The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: georgesgiralt on February 28, 2016, 07:13:29 AM
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Hi Lads,
I've found a quite new rear wheel to replace mine which has a worn out brake. And I can't find someone in town able to turn the brake properly. (i guess I've exceeded the limit, though).
So the wheel is new. But the bearings have seen water and are toast.
I'm surprised that the BMW fiche does not show adjusting rings for the pre load. How is it set on these rear wheels ?
TIA and have a nice Sunday.
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After reading through this information, take a break and determine what you'll need to do with your new rear wheel -sans bearings.
http://bmwmotorcycletech.info/section4.htm
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Ouch !
Snowbum ! I'll clean my goggles, take a couple aspirin and start reading...
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Georges,
As painful as it may be - I would recommend reading through Snowbum's article.
I'll start off by saying a lot of people don't agree with me at times regarding wheel bearings and preload, I'm a bit over the top anal and nerdy. I've invested a lot of time with this procedure, both the rolling inch-ounce pull and "feel" procedures. There's not an easy or short answer to your question. But done properly your bearings will last longer than you will if maintained and adjusted. The design is robust and over-engineered.
You'll need at least a couple special tools ... a bearing race puller and take-up collar. I never recommend tapping out outer races with a drift or narrow punch. Cycle Works offers both these recommended special tools to name just one supplier.
I'll just say at this time it's important you have a general understanding of the wheel bearing function on our bikes and how preload is determined with our bearing stacks in regards to the tapered roller bearings.
The outer bearing races are fixed in position by way of the wheel hub. The target for preload is to apply the appropriate pressure of the tapered rollers against the fixed outer races under torque by way of the axle nut. In other words; finding the correct position of the rollers inside the bearing stack as they contact the outer races ... this is determined by the width of the wedding band. Keep in mind the wedding band is in contact with the inner spacer, which is a constant width. Adjustment is made with the width or thickness of the wedding band.
If the wedding band is too thick - the preload will be too "light" or "loose". If the wedding band is too narrow - the preload will be too "heavy" or "tight". The rollers are brought inward towards the outer races by way of the axle nut until they are mated or limited by way of the inner spacer and wedding band.
Never exceed 35 Ft-lb of torque on your axle nut.
*Note: wheel picture is from my R100/7, not my R65.
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I have found that if you replace the bearings with the same brand, you usually get away without having to fiddle with the "wedding ring" adjusters - also you do have a certain degree of tension adjustment available in the form of the axle nut.
Doing the job properly means that your wheel bearings could do several trips to the Moon and back before wearing out. Accepting slightly higher tension than ideal means that they will probably only do a couple of hundred thousand miles.
I try not to lose sleep worrying about if my bearing tensions are "just right' - I do however look at them and re-pack every major service and if they show distress, swap them out.
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Thanks guys, I already own the Cycleworks puller (I used it to remove the bearings on the swing arm prior to the powder coating).
I know the rationale with tapered roller bearings as my studies where those of an engineer (even if I did not use that knowledge to earn a living). I just wanted to know if there was something special about these bearing on the R65.
Tomorrow morning I'll buy a couple of bearings and prepare my air gun !
Thanks lads !
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Yes. Two schools of thought each has it's place in our big church. Thank you, Tony. ;)
Both Mike V's and Tony's techniques can be considered correct as each method has its pluses and minuses.
While I yearn for the patience, knowledge and skills of the Valenti School of Precision, I confess I utilize the same thought process as DownUnder Tony. That is, if I'm utilizing the same brand of bearings and changing nothing else -which I have done, I'll try not to fix something that ain't broke...yet.
That whole wedding band +/- measurement is just counterintuitive to my pea brain.
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Respectfully, Georges states he has a different wheel and will be installing new bearings, unless I've misunderstood something.
Chances are slim his different wheel and new bearings will offer the same preload with his original wedding band and bearing stack components. Not impossible, but doubtful.
