Hobbled hubs?

As a bike ridden in all weather conditions, Hyro, my pet Giant TCX, has generally done himself proud. The cyclocross lineage means the bike just laps it up and asks for more, despite my previous reservations surrounding its press-fit BB86 bottom bracket shell.

One problem has crept up with increasingly worrying regularity though: the stock S-X2 wheelset’s hubs have weather sealing that’s gone south pretty quickly this past year.

The weather seals on the rear hub are still in relatively good shape.

The S-X2 hubs are relatively simple items, relying on a cup-and-cone system of loose bearings that allow for easy adjustment. The design is such that Shimano employs it on pretty much all of its hubs.

Around the ends of the hubs’ axles resides a pair of rubber cones that acts as the weather sealing for the bearings. This is where things go funky, and where it’s obvious that costs were cut. It is much too easy to make the edges of these seals sink into the innards of the bearing races, actually aiding water ingress instead of hindering it as they are meant to. In addition, the longevity of the rubber material used is itself a little questionable, as the seals’ edges now have cuts and divots along them.

The cone-shaped rubber weather seals get deformed and sink into the hubs like this from time to time. When this happens, the chances of water ingress increase greatly, washing out the inside grease and causing premature damage to the internals.

On the S-X2 hubs or any other design (Shimano’s included) that relies on loose ball bearings, the hubs themselves are wear items, as they contain the bearing races that the ball bearings run and spin in. Abandoning their maintenance leaves you with pitted races, making for rough-spinning and gritty-feeling wheels. Spending a little more on hubs usually gets you better bearing seals…or a move from loose bearings to cartridge bearings, which are easier to maintain because the hub shell and its parts are no longer subject to bearing-related wear.

Currently I don’t have the tools nor the knowledge to service these hubs; I have only one size of cone wrench, and it doesn’t really fit the locknuts so well. (There are four sizes that are most often used, and even then, the migration to cartridge bearings means these wrenches are slowly going out of fashion.) Now that I’ve highlighted the weaknesses of the S-X2 hubs, I figure I might as well replace them with something else, and have the wheelset subsequently rebuilt, before they terminally fail on me and paralyze Hyro.


2 thoughts on “Hobbled hubs?

  1. I have had what I think is the same problem on my TCX SLR. Basically after truly nasty rides {gravel and sandy roads in the rain) I end up with hubs that sound like they are full of grit. I have had them cleaned and repacked a few times but after 15000km I figured it was time for a small upgrade. I have some American Classic TCX’s on order which with sealed bearings might be a little better. Also looking forward to them being a little lighter that the stock SX2’s and I plan to set them up tubeless.


    1. Interesting. Me, I went with overhauling the stock hubs, just as an experiment. That’s the subject of a future post.


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