Boxerworks.com

UPDATE.
It appears the consensus would be that the SKF 30203J2/VT108 are not the original BMW supplied bearings.
Just for grins, I have ordered 4 OEM bearings from MAX and 1 SKF 30203J2/VT108 from an online vendor. I intend to use all OEM parts. I have also ordered a couple of wedding band spacers......1 larger & 1 smaller than the one I currently have.
I've spent considerable time reading the article: http://bmwmotorcycletech.info/section4.htm.
Hopefully I can learn to use the nifty little spring scale and a roll of string to get the preloads set correctly.
I see the poster just 2 or three above managed to actually post a photo of his "J" bearing into the forum in spite of the Gallery being full? How'ed he do that??? I have a good photo of the SKF bearing but I do not have a photo hosting service.
I'll make a very careful comparison of the new BMW supplied outer race "back to back" against the used SKF J2 race to see if the radius' appear different?

Also, I have at least one response from SKF engineering re: the "VT108 designator" on the bearing. VT108 specifies the required grease, in this case: Grease: Shell Retinax A, Filling degree (For BT1), Basic oil type Mineral, Basic oil viscosity 220 mm2/s at 40 degrees C and 16 mm2/s at 100 degrees C, Thickener Li, Temperature range -20/+110 degrees C, Consistency NLGI=2 ; special grease quantity for TRB's .
I have sent them back a second inquiry about the J2 and included a photo of the failed inner race. I wonder if they will respond further?

PITAPan wrote:. . . If this bunch can't manage greater collective IQ that the ones at the "other" place, you're correct on "temporary". . .

That's an interesting statement PITAPan. If this bunch doesn't meet your standards, it would likely work out better for everybody that way.


Ken

So nice to have something to look forward to....

Ken in Oklahoma wrote:

PITAPan wrote:. . . If this bunch can't manage greater collective IQ that the ones at the "other" place, you're correct on "temporary". . .

That's an interesting statement PITAPan. If this bunch doesn't meet your standards, it would likely work out better for everybody that way.


Ken

Why "interesting"? Because I stated what, AFAIK, everybody actually does?

Do you enjoy the company of people that don't hold and exercise some sorts of standards? Ones that you are at least somewhat in sync with?

When someone says,: who the fuck cares?". What kind of person would you say that is? Four words can speak volumes about character. Once.

Knowledge varies. I've been riding and maintaining airheads (duals) long enough that I seldom have a question about what's going on, and when I do I turn to professionals, who then have problems with it. But their opinions are valuable. Not so with other machines. I recently had a problem on a car where I suspected what the symptom meant, but wasn't sure, and tearing in to investigate is labor intensive. So I poke around the net for people with the same question, read a bunch of junk answers and finally find a good one. Guy gives a brief crisp answer, lays out what the symptom means and why the part mas designed to give that symptom for a certain failure. Lays out the dots and connects them well. The thread then trailed off into the usual tangential opinions about fixes--- it was worth reading and considering and informs my eventual repair strategy. I could have gotten the first part of the info pretty quickly by contacting one of my parts suppliers. But I didn't want to bug him unnecessarily and what he is going to say about fixes is hardly going to be disinterested.

I abandoned the airheads list years and years ago because the stupid level got over the top too often. My respect for Oak (undoubtedly as knowledgeable as they come---to a point) was decreasing exponentially. Dots he got, in spades. Connecting them? mmm....

I follow the IBMWR Tech list ( oilheads and beyond) because that bunch take less knowledge farther than most groups I have seen. Lot of seriously technical types. Less dots, but some potent connecting. Not a huge amount that applies to my ride, but bits here and there worth collecting. I have some vague theories about why this group should differ from the airhead groups...nothing particularly solid.

