OT - Bearing vendor Q's, Bearing fit Q's

I'm rebuilding the bottom end of my motorcycle (both the transmission and crankcase) due to a bearing failure and collateral damage. All of the bearing were replaced with new bearings from a local bearing supply house. My first question is more about business interaction than a technical question.

I approached the bearing supplier with a list of bearing part numbers which I copied from the OEM bearing part number stamped in the races or molded into the shielding. None of these bearings are particularly special - no funky flanges, high ball counts, thin races, etc...

The salesman claims it took three tries to get the correct bearings from their warehouse, and even then some bearings were shielded when I requested unshielded (at added cost to me, no doubt). When I went to pick them up, one pair was clearly wrong (not the same part number I'd requested), and the quantities were wrong on two other bearings.

Adding insult to injury, the salesman quoted me one price over the phone, and when I went to pick it up, the inside sales guy charged me a significantly higher price because he claimed that one bearing (a big, expensive one) had not been included on the ticket -- this final total was actually higher than OEM parts, not to mention that it took longer to receive usable parts.

Is this how all bearing vendors do business? If so, how the hell do they stay in business??!! Or, did I get sh!t service and screwed on the price, as well? Did I communicate poorly? Did I have the big neon "SUCKER" sign on my forehead? How could I have made this transaction work better?

Now, the technical question: One of the bearings is apparently a higher-class fit than the OEM part. On the output shaft, the OEM bearing will slide all the way down the length of the shaft, but the new replacement bearing will only slide on as far as the root of the splines for the sprocket then jams.

Presumably, the new bearing could be heated/the shaft cooled, or pressed on in a hydraulic press, but none of those solutions is viable for a motorcycle transmission. The ID of the bearing needs to be a looser fit so it can be assembled by hand.

Is it possible to enlarge the ID of a ball bearing? I don't believe I can chuck a bearing accurately enough to cut or grind with a fixtured tool (i.e. a cutting tool or a grinding tool in the tool post), but is it possible to hone the ID with a lap and not ruin the concentricity? It doesn't need much, only about 2~3 tenths. Then there's the problem of keeping the inner race from turning... If there are techniques for this situation, I'd like to hear about them.

Given my experience dealing with the bearing supply place, I'm not anticipating a positive experience requesting to exchange the bearing. How would you approach the bearing vendor to secure an exchange? Should I just suck it up and go buy a replacement, maybe from a different vendor?

I can measure to tenths, but I don't know how to specify a class of fit for the replacement. Any help there, perhaps a link on the subject, would be most appreciated.

Thanks for any advice.

Racer Al,

I don't have all your answers, but will add this thought. I have never seen a bearing ID (or OD) that would slide onto its fit. Something has to hold the inner and outer race stationary so the balls or rollers can 'do their thing'.

Often a shaft can be worn and not be apparent which will result in a 'flop fit'. Bearings come in inch or metric and should all be the same by number. A 6208 ZZ of anyone's brand should have the same ID or OD...they're standard.

I have not worked on many motorcycles so I might be all wet in your case.


Stuart

Al,
You neglected to post a picture of your forehead

There can be some batch variation to bearing ID's. It only takes a couple of tenths to remove the 'hand assemble' fit from a bearing.

Take careful measurements to make sure that you've not got metric and imperial bores mixed together, for example 16mm vs 5/8, or 30mm vs 1 and 3/16. There are a few thousandths difference between these which you might not notice visually, but you could easily measure the discrepancy, if it were that large.

I've 'resized' bearing bores as follows, and I apologize for the crudeness of the method Take a close fitting flapwheel that will fill the ID bore, and give it a couple of bursts with the die grinder while you slide the flapwheel back and forth in the bore. You can kind of pinch the sides of the inside race with your finger tips or vice grips to keep them from spinning. This will quickly ruin a good bearing bore When I did it, I was trying to make easy sliders for the purpose of spindle liners, so I was not concerned about tenths. Of course, if the bearing is not sealed, it will get full of grit, too.

I suppose if a person wanted to get serious, you could make a sandwich type clamp device with raised bosses to grip the inner race from each end. Then, you could perhaps rig up a lap to carefully remove material from the inner race. I usually lap stuff by hand, but maybe someone with a Sunnen hone would have ideas on how to hold this safely while it is being lapped. There are always moments when the part could seize onto the lap, and you don't want to get wrapped up in your work.

Don't try to resize the bearing. Prepare a tubular drift that just fits over the shaft. Clean the shaft thoroughly, including any required deburring. Wipe a little light oil on it. Place the bearing in a clean plastic bag. Place the plastic bag in a bowl of almost boiling water. Take bearing out of bag (mind fingers), place on shaft and push on firmly with drift. a couple of tenths is 20deg C on a 25mm diameter, so you aren't looking for much. Also the temperature won't harm the bearing at all, it might get near that hot in use!


