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I picked up a bearing kit from Pivot Works for the rear wheel (PWRWK-H11-021) and I'm wondering if I should remove the shields and grease the bearings? There's no mention of it anywhere. I will pack marine grease during installation (I also have Bel-Ray, the blue stuff). I find the marine grease lasts longer and repels water better. Any thoughts?

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I picked up a bearing kit from Pivot Works for the rear wheel (PWRWK-H11-021) and I'm wondering if I should remove the shields and grease the bearings? There's no mention of it anywhere. I will pack marine grease during installation (I also have Bel-Ray, the blue stuff). I find the marine grease lasts longer and repels water better. Any thoughts?

Went to AutoZone and borrowed a bearing puller and slide hammer. Heated each side for about a minute and popped them out. Nice and easy for once!!! The sprocket side bearings had no "inner shields". It makes sense since their not exposed to direct dirt. If anybody recommends the Bel-Ray over the marine grease, speak up before I get the new ones in. Thanks.20181017_121042.jpeg20181017_121008.jpeg

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First figure out whether you have "Shields' or "Seals" in you new bearings. Seals have a rubber contact ring that touches the inner ring of the bearing (its not called a "race"). I suspect you may as sometimes the stamped steel of the seal covers nearly the entire opening making difficult to tell. I highly recommend SEALS on both sides. Shield have there purpose but not for off-road bikes. Shields don't protect from water.

Anyhow, do NOT remove the Seal/Shield. Depending on manufacturer, bearings with enclosures on 1 side may already be greased. If that's the case leave it alone. If they are ungreased, go ahead and shove a bunch in there from the open end. Any good marine grease will be adequate.  Pack as much as you can around the bearings inside and out. This is mostly for additional sealing. Marine grease has polymer tackifiers(sp) that resist water better than Lithium, Sodium and other soaps.  If you dip your fingers in marine grease and spread them apart and you see a bunch of strings, that's good.

Go ahead and heat your hubs again but be sure you press only on the outer ring (again, not "race") during installation. Perhaps a big socket will fit. I've been known to grind off a little of the old bearing OD and use that as something to hammer on.

Good luck.

Gary

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I would pack inside and around the bearings, but dont remove the shields. They are sealed bearings that need no lubrication. I use the bellray blue grease but if you have used the marine grease and it resists water better then I would use it. All it will be doing is keeping corrosion at bay

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Thanks guys. My riding is over for the season and now it's time for preventive maintenance.

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I always pop off the seals, wipe out the minuscule amount of grease that is in there from the factory, re-pack the wheel bearings full with Bel-Ray, pop the seals back in and install.  I pop the seals and re-grease during regular maintenance, generally when changing tires or after a really wet ride.  I don't think I've ever had one of my regularly maintained bearings fail.

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Jayc250x,

How do you "pop" off the seal? If sticking a small screwdriver between the seal and inner ring, the seal has been compromised. If it's only a Shield, no big deal. I guess do whatever works for you and puts your mind at ease. A quality bearing manufacturer should grease to around 65% of the available air space inside the bearing. The stuff needs to find "quiet spaces" inside the bearing so as not to continually churn, which creates heat and accelerated breakdown. As mentioned above, by far the best thing to do is pack as much grease outside the bearing to create a viscus seal. This also helps the auxiliary seal trying to keep the world out of there in the first place. 

 

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58 minutes ago, jayc250x said:

I always pop off the seals, wipe out the minuscule amount of grease that is in there from the factory, re-pack the wheel bearings full with Bel-Ray, pop the seals back in and install.  I pop the seals and re-grease during regular maintenance, generally when changing tires or after a really wet ride.  I don't think I've ever had one of my regularly maintained bearings fail.

You will never find a bearing packed full of grease. 30% of the air space filled in the bearing is the industry standard for numerous reasons. I simple search on over packing bearings will explain the reasons why. A simple call to any of the bearing manufactures will also do the same.

 

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1 hour ago, Rotax said:

You will never find a bearing packed full of grease. 30% of the air space filled in the bearing is the industry standard for numerous reasons. I simple search on over packing bearings will explain the reasons why. A simple call to any of the bearing manufactures will also do the same.

 

Correct over-filling will cause extra heat and degradation.  However I think it is less of a concern here than on a vehicle that will accumulate 100k miles and run for hours at a time at high wheel rpm.

