to remove the outer needed if the bearings are ever Failure to heat the hub can RUIN a

Do NOT confuse an outer bearing with the description of a cast-in insert, they are NOT the same

4. The wheel on the earliest models may a chrome cover with bolts and on one side the bearing is INternally, the entire assembly is at one time NORMALLY (UNmodified). is applicable to /5/6/7 with the ALL hubs. and also to DRUM front wheels on the /5 and R60/6.

5. article has photos of the assemblies.

6. On the early wheels, the /5 types, you can use the rear axle as a together with a piece of 3/4 steel pipe. You slide the in through the side OPPOSITE the removable seal carrier. Use the of pipe as a spacer, and tighten the nut to put on some preload. ((for the wheel, you take out the spacer for the thinner front axle)).

For all the type of wheel hubs:

something like a propane or two. heat the hub up evenly to sizzle temperature. You may wish to use an hot plate with A PIECE OF METAL PLATE ON TOP, IF THE HOT IS THE OPEN-COILED TYPE. I usually use a hot

You can then LIGHTLY! tap the axle totally through, towards the that the seal carrier was on.

You check the preload of the assembly, it may adjusting. The preload is set by a spacer, called a ‘wedding band’ and come in .05 mm graduated sizes; a is below in this article. spacer is located in a recess for it in the small spacer tube.

IF you have a wedding band that is a wee bit too thick, you CAN thin it, a flat piece of glass or a plate, and a piece of silicon paper, to carefully, and evenly, it. Take your time, be it is flat, so do this finger in figure eights, rotating finger to new positions. or, make to help do it, like a thick piece of hard rubber. the wedding band ring

NOTE. The early hubs, must be heated, contain a diameter internal sleeve of steel. Thinning (narrowing) it has the effect as INCREASING the thickness of the band.

If you work carefully and you can ‘reshim’ without purchasing because you can thin the inner band OR the outer large and get opposite effects! This may not if you are installing new bearings, as the change may be too excessive to consider flat

Also see #7 below.

After the (cooled) assembly, reassemble on the add the pipe, tighten the nut. in freezer for a few hours. Fire up the or heating plate again, the hub, and remove the inner from the freezer and put the assembly into the hub, tapping with a mallet to seat it all Then replace the seal centering if needed with the

Some earlier minor modifications to the inner spacer will allow this to be mostly avoided in the future. on this is in several places in article.

***IF you do not feel to do ANY work in this entire take it to a BMW airhead expert. NOT all shops understand airhead However, if you read this through, slowly, THREE and then refer to it as you work on own wheel(s), you will likely all the knowledge you probably need.

I understand that there is a LOT of that is initially confusing in long article. Bear me, do what I say, and you will become good at this.

7. I will get into the inner hub a bit more to try to eliminate any confusion. T he /5 hub (with many similarities to the up into 1978 actually) has TWO good sized spacers The MUCH larger of them, a big round long sleeve, the two bearing’s OUTER races, and is so long as the OUTER bearing are in place, which are, as you now shrunk into place is, installed with hub hot).

The spacer, which has two ‘ridges’ on it, is captive due to this smaller ridges (fins) being a small amount too large in to allow it to be removed through the left-side outer race.

you have heated the hub and therefore left outer race is with the assembly, then you can the smaller ridged spacer the assembly, and grind its finned down SOME, so that in the future, can be easily removed through the then still-in-place race. In this manner, in the . you can easily service the left for cleaning and greasing without just using your

When that left inner cage rollers is removed, you can easily remove the spacer and wedding band (with fingers!) to the left, through the still captive race. This gives you so you can apply/force some grease the still captive RIGHT bearing. Thus, with a modification, done on any grinding in a few minutes, you will not have to the hub ever again, unless you to replace a bearing.

The RIGHT side bearing, captive, can be greased well-enough, if not using a special tool, previously;. from Ed Korn or successor, see my tools page. or, you can use a diameter long round type of extension on your gun, the type of adapter has a tapered tip, and available autoparts stores.

8. /5 through wheel bearings are the same type as the swing arm bearings, #30203A, and these are 17 x 40 x 12 mm.

NOTE. The model was made from 1981 to about October of some front wheels a BALL bearing, 17 x 40 x 12, part

9. There are some complications in the parts, seals, felts, and confusion in early and late 1978, some in 1972. Proceed slowly, and carefully. Ask if you have to.

Wheel Bearing

Wheel seals are not overly to being installed squarely to proper depth. They DO and work MUCH better if squarely. You do NOT need special for removing replacing seals.

The time you do a preload procedure, the wheel seals to your BMW and match them with new or get the proper part number off one of the websites. be sure to purchase an or a few extras. You can also pay some to the table chart and numbers in the chart. I DO suggest that you sure the previous owner put in the ones!

Look at the molded in the old seal’s inner seal but there may be none, or a part BMW or a nonsensical number. but the dealer’s department will have the up to information. PROVIDING the parts knows how to interpret what he on his screen! Reading the information in the chart in this article inform you rather well, and you can use fiche from one of the dealerships so those.

SO. my suggestion is that seals be installed flush and with the hub, but a teeny bit not over 1/16 or so, won’t anything. I try to install them or to within the thickness of two common covers inward. Note there are also NON-metal-cased of these seals, I am not a fan of them, can be (sometimes) harder to put in properly/squarely and to in, but they work fine.

will be able to push seals in with fingertips.

I install seals using the tool box socket (such as 1 the OD is usually about correct) as a with a soft hammer, evenly, slowly, all-around. If the cants mildly, then the socket to fix the problem. Appropriate means almost the outer of the seal (or, you can say that it is not the wheel bore inside

DO NOT put pressure on the inner rubber area.

In ALL instances, the open or spring area of the seal INWARDS.


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