BMW F800GS rear wheel Bearing failures and solutions
FYI,,i was lurking in the new posts this morning,,,Ya'll have a serious problem going on so i'm posting this in the hopes it may help all of us getting to the bottom of the rear wheel bearing failures,,
there was so much speculation and mis-information and groping in the dark that i decided to help you all get a better handle /understanding of what you are up against...PLEASE remember there is nothing generically wrong with BMW's basic design or the 6204 bearing used...
On the outside possibility that it was a bad run of bearings,,[highly unlikely] we can better trace that by you all collating the following info ie:
A,,sprocket carrier bearing/brand
B,,inner bearing of hub/brand
C,,outer.disc side bearing/brand
then we can ascertain if bad bearings are the cause that yielded the chronicled effects...
FYI,,what i failed to mention in my PM to tmex was the incredible importance of the proper bearing bore size in the hub itself,,,the lil bit of info relating that the disc side bearing drops in partway and then needed hammering in the rest of the way after the hub was heated and bearing frozen,,get's my crap detector going BIG WTF TIME:huh..properly dimensioned bores allow the bearing to BOING drop down all the way....tis a thing of beauty heat and cold...my favorite technique,,,,no chance of ruining your bearing:super
a rough rule of thumb i use in building my hubs is .0005'' per inch of bore,,so that would equate to circa .001'' for a 6204 bearing.. any smaller bore size would invariably yield notchy/crunchy bearings. hence ,,you could check this easily by taking a new nice n smooth turning bearing ,,,installing it per factory guidelines ,,letting the hub cool to room temp ,,turn the bearing with your finger,,, it should be smooth,,,if not you have located the problem.....,,realize there may be other issues as related below,,,
I just realized IF the bearing bore is the problem ie too small ,,ya'll have a major problem on your hand,,since there are NO wheels OR hubs available as of this minute,,, the Rx would be to re-bore the hub, a good machinist in your neck of the woods could possibly handle this on a mill.,,we routinely perform that service circa $60 per side plus parts and $20 bearing R&R...any guinea -pigs in the denver area,,,come on by and we'll check this out!!!
Some inmates have asked how much to do this: $99 Advrider special both sides speced to .001'' and a pair of doubles sealed bearings..will install yor stuff..ie pick up your parts from BMW or your favorite bearing house if it is important to you...:thumb
OK,,,here's a lil tip for you bearing installers,,,often after hammering/pressing in the bearings,,you test the bearing and WTF !!!!they are binding /notchy,,panic not !!!you may have a tiny bit of pre-load on them,,just insert the axle give it a slight rap with your hammer ,,do the same from the other side and VOILA 90% of the time your bearings will loosen and feel just like you had hoped for!!!
OK,,,here's the gist of a PM i sent to tmex and his thread; if this data doesn't make it over to his thread[i can not post outside of vendor forum],,,then possibly some F800GS owner could let the guys in that thread know we are working on a solution to their problem by getting a post or link established...this problem needs to be solved ASAP before someone gets injured!!!
first i empathize for all you bmw riders with issues like these ...bmw motorad is notorious for sandbagging and not admitting culpability for fear of litigation and having recalls issued..it is a given with these folks..
ok,,here's what you need to keep in mind....
1. 6204 double sealed bearings regardless of manufacture have been used by everybody on front and rear wheels for a long time without any major issues...true some don't have as much grease as others,,,we know which brands are skimpy,,, and routinely repack them with upgraded hi-temp wheel bearing grease,,,and for dual sport adv riders even offer waterproof grease for the water-crossing species:wink:,,,so the odds are against you looking to the bearings as the culprit....
2.cocked bearings would be fairly noticeable and show signs of wrong installation in the hub...no one has noticed or reported that..so eliminate that too.
3,here's where it gets interesting,,,there are two basic approaches to wheel-bearing set-ups.,,,i'll call them:
type A,, probably the most common,,,uses precisely machined lateral flanges on the ID of the hub to locate the bearings....an inner spacer is used to prevent crush when tightening all the components /spacers on the axle... this spacer needs to be minimally .010''+.002-.000/steel or .020'' +.003-.000/aluminum to be effective.... so the hub essentially has a little bit of lateral float built in... a simple elegant fairly bullet-proof technique which fails only when :
a,,,the manufacturer uses too soft axle spacer BWOE KTM several years ago on the rear dirt bikes,,too much torque would crush them resulting in many blown up rear hubs:cry
b,,someone specs a spacer the same size or smaller than the inner lip dimension.:huh,,has happened,,,but highly unlikely!!
type B,,used by Kawasaki,Honda,BmW,Triumph etc, uses some means of retaining one bearing on one side [usually the side where the disc brake is on. ie to make sure the wheel consistently is spaced /aligned properly with the disc],,Kawasaki,KTM and BMW routinely use a circlip to retain that bearing in place,,,honda and triumph usually use a nut to hold it.,,,what usually happens next is that on the other side the bore in the hub often doesn't have an inner lip or the lip is usually bored far deeper than the width of the inner spacer...VOILA you have no worries about proper inner axle spacer dimensions because the bearing should self adjust....