To answer the earlier question from Gary, the seal can be removed without damaging it.  It's not just jamming a screwdriver in and prying it out.  With a small pick tool you can work it around and hook under the lip and then pop it out.  Then carefully reinstall and spin the bearing to help work it back in.  You'll be able to see and feel when it's back in place correctly.  I've done it plenty of times.

Edited by mbrick
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Far too many 'muricans want to do way too much to things they are far too ignorant about to be deterred by anyone who just happens to be a knowledgeable, trained "expert" in the field. Nope, we don't need no stinkin experts!

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Guys, I simply responded to the OP taking into account his situation and urgency. I can't speak to the knowledge of who, at the manufacturer, jayc250x spoke with but you should also ask them if they will honor their bearing warranty after you tell them what you are doing to them. I've also popped off seals 100's of time for various reasons but none for re-use. Just because it can be done doesn't mean it should. But as I mentioned earlier, do what makes you feel good.

I could write a novel about proper care and feeding of bearings, installation, grease compatibility, shaft/housing fits, life calculations, tolerances, environmental testing criteria, etc, etc, and may already have with my stack of white papers I've got filed away. I tried to keep my original post simple.

Gary - Sales manager, applications engineer, new product development, clinical competitor testing committee, Industry specialist, technical liaison - SKF Bearing USA, INA Bearing International.

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I repack in waterproof grease as well.

Use your pick tool on the OD of the seal, that part doesn't move and is less prone to damage, unlike the ID which has seal lips.

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48 minutes ago, Blueleader said:

I repack in waterproof grease as well.

Use your pick tool on the OD of the seal, that part doesn't move and is less prone to damage, unlike the ID which has seal lips.

I'll do this. Leave them as they are and take them out of the freezer. Heat the hub, then lube it slightly. Press the first one in (sprocket side), lube generously, press the next one in and lube. Lube the seal and then lube it enough that it will squeeze out (the grease) when the spacer goes in. Clean off excess and install.

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19 hours ago, Rotax said:

You will never find a bearing packed full of grease. 30% of the air space filled in the bearing is the industry standard for numerous reasons. I simple search on over packing bearings will explain the reasons why. A simple call to any of the bearing manufactures will also do the same.

I know the industry standards and all of that, but I over fill them anyway 'cause I'm an anarchist.  Like I said, I've never had to replace a single bearing that I maintained this way, but I've had to replace many factory-filled ones.  I generally don't ride very fast here in our New England tight woods and rocks, so maybe that's why I've been successful. YMMV.

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On 10/17/2018 at 5:24 PM, Gary Strombeck said:

Jayc250x,

How do you "pop" off the seal? If sticking a small screwdriver between the seal and inner ring, the seal has been compromised. If it's only a Shield, no big deal. I guess do whatever works for you and puts your mind at ease. A quality bearing manufacturer should grease to around 65% of the available air space inside the bearing. The stuff needs to find "quiet spaces" inside the bearing so as not to continually churn, which creates heat and accelerated breakdown. As mentioned above, by far the best thing to do is pack as much grease outside the bearing to create a viscus seal. This also helps the auxiliary seal trying to keep the world out of there in the first place. 

 

Seals are easily removable.  The come right in and out and don't get damaged.  To reinstall you simply put them in position and press down with your fingers, and they pop right back in.  They have a thin flexible rubber rim that creates the seal on both sides.  I don't pack them completely full, but it's probably closer to 80%.

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Seals are easily removable.  The come right in and out and don't get damaged.  To reinstall you simply put them in position and press down with your fingers, and they pop right back in.  They have a thin flexible rubber rim that creates the seal on both sides.  I don't pack them completely full, but it's probably closer to 80%.
The bearings went in without a hitch. In addition new sprockets, chain, slider, block, and fresh tire were added. I did the rear shock and linkage last winter, so the ass end is done. I'll probably figure out a way to get it out of the basement and break it all in before the snow hits. I'm getting decent compression (185-195), but I don't know how old the piston is. Looks fine but I'll take off the jug and get it measured. I was told it's not bored over. I've put 30 hours on the piston myself so it's time for a rebuild. My cherry run for a top end swap. I've had the jug off multiple times to rebuild the power valve last winter, so I'm not too concerned. What's the compression supposed to be after the rebuild and heat cycles? I should mention that it's an '01 cr250.20181018_172603.jpeg20181018_153225.jpeg20180621_160921.jpeg

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