Both bearings in the front wheel of the cheapo Fulcrums which came with my gf’s PX Tempest siezed up recently. Mid ride, suddenly the wheel wouldn’t turn. Very odd – popped the seals off and they’re not obviously corroded, but both stuck solid. I know they’re cheap wheels but they’ve probably done less than 1000 dry miles. Absolute crap.

After luckily spotting that the bearing code on the seal doesn’t actually match the bearing size (the ID was 1mm different!), got some new bearings and popped them in. The axle has a screw-on cap at one end (red), but, strangely, no inner sleeve (green) to keep the inner bearing races separated. Any preload from the axle screw-on cap will be pushing the inner races together, rather than clamping them onto a sleeve. Is this normal?! Seems like there’s a bit missing, unless the bearings are supposed to be angular contact (they’re not).

I had similar problems with mine. I put it down to hanging the bike up in a damp garage. I also had problems with the sizing of the bearings. New bearings seem ok so far though. 🤞

They use 18307 bearings with 6903 seals.

Yes thats how the bearing preload system works, so you want to start with play, and sneak up on just no play, also taking into account any compression from a Q/R. Doing it on the bike with lets you get it perfect.

Seems pretty weird if you are used to other hubs that have an internal tube to support the inner races.