I would recommend measuring your wedding band thickness with a quality caliper, recording it, installing the new races and lightly oiled bearings, install the bearing stack with a take-up collar, torque the axle nut to ±25 to 30 Ft-lbs and check the rolling resistance by feel. If the bearings feel loose, start hand milling the wedding band in 0.05mm increments and retrying the feel. If the bearings feel tight you will need to purchase a thicker or wider wedding band. You're after a slight amount of drag with a smooth spinning axle, and no lash or play in either a radial or axial plane.
I would also recommend inspecting your top hat spacers for wear grooves from the seal wipers. If so replace them. And I highly recommend new seals, annually or at every bearing service.
There you have two different options or schools of thought as Monte mentions on how to proceed. While the range of acceptable preload is fairly wide, it's an application I like to get right for safety and piece of mind. I depend on my wheels to hold me up and support my tires, power train, frame geometry and suspension's function.
Keep us in the loop ... happy to help if called upon.
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Mike V, how does the pipes on the axle to press on the hat spacers, inner bearing race working for you ??
Make it easier to set the rear wheel bearings ??
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Bob,
The take-up collar is essential for obtaining and measuring the preload with the wheel off the bike. It basically takes up the space of the rear drive, top-hats and frame arm in order to apply torque on the stack.
The top-hats are not used when using the take-up collar.
I modified my spacers offered by Dan Neiner at Cycle Works. This is a very long story I will try to make very short, to share my experience regarding the importance of the take-up collar. I hear a lot of the guys just using a 3/4" pipe from the local hardware store. I disagree with doing it that way (personal opinion). The reason is, if the take-up collar is not centered on the inner shoulder of the rollers and the take-up collar ends are not perfectly perpendicular to the axle, you will get stepping-out in the rotational movement. You know; when turning the axle it will reflect in a go-stop-go-stop type action. Makes it impossible to replicate the assembled situation, or measure the preload with a pull scale. The scale will bounce all over the place.
So I had my collars turned on a lathe and PVC inserts made so the inner diameter of the collar closely matched the diameter of the axle. In my spare time I want to search a metal shop for the correct inner and outer diameter of round stock so I can trash the idea of the inner PVC inserts. Snowbum mentions the correct inner and outer size on his web page.
You guys can use a pipe section from the hardware if you like, it will work but I was doing a lot of testing and discovered the most important thing about the collar is the precision of the ends to give me a constant consistent rolling action while measuring the radial rotational torque. I know, anal and unnecessary a lot of you guys will say. Maybe, but for my testing it was very necessary. After you have the correct collars the whole process is very simple and fast and accurate.
Did I answer your question?
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If he has the Wedding ring that come with the new wheel he has a good chance the new bearing will preload within spec And if not hopefully they will be on the loose side and he can just sand a little off the spacer and be good to go.
If you want actual shims you could check with a industrial supply company and you could get very thin shims and use a narrower wedding ring with the shims.
Here in the USA a company called McMaster Carr has this kind of stuff.
Max Motors shows new spacers ranging from 6.300mm to 7.700 mm
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While we are on the subject
What are the Timken numbers for the bearings.
I would like to know before hand how available they are :D
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40x17x14
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40x17x14
Sorry Bob that is only the size
The cup and cone should have a Timken part # on them
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What are the Timken numbers for the bearings.
The bearing number is 30203. Very common and most likely found at your local auto parts store.
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Hello !
I made a take-up-collar to be able to pre-load the wheel bearing when doing wheel balance with a new tire.
I went the other way around this problem. I bought a plastic 19 mm tube and put at both ends the top hat spacers I replaced on the wheel because the lip seal has worn them out. This way the tube is centered on the axle and the ends are perfectly pressing on the top hat spacer on the wheel.
The 19 mm tube is a very cheap gray tube used (at least in France) to hold electric wires when doing apparent installation. I cut it using a miter saw so the ends are reasonably perpendicular to the axle.
As per the bearings, the old one I have in front of me are SKF 30203 J2/VT10B I suspect the J2 and VT10B are tolerance markings from the SKF company. Some rollers are badly rusted and seized into their cage. Happily enough my wheel centering device has rollers of it's own so I could ascertain the true and wobble of the newly got wheel using them because the axle refused to make one full turn ....
