Hello all,
Considering the axle and front hub bearings are sealed, they would be packed with grease, correct? If so, is it pointless to try and grease them?
Thank you
Depends but short answer is they are not really “sealed” and you should clean and rebuild them if you know what your doing. However if you have never done anything to them(shot oil into them) and they have not seen rain. Your likely ok to keep running them.
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They are shielded, not sealed so they get dirt in. What I do is to put a super good lubricant (Xeramic bearing lube) when they are new, then never touch them. Buy some spares and after a while if you feel they are worn out or “crunchy”, you throw the new ones in. Not really a scientific approach but…I try to leave them alone as greasing or lubing them means high chances to move around dirt into the races and make things worse…If you want to service them properly you have to take the axle out, remove them, open the shield, clean and (lightly) grease…at that point it’s a waste of time for a bearing that may be worn out already, not worth it…throw in a new set and you are good. They are cheap enough
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Great plan, and I’ll replace my current ones as I’ve likely pushed so much dirt into them 
Thank you both
You can always pop the shields/seals and pull the cages and clean up the bearing. Re poilish the races and balls and use a quality grease.
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I suppose I can try and pull them apart, if it doesn’t work out I can replace them
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I toss and replace every winter. Bearings are cheap.
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Considering what other things cost in the sport, it is haha
now of course when I go to look at them, I come across ceramics lol. No need for that, right?
Cheap bearings are slow… lol
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Absolutely 0 speed difference between my rebuildable SKFs, my Ceramics, and my $10 each bearings. 
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+1 ceramics are a big chunk of money for next to no benefit. Popping the dust shields off and cleaning them properly isn’t a bad idea, especially after a particularly dirty weekend (rain or dusty track). I have rarely ever gone through that hassle though. I flush them out with ether at the end of the day and re-lube. Maybe not the most correct way to keep them in tip-top shape, but like Burpo, if they get crunchy I just replace them. I have done 3-4 seasons on a set of bearings with no issue though, so honestly, axle bearing maintenance is pretty low on my priority list.
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Agree with you TJ, My karts have done 4 seasons on the bearings now, before big races I clean/ flush them out with break cleaner to they spin nice with no gritty sound then I spray some WD 40 in them to it pours out the sides but go easy on the break disc side with the WD 40 or anything oily as if it gets onto the break disc and you will reduce the breaking and you will need to clean the break disc with break cleaner again. I also like to spray some WD 40 in the grub screw holes for the third bearing to make it slip easier on axle to help the kart flex obviously only when I’m not running the grub screws on third bearing.
This method has worked successfully for me for 20+ years with no problems.
Bearings seam to last a very long time!
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seems like I’m not gonna get the .5 seconds I need from the bearings hahahaha.
I guess I’ll just pop one side of the shield off and clean them out good considering I have never cleaned them, just kept applying lube.
I like to spray my bearings with PTFE spray, super smooth 
New bearings every season, cheap enough! Also a great time to check for cracks and alignment
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I clean mine with brake cleaner until I hear no gritty sound then spray them with tri-flow.
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I spray mine with Kerosene and 2T oil mix until all dirt and stones are out. Then Xeramic bearing spray. They spin super easy but I think next set of bearings I leave them as is and do nothing. I feel because I flushed all the grease out now sand gets in easier, especially when it rains.
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How do you actually pull the dust shields off without destroying them? I’ve read people say they pull them off, clean and put them back on but the one time I tried to pull them, it bent the shield and messed it up.
A tip I got from one of TJ’s videos was to use starting fluid to flush the bearings instead of brake cleaner. Way less corrosive to paint and plastics.
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Source the thinnest pick tool you could ever get your hands on and just pull them carefully right up 
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The right fluid to clean out the bearings is 87 octane gasoline, because grease is soluble in it. Use a spray bottle to spray it in and a drip tray to collect it, and incinerate the waste rather than letting it evaporate. Leaving it around is a much worse fire hazard than burning it in a firepit.
I like Mobil Centaur 461 NLGI#1 grease for axle bearings, but use the thicker NLGI 2 stuff for the rest of the front end. They are both totally waterproof. Grease both keeps the dirt out of the bearings and lubricates them. You will feel a little more drag than if you used TriFlo or ATF to oil them, but there’s no oil seal or oil feed on the axle bearings of a kart!
If the bearings still feel “gritty” after you’ve cleaned them and greased them, they’re scrap. Usually that results from operators using oil or too-light grease in the bearings and allowing dirt and water in.
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