FYI..notice this leaves the captured bearing be responsible for all the lateral loads imposed by that wheel:uhoh,,,this technique is usually utilized for front hubs,,,although i have seen it on some honda rears BUT for lighter machinery dirtbikes the bigger stuff ussually had bigger/beefier bearings installed on that side...so this could be an outside probable cause for the disc side bearing going bad:dunno
Rx,,,,this would leave the following areas to be scrutinized in my estimation:
1..the simplest is to first ascertain if there is an inner lip on the side opposite of the captured bearing....if there isn't well we have to look somewhere else,,,,IF THERE IS,,,install the captured bearing first ,,,get your calipers and measure the distance from the bearing to the lip,,jot i down and then measure your spacer,,like i wrote above..it HAS TO BE LONGER minimally by those specs!!! if it's smaller or the same well you are on to another probable cause of your symptoms and their consequences.
2,,FYI i'm inserting this here as an edit .. the next probable cause has to do with too tight bore,which i discussed in detail above and IMHO is the first thing i would be checking!!
3,,the last probable cause is a matter of improper bearing installation...BWOE,too much pressure creating preload conditions symptomatic of some of the observations of the fellow who cut up the bearings ,,,or BWOE that if in type A the spacer was too big as well as type B...IF the bearing installer had his stops wrong and compressed the outer races beyond the inner spacers dimensions
hope this shines a little light on the subject,,i'll double check the next rear wheels i get and report back in....
OHHHh,,,heed the advice of the fellow who suggested you all get BMW to do the work,,he's ABSOLUTELY right,,until you get a work order written up by them....it just minimizes their number of ''problem cases'',, it' is counterproductive to fix their problem on your time and dime....
i can rest assure all i am on your side and will assist getting to the root of the problem...i'm fairly positive that the above info should put you on target .:thumb
BMW F800GS owners TAKE HEED regarding your rear wheel bearings!!!
FYI,,,it has been over a month and a half since tmex had his rear wheel bearing disintegrate,,he chronicled his adventure and search for the cause in his thread dated 8-24-09
i just stumbled on it in the wee hours this morning and started a new thread on the subject immediately,,,,hoping to get this situation resolved ,,,,because dear F800GS owners you may not be as lucky as tmex was,,,his incident happened on a trail ride..here's his rear wheel bearing...
,,,not everyone may be so fortunate to be on a dirt trail,,in that thread there are over a dozen riders who have chimed in with similar or impending results....
like fellow advrider ChiTown...
it puzzles and pains me that based on the posts of the lucky souls sharing their data and experiences on this topic that BMW does not take this situation far more seriously....
i am almost positive that someone at BMW Motorrad knows about this and is probably trying to rectify it ...it would explain why there have been no hubs or rear wheels available from BMW for the last 4 months,,,we already speced a Superlite cush-drive version ala KTM 950/990 Adventure,,will be circa 1lb lighter then your stocker,,
FYI,,,replacing the bearings if BWOE there is a problem with the inner bore of the hub being too small,,,would just be a stop gap measure and invariably result in the same damages to the replaced bearings...unless you can spec very loose bearings circa C-3 or looser.
so all of you who have replaced your bearings even with better ones with better grease...
PAY ATTENTION TO YOUR REAR BEARINGS EVERY OPPORTUNITY YOU GET !!!!...there is a cause and effect for most everything
Be part of the solution and resolution!!!,,,pass the word to your fellow riders,,,
take it to BMW for your repair so that they eventually will get it that this is not an isolated incident,,,there is a certain power in numbers
don't take on the blame that perhaps you got a little water on it in that stream crossing or power wash,,,these bikes were designed for that kind of activity,,
keep posting the incidents in these and other similar threads and forums,,thank god we have an internet,,,put it on you tube
use your crap detector to separate the wheat from the chafe in all the advice being bantered about,,,
If i had to give BMW Motorrad some advice based on their actions over the past decade in similar circumstances: The truth will set you free!!!
Inform your customers,,,''ooops we have a problem,,we will resolve it on our dime,,,please do not ride your motorcycle til we can rectify it'',,,,,or ''it's serviceable but come in for a quick check'',,something to that effect.
Honestly BMW MOTORRAD we want to trust you again!!!,,,,we can accept that s___ happens,,,let us know,,,we'll even help in the resolution and rectification
Just don't play with our lives because you have an image problem or are scared S___less by the throngs of litigators waiting in the wings...i'm positive juries will be far more harsh on you all if they realize you have been hiding the truth and facts..
'nuff said for today,,i welcome your thoughts on this matter,,,
laissez le bon temps rouler,,
Once again thanks for your willingness to shed some light on this...I actually understood about 1% of it (the take yer bike to BMW part)!
Woody; Thanks for chiming in. Your point of view based on years of experience is very valuable. The first thing I checked when disassembling the wheel was the length of the spacer. I removed the drive side bearing first, the spacer stuck out beyond the shoulder of the bore. This not anything I needed to measure as it was apparent.
Thanks for the info Woody.
