As a mountain bike rider, I spend a lot of time maintaining hubs and bearings. The problem I am facing is related to the much higher amount of dust, sand and mud trying to damage parts of the bike, as well as the fairly humid conditions in which MTB bikes are used.
At first, I used high-end maintenance components. By that I mean the best bearings I could get, usually SKF because their offer on the local market is very good. However, over the years I have started to use slightly cheaper solutions for some parts that show less fatigue.
Just to put things in perspective, most road bikes have 8 bearings, 10 if you include the ones in the headset. The average full suspension MTB can have up to three times as many bearings depending on the rear suspension design. That's a lot more money when using premium components for maintenance. Also, I have found that some of the suspension bearings, especially those exposed to lower lateral forces, show less wear, even under extreme conditions. My last bearing change was - top quality SKF bearings in the front and rear hubs, and as well in the main suspension pivot. In all other positions, I installed much cheaper bearings from unknown manufacturers (ie Chinese middle class).
Lubricating the bearings I did only in terms of preventing moisture and dirt from getting to them. One of the experiments with removing the protective rings around the bearings and reinstalling them showed me that no matter how carefully I do this action at home, the protective rings never show the same resistance to external factors as factory new bearings.
In addition, some bearings on MTB bikes are literally impossible to remove from the frame without damaging the bearing, and even those where it is possible require a special tools, a lot of time and careful work in order not to damage the frame. I went with logic - when I'm already going through so much work, I better install new bearings :)
For lubrication, I usually use grease recommended by the manufacturer. I know that a DT Swiss 20g tube of Grease costs twice as much as no name grease of the same viscosity (same at least on paper), but the bikes I maintain are worth much more than the 11.99 a tube of grease costs :)
!BEER !PIZZA
Great comment! So, in your experience, is it worth it installing SKF bearings on hubs? I use that Chinese ARC mt009 rear hub from AliExpress and it's still going strong after 10k kilometers and many many bangs on rock gardens... I wanna see how long until the bearings give away so I can compare to SKF (it'll take a looooong time so we have that data). My previous generic rear hub didn't make it that far in the same environment (blew both freehub bearings which also destroyed the freehub casing).
In terms of grease I use maritime calcium-based nlgi-2. I wanna switch to premium grease but don't have cash atm.. they smell nicer and seem to take a lot longer to become all black.
In my experience, there is a difference between premium SKF bearings and Chinese copies, primarily in durability and resistance to external factors. The rolling resistance is so low that I didn't notice the difference. My driving style is far from consistent and I am far from being able to notice such small fluctuations :)
I found information on several forums that premium bearings at the beginning of use, the first hundred kilometers or so, have a little more resistance - probably until the lubricant is brought to working conditions.
What I noticed during maintenance is that the durability of premium bearings to lateral forces and the sealing of the cartridge is much better. I noticed this first of all on the bearings of the main pivot of the suspension, which are the most exposed to such forces and dirt. It is very difficult to notice differences in durability on hubs since any bearings literally last for tens of thousands of kilometers without problems, as you yourself noted. What I was guided by when choosing premium bearings is the fact that the process of replacing bearings in a free hub requires a lot of work, so even the potential delay of service for several months or year is reason enough for the investment.
Gotcha! I might try SKF on my GXP cranks. GXP are notoriouly faulty in terms of design, but perhaps better bearings will help... Enduro (brand) bearings didn't last, not to mention cheap ones.
Yup, it's quite annoying. I do have the tools, however. Bearing pullers, press and all that stuff you can find fantastic quality ones on Aliexpress
I have no experience with the Sram GXP set as all my bikes use some Shimano hollowtech. Wheel sets are DT Swiss & Shimano XT, so no Sram there neither :) Anyway, I hope good bearings will help. Let me know how it went when you have some conclusions