Freehub seizure? Diagnosis needed.

turbo_hamster

Riding fast down a not-too-steep hill, suddenly I was unable to turn the cranks, and was under heavy braking. The bike came to a halt (I couldn't tell if the back wheel locked up, or just braked very heavily). Neither cranks nor wheel would rotate forwards, but I could easily push the bike backwards. The rotor did not seem to be hot. After fiddling around for a few minutes, the wheel "unseized" and I went on my way.

The same happened several miles later, as I was ascending a steep hill. This time the bike just stopped and I toppled off onto the verge. Same story, no sign of a jammed chain (I wasn't changing gear anyway). After some vague fiddling around, the wheel released and I rode home - nervously.

I would eliminate a rogue disc brake, as the wheel rotated backwards freely. The freehub clearly was not working as I couldn't coast.

I haven 't been working on the rear wheel, but could the freehub have been slightly displaced while riding? Or is this a maintenance issue?

trevor.hall12

How old are the wheels and freehub ,is the axle turning OK
How are the wheel bearings ?

turbo_hamster

Bearings seem fine, no sideways play. The wheels (and bike) were bought May 2018. I ride it usually twice a week outside (another bike for turbo work). The wheels have done a fair bit of work, but nothing excessive.

Ben6899

Mavic?

turbo_hamster

DS Swiss - not star ratchet, the one with pawls.