Which after market replacement bearings would you recommend for the rear wheel? :ear
F800GS replacement bearings...
generally i tend to use cost effective middle of the price range bearings,,,Koyo,SK,,,,i try to buy Timkens for all my Harley riders[politically correct:wink:],,,i check for how much grease if any they are putting in them and repack accordingly..a value added service i do not charge for,,,,:thumb
gadget,,,tempted as i am to take my destiny in my own hands and buy top-notch bearings AND install them myself;;;;in this F800GS rear bearing fiasco,,,i am inclined to force BMW to chronical the problem via a work order and pay for the parts n labor,,,we the consumer have already paid for their assumed/reputed/advertised superior QUALITY and workmanship....it is extremely counter-productive for us to fix it ourselves in this scenario,,we are essentially enablers. ,,,and IF as i suspect the bore is too small on the disc side,,,better bearings will NOT solve the problem,,,the hub needs to be bored out :thumb
i try not to buy chinese because i do not support their labor/business practices....although it has been getting ever harder to do that these days,,,
and i try to use the heat n freeze technique as often as i can,,especially on the hi end wheels we build and service,,,poor install/removal techniques i'd say shorten the life span of your bearings more than anything else.
happy weekend to ya
one less probable cause in rear BMW F800GS bearing fiasco
FYI,,it is essential with this style set-up that you double check how smooth your bearings rotate after installing them..because if you tap them via the outer races you stand the chance of too much pre-load,,hence the axle tapping trick i mentioned in my previous post.
OBTW some more kudos to ya for being one of the cool analytical contributors in tmex's thread on this subject.. a few others i want to acknowledge are docking pilot,,EnderThex,indy Unlimited,Bayner and tmex himself to name a few:thumb
any F800GS owner wanting to stop by shop for bearing check,,holler
hi,all you BMW F800GS owners in the denver area,,,,,i want to get to the bottom of this,,,so guinea pigs are welcome,,,:ear,,,or mail your wheel in for an analysis,,,will take pics and measurements and share the results.....
FYI,,,this should have been brought to my attention along time ago,,,that's part of offering my services via this thread,,,remember that bearings are part of your wheels,,a forte of mine:wink:
Woody, I have been wondering if maybe the bearings are meant to be tapered OD (no clue if that even exists)? If they drop in half way and need to be pressed the rest of the way it would make sense to me that the hub would be machined as tapered. What say?
BMW F800GS tapered rear bearing bores?????
what we did find out though is there is a slight 'step' in the bore,,,this is probably the ''falls in part way '' that some people experience,,,
FYI,,if properly heated in a properly speced bore,,,,the bearing will drop in all the way with no fuss or muss....the reason people need to pound em in the rest of the way is either the hub is too cool or most likely,the bore is too tight
as soon as i saw a persistent pattern of riders heating/freezing per the manual and ALL reporting it dropped halfway and then needed to be beat in...:huh:huh:huh:huh:huh,,,,i've been through that scenario the cause of which is usually someone made a mistake in machining the bore,,,if the hubs are apart we just toss em in the lathe,,, otherwise bore em in the mill to save re-lace n true costs...have repaired hundreds...:thumb
some more clarification regarding bearing bores
the bottom line is still this:
After doing the proper heat n freeze technique,,that bearing should drop in all the way and be held with circa .001'' of crush....AND apparantly that is not the experience of many owners:cry:cry:cry
here's the F800GS recall thread...
FYI...perhaps a good place to add/mention your rear bearing issues:dunno
replacing with 'better bearings'' is NOT the answer/solution to this problem
Folks,,,if on certain hubs that have displayed the crunshy and failed bearing syndrom...and you have noticed that after following BMW's procedure for heating hub and chilling the bearing...that the bearing ONLY DROPS IN PART WAY....
and you then have to beat it tin the rest of the way....
FOLKS..YOU HAVE A BIG PROBLEM ON YOUR HANDS!!!!
Remember the definition of 'insanity': 'Doing the same thing over and over again and expecting a different result....''
i predicted this a few weeks ago...
here's a testimonial from tmex's thread from a few days ago...
Joined: Feb 2009
Location: San Luis Obispo CA
</td> <td class="alt1" id="td_post_11085145"> <!-- icon and title --> Second set of bearing fail at 1380 miles
<hr style="color: rgb(87, 87, 87);" size="1"> <!-- / icon and title --> <!-- message --> I replaced the stock bearings, which were bad, at 660 miles with SKF bearings. Now I took off the rear wheel to put on new tires at 1380 miles and now the SKF bearings are rough on both sides. Now what?
<!-- / message --> </td> </tr> <tr> <td class="alt2"> [IMG]images/statusiconCrash/user_offline.gif[/IMG] </td> <td class="alt1" align="right"> <!-- controls --> [IMG]images/buttonsCrash/quote.gif[/IMG]
i have offered to do a free analysis to anyone suffering these symptoms...i'm leaving for vermont this friday..will be back on the 31st...hope no one gets hurt in the meantime...
i still assert that the odds are the bearing bore is too small ie has too much crush on it,,,thus preloading the bearing and leading to premature failure..:thumb
here's the ANSWERS to your bearings seizing/disintegratng
Thanks to RedHawks47 for finding a little mistake in my typing. The above should now be correct.
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