Oh. Yes you were shafted. A good bearing supplier should come in cheaper than the OEM for better product, should supply exactly what you ask for, or tell you the problem before ordering a special and should not alter a quoted price (note:- estimated doesn't mean quoted). Maybe I've just got an excellent supplier!

Bearings come with precise ID's and OD's. These diameters not only allow them to fit bores and shafts properly but take into consideration how much this interference fit will affect the running clearance of the rolling element...the balls or rollers once things heat up. Forcing or jury rigging a bearing into or onto a fit will condemn that bearing to a short life.

If a bearing doesn't fit, it usually isn't the bearing that's at fault, it's a bum fit on the shaft or bearing pocket. Unless this is repaired too, why put shiny new bearings in only to have them fizzle out prematurely...and have to do the job again.

Stuart

OEM and replacement bearings are identified with the same number (63/22 LAX), except for the suffix which indicates shielding: I needed shielded one side, they sold me shielded two sides, and I removed one side. To my thinking, matching P/Ns should eliminate the possibility of mixing Standard & Metric bearings, and theoretically, should have identical critical dimensions, but they don't.

I understand that bearings need some snugness on the shaft to work properly or the shaft that the bearing supports will be damaged. The OEM fit was a very snug sliding fit, very fiddly to get it to start, and it sort of 'chirped' when sliding onto the shaft.

Mark, the problem is that the bearing is held in place inside the transmission cases with a pair tabs held in by screws, which are inaccessible when the shaft is in place. I suppose I could heat the entire assembly, but I'd hate to over-do it and melt the seals. I'm also loathe to hammer too much (or again, I should say, as it got hammered more than I would like trying to assemble and disassemble the parts) . I am concerned about abusing the opposing bearing. And, yes, thanks for confirming that this bearing vendor treated me like a city dog treats a fire hydrant. Your comment fits my perception of how it should work with bearing vendors.

The measurements were taken by measuring the bearing 10 times in 10 different spots, then throwing out the high and low numbers, then averaging the resulting numbers. The OEM bearing is .86613", and the replacement bearing is .86533", a difference of .0008", which is a little more than I had figured.

I figure that if I'm in the market for a replacement bearing, I'm not really wasting anything by trying to "adjust" the poorly-fitting bearing. I figure I can build my own flap wheel out of 600-grit w/d sandpaper for a bit better controlability. For what it's worth, I actually have the seals for this bearing, which I can reinstall for the adjustment. It won't hurt anything to put a swatch of duct tape across the sides to hopefully keep most of the grit out. Maybe a C-clamp across the bearing races will keep it from spinning.

And here's a recent pic of me in front of Half Dome in Yosemite. It makes it difficult to get good comfort in a helmet.

I just did a google search for "63/22 LAX", and found only references to rebuilding my model of MC, and the forum users stated that the bearing had to be purchased from the OEM. Perhaps this is in fact a special bearing with a looser fit?

sounds like an asshole vendor to me. the place i buy bearings from is a joy to deal with. their stock list is right there on the computer screen in front of me along with prices and they always make sure i know of my options for each size i need..."you want a WIB or NTN for this price or a super high quality chinese one for half that?" now if i want to deal with your type of vendor i can always go to the SKF dealer, they have a plush sales area with a carpeted floor that's easy on the knees when they get you down on all fours....

regarding number of shields: no place i know of offers standard bearings with a single shield because the minute price difference between that and two shields isn't worth the hassle of stocking both.



dave

22mm = .86614", so the old bearing sounds like it was right on the money so far as being standard, and the new one is substandard by a considerable amount that I have never seen in a ball bearing.

Al, You are officially getting screwed. There is a huge range of discounts in the bearing industry, from "We've never seen you before" to You are our biggest customer" and the range is about 3X to 4X from lowest to highest price, sometimes more, for exactly the same bearing. If you have ANY industrial connections in your new location try to buy through them to get a better price.

Bearing IDs in the 20 to 25 mm range are typically nominal size to .0004" undersize. Sounds like your OEM bearing is normal and the new one is undersized. I see odd sized bearing occasionally, both oversize and undersized, I guess they slip through inspection somehow.

There are special order bearing made that have special diameters, and they are often not marked as special except on the box. you could have one of them, or you could have a defective one.

I modify some bearings by honing because it's cheaper and more flexible than special ordering them here's a drawing of a fixture I made to hold 4 bearings at a time. I put heavy grease on the edges of the inner races to seal out the honing oil and the grit it contains, and there is an o-ring to seal the cap to keep the oil away from the bearing ODs. There is also a tommy bar to keep it from spinning in the operators hands. The ID is a close fit to align the bearings, and the lip on the cap clamps the inner races together and keeps them from turning.

There are some specialty bearing suppliers that specialize in motorcycle specific bearings, RBC is one that comes to mind, you can probably find a few with Google.

