Originally Posted by
Chris_W
A lot of people on this thread seem to be confused about the nomenclature; for me, it should be loose-ball bearings vs. cartridge bearings, using the word "sealed" for either type is misleading/confusing.
While you are right that we should be clearer when referring to bearings, I assure you that the term "sealed" is neither misleading nor confusing. Loose bearing hubs and cartridge bearing hubs are indeed "sealed" against water and, more importantly, dirt intrusion. Hubs, even good hubs, up to the late 80s or early 90s had rudimentary "seals" at best. The seal was a press fit ring that deflected some dust and some water but not much. These hubs required regular rebuilds...usually 3 to 6 months...to remove contaminants and you still pitted cones. Back in the bad old days, you replaced the bearings during a rebuild not because the bearings had been ovalized due to load but because they had been ovalized due to wear. I occasionally see bearings that have been flattened due to wear in these old hubs at the co-op.
Mountain biking...as it has done for most bicycle technology...drove the development of better seals because the rebuild interval could be as bad as 300 to 400 miles in off-road use. Shimano developed much better contact seals for their hubs and introduced the conical rubber seals that are common on all Shimano hubs today in 1995. There previous seals just weren't up to the job but the new seals solved the problem and lengthened the maintenance interval. You can go for years now without servicing a hub without deleterious results.
Cartridge bearing hubs are also "sealed". As I pointed out above, Phil Wood uses bearings that can be used in submersible pumps. The Suntour cartridge hubs that I used in the mid80s didn't use submersible quality bearings, they had a labyrinth seal on the inside of the hub and a tight contact seal on the outside but they were much better sealed than other hubs of the day. Because the cartridge was tightly press fit into the hub, the outer seal was all that was needed to seal out water and dirt.
Originally Posted by
Chris_W
The OP is correct that there is a strong trend recently for wheels to more and more often contain cartridge bearings. Almost all wheels that are sold as a complete units with hubs, spokes, and rims that are designed to work together have cartridge bearings. The main exception to this is Shimano - every one of their hubs that are sold separately and as part of complete wheelsets has loose-ball bearings.
I would say that you are overstating the usage of cartridge bearings. Almost all
expensive, high quality wheels use cartridge bearings. There are lots and lots of wheels out there at lower price points using loose bearing hubs.
Originally Posted by
Chris_W
I have read that a good quality, well-adjusted loose-ball hub will run slightly smoother, with less resistance, than any cartridge-bearing hub. I assume that this is partly because the preload can be precisely adjusted and partly because the bearings are smaller in hubs that use cartridge bearings, all else being equal (e.g., hub shell size and weight). However, that is only the case when the hubs are maintained properly. Unfortunately, many people don't know how to maintain their hubs, or even that it should be done. Therefore, a lot of loose-ball hubs are ridden improperly adjusted and/or contaminated with dirt. Cartridge bearings don't need much attention except when they need replacing, so are more often being ridden in a better state, and so in fact when taking the average of all wheels that are being ridden in their current condition, the cartridge bearing hubs are probably running smoother than the loose-ball hubs, even though the opposite would be true if they were to be all put in their ideal state.
What you have read is wrong. In practice, all of the cartridge bearing hubs that I have used are run smoother than just about any loose bearing hub I've compared them to. There are some very good reasons for this. When you attach a wheel to a bicycle, whether you use a nut or a quick release, you are compressing the bearings. You are actually compressing the whatever method is being used for holding the bearings in place. With a cartridge bearing hub such as the Phil Wood (most of there hubs use similar mechanisms), you are compressing the end caps which put a little tension on the inner part of the cartridge bearing race. You don't actually compress any part of the rolling bearings.
Compare that to a cup and cone bearing. You are compressing the cone (as well as the lock nut). The cone is a wedge that is driven into the space between the bearings and the axle making the tighter. You
have to adjust the bearings so that there is a tiny amount of play in the bearings before you mount the wheel so that the bearings are too tight after the wheel is attached. How much play is left in the bearings is a matter of guess work and will actually vary depending on how tight you tighten the quick release or nuts. With the advent of lawyer lips, you are constantly changing the compressive forces with quick releases due to the method of removal. Your bearings are never going to be "perfectly" adjusted.
From a size perspective, a Phil Wood PWX92 bearing used in an FSC hub has a thickness of 7mm (0.275") which is a typical width for hub bearings. When you take into consideration the wall thickness of the bearing housing, that still leaves enough room for a 1/4" bearing which is the same size as the loose ball bearings that Shimano uses for the rear hub. And it is larger than the bearings that Shimano typically uses for the front hub.
Originally Posted by
Chris_W
If cared for properly, loose-ball bearings will outlast cartridge bearings by a significant margin, mainly because the surfaces of the cups and cones are more durable than in the cartridge bearings. Unfortunately, if they are not cared for properly and they are ridden for long enough to damage the cups, then the whole hub is finished and needs replacing. With cartridge bearings, no matter how bad the bearings get, if you put some new ones in then they should be as good as new since you are replacing the surfaces as well as the bearings themselves. So, for someone who doesn't want to touch their hubs, and wants to have a mechanic replace the bearings for them every few years, cartridge-bearing hubs are probably a better choice.
Again, not in my experience. Cup damage is very rare even in abused hubs. I've seen hubs where the bearings were ground to hemispheres and the cones were more triangular than round but the cups were still fine. The larger surface area of the cup compared to the cone mitigates the damage. But even when maintained properly, loose ball bearings aren't going to outlast cartridge bearings by any significant margin. Automobiles use sealed cartridge bearings for steering applications and they have for decades. We used to have to grease the front ends of cars as often as we changed the oil (3000 miles or 3 months) back in the days of loose bearings. Now you can go for hundreds of thousands of miles without any kind of maintenance on the steering system. An those bearings are "bearing" much heavier loads than any bicycle can every place on a cartridge bearing.
We also use cartridge bearings in lots of headsets and almost all bottom brackets. I seldom hear anyone extolling the virtues of loose bearing bottom brackets. Most everyone realizes that those are a royal pain in the regions south of your coccyx and opt for maintenance free cartridge bearing bottom brackets.
My experience with 10 different brands of hubs (almost 20 different hubs) and 10s of thousands of miles in very harsh conditions have resulted in exactly 1 bearing failure. I replaced the bearings in the Suntour hubs once but that was because I was young and ignorant and thought I had to "maintain" the bearings and I flushed out the grease.
Originally Posted by
Chris_W
Servicing and replacing loose-ball bearings is pretty easy once you've learned the basics and you have a few cone wrenches. For cartridge bearings, servicing and replacing bearings can be a real problem and requires specialist tools to do it right, although you can often improvise with a blunt instrument and a hammer, but this should be avoided when possible. This is the main reason why every wheel I own has a Shimano hub, with loose-ball bearings; it is an added bonus for me to know that I'm also getting slightly reduced rolling resistance because of this, but I wouldn't recommend such hubs for the majority of people.
Again, not in my experience. The tool for removing the cartridge bearing in most hubs is a spring clip that you use an axle or drift to drive out.
The tool cost $4 here. Pressing the bearing back in is trivial as well. A piece of all thread and a large thick fender washer will do the job.
If you spend the money for a Phil Wood hub, the whole operation can be done, literally, out in the middle of a field with a rock and a couple of allen wrenches. For the rear hub, you don't even need the rock.
As for the rolling resistance, the difference is probably trivial
if the loose bearing hub is adjusted properly which isn't often the case, even for those of us who know how to do it. I'd give the edge to cartridge based on my experience with them. I've had them spin on the work stand for up to 10 minutes. Long enough that I was almost considering them to be perpetual motion machines.