Observing your own style, which is distinctive at times, I have though, "gee, I could fake that". But then I wouldn't be PITAPan anymore. There is a price for that and I guess I don't care to pay it. Too old and grumpy.

ibjman wrote:UPDATE.
It appears the consensus would be that the SKF 30203J2/VT108 are not the original BMW supplied bearings.
Just for grins, I have ordered 4 OEM bearings from MAX and 1 SKF 30203J2/VT108 from an online vendor. I intend to use all OEM parts. I have also ordered a couple of wedding band spacers......1 larger & 1 smaller than the one I currently have.
I've spent considerable time reading the article: http://bmwmotorcycletech.info/section4.htm.
Hopefully I can learn to use the nifty little spring scale and a roll of string to get the preloads set correctly.
I see the poster just 2 or three above managed to actually post a photo of his "J" bearing into the forum in spite of the Gallery being full? How'ed he do that??? I have a good photo of the SKF bearing but I do not have a photo hosting service.
I'll make a very careful comparison of the new BMW supplied outer race "back to back" against the used SKF J2 race to see if the radius' appear different?

Also, I have at least one response from SKF engineering re: the "VT108 designator" on the bearing. VT108 specifies the required grease, in this case: Grease: Shell Retinax A, Filling degree (For BT1), Basic oil type Mineral, Basic oil viscosity 220 mm2/s at 40 degrees C and 16 mm2/s at 100 degrees C, Thickener Li, Temperature range -20/+110 degrees C, Consistency NLGI=2 ; special grease quantity for TRB's .
I have sent them back a second inquiry about the J2 and included a photo of the failed inner race. I wonder if they will respond further?

To drift back on topic:

I don't care for snowbums Method because of the spring scale. Those things are not accurate and there is a problem with the difference between the breakout torque and the running torque. Those two are not the same and the spring scale doesn't sort them.

I started to set mine up with a simple torque beam. It's the same idea as winding a thread (not a string please) around the axle but the the torque radius is much bigger. Wrap the string around the axle and the torque radius is the radius of the axle. But stick a very light rod through the hole in the axle and you can heave a beam several inches long. Hang a weight off it at a calculated distance and you exert the torque per the spec in the manual.

So I took a 12" length of thin aluminum tubing from the hobby store (place that has lots of model airplane stuff). I put a wrap of tape around around it about an inch in from the end so it was a snug fit in the axle. Then I packed some plasticine in the short end so it balanced right on the middle of the band of tape (worked on the table with it over a pencil) . Then installed the bearings in the wheel with some very light oil, put in the axle and axle nut with a spacer sleeve and torqued the nut to spec with a torque wrench. Then the tube went in the hole in the axle. Lastly a small weight was hung on the rod with a loop of thread at a measured distance to apply the specified torque to the bearing. Tiny bit of tape on the thread to keep it from sliding around on the rod. I have a number of small accurate scales with which to make up a small weight and I also have syringes which work as well. If you don't know what a baggie weighs you've lived a clean life, congratulations, but you know what water weighs, just a matter of measuring it accurately and syringes do that. Drugstores have big ones for administering oral medications. So does any vet.

In use you get it all set up. Eyeball your weight to make sure the wheel is pretty vertical (not ultra critical) and then hold the beam up at 45 degrees. If you let go it will exert too little torque. It shouldn't move. So you rotate it with a tooth pick until it is horizontal and then release. It should move a tiny bit and then stop. You are applying running torque so you get the last bit of accuracy.

What I found out was that both of the wedding band spacers I had on hand were too short and the bearing preload was way too high. So high that sliding the string to the end of the beam didn't do it, I would have had to make up a bigger weight. So, I tried decreasing the torque on my axle nut. I think I backed off 15lb-ft or something, don't really remember. But that got me pretty close. So I said screw it and just greased up the bearing and installed the wheel on the bike---not tightening the axle nut as much as I would have otherwise.

I also realized that while I could get very accurate about the torque spec for the bearing, because it depended on the torque on the axle nut, and I couldn't reproduce that torque on the bike, I was being silly about it all. Tightening the nut against my spacer to take measurements was not that same as tightening it against the rear drive on installation. Knowing that there is a wide range of preloads on the bearing that work fine I could just do it by feel like I always have and I'm good.

