Just replaced the 6804 (61804) bearings on my front bulb hub. Guess the last ones did okay. had a few years out of them and never needed to do anything to them. I always lift the seals and pack them with a thicker grease (silkolene RG2). I know it drags more but I don’t really notice. After all, on a push bike, they’re not really running at maximum design speed!

Anyway, these have failed in the same way as the last few sets, the bearings still feel smooth and they’re not too dirty inside, slight discolouration of the grease. However, they developed some play which feels like a loose headset when riding (no, the headset is fine!)

Just wondering how other peoples bearings die and if anyone had tried higher tolerance bearings and what sort of luck they had with them. I normally use the standard issue HOPE ones (INA I think). Worth trying a grade 5 type?

Higher tolerance doesn’t mean they’re any more likely to resist contamination and wear, simply that they’ve initially got less slop in them. The difference between those and lower tolerance bearings is dwarfed by the wear required to get noticeable play!

yup, it’s like the hulk and Stuart Little

Try not lifting the seals and repacking them – they were packed with the correct grease for a wide range of applications (including the one you’re giving them) at the factory in a clean environment and sealed using tools that properly align the seals. While you may be able to very very carefully repack them, there simply is no need.

What’s more you can actually cause MORE wear by using too thick a grease – this causes the balls to skid around the race as rotating in the grease (when unloaded) is harder. If your balls skid you cause faster wear than if they rotate. Think about it – normally the balls surface is stationary in relation to the race, meaning very little wear occurs.

Edit: I’m not a bearing expert, it’s just what I’ve read while looking for bearings at work.

Just re-read the OP – if you’re getting a few years use out of industrial “sealed” bearings on a MTB, you’re doing pretty well. Wouldn’t really worry about it, and just make sure you’re getting them from a cheap source (generice bearing supplier, not bike shop).

yes, I agree, 2 years isnt too bad. I’ve had 6 from my original Hopes, and 4 from my last set in my DDG hubs. Never touched either of them, ridden them throughrivers etc. Watch out for your bearing suppliers taking the mick – when I accidentally brinnelled one in a rear hub before a trip to the alps one charged me £9 for a bloody bog standard one but I had no choice due to timescales!

Coffeeking’s point about skidding in thick grease makes sense but I started doing the seal lift and repack in response to the fact that before that, bearings died because they felt dog rough. The repacking from new has solved that and got me a bit more bearing life. Just thought that a starting with a tighter tolerance might mean they run for longer before being noticeably out of tolerance.

They cost a fair bit more, but I used to use labyrinth sealed ones (Got them from Royce, but should be available from decent bearing suppliers), they seemed to last hell of a lot longer for me. I found that adding grease helped too, they’re high speed bearings that are greased with that in mind(according to an article I read in the dim and distant, they may even explode at high speeds if full of grease).

1 to 2 years is typical for my bearings. Very few of my bearings ever die from wear from use. Water and dirt ingress is by far my biggest concern and the cause for 99% of my bearing failures, almost exclusively due to water induced corrosion. Packing extra grease substantially reduces this.

Upgrading to stainless bearings (and races) where possible has helped markedly with this, since the bearings are harder and corrosion resistant, but they do need still need re-greasing at regular intervals to avoid mechnical wear associated with the presence of dirt and lack of mechanical lubrication.

I’d rather see the return of grease nipples on hubs and BB’s – so much easier and more reliable.

If you take a look at most, if not all cheaper bearings, you’ll see that the inner ‘seal’ that is adjacent to the rotating inner race is actually only a close fit – theres often no wiper or lip seal at all. Some of the more expensive bearings do have a proper lip seal. whether this makes a difeference or not I’ve not really noticed, but it surely must help.

Alternatively change to some hubs that you can adjust when play develops, Shimano, CK, etc. 8)

Useful thread thanks, perhaps a little OT but re bearing wear, how is it that bearings used in vehicles last so much longer than our mtb ones? If it is down to “exposure” to the elements then it is surely possible to make effective seals – even at a premium price it would be worth it to banish that problem – or is itthe dark hand of planned obsolesence?

Tom

I think it comes down to scale. Since the weight penalty of a substantial bearing set on a car is negligeable, car markers can afford to through big balls and races at the problem reducing the opportunity for wear regardless of the additional weight. Also, rusty bearings ina car arent as big a problem as for us Im guessing 🙂

Too add to that the more you seal up a bearing the more resistance you put into it which isn’t so much of a problem for engine powered ones but you would notice it on the bike if every thing dragged.

the other thing is, the deep groove ball bearings found on most bikes are not ideal for the sort of loading caused by mountain biking, it’s just that they’re relatively cheap and pretty idiot proof.

IME smearing the back of the dust cap with a heavy waterproof grease helps a lot. You avoid the problems associated with repacking, whilst the extra grease prevents water/dirt ingress onto the seal to start with, meaning it has a much easier life. As this grease breaks down a wipe clean and resmear is real easy and quick.
I do this on my Hope XCs, Ringle hubs, and HT2 BBs (under the tophat), and even KCNC mech pulleys.

Interestingly, ACROS headsets and BB come with instructions for how to prise off the seals and regrease. It can’t be that bad if they’re suggesting doing that for maintenance.

Coffeeking’s point about skidding in thick grease makes sense

No it doesn’t – think of the pressure on the bearing and the viscosity of the grease. The amount and type of grease pre-installed relates to the design use – machines in factories etc, not external use with water, muc off etc around.

IMO/E it’s way more important to fill the bearing with grease to stop crap getting in then worry about contamination or seal distortion (both easily avoidable for all but the mentally sub-normal or feckless).

I bet many car bearings are way rougher than bike ones. Cyclists are obsessed about bearings not feeling rough and having any drag. Truth is, neither will slow you down measureably (within normal parameters).