Edit - Here's KML's list - KML is a very high quality import, they show a 63/22 with rubber seals. They are not a retail seller, you'd have to order KML through a retailer/wholesaler. http://www.kml-bearing.com/bearing_applications/motorcycle_bearings/index.jsp

I would have walked out of that bearing house without any bearings. Let them figure out what they can do with them.
I use Motion Industries if I need something right away, Headco sometimes. If I have a few days lead, I call Dalton Bearing in Dalton Ga. They have always beat Motion and Headco by at least 25% on price.
Sometimes they dont have the pieces I need. I've had just sizes and roller counts with no numbers and they will figure things out.
I also always have gotten call backs from them on prices and availability if they had to look around.
Dalton Brg, 706 226-2022. Good guys.

Yeah, no dinner, no drinks, no dancing. Just straight to the screwing. Story of my life. Serves me right for not asking for a written quote addressed to my graphic design business, which has a fairly generic name and could be almost any business.

One thing I will say in favor of the new digs in Oakland is that there are absolutely a TON of industrial suppliers, at least compared to Washington DC. I don't ever need to do business with this supplier again, there are at least a dozen others I found in the yellow pages.

Mud, thanks for that fixture idea, it's a good one. I'll store it away for future reference should I need it.

I might just be a hack, but I basically did what Hu suggested and sanded out the ID of the offending bearing. I chucked a length of dowel in my lathe, wrapped some soft foam around the dowel, and sandpaper around the foam, then slid the bearing over the compressed foam/sandpaper. I was thinking of powering it up, but decided to be a bit cautious instead. I just slid the bearing axially over the sandpaper for a couple strokes, rotated the inner race a bit on the sandpaper, repeat as necessary.

I was quite surprised that it took literally two minutes to clean up the ID enough to get a *very* tight hand fit. It's significantly tighter than the OEM bearing, which is probably good.

Thanks, everyone for your help and advice!

J Henricksen, I'll keep those in mind. I'm quite sure that, even with shipping, your vendor could have delivered the goods in a more timely manner!

I believe that in the future, I will measure the OEM bearings and provide the measurements in addition to the part numbers. That ought to help avoid some confusion.

Well nobody else asked, so I gotta.

What was the bike, and what precipitated the explosion?

Anyone hurt?

Jim

Racer Al,
You weren't by chance dealing with Motion Industries were you?.....That sounds like them....
What's surprising is that they didn't make you wait 4 days just to get a price quote........
I've yet to find a "good" bearing/power tranfer supply house

+1 for getting lousy service.

Call Accurate Bearing(.com) ask for Tony.

You can buy "China cheap" through "super high end" your choice.

Be a cold day in !!!! before I go back in a Motion Brg

Emergency call, needed a 3/4 standard pillow block, nothing special.

$84.00

I asked if correct, "of course" was the reply( yea sure )

had no choice but to buy it.

I've actually resized bearings quite a few times by disassembling them (only possible with a plastic ball retainer) and honing the inner race.

Once the plastic retainer is pushed out (carefully), shove all the balls over to one side and the inner race can be removed.

I made a holder, which I honed to the OD of the inner race. Lightly clamped the inner race, hone to size, clean and reassemble the bearing.

Alternatively, a holder can be made that grabs the inner race by its faces and seals out anything else from getting in the bearing, and hone that way (way more work than disassembling, but might be the best method possible if the ball retainer is riveted steel halves).

fwiw...

PM

I know this if far afield of the original post, but i am stumped why one would need to screw with a bearing. I have built many machines and many spindles that were equipped with ball bearings. The shaft or bearing pocket was built to fit the bearing. If any polishing was to be done to tweek the fit, it was done to the shaft or pocket, not the bearing.

I guess I would sympathize with the next gentleman that came along to replace the noisy bearing only to find that no over-the-counter bearing would fit properly and that he had to break out the die grinder and flap wheel!

Stuart

Jim, this was a DRZ 400. It was a long domino effect - over a year ago, I 'dusted' the motor when a hose on the clean side of the airbox came adrift on a dirt ride, slightly damaging the rings. It didn't consume a noticeable amount oil around town. However, I took it on a long highway trip (900 miles, continuous high RPM) and it consumed *all* the oil, which damaged the piston and cylinder. My fault, really, for not checking it more frequently under those conditions. I fixed that mess and the bearing in question came apart on the break-in run, ruining the oil pump and all the bearings. I'm about fed up with it, honestly.

The vendor was a local bearing specialist in San Fransisco, and it wasn't Motion Industries. I'm not sure I'm pissed enough to name names, since I didn't ask the knowledgeable folks here at PM for a reputable dealer, I just picked the first one I came across on Google Local. Like atomarc, I thought they were so high precision and uniform that I shouldn't need to worry about anything other than matching the part numbers.

I don't think you got good service, but you probably didn't give them the info they needed to do a good job.

I ALWAYS take in the bearings and let the folks at the counter look at them.... That ensures no confusion. Sometimes the numbers on the bearing don't actually tell the story, or at least not the FULL story. Shields etc should be indicated, but may be different from expected.

it's simplest to show them the bearing, and then they know. Even pieces.. they are used to seeing pieces.......