At some point I will get a larger wedding band and I'll also calibrate my wrist against my torque wrench to see what I am really doing when I tighten my axle nut with the toolkit wrench as I normally do. I don't carry a torque wrench on the road (but I know people that do and they aren't the sort I question much). Then I'll check preload with the beam (once made it quick unless you used a water weight) but I'll just tighten the axle nut by feel and then a little bit less to account for the nut friction at the rear drive.

Edit:

2 points.

1) look at the grease seals 3 times. if hardened, beat up from too many removals, etc. replace them. it can be done later, use the old ones and put in the new after your next part order.

2) if you have a disk brake in the picture, remove the discs first thing. yeah, you can protect them with blocks, etc. but let that wheel flop over one time and things just got pretty expensive. I drop stuff here and there so I go super safe and pull them and put in a box. The bearing bores get cleaned, the wheel scrubbed, bearings inspected and set up, etc. so it's a lot of handling.

I've been wondering who the hell this new bloke, PITAPan, reminded me of, and I now recognise the style.
It's good to see you here. This place could do with a little more 'frisson'. It creates interesting discussions, and normally mild-mannered people get to evacuate their poison glands more frequently. It's all for the greater good.

Welcome aboard, PITAPan.

ps: Setting up a photo hosting account is simple enough. Google 'free image hosting', choose one of the many offerings and follow instructions. I've been happy with PictureTrail. Note that it is good to resize images down below about 800 pixels wide. Here is a bonus picture of my cat. He is also older and grumpier now.

The way I wrench?
My wrenching is second to no one, when it comes to entertaining the forum with my exploits.

My preload learning journey was complete in my mind when I installed NSK 30203J bearings.
I could not understand why there was another failure.
It took a little investigation to find that my preload theories were adequate and that the excessive radius on the bearing was responsible for giving incorrect preload.

Wow.......no end to the good info coming.......another complete procedure........I am surprised that someone hasn't made some tools for reading the axel torque for sale??? I'm guessing that my standard inch pound torque wrench isn't a fine enough calibration for these tiny bearings......does any mfg. make a small grams type torque wrench???
I agree with the above that the string pull method would seem iffy because of the "starting torque" verses the running torque. I felt that the original author covered that objection well, in mentioning the use of a really long string to get the measurement stable after the beginning of the pull.
In truth, I am a reasonably qualified tech, being a retired ASE Master truck tech.
I feel reasonably confident that I could set these up reasonably well just by hand feel. I have already ordered the grams scale.....so I'll give it a try and see what I get. As for the seals, I have those on order from MAX as well. I'll install them last after the pre load is obtained.

I'm having a wonderful time now, trying to see how close to "on spec" I can come in learning about the proper properties for the grease.
The SKF spec is so outdated (Shell Grease: Shell Retinax A, Filling degree (For BT1), Basic oil type Mineral, Basic oil viscosity 220 mm2/s at 40 degrees C and 16 mm2/s at 100 degrees C, Thickener Li, Temperature range -20/+110 degrees C, Consistency NLGI=2 ; special grease quantity for TRB's) ...........that I can not find any reference anywhere as to the updated modern shell product. I was very interested in the 220 & 16 mm2/s specs. I found at least 1 grease that has slightly higher numbers Castrol Blue grease) and a lot of greases that have lower numbers. Can I assume that in this case the slightly higher viscosity numbers would be preferable to slightly lower numbers????
As a side note: Personally, in forums, I do my best to stay "on Topic", consider everyone's point equally, and never try to be in "controversy". I consider it to be a place to Learn, not a place to argue.
Rgards, Ibjman

I would try wheel bearing grease.

ibjman wrote:As a side note: Personally, in forums, I do my best to stay "on Topic", consider everyone's point equally, and never try to be in "controversy". I consider it to be a place to Learn, not a place to argue.
Rgards, Ibjman

Good luck with that. You may find you're on the wrong forum.

Airbear wrote:...., and normally mild-mannered people get to evacuate their poison glands more frequently. It's all for the greater good.

What? No road rage threads???


And...thanks.