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What are the Timken numbers for the bearings.
The bearing number is 30203. Very common and most likely found at your local auto parts store.
Thanks Mike and George ;D
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So I went to the bearing seller in my town yesterday. 40 Euro less and a couple of Made in France Timken in my pocket.
This morning:
remove old SKF outer races
Install new Timken outer race
Check pre-load with the wedding band I have.
Decide if I need a new one or not....
Empty the R65 tank and try to fix the stumble problem I have for weeks now....
Try to work a bit ;-)
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It's worth bearing in mind that even if the bearings are identical dimensions BMW were notorious for setting them up at the factory with excessive pre-load. In my case I found it was grossly excessive pre-load and I had to insert a shim which from recollection was 3 or 4 thou.
Like Monte I much admire Mike Valenti's precision approach to the measurement of bearing drag and it's a pity BMW were not as contentious. There was something else I learnt in setting up my bearings and that's the fact that unless you are extraordinarily lucky the interval between available sizes of wedding band is simply far too big.
Using Duane Ausherman's shake the wheel test I found I was easily able to detect half a thou difference in shimming while the wedding bands only came in 2 thou intervals. As I needed to reduce pre-load, rather than buy a thicker wedding band and lap it down I ended up making my own shims.
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So,
I've changed bearings. First, removing them with the Northwood airhead tool was a song. Installing the new outer race in was also easy, using the enormous socket I own.
But, when I installed the axe and the plastic tubing I use to balance the wheel, i discovered that cheap plastic is not a proper material. When I used the torque wrench to set the pre-load, the plastic exploded !
So it took me some time to find a metallic tube (22 mm dia copper tubing from my plumbing supply) and make a spacing tube. copper is too soft. When I applied the torque, the top hat I use to center the tube on the axe sank into it...
But I was able to find that the preload was 20 Ncm so in between the 15~30 Ncm Bmw specifies... All is well !
I have to grease the two bearings, install the lip gaskets and top hats and I'll have a nex wheel ready !
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It's worth bearing in mind that even if the bearings are identical dimensions BMW were notorious for setting them up at the factory with excessive pre-load. In my case I found it was grossly excessive pre-load and I had to insert a shim which from recollection was 3 or 4 thou.
Like Monte I much admire Mike Valenti's precision approach to the measurement of bearing drag and it's a pity BMW were not as contentious. There was something else I learnt in setting up my bearings and that's the fact that unless you are extraordinarily lucky the interval between available sizes of wedding band is simply far too big.
Using Duane Ausherman's shake the wheel test I found I was easily able to detect half a thou difference in shimming while the wedding bands only came in 2 thou intervals. As I needed to reduce pre-load, rather than buy a thicker wedding band and lap it down I ended up making my own shims.
I'm in agreement again with most all points Barry - as usual. I too find the factory preload of 21 to 42 inch ounces excessive. In fact my target is much in the lighter range of 15 to 25 inch ounces. Leaning towards 15.
And I agree with your comment of the factory steps in wedding band sizes may not get you to where you want to go without milling, or shimming. 0.05mm can make you or break you if you're close to either side of the limits.
I no longer use Duane's shims (or others), just a personal preference for me. Those 0.05mm shims are very easy to overlook and loose count of. And if anyone other than myself ever get's into the stack they will surely overlook them. My recommendation if you choose to use the shims is to be sure and clearly document how many you've used in your personal records.
The well known /2 shake test is a good final test after installation but I wouldn't advise using it for adjustment alone on the newer wheels.
Just as a clarifier, as I expected - a lot of you feel I go over and beyond for this process. Most of my posts reflect my experience with testing which I was very critical of, in the way of parts, fitment and procedure. I want to share the details I've learned for the sake of completeness and safety. Most of our wheels have the steel hub inserts which make this procedure much less complicated. My testing was for the all aluminum drum brake snowflake hubs on my R100/7 for which the R&R and preload is much more involved. Shortcuts are fine, just be sure to be careful in what you do for your own safety.
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Hello guys,
I've discovered a problem. The left lip seal has to be inserted INTO the hub otherwise the top hat spacer will not touch the bearing and the slip seal...
I bet the dealer sold me a wrong reference for this top hat spacer ...
What do you think ? May I have the seal a little buried in the hub or has it to be flush with the hub ?
Mike, measuring the torque using a scale and a thread is not at all difficult nor overkill. I was lucky to find a couple of years ago a digital scale you can use to weight you luggage in airport. This served well today ! As I'm also anal, I used the exact value for g to make the calculations from kg indicated on the scale to N needed in the Ncm figure given by Mr BMW ... I am in the lower value and can't turn the axe by hand now that the new seals are in place 8-)
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Mike,
Having just re-read my post, I didn't mean to say I wished BMW were as contentious as you I meant as conscientious as you. Hope that didn't cause any offence. I'll plead spell checker.
Georges,
I'm not quite clear on what the problem is with the top hat spacer. Before installing the seal it's normal to push the top hat through from the back of the seal. To do it after seal installation is possible but risks damage to seal surface.
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Mike,
Having just re-read my post, I didn't mean to say I wished BMW were as contentious as you I meant as conscientious as you. Hope that didn't cause any offence. I'll plead spell checker.
Georges,
I'm not quite clear on what the problem is with the top hat spacer. Before installing the seal it's normal to push the top hat through from the back of the seal. To do it after seal installation is possible but risks damage to seal surface.
Barry,
None taken! I understood what you were saying.
Georges,
The top hats can be inserted either with the brim behind the seal or outside the seal. I personally prefer the brim behind the seal so they always stay in place. The seal face should be inserted flush with the hub.
What year is your bike?
Not quite sure what the problem is either ... did you record what top hat was on what side during disassembly? Do you have your axle spacer installed? Can't refer to any of my pictures at the moment since I'm corresponding from work but I'll check in tonight when I return home.
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Mike,
The bike is a 1982.
My problem is that the new top hat is not the good one. It is too short. If the hat touches the bearing, the lip of the seal is free. So in order to have the hat on the bearing and the lip sealing the spacer, I've to install the lip seal way into the hub.
Tomorrow, I'll check with the BMW part number on the pouch and the fiche to see where the error lies.
Thank you for your help !
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<snipped>
I am in the lower value and can't turn the axe by hand now that the new seals are in place
Doesn't sound right to me. ???
Are the seals interrupting the rollers?
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My problem is that the new top hat is not the good one. It is too short. If the hat touches the bearing, the lip of the seal is free. So in order to have the hat on the bearing and the lip sealing the spacer, I've to install the lip seal way into the hub.
Tomorrow, I'll check with the BMW part number on the pouch and the fiche to see where the error lies.
There are at least two different lengths of top hat spacer. 9mm, 13mm and maybe more. Looks like you were supplied with the wrong length.
I know on my rear wheel the spacer doesn't protrude very much beyond the seal lip so a shorter spacer would not work.
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Mike, I do not own a spare axle. So I tried to turn the bearings by applying my thumbs on the top hat spacers. I've not enough force in my fingers to rotate the top hat spacers and the bearings this way.
As my rear axle is pitted and somewhat rusty, I'll order a new one and use this one as a spare and on my wheel balancing device.
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So, yesterday, I got the top hat spacer.
There are three size : small medium and tall.
The small is said 9.2 mm and is used on the brake side of the rear wheel. Standard fitting.
The medium one is said 10.7 mm high and is also used on the right hand side of the rear wheel when one want to use larger rear tires.
And then there is the tall one. It is used on both side of the front wheel and on the left side of the rear wheel.
I had a 10.7 tall one served in a pouch labeled like the tall one. So this is why i was confused !
Now, the rear wheel is ready to be fitted, when I get the brake pad from the guy refurbishing them !
Thanks for your help.