Hubs Part Deux - The Axis on Which the Wheel Spins
The big things here are axles, bearings, and bearing bores.
- The critical thing in this whole topic is that the bearings remain parallel (faced) to each other, and concentric with each other. Any deviation from that will reduce bearing life. Both begin with proper construction of the hub shell, and its bearing bores (the seating pockets for the bearings). If these are off to begin with, things are relatively hopeless. Everything in the world has a tolerance, but you want that tolerance to be small as possible. The shells of all of the hubs that we use are forged and then machined, which is the way you want things made. The forging creates the general shape and makes the material as strong as it can be, then machining cleans everything up and takes it to a tight tolerance. The bearing bores also need to be very round, as if they are out of round, then the bearing will either have a pinch point which will wear the balls and score the races, or the bearing will be able to move which takes it out of face and concentricity. You might not immediately notice a hub with bad characteristics here, but it would become apparent over time.
- Stress transmitted through the spokes can actually deform a hub shell. Some builders and brands use really high spoke tensions, which place unwanted strain on the hub shell. Some very lightweight hubs have the absolute bare minimum material to manage spoke stress (and they also usually use tiny small bearings, which are more easily stressed). This is why we aren’t raving enthusiasts of very lightweight hub designs. There are good ones, but they cost a lot of money and generally require more maintenance.
- Axles can be made from aluminum or steel. Steel is heavier but ultimately stronger, stiff and more durable. And flex in the axle will mean the bearings disorient relative to one another. Stiffer is better, but again comes at the expensive of weight. Axles are replaceable items, which you are unlikely to ever have to do, but if you ride your bike like you’re in a Martin Ashton video, you might eventually bend an axle. Despite the added weight, we think steel axles are a plus in the White Industries column.
- Bearings can either be cartridge bearings, or loose ball bearings. Shimano and Campagnolo hubs are the prominent loose ball bearings. Proponents say that loose ball bearings are longer lasting and easier to service. Personally, I think replacing a cartridge bearing as (rarely) needed is about a 5’ operation and super easy and inexpensive. All of the hubs we sell are cartridge bearing type hubs, and come with quality bearings. Quality, in bearing-ese, means that they are precise and made of hard, corrosion resistant material. All of the hubs we use have very good bearings, with Kings in particular being of legendary quality. We generally believe that ceramic bearings are a waste, as any benefits they offer (tolerance to being run dry, decreased friction at very high rpm, minor weight savings) are small and you have to spend a lot of money to get those benefits. Bargain ceramic bearings are typically not even as good as high quality steel bearings. Nonetheless, if you feel like you absolutely must have ceramics, they are easy to source and install for any of the hubs we use.
- Bearing sealing gets more important if you ride in crappy conditions often. White Industries hubs are slightly more exposed than the others. Kings have the most protective seals. The tradeoff is bearing drag versus durability. Our take is that the bearing drag penalty is minimal, as is the difficulty of maintaining a less-well protected bearing. So it's really not that huge a deal all around.
- Bearing pre-load adjustment is standard on White Industries and King hubs. This allows you to more precisely eliminate lateral play in the hub, using the minimum side pressure against the bearings. Both are relatively easy to use, though you do have to be aware of it. Industry Nine and Novatec hubs have no bearing adjustment. For most people, this is actually a benefit – though this may not be as optimal as a near-perfectly adjusted pre-load system, they require zero thought